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* [PATCH 01/15] arm64: Fold proc-macros.S into assembler.h
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

To allow the assembler macros defined in arch/arm64/mm/proc-macros.S to be used
outside the mm code move the contents of proc-macros.S to asm/assembler.h.  Also,
delete proc-macros.S, and fix up all references to proc-macros.S.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/include/asm/assembler.h | 48 +++++++++++++++++++++++++++-
 arch/arm64/kernel/head.S           |  1 -
 arch/arm64/kvm/hyp-init.S          |  1 -
 arch/arm64/mm/cache.S              |  2 --
 arch/arm64/mm/proc-macros.S        | 64 --------------------------------------
 arch/arm64/mm/proc.S               |  3 --
 6 files changed, 47 insertions(+), 72 deletions(-)
 delete mode 100644 arch/arm64/mm/proc-macros.S

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index b51f2cc..3b46501 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -1,5 +1,5 @@
 /*
- * Based on arch/arm/include/asm/assembler.h
+ * Based on arch/arm/include/asm/assembler.h, arch/arm/mm/proc-macros.S
  *
  * Copyright (C) 1996-2000 Russell King
  * Copyright (C) 2012 ARM Ltd.
@@ -23,6 +23,8 @@
 #ifndef __ASM_ASSEMBLER_H
 #define __ASM_ASSEMBLER_H
 
+#include <asm/asm-offsets.h>
+#include <asm/pgtable-hwdef.h>
 #include <asm/ptrace.h>
 #include <asm/thread_info.h>
 
@@ -193,4 +195,48 @@ lr	.req	x30		// link register
 	str	\src, [\tmp, :lo12:\sym]
 	.endm
 
+/*
+ * vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
+ */
+	.macro	vma_vm_mm, rd, rn
+	ldr	\rd, [\rn, #VMA_VM_MM]
+	.endm
+
+/*
+ * mmid - get context id from mm pointer (mm->context.id)
+ */
+	.macro	mmid, rd, rn
+	ldr	\rd, [\rn, #MM_CONTEXT_ID]
+	.endm
+
+/*
+ * dcache_line_size - get the minimum D-cache line size from the CTR register.
+ */
+	.macro	dcache_line_size, reg, tmp
+	mrs	\tmp, ctr_el0			// read CTR
+	ubfm	\tmp, \tmp, #16, #19		// cache line size encoding
+	mov	\reg, #4			// bytes per word
+	lsl	\reg, \reg, \tmp		// actual cache line size
+	.endm
+
+/*
+ * icache_line_size - get the minimum I-cache line size from the CTR register.
+ */
+	.macro	icache_line_size, reg, tmp
+	mrs	\tmp, ctr_el0			// read CTR
+	and	\tmp, \tmp, #0xf		// cache line size encoding
+	mov	\reg, #4			// bytes per word
+	lsl	\reg, \reg, \tmp		// actual cache line size
+	.endm
+
+/*
+ * tcr_set_idmap_t0sz - update TCR.T0SZ so that we can load the ID map
+ */
+	.macro	tcr_set_idmap_t0sz, valreg, tmpreg
+#ifndef CONFIG_ARM64_VA_BITS_48
+	ldr_l	\tmpreg, idmap_t0sz
+	bfi	\valreg, \tmpreg, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
+#endif
+	.endm
+
 #endif	/* __ASM_ASSEMBLER_H */
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 90d09ed..9ad8b1f 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -31,7 +31,6 @@
 #include <asm/cputype.h>
 #include <asm/memory.h>
 #include <asm/thread_info.h>
-#include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
 #include <asm/page.h>
 #include <asm/virt.h>
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 178ba22..2e67a48 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -20,7 +20,6 @@
 #include <asm/assembler.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_mmu.h>
-#include <asm/pgtable-hwdef.h>
 
 	.text
 	.pushsection	.hyp.idmap.text, "ax"
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index eb48d5d..9e13cb5 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -24,8 +24,6 @@
 #include <asm/cpufeature.h>
 #include <asm/alternative.h>
 
-#include "proc-macros.S"
-
 /*
  *	flush_icache_range(start,end)
  *
diff --git a/arch/arm64/mm/proc-macros.S b/arch/arm64/mm/proc-macros.S
deleted file mode 100644
index 4c4d93c..0000000
--- a/arch/arm64/mm/proc-macros.S
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * Based on arch/arm/mm/proc-macros.S
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <asm/asm-offsets.h>
-#include <asm/thread_info.h>
-
-/*
- * vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
- */
-	.macro	vma_vm_mm, rd, rn
-	ldr	\rd, [\rn, #VMA_VM_MM]
-	.endm
-
-/*
- * mmid - get context id from mm pointer (mm->context.id)
- */
-	.macro	mmid, rd, rn
-	ldr	\rd, [\rn, #MM_CONTEXT_ID]
-	.endm
-
-/*
- * dcache_line_size - get the minimum D-cache line size from the CTR register.
- */
-	.macro	dcache_line_size, reg, tmp
-	mrs	\tmp, ctr_el0			// read CTR
-	ubfm	\tmp, \tmp, #16, #19		// cache line size encoding
-	mov	\reg, #4			// bytes per word
-	lsl	\reg, \reg, \tmp		// actual cache line size
-	.endm
-
-/*
- * icache_line_size - get the minimum I-cache line size from the CTR register.
- */
-	.macro	icache_line_size, reg, tmp
-	mrs	\tmp, ctr_el0			// read CTR
-	and	\tmp, \tmp, #0xf		// cache line size encoding
-	mov	\reg, #4			// bytes per word
-	lsl	\reg, \reg, \tmp		// actual cache line size
-	.endm
-
-/*
- * tcr_set_idmap_t0sz - update TCR.T0SZ so that we can load the ID map
- */
-	.macro	tcr_set_idmap_t0sz, valreg, tmpreg
-#ifndef CONFIG_ARM64_VA_BITS_48
-	ldr_l	\tmpreg, idmap_t0sz
-	bfi	\valreg, \tmpreg, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
-#endif
-	.endm
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index e4ee7bd..456c1c5 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -23,11 +23,8 @@
 #include <asm/assembler.h>
 #include <asm/asm-offsets.h>
 #include <asm/hwcap.h>
-#include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
 
-#include "proc-macros.S"
-
 #ifdef CONFIG_ARM64_64K_PAGES
 #define TCR_TG_FLAGS	TCR_TG0_64K | TCR_TG1_64K
 #else
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 07/15] arm64/kexec: Add core kexec support
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

Add three new files, kexec.h, machine_kexec.c and relocate_kernel.S to the
arm64 architecture that add support for the kexec re-boot mechanism
(CONFIG_KEXEC) on arm64 platforms.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/Kconfig                  |  10 +++
 arch/arm64/include/asm/kexec.h      |  48 ++++++++++++
 arch/arm64/kernel/Makefile          |   2 +
 arch/arm64/kernel/machine_kexec.c   | 152 ++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/relocate_kernel.S | 131 +++++++++++++++++++++++++++++++
 include/uapi/linux/kexec.h          |   1 +
 6 files changed, 344 insertions(+)
 create mode 100644 arch/arm64/include/asm/kexec.h
 create mode 100644 arch/arm64/kernel/machine_kexec.c
 create mode 100644 arch/arm64/kernel/relocate_kernel.S

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 07d1811..d9631ac 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -491,6 +491,16 @@ config SECCOMP
 	  and the task is only allowed to execute a few safe syscalls
 	  defined by each seccomp mode.
 
+config KEXEC
+	depends on PM_SLEEP_SMP
+	select KEXEC_CORE
+	bool "kexec system call"
+	---help---
+	  kexec is a system call that implements the ability to shutdown your
+	  current kernel, and to start another kernel.  It is like a reboot
+	  but it is independent of the system firmware.   And like a reboot
+	  you can start any kernel with it, not just Linux.
+
 config XEN_DOM0
 	def_bool y
 	depends on XEN
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
new file mode 100644
index 0000000..46d63cd
--- /dev/null
+++ b/arch/arm64/include/asm/kexec.h
@@ -0,0 +1,48 @@
+/*
+ * kexec for arm64
+ *
+ * Copyright (C) Linaro.
+ * Copyright (C) Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#if !defined(_ARM64_KEXEC_H)
+#define _ARM64_KEXEC_H
+
+/* Maximum physical address we can use pages from */
+
+#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
+
+/* Maximum address we can reach in physical address mode */
+
+#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
+
+/* Maximum address we can use for the control code buffer */
+
+#define KEXEC_CONTROL_MEMORY_LIMIT (-1UL)
+
+#define KEXEC_CONTROL_PAGE_SIZE	4096
+
+#define KEXEC_ARCH KEXEC_ARCH_ARM64
+
+#if !defined(__ASSEMBLY__)
+
+/**
+ * crash_setup_regs() - save registers for the panic kernel
+ *
+ * @newregs: registers are saved here
+ * @oldregs: registers to be saved (may be %NULL)
+ */
+
+static inline void crash_setup_regs(struct pt_regs *newregs,
+				    struct pt_regs *oldregs)
+{
+	/* Empty routine needed to avoid build errors. */
+}
+
+#endif /* !defined(__ASSEMBLY__) */
+
+#endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 22dc9bc..989ccd7 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -36,6 +36,8 @@ arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
 arm64-obj-$(CONFIG_PCI)			+= pci.o
 arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
 arm64-obj-$(CONFIG_ACPI)		+= acpi.o
+arm64-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o	\
+					   cpu-reset.o
 
 obj-y					+= $(arm64-obj-y) vdso/
 obj-m					+= $(arm64-obj-m)
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
new file mode 100644
index 0000000..8b990b8
--- /dev/null
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -0,0 +1,152 @@
+/*
+ * kexec for arm64
+ *
+ * Copyright (C) Linaro.
+ * Copyright (C) Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kexec.h>
+#include <linux/of_fdt.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include <asm/cacheflush.h>
+#include <asm/system_misc.h>
+
+#include "cpu-reset.h"
+
+/* Global variables for the arm64_relocate_new_kernel routine. */
+extern const unsigned char arm64_relocate_new_kernel[];
+extern const unsigned long arm64_relocate_new_kernel_size;
+
+static unsigned long kimage_start;
+
+void machine_kexec_cleanup(struct kimage *kimage)
+{
+	/* Empty routine needed to avoid build errors. */
+}
+
+/**
+ * machine_kexec_prepare - Prepare for a kexec reboot.
+ *
+ * Called from the core kexec code when a kernel image is loaded.
+ */
+int machine_kexec_prepare(struct kimage *kimage)
+{
+	kimage_start = kimage->start;
+	return 0;
+}
+
+/**
+ * kexec_list_flush - Helper to flush the kimage list to PoC.
+ */
+static void kexec_list_flush(unsigned long kimage_head)
+{
+	unsigned long *entry;
+
+	for (entry = &kimage_head; ; entry++) {
+		unsigned int flag = *entry & IND_FLAGS;
+		void *addr = phys_to_virt(*entry & PAGE_MASK);
+
+		switch (flag) {
+		case IND_INDIRECTION:
+			entry = (unsigned long *)addr - 1;
+			__flush_dcache_area(addr, PAGE_SIZE);
+			break;
+		case IND_DESTINATION:
+			break;
+		case IND_SOURCE:
+			__flush_dcache_area(addr, PAGE_SIZE);
+			break;
+		case IND_DONE:
+			return;
+		default:
+			BUG();
+		}
+	}
+}
+
+/**
+ * kexec_segment_flush - Helper to flush the kimage segments to PoC.
+ */
+static void kexec_segment_flush(const struct kimage *kimage)
+{
+	unsigned long i;
+
+	pr_devel("%s:\n", __func__);
+
+	for (i = 0; i < kimage->nr_segments; i++) {
+		pr_devel("  segment[%lu]: %016lx - %016lx, %lx bytes, %lu pages\n",
+			i,
+			kimage->segment[i].mem,
+			kimage->segment[i].mem + kimage->segment[i].memsz,
+			kimage->segment[i].memsz,
+			kimage->segment[i].memsz /  PAGE_SIZE);
+
+		__flush_dcache_area(phys_to_virt(kimage->segment[i].mem),
+			kimage->segment[i].memsz);
+	}
+}
+
+/**
+ * machine_kexec - Do the kexec reboot.
+ *
+ * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC.
+ */
+void machine_kexec(struct kimage *kimage)
+{
+	phys_addr_t reboot_code_buffer_phys;
+	void *reboot_code_buffer;
+
+	BUG_ON(num_online_cpus() > 1);
+
+	reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
+	reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
+
+	/*
+	 * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
+	 * after the kernel is shut down.
+	 */
+	memcpy(reboot_code_buffer, arm64_relocate_new_kernel,
+		arm64_relocate_new_kernel_size);
+
+	/* Flush the reboot_code_buffer in preparation for its execution. */
+	__flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);
+
+	/* Flush the new image. */
+	kexec_segment_flush(kimage);
+
+	/* Flush the kimage list. */
+	kexec_list_flush(kimage->head);
+
+	pr_info("Bye!\n");
+
+	/* Disable all DAIF exceptions. */
+	asm volatile ("msr daifset, #0xf" : : : "memory");
+
+	setup_mm_for_reboot();
+
+	/*
+	 * cpu_soft_restart will shutdown the MMU, disable data caches, then
+	 * transfer control to the reboot_code_buffer which contains a copy of
+	 * the arm64_relocate_new_kernel routine.  arm64_relocate_new_kernel
+	 * uses physical addressing to relocate the new image to its final
+	 * position and transfers control to the image entry point when the
+	 * relocation is complete.
+	 */
+
+	cpu_soft_restart(virt_to_phys(cpu_reset),
+		is_hyp_mode_available(),
+		reboot_code_buffer_phys, kimage->head, kimage_start);
+
+	BUG(); /* Should never get here. */
+}
+
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+	/* Empty routine needed to avoid build errors. */
+}
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
new file mode 100644
index 0000000..71cab0e
--- /dev/null
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -0,0 +1,131 @@
+/*
+ * kexec for arm64
+ *
+ * Copyright (C) Linaro.
+ * Copyright (C) Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kexec.h>
+
+#include <asm/assembler.h>
+#include <asm/kexec.h>
+#include <asm/kvm_arm.h>
+#include <asm/page.h>
+
+/*
+ * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
+ *
+ * The memory that the old kernel occupies may be overwritten when coping the
+ * new image to its final location.  To assure that the
+ * arm64_relocate_new_kernel routine which does that copy is not overwritten,
+ * all code and data needed by arm64_relocate_new_kernel must be between the
+ * symbols arm64_relocate_new_kernel and arm64_relocate_new_kernel_end.  The
+ * machine_kexec() routine will copy arm64_relocate_new_kernel to the kexec
+ * control_code_page, a special page which has been set up to be preserved
+ * during the copy operation.
+ */
+.globl arm64_relocate_new_kernel
+arm64_relocate_new_kernel:
+
+	/* Setup the list loop variables. */
+	mov	x18, x0				/* x18 = kimage_head */
+	mov	x17, x1				/* x17 = kimage_start */
+	dcache_line_size x16, x0		/* x16 = dcache line size */
+	mov	x15, xzr			/* x15 = segment start */
+	mov	x14, xzr			/* x14 = entry ptr */
+	mov	x13, xzr			/* x13 = copy dest */
+
+	/* Clear the sctlr_el2 flags. */
+	mrs	x0, CurrentEL
+	cmp	x0, #CurrentEL_EL2
+	b.ne	1f
+	mrs	x0, sctlr_el2
+	ldr	x1, =SCTLR_EL2_FLAGS
+	bic	x0, x0, x1
+	msr	sctlr_el2, x0
+	isb
+1:
+
+	/* Check if the new image needs relocation. */
+	cbz	x18, .Ldone
+	tbnz	x18, IND_DONE_BIT, .Ldone
+
+.Lloop:
+	and	x12, x18, PAGE_MASK		/* x12 = addr */
+
+	/* Test the entry flags. */
+.Ltest_source:
+	tbz	x18, IND_SOURCE_BIT, .Ltest_indirection
+
+	mov x20, x13				/*  x20 = copy dest */
+	mov x21, x12				/*  x21 = copy src */
+
+	/* Copy page. */
+1:	ldp	x22, x23, [x21]
+	ldp	x24, x25, [x21, #16]
+	ldp	x26, x27, [x21, #32]
+	ldp	x28, x29, [x21, #48]
+	add	x21, x21, #64
+	stnp	x22, x23, [x20]
+	stnp	x24, x25, [x20, #16]
+	stnp	x26, x27, [x20, #32]
+	stnp	x28, x29, [x20, #48]
+	add	x20, x20, #64
+	tst	x21, #(PAGE_SIZE - 1)
+	b.ne	1b
+
+	/* dest += PAGE_SIZE */
+	add	x13, x13, PAGE_SIZE
+	b	.Lnext
+
+.Ltest_indirection:
+	tbz	x18, IND_INDIRECTION_BIT, .Ltest_destination
+
+	/* ptr = addr */
+	mov	x14, x12
+	b	.Lnext
+
+.Ltest_destination:
+	tbz	x18, IND_DESTINATION_BIT, .Lnext
+
+	mov	x15, x12
+
+	/* dest = addr */
+	mov	x13, x12
+
+.Lnext:
+	/* entry = *ptr++ */
+	ldr	x18, [x14], #8
+
+	/* while (!(entry & DONE)) */
+	tbz	x18, IND_DONE_BIT, .Lloop
+
+.Ldone:
+	dsb	sy
+	ic	ialluis
+	dsb	sy
+	isb
+
+	/* Start new image. */
+	mov	x0, xzr
+	mov	x1, xzr
+	mov	x2, xzr
+	mov	x3, xzr
+	br	x17
+
+.align 3	/* To keep the 64-bit values below naturally aligned. */
+
+.Lcopy_end:
+.org	KEXEC_CONTROL_PAGE_SIZE
+
+/*
+ * arm64_relocate_new_kernel_size - Number of bytes to copy to the
+ * control_code_page.
+ */
+.globl arm64_relocate_new_kernel_size
+arm64_relocate_new_kernel_size:
+	.quad	.Lcopy_end - arm64_relocate_new_kernel
diff --git a/include/uapi/linux/kexec.h b/include/uapi/linux/kexec.h
index 99048e5..ccec467 100644
--- a/include/uapi/linux/kexec.h
+++ b/include/uapi/linux/kexec.h
@@ -39,6 +39,7 @@
 #define KEXEC_ARCH_SH      (42 << 16)
 #define KEXEC_ARCH_MIPS_LE (10 << 16)
 #define KEXEC_ARCH_MIPS    ( 8 << 16)
+#define KEXEC_ARCH_ARM64   (183 << 16)
 
 /* The artificial cap on the number of segments passed to kexec_load. */
 #define KEXEC_SEGMENT_MAX 16
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 06/15] Revert "arm64: remove dead code"
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

This reverts commit b08d4640a3dca68670fc5af2fe9205b395a02388.

Add back the setup_mm_for_reboot() needed for kexec.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/include/asm/mmu.h |  1 +
 arch/arm64/mm/mmu.c          | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 0302087..79fcfb0 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -28,6 +28,7 @@ typedef struct {
 #define ASID(mm)	((mm)->context.id & 0xffff)
 
 extern void paging_init(void);
+extern void setup_mm_for_reboot(void);
 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
 extern void init_mem_pgprot(void);
 extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 9211b85..8cffad9 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -461,6 +461,17 @@ void __init paging_init(void)
 }
 
 /*
+ * Enable the identity mapping to allow the MMU disabling.
+ */
+void setup_mm_for_reboot(void)
+{
+	cpu_set_reserved_ttbr0();
+	flush_tlb_all();
+	cpu_set_idmap_tcr_t0sz();
+	cpu_switch_mm(idmap_pg_dir, &init_mm);
+}
+
+/*
  * Check whether a kernel address is valid (derived from arch/x86/).
  */
 int kern_addr_valid(unsigned long addr)
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 09/15] arm64/kexec: Enable kexec in the arm64 defconfig
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 34d71dd..c80d8a4 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -55,6 +55,7 @@ CONFIG_PREEMPT=y
 CONFIG_KSM=y
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_CMA=y
+CONFIG_KEXEC=y
 CONFIG_CMDLINE="console=ttyAMA0"
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_COMPAT=y
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 02/15] arm64: Convert hcalls to use HVC immediate value
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

The existing arm64 hcall implementations are limited in that they only allow
for two distinct hcalls; with the x0 register either zero or not zero.  Also,
the API of the hyp-stub exception vector routines and the KVM exception vector
routines differ; hyp-stub uses a non-zero value in x0 to implement
__hyp_set_vectors, whereas KVM uses it to implement kvm_call_hyp.

To allow for additional hcalls to be defined and to make the arm64 hcall API
more consistent across exception vector routines, change the hcall
implementations to use the 16 bit immediate value of the HVC instruction to
specify the hcall type.

Define three new preprocessor macros HVC_CALL_HYP, HVC_GET_VECTORS, and
HVC_SET_VECTORS to be used as hcall type specifiers and convert the
existing __hyp_get_vectors(), __hyp_set_vectors() and kvm_call_hyp() routines
to use these new macros when executing an HVC call.  Also, change the
corresponding hyp-stub and KVM el1_sync exception vector routines to use these
new macros.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/include/asm/virt.h | 27 +++++++++++++++++++++++++++
 arch/arm64/kernel/hyp-stub.S  | 32 +++++++++++++++++++++-----------
 arch/arm64/kvm/hyp.S          | 16 +++++++++-------
 3 files changed, 57 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 7a5df52..eb10368 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -18,6 +18,33 @@
 #ifndef __ASM__VIRT_H
 #define __ASM__VIRT_H
 
+/*
+ * The arm64 hcall implementation uses the ISS field of the ESR_EL2 register to
+ * specify the hcall type.  The exception handlers are allowed to use registers
+ * x17 and x18 in their implementation.  Any routine issuing an hcall must not
+ * expect these registers to be preserved.
+ */
+
+/*
+ * HVC_CALL_HYP - Execute a hyp routine.
+ */
+
+#define HVC_CALL_HYP 0
+
+/*
+ * HVC_GET_VECTORS - Return the value of the vbar_el2 register.
+ */
+
+#define HVC_GET_VECTORS 1
+
+/*
+ * HVC_SET_VECTORS - Set the value of the vbar_el2 register.
+ *
+ * @x0: Physical address of the new vector table.
+ */
+
+#define HVC_SET_VECTORS 2
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index a272f33..017ab519 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -22,6 +22,7 @@
 #include <linux/irqchip/arm-gic-v3.h>
 
 #include <asm/assembler.h>
+#include <asm/kvm_arm.h>
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
@@ -53,14 +54,22 @@ ENDPROC(__hyp_stub_vectors)
 	.align 11
 
 el1_sync:
-	mrs	x1, esr_el2
-	lsr	x1, x1, #26
-	cmp	x1, #0x16
+	mrs	x18, esr_el2
+	lsr	x17, x18, #ESR_ELx_EC_SHIFT
+	and	x18, x18, #ESR_ELx_ISS_MASK
+
+	cmp	x17, #ESR_ELx_EC_HVC64
 	b.ne	2f				// Not an HVC trap
-	cbz	x0, 1f
-	msr	vbar_el2, x0			// Set vbar_el2
+
+	cmp	x18, #HVC_GET_VECTORS
+	b.ne	1f
+	mrs	x0, vbar_el2
 	b	2f
-1:	mrs	x0, vbar_el2			// Return vbar_el2
+
+1:	cmp	x18, #HVC_SET_VECTORS
+	b.ne	2f
+	msr	vbar_el2, x0
+
 2:	eret
 ENDPROC(el1_sync)
 
@@ -100,11 +109,12 @@ ENDPROC(\label)
  * initialisation entry point.
  */
 
-ENTRY(__hyp_get_vectors)
-	mov	x0, xzr
-	// fall through
 ENTRY(__hyp_set_vectors)
-	hvc	#0
+	hvc	#HVC_SET_VECTORS
 	ret
-ENDPROC(__hyp_get_vectors)
 ENDPROC(__hyp_set_vectors)
+
+ENTRY(__hyp_get_vectors)
+	hvc	#HVC_GET_VECTORS
+	ret
+ENDPROC(__hyp_get_vectors)
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index e583613..073b8bf 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -29,6 +29,7 @@
 #include <asm/kvm_asm.h>
 #include <asm/kvm_mmu.h>
 #include <asm/memory.h>
+#include <asm/virt.h>
 
 #define CPU_GP_REG_OFFSET(x)	(CPU_GP_REGS + x)
 #define CPU_XREG_OFFSET(x)	CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)
@@ -924,12 +925,9 @@ __hyp_panic_str:
  * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
  * passed in r0 and r1.
  *
- * A function pointer with a value of 0 has a special meaning, and is
- * used to implement __hyp_get_vectors in the same way as in
- * arch/arm64/kernel/hyp_stub.S.
  */
 ENTRY(kvm_call_hyp)
-	hvc	#0
+	hvc	#HVC_CALL_HYP
 	ret
 ENDPROC(kvm_call_hyp)
 
@@ -960,6 +958,7 @@ el1_sync:					// Guest trapped into EL2
 
 	mrs	x1, esr_el2
 	lsr	x2, x1, #ESR_ELx_EC_SHIFT
+	and	x0, x1, #ESR_ELx_ISS_MASK
 
 	cmp	x2, #ESR_ELx_EC_HVC64
 	b.ne	el1_trap
@@ -968,15 +967,18 @@ el1_sync:					// Guest trapped into EL2
 	cbnz	x3, el1_trap			// called HVC
 
 	/* Here, we're pretty sure the host called HVC. */
+	mov	x18, x0
 	pop	x2, x3
 	pop	x0, x1
 
-	/* Check for __hyp_get_vectors */
-	cbnz	x0, 1f
+	cmp	x18, #HVC_GET_VECTORS
+	b.ne	1f
 	mrs	x0, vbar_el2
 	b	2f
 
-1:	push	lr, xzr
+1:	/* Default to HVC_CALL_HYP. */
+
+	push	lr, xzr
 
 	/*
 	 * Compute the function address in EL2, and shuffle the parameters.
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 00/15] arm64 kexec kernel patches v11
@ 2015-11-06 19:14 ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

Hi All,

This series adds the core support for kexec re-boot and kdump on ARM64.  This
version of the series combines Takahiro's kdump patches with my kexec patches.

To load a second stage kernel and execute a kexec re-boot or to work with kdump
on ARM64 systems a series of patches to kexec-tools [2], which have not yet been
merged upstream, are needed.

I have tested kexec with the ARM Foundation model, and Takahiro has reported
that kdump is working on the 96boards HiKey developer board.  Kexec on EFI
systems works correctly.  More ACPI + kexec testing is needed.

Patch 1 here moves the macros from proc-macros.S to asm/assembler.h so that the
dcache_line_size macro it defines can be uesd by kexec's relocate kernel
routine.

Patches 2 & 3 rework the ARM64 hcall mechanism to give the CPU reset routines
the ability to switch exception levels from EL1 to EL2 for kernels that were
entered in EL2.

Patch 4 allows KVM to handle a CPU reset.

Patches 5 & 6 add back the ARM64 CPU reset support that was recently removed
from the kernel.

Patches 7 - 9 add kexec support.

Patches 10-15 add kdump support.

Please consider all patches for inclusion.

Changes since v10:

o Move the flush of the new image from arm64_relocate_new_kernel to machine_kexec.
o Pass values to arm64_relocate_new_kernel in registers, not in global variables.
o Fixups to setting the sctlr_el1 and sctlr_el2 flags.

[1]  https://git.kernel.org/cgit/linux/kernel/git/geoff/linux-kexec.git
[2]  https://git.kernel.org/cgit/linux/kernel/git/geoff/kexec-tools.git

-Geoff

The following changes since commit 6a13feb9c82803e2b815eca72fa7a9f5561d7861:

  Linux 4.3 (2015-11-01 16:05:25 -0800)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/geoff/linux-kexec.git kexec-v11

for you to fetch changes up to 2b09b58c7586a4ca929400327d394fec3135fdd0:

  arm64: kdump: relax BUG_ON() if more than one cpus are still active (2015-11-06 10:38:13 -0800)

----------------------------------------------------------------
AKASHI Takahiro (7):
      arm64: kvm: allows kvm cpu hotplug
      arm64: kdump: reserve memory for crash dump kernel
      arm64: kdump: implement machine_crash_shutdown()
      arm64: kdump: add kdump support
      arm64: kdump: update a kernel doc
      arm64: kdump: enable kdump in the arm64 defconfig
      arm64: kdump: relax BUG_ON() if more than one cpus are still active

Geoff Levand (8):
      arm64: Fold proc-macros.S into assembler.h
      arm64: Convert hcalls to use HVC immediate value
      arm64: Add new hcall HVC_CALL_FUNC
      arm64: Add back cpu_reset routines
      Revert "arm64: remove dead code"
      arm64/kexec: Add core kexec support
      arm64/kexec: Add pr_devel output
      arm64/kexec: Enable kexec in the arm64 defconfig

 Documentation/kdump/kdump.txt       |  32 ++++-
 arch/arm/include/asm/kvm_host.h     |  10 +-
 arch/arm/include/asm/kvm_mmu.h      |   1 +
 arch/arm/kvm/arm.c                  |  79 ++++++------
 arch/arm/kvm/mmu.c                  |   5 +
 arch/arm64/Kconfig                  |  22 ++++
 arch/arm64/configs/defconfig        |   2 +
 arch/arm64/include/asm/assembler.h  |  48 ++++++-
 arch/arm64/include/asm/kexec.h      |  80 ++++++++++++
 arch/arm64/include/asm/kvm_host.h   |  16 ++-
 arch/arm64/include/asm/kvm_mmu.h    |   1 +
 arch/arm64/include/asm/mmu.h        |   1 +
 arch/arm64/include/asm/virt.h       |  49 +++++++
 arch/arm64/kernel/Makefile          |   3 +
 arch/arm64/kernel/cpu-reset.S       |  84 ++++++++++++
 arch/arm64/kernel/cpu-reset.h       |  22 ++++
 arch/arm64/kernel/crash_dump.c      |  71 +++++++++++
 arch/arm64/kernel/head.S            |   1 -
 arch/arm64/kernel/hyp-stub.S        |  43 +++++--
 arch/arm64/kernel/machine_kexec.c   | 248 ++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/relocate_kernel.S | 131 +++++++++++++++++++
 arch/arm64/kernel/setup.c           |   7 +-
 arch/arm64/kernel/smp.c             |  16 ++-
 arch/arm64/kvm/hyp-init.S           |  34 ++++-
 arch/arm64/kvm/hyp.S                |  44 +++++--
 arch/arm64/mm/cache.S               |   2 -
 arch/arm64/mm/init.c                |  83 ++++++++++++
 arch/arm64/mm/mmu.c                 |  11 ++
 arch/arm64/mm/proc-macros.S         |  64 ----------
 arch/arm64/mm/proc.S                |   3 -
 include/uapi/linux/kexec.h          |   1 +
 31 files changed, 1074 insertions(+), 140 deletions(-)
 create mode 100644 arch/arm64/include/asm/kexec.h
 create mode 100644 arch/arm64/kernel/cpu-reset.S
 create mode 100644 arch/arm64/kernel/cpu-reset.h
 create mode 100644 arch/arm64/kernel/crash_dump.c
 create mode 100644 arch/arm64/kernel/machine_kexec.c
 create mode 100644 arch/arm64/kernel/relocate_kernel.S
 delete mode 100644 arch/arm64/mm/proc-macros.S

-- 
2.5.0

^ permalink raw reply	[flat|nested] 36+ messages in thread
* [PATCH 04/15] arm64: kvm: allows kvm cpu hotplug
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

The current kvm implementation on arm64 does cpu-specific initialization
at system boot, and has no way to gracefully shutdown a core in terms of
kvm. This prevents, especially, kexec from rebooting the system on a boot
core in EL2.

This patch adds a cpu tear-down function and also puts an existing cpu-init
code into a separate function, kvm_arch_hardware_disable() and
kvm_arch_hardware_enable() respectively.
We don't need arm64-specific cpu hotplug hook any more.

Since this patch modifies common part of code between arm and arm64, one
stub definition, __cpu_reset_hyp_mode(), is added on arm side to avoid
compiling errors.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm/include/asm/kvm_host.h   | 10 ++++-
 arch/arm/include/asm/kvm_mmu.h    |  1 +
 arch/arm/kvm/arm.c                | 79 ++++++++++++++++++---------------------
 arch/arm/kvm/mmu.c                |  5 +++
 arch/arm64/include/asm/kvm_host.h | 16 +++++++-
 arch/arm64/include/asm/kvm_mmu.h  |  1 +
 arch/arm64/include/asm/virt.h     |  9 +++++
 arch/arm64/kvm/hyp-init.S         | 33 ++++++++++++++++
 arch/arm64/kvm/hyp.S              | 32 ++++++++++++++--
 9 files changed, 138 insertions(+), 48 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index c4072d9..4c6a38c 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -211,6 +211,15 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
 	kvm_call_hyp((void*)hyp_stack_ptr, vector_ptr, pgd_ptr);
 }
 
+static inline void __cpu_reset_hyp_mode(phys_addr_t boot_pgd_ptr,
+					phys_addr_t phys_idmap_start)
+{
+	/*
+	 * TODO
+	 * kvm_call_reset(boot_pgd_ptr, phys_idmap_start);
+	 */
+}
+
 static inline int kvm_arch_dev_ioctl_check_extension(long ext)
 {
 	return 0;
@@ -223,7 +232,6 @@ void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
 
 struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
 
-static inline void kvm_arch_hardware_disable(void) {}
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 405aa18..dc6fadf 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -66,6 +66,7 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_mmu_get_boot_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
+phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 78b2869..5005e6e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -16,7 +16,6 @@
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-#include <linux/cpu.h>
 #include <linux/cpu_pm.h>
 #include <linux/errno.h>
 #include <linux/err.h>
@@ -61,6 +60,8 @@ static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
 static u8 kvm_next_vmid;
 static DEFINE_SPINLOCK(kvm_vmid_lock);
 
+static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);
+
 static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
 {
 	BUG_ON(preemptible());
@@ -85,11 +86,6 @@ struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
 	return &kvm_arm_running_vcpu;
 }
 
-int kvm_arch_hardware_enable(void)
-{
-	return 0;
-}
-
 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
 	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
@@ -915,7 +911,7 @@ long kvm_arch_vm_ioctl(struct file *filp,
 	}
 }
 
-static void cpu_init_hyp_mode(void *dummy)
+int kvm_arch_hardware_enable(void)
 {
 	phys_addr_t boot_pgd_ptr;
 	phys_addr_t pgd_ptr;
@@ -923,6 +919,9 @@ static void cpu_init_hyp_mode(void *dummy)
 	unsigned long stack_page;
 	unsigned long vector_ptr;
 
+	if (__hyp_get_vectors() != hyp_default_vectors)
+		return 0;
+
 	/* Switch from the HYP stub to our own HYP init vector */
 	__hyp_set_vectors(kvm_get_idmap_vector());
 
@@ -935,38 +934,50 @@ static void cpu_init_hyp_mode(void *dummy)
 	__cpu_init_hyp_mode(boot_pgd_ptr, pgd_ptr, hyp_stack_ptr, vector_ptr);
 
 	kvm_arm_init_debug();
+
+	return 0;
 }
 
-static int hyp_init_cpu_notify(struct notifier_block *self,
-			       unsigned long action, void *cpu)
+void kvm_arch_hardware_disable(void)
 {
-	switch (action) {
-	case CPU_STARTING:
-	case CPU_STARTING_FROZEN:
-		if (__hyp_get_vectors() == hyp_default_vectors)
-			cpu_init_hyp_mode(NULL);
-		break;
-	}
+	phys_addr_t boot_pgd_ptr;
+	phys_addr_t phys_idmap_start;
 
-	return NOTIFY_OK;
-}
+	if (__hyp_get_vectors() == hyp_default_vectors)
+		return;
 
-static struct notifier_block hyp_init_cpu_nb = {
-	.notifier_call = hyp_init_cpu_notify,
-};
+	boot_pgd_ptr = kvm_mmu_get_boot_httbr();
+	phys_idmap_start = kvm_get_idmap_start();
+
+	__cpu_reset_hyp_mode(boot_pgd_ptr, phys_idmap_start);
+}
 
 #ifdef CONFIG_CPU_PM
 static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
 				    unsigned long cmd,
 				    void *v)
 {
-	if (cmd == CPU_PM_EXIT &&
-	    __hyp_get_vectors() == hyp_default_vectors) {
-		cpu_init_hyp_mode(NULL);
+	switch (cmd) {
+	case CPU_PM_ENTER:
+		if (__hyp_get_vectors() != hyp_default_vectors)
+			__this_cpu_write(kvm_arm_hardware_enabled, 1);
+		else
+			__this_cpu_write(kvm_arm_hardware_enabled, 0);
+		/*
+		 * don't call kvm_arch_hardware_disable() in case of
+		 * CPU_PM_ENTER because it does't actually save any state.
+		 */
+
+		return NOTIFY_OK;
+	case CPU_PM_EXIT:
+		if (__this_cpu_read(kvm_arm_hardware_enabled))
+			kvm_arch_hardware_enable();
+
 		return NOTIFY_OK;
-	}
 
-	return NOTIFY_DONE;
+	default:
+		return NOTIFY_DONE;
+	}
 }
 
 static struct notifier_block hyp_init_cpu_pm_nb = {
@@ -1064,11 +1075,6 @@ static int init_hyp_mode(void)
 	}
 
 	/*
-	 * Execute the init code on each CPU.
-	 */
-	on_each_cpu(cpu_init_hyp_mode, NULL, 1);
-
-	/*
 	 * Init HYP view of VGIC
 	 */
 	err = kvm_vgic_hyp_init();
@@ -1142,26 +1148,15 @@ int kvm_arch_init(void *opaque)
 		}
 	}
 
-	cpu_notifier_register_begin();
-
 	err = init_hyp_mode();
 	if (err)
 		goto out_err;
 
-	err = __register_cpu_notifier(&hyp_init_cpu_nb);
-	if (err) {
-		kvm_err("Cannot register HYP init CPU notifier (%d)\n", err);
-		goto out_err;
-	}
-
-	cpu_notifier_register_done();
-
 	hyp_cpu_pm_init();
 
 	kvm_coproc_table_init();
 	return 0;
 out_err:
-	cpu_notifier_register_done();
 	return err;
 }
 
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 6984342..69b4a33 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1644,6 +1644,11 @@ phys_addr_t kvm_get_idmap_vector(void)
 	return hyp_idmap_vector;
 }
 
+phys_addr_t kvm_get_idmap_start(void)
+{
+	return hyp_idmap_start;
+}
+
 int kvm_mmu_init(void)
 {
 	int err;
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index ed03968..e86421a 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -220,6 +220,7 @@ struct kvm_vcpu *kvm_arm_get_running_vcpu(void);
 struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);
 
 u64 kvm_call_hyp(void *hypfn, ...);
+void kvm_call_reset(phys_addr_t boot_pgd_ptr, phys_addr_t phys_idmap_start);
 void force_vm_exit(const cpumask_t *mask);
 void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
 
@@ -244,7 +245,20 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
 		     hyp_stack_ptr, vector_ptr);
 }
 
-static inline void kvm_arch_hardware_disable(void) {}
+static inline void __cpu_reset_hyp_mode(phys_addr_t boot_pgd_ptr,
+					phys_addr_t phys_idmap_start)
+{
+	/*
+	 * Call reset code, and switch back to stub hyp vectors.
+	 */
+	kvm_call_reset(boot_pgd_ptr, phys_idmap_start);
+}
+
+struct vgic_sr_vectors {
+	void	*save_vgic;
+	void	*restore_vgic;
+};
+
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 6150567..ff5a087 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -98,6 +98,7 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_mmu_get_boot_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
+phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 3070096..bca79f9 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -58,9 +58,18 @@
 
 #define HVC_CALL_FUNC 3
 
+/*
+ * HVC_RESET_CPU - Reset cpu in EL2 to initial state.
+ *
+ * @x0: entry address in trampoline code in va
+ * @x1: identical mapping page table in pa
+ */
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
+#define HVC_RESET_CPU 4
+
 #ifndef __ASSEMBLY__
 
 /*
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 2e67a48..1925163 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -139,6 +139,39 @@ merged:
 	eret
 ENDPROC(__kvm_hyp_init)
 
+	/*
+	 * x0: HYP boot pgd
+	 * x1: HYP phys_idmap_start
+	 */
+ENTRY(__kvm_hyp_reset)
+	/* We're in trampoline code in VA, switch back to boot page tables */
+	msr	ttbr0_el2, x0
+	isb
+
+	/* Invalidate the old TLBs */
+	tlbi	alle2
+	dsb	sy
+
+	/* Branch into PA space */
+	adr	x0, 1f
+	bfi	x1, x0, #0, #PAGE_SHIFT
+	br	x1
+
+	/* We're now in idmap, disable MMU */
+1:	mrs	x0, sctlr_el2
+	ldr	x1, =SCTLR_EL2_FLAGS
+	bic	x0, x0, x1		// Clear SCTL_M and etc
+	msr	sctlr_el2, x0
+	isb
+
+	/* Install stub vectors */
+	adrp	x0, __hyp_stub_vectors
+	add	x0, x0, #:lo12:__hyp_stub_vectors
+	msr	vbar_el2, x0
+
+	eret
+ENDPROC(__kvm_hyp_reset)
+
 	.ltorg
 
 	.popsection
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 073b8bf..c9804ac 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -931,6 +931,11 @@ ENTRY(kvm_call_hyp)
 	ret
 ENDPROC(kvm_call_hyp)
 
+ENTRY(kvm_call_reset)
+	hvc	#HVC_RESET_CPU
+	ret
+ENDPROC(kvm_call_reset)
+
 .macro invalid_vector	label, target
 	.align	2
 \label:
@@ -974,10 +979,27 @@ el1_sync:					// Guest trapped into EL2
 	cmp	x18, #HVC_GET_VECTORS
 	b.ne	1f
 	mrs	x0, vbar_el2
-	b	2f
-
-1:	/* Default to HVC_CALL_HYP. */
+	b	do_eret
 
+	/* jump into trampoline code */
+1:	cmp	x18, #HVC_RESET_CPU
+	b.ne	2f
+	/*
+	 * Entry point is:
+	 *	TRAMPOLINE_VA
+	 *	+ (__kvm_hyp_reset - (__hyp_idmap_text_start & PAGE_MASK))
+	 */
+	adrp	x2, __kvm_hyp_reset
+	add	x2, x2, #:lo12:__kvm_hyp_reset
+	adrp	x3, __hyp_idmap_text_start
+	add	x3, x3, #:lo12:__hyp_idmap_text_start
+	and	x3, x3, PAGE_MASK
+	sub	x2, x2, x3
+	ldr	x3, =TRAMPOLINE_VA
+	add	x2, x2, x3
+	br	x2				// no return
+
+2:	/* Default to HVC_CALL_HYP. */
 	push	lr, xzr
 
 	/*
@@ -991,7 +1013,9 @@ el1_sync:					// Guest trapped into EL2
 	blr	lr
 
 	pop	lr, xzr
-2:	eret
+
+do_eret:
+	eret
 
 el1_trap:
 	/*
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 03/15] arm64: Add new hcall HVC_CALL_FUNC
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

Add the new hcall HVC_CALL_FUNC that allows execution of a function at EL2.
During CPU reset the CPU must be brought to the exception level it had on
entry to the kernel.  The HVC_CALL_FUNC hcall will provide the mechanism
needed for this exception level switch.

To allow the HVC_CALL_FUNC exception vector to work without a stack, which is
needed to support an hcall at CPU reset, this implementation uses register x18
to store the link register across the caller provided function.  This dictates
that the caller provided function must preserve the contents of register x18.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/include/asm/virt.h | 13 +++++++++++++
 arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index eb10368..3070096 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -45,6 +45,19 @@
 
 #define HVC_SET_VECTORS 2
 
+/*
+ * HVC_CALL_FUNC - Execute a function at EL2.
+ *
+ * @x0: Physical address of the function to be executed.
+ * @x1: Passed as the first argument to the function.
+ * @x2: Passed as the second argument to the function.
+ * @x3: Passed as the third argument to the function.
+ *
+ * The called function must preserve the contents of register x18.
+ */
+
+#define HVC_CALL_FUNC 3
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 017ab519..e8febe9 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -67,8 +67,19 @@ el1_sync:
 	b	2f
 
 1:	cmp	x18, #HVC_SET_VECTORS
-	b.ne	2f
+	b.ne	1f
 	msr	vbar_el2, x0
+	b	2f
+
+1:	cmp	x18, #HVC_CALL_FUNC
+	b.ne	2f
+	mov	x18, lr
+	mov	lr, x0
+	mov	x0, x1
+	mov	x1, x2
+	mov	x2, x3
+	blr	lr
+	mov	lr, x18
 
 2:	eret
 ENDPROC(el1_sync)
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 08/15] arm64/kexec: Add pr_devel output
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

To aid in debugging kexec problems or when adding new functionality to kexec add
a new routine kexec_image_info() and several inline pr_devel statements.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/kernel/machine_kexec.c | 63 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 8b990b8..da28a26 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -25,6 +25,48 @@ extern const unsigned long arm64_relocate_new_kernel_size;
 
 static unsigned long kimage_start;
 
+/**
+ * kexec_is_dtb - Helper routine to check the device tree header signature.
+ */
+static bool kexec_is_dtb(const void *dtb)
+{
+	__be32 magic;
+
+	return get_user(magic, (__be32 *)dtb) ? false :
+		(be32_to_cpu(magic) == OF_DT_HEADER);
+}
+
+/**
+ * kexec_image_info - For debugging output.
+ */
+#define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i)
+static void _kexec_image_info(const char *func, int line,
+	const struct kimage *kimage)
+{
+	unsigned long i;
+
+#if !defined(DEBUG)
+	return;
+#endif
+	pr_devel("%s:%d:\n", func, line);
+	pr_devel("  kexec kimage info:\n");
+	pr_devel("    type:        %d\n", kimage->type);
+	pr_devel("    start:       %lx\n", kimage->start);
+	pr_devel("    head:        %lx\n", kimage->head);
+	pr_devel("    nr_segments: %lu\n", kimage->nr_segments);
+
+	for (i = 0; i < kimage->nr_segments; i++) {
+		pr_devel("      segment[%lu]: %016lx - %016lx, %lx bytes, %lu pages%s\n",
+			i,
+			kimage->segment[i].mem,
+			kimage->segment[i].mem + kimage->segment[i].memsz,
+			kimage->segment[i].memsz,
+			kimage->segment[i].memsz /  PAGE_SIZE,
+			(kexec_is_dtb(kimage->segment[i].buf) ?
+				", dtb segment" : ""));
+	}
+}
+
 void machine_kexec_cleanup(struct kimage *kimage)
 {
 	/* Empty routine needed to avoid build errors. */
@@ -38,6 +80,8 @@ void machine_kexec_cleanup(struct kimage *kimage)
 int machine_kexec_prepare(struct kimage *kimage)
 {
 	kimage_start = kimage->start;
+	kexec_image_info(kimage);
+
 	return 0;
 }
 
@@ -107,6 +151,25 @@ void machine_kexec(struct kimage *kimage)
 	reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
 	reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
 
+	kexec_image_info(kimage);
+
+	pr_devel("%s:%d: control_code_page:        %p\n", __func__, __LINE__,
+		kimage->control_code_page);
+	pr_devel("%s:%d: reboot_code_buffer_phys:  %pa\n", __func__, __LINE__,
+		&reboot_code_buffer_phys);
+	pr_devel("%s:%d: reboot_code_buffer:       %p\n", __func__, __LINE__,
+		reboot_code_buffer);
+	pr_devel("%s:%d: relocate_new_kernel:      %p\n", __func__, __LINE__,
+		arm64_relocate_new_kernel);
+	pr_devel("%s:%d: relocate_new_kernel_size: 0x%lx(%lu) bytes\n",
+		__func__, __LINE__, arm64_relocate_new_kernel_size,
+		arm64_relocate_new_kernel_size);
+
+	pr_devel("%s:%d: kimage_head:              %lx\n", __func__, __LINE__,
+		kimage->head);
+	pr_devel("%s:%d: kimage_start:             %lx\n", __func__, __LINE__,
+		kimage_start);
+
 	/*
 	 * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
 	 * after the kernel is shut down.
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 05/15] arm64: Add back cpu_reset routines
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

Commit 68234df4ea7939f98431aa81113fbdce10c4a84b (arm64: kill flush_cache_all())
removed the global arm64 routines cpu_reset() and cpu_soft_restart() needed by
the arm64 kexec and kdump support.  Add simplified versions of those two
routines back with some changes needed for kexec in the new files cpu_reset.S,
and cpu_reset.h.

When a CPU is reset it needs to be put into the exception level it had
when it entered the kernel. Update cpu_reset() to accept an argument
which signals if the reset address needs to be entered at EL1 or EL2.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/kernel/cpu-reset.S | 84 +++++++++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/cpu-reset.h | 22 ++++++++++++
 2 files changed, 106 insertions(+)
 create mode 100644 arch/arm64/kernel/cpu-reset.S
 create mode 100644 arch/arm64/kernel/cpu-reset.h

diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S
new file mode 100644
index 0000000..0423f27
--- /dev/null
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -0,0 +1,84 @@
+/*
+ * cpu reset routines
+ *
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2015 Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/virt.h>
+
+#define SCTLR_ELx_I	(1 << 12)
+#define SCTLR_ELx_SA	(1 << 3)
+#define SCTLR_ELx_C	(1 << 2)
+#define SCTLR_ELx_A	(1 << 1)
+#define SCTLR_ELx_M	1
+#define SCTLR_ELx_FLAGS	(SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C |	\
+			 SCTLR_ELx_SA | SCTLR_ELx_I)
+
+.text
+.pushsection    .idmap.text, "ax"
+
+.align 5
+
+/*
+ * cpu_soft_restart(cpu_reset, el2_switch, entry, arg0, arg1) - Perform a cpu
+ * soft reset.
+ *
+ * @cpu_reset: Physical address of the cpu_reset routine.
+ * @el2_switch: Flag to indicate a swich to EL2 is needed, passed to cpu_reset.
+ * @entry: Location to jump to for soft reset, passed to cpu_reset.
+ * arg0: First argument passed to @entry.
+ * arg1: Second argument passed to @entry.
+ */
+
+ENTRY(cpu_soft_restart)
+	mov	x18, x0				// cpu_reset
+	mov	x0, x1				// el2_switch
+	mov	x1, x2				// entry
+	mov	x2, x3				// arg0
+	mov	x3, x4				// arg1
+	ret	x18
+ENDPROC(cpu_soft_restart)
+
+/*
+ * cpu_reset(el2_switch, entry, arg0, arg1) - Helper for cpu_soft_restart.
+ *
+ * @el2_switch: Flag to indicate a swich to EL2 is needed.
+ * @entry: Location to jump to for soft reset.
+ * arg0: First argument passed to @entry.
+ * arg1: Second argument passed to @entry.
+ *
+ * Put the CPU into the same state as it would be if it had been reset, and
+ * branch to what would be the reset vector. It must be executed with the
+ * flat identity mapping.
+ */
+
+ENTRY(cpu_reset)
+	/* Clear sctlr_el1 flags. */
+	mrs	x12, sctlr_el1
+	ldr	x13, =SCTLR_ELx_FLAGS
+	bic	x12, x12, x13
+	msr	sctlr_el1, x12
+	isb
+
+	cbz	x0, 1f				// el2_switch?
+
+	mov	x0, x1				// entry
+	mov	x1, x2				// arg0
+	mov	x2, x3				// arg1
+	hvc	#HVC_CALL_FUNC			// no return
+
+1:	mov	x18, x1				// entry
+	mov	x0, x2				// arg0
+	mov	x1, x3				// arg1
+	ret	x18
+ENDPROC(cpu_reset)
+
+.popsection
diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h
new file mode 100644
index 0000000..79816b6
--- /dev/null
+++ b/arch/arm64/kernel/cpu-reset.h
@@ -0,0 +1,22 @@
+/*
+ * cpu reset routines
+ *
+ * Copyright (C) 2015 Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#if !defined(_ARM64_CPU_RESET_H)
+#define _ARM64_CPU_RESET_H
+
+#include <asm/virt.h>
+
+void __attribute__((noreturn)) cpu_reset(unsigned long el2_switch,
+	unsigned long entry, unsigned long arg0, unsigned long arg1);
+void __attribute__((noreturn)) cpu_soft_restart(phys_addr_t cpu_reset,
+	unsigned long el2_switch, unsigned long entry, unsigned long arg0,
+	unsigned long arg1);
+
+#endif
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 00/15] arm64 kexec kernel patches v11
@ 2015-11-06 19:14 ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

Hi All,

This series adds the core support for kexec re-boot and kdump on ARM64.  This
version of the series combines Takahiro's kdump patches with my kexec patches.

To load a second stage kernel and execute a kexec re-boot or to work with kdump
on ARM64 systems a series of patches to kexec-tools [2], which have not yet been
merged upstream, are needed.

I have tested kexec with the ARM Foundation model, and Takahiro has reported
that kdump is working on the 96boards HiKey developer board.  Kexec on EFI
systems works correctly.  More ACPI + kexec testing is needed.

Patch 1 here moves the macros from proc-macros.S to asm/assembler.h so that the
dcache_line_size macro it defines can be uesd by kexec's relocate kernel
routine.

Patches 2 & 3 rework the ARM64 hcall mechanism to give the CPU reset routines
the ability to switch exception levels from EL1 to EL2 for kernels that were
entered in EL2.

Patch 4 allows KVM to handle a CPU reset.

Patches 5 & 6 add back the ARM64 CPU reset support that was recently removed
from the kernel.

Patches 7 - 9 add kexec support.

Patches 10-15 add kdump support.

Please consider all patches for inclusion.

Changes since v10:

o Move the flush of the new image from arm64_relocate_new_kernel to machine_kexec.
o Pass values to arm64_relocate_new_kernel in registers, not in global variables.
o Fixups to setting the sctlr_el1 and sctlr_el2 flags.

[1]  https://git.kernel.org/cgit/linux/kernel/git/geoff/linux-kexec.git
[2]  https://git.kernel.org/cgit/linux/kernel/git/geoff/kexec-tools.git

-Geoff

The following changes since commit 6a13feb9c82803e2b815eca72fa7a9f5561d7861:

  Linux 4.3 (2015-11-01 16:05:25 -0800)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/geoff/linux-kexec.git kexec-v11

for you to fetch changes up to 2b09b58c7586a4ca929400327d394fec3135fdd0:

  arm64: kdump: relax BUG_ON() if more than one cpus are still active (2015-11-06 10:38:13 -0800)

----------------------------------------------------------------
AKASHI Takahiro (7):
      arm64: kvm: allows kvm cpu hotplug
      arm64: kdump: reserve memory for crash dump kernel
      arm64: kdump: implement machine_crash_shutdown()
      arm64: kdump: add kdump support
      arm64: kdump: update a kernel doc
      arm64: kdump: enable kdump in the arm64 defconfig
      arm64: kdump: relax BUG_ON() if more than one cpus are still active

Geoff Levand (8):
      arm64: Fold proc-macros.S into assembler.h
      arm64: Convert hcalls to use HVC immediate value
      arm64: Add new hcall HVC_CALL_FUNC
      arm64: Add back cpu_reset routines
      Revert "arm64: remove dead code"
      arm64/kexec: Add core kexec support
      arm64/kexec: Add pr_devel output
      arm64/kexec: Enable kexec in the arm64 defconfig

 Documentation/kdump/kdump.txt       |  32 ++++-
 arch/arm/include/asm/kvm_host.h     |  10 +-
 arch/arm/include/asm/kvm_mmu.h      |   1 +
 arch/arm/kvm/arm.c                  |  79 ++++++------
 arch/arm/kvm/mmu.c                  |   5 +
 arch/arm64/Kconfig                  |  22 ++++
 arch/arm64/configs/defconfig        |   2 +
 arch/arm64/include/asm/assembler.h  |  48 ++++++-
 arch/arm64/include/asm/kexec.h      |  80 ++++++++++++
 arch/arm64/include/asm/kvm_host.h   |  16 ++-
 arch/arm64/include/asm/kvm_mmu.h    |   1 +
 arch/arm64/include/asm/mmu.h        |   1 +
 arch/arm64/include/asm/virt.h       |  49 +++++++
 arch/arm64/kernel/Makefile          |   3 +
 arch/arm64/kernel/cpu-reset.S       |  84 ++++++++++++
 arch/arm64/kernel/cpu-reset.h       |  22 ++++
 arch/arm64/kernel/crash_dump.c      |  71 +++++++++++
 arch/arm64/kernel/head.S            |   1 -
 arch/arm64/kernel/hyp-stub.S        |  43 +++++--
 arch/arm64/kernel/machine_kexec.c   | 248 ++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/relocate_kernel.S | 131 +++++++++++++++++++
 arch/arm64/kernel/setup.c           |   7 +-
 arch/arm64/kernel/smp.c             |  16 ++-
 arch/arm64/kvm/hyp-init.S           |  34 ++++-
 arch/arm64/kvm/hyp.S                |  44 +++++--
 arch/arm64/mm/cache.S               |   2 -
 arch/arm64/mm/init.c                |  83 ++++++++++++
 arch/arm64/mm/mmu.c                 |  11 ++
 arch/arm64/mm/proc-macros.S         |  64 ----------
 arch/arm64/mm/proc.S                |   3 -
 include/uapi/linux/kexec.h          |   1 +
 31 files changed, 1074 insertions(+), 140 deletions(-)
 create mode 100644 arch/arm64/include/asm/kexec.h
 create mode 100644 arch/arm64/kernel/cpu-reset.S
 create mode 100644 arch/arm64/kernel/cpu-reset.h
 create mode 100644 arch/arm64/kernel/crash_dump.c
 create mode 100644 arch/arm64/kernel/machine_kexec.c
 create mode 100644 arch/arm64/kernel/relocate_kernel.S
 delete mode 100644 arch/arm64/mm/proc-macros.S

-- 
2.5.0


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^ permalink raw reply	[flat|nested] 36+ messages in thread
* [PATCH 07/15] arm64/kexec: Add core kexec support
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

Add three new files, kexec.h, machine_kexec.c and relocate_kernel.S to the
arm64 architecture that add support for the kexec re-boot mechanism
(CONFIG_KEXEC) on arm64 platforms.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/Kconfig                  |  10 +++
 arch/arm64/include/asm/kexec.h      |  48 ++++++++++++
 arch/arm64/kernel/Makefile          |   2 +
 arch/arm64/kernel/machine_kexec.c   | 152 ++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/relocate_kernel.S | 131 +++++++++++++++++++++++++++++++
 include/uapi/linux/kexec.h          |   1 +
 6 files changed, 344 insertions(+)
 create mode 100644 arch/arm64/include/asm/kexec.h
 create mode 100644 arch/arm64/kernel/machine_kexec.c
 create mode 100644 arch/arm64/kernel/relocate_kernel.S

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 07d1811..d9631ac 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -491,6 +491,16 @@ config SECCOMP
 	  and the task is only allowed to execute a few safe syscalls
 	  defined by each seccomp mode.
 
+config KEXEC
+	depends on PM_SLEEP_SMP
+	select KEXEC_CORE
+	bool "kexec system call"
+	---help---
+	  kexec is a system call that implements the ability to shutdown your
+	  current kernel, and to start another kernel.  It is like a reboot
+	  but it is independent of the system firmware.   And like a reboot
+	  you can start any kernel with it, not just Linux.
+
 config XEN_DOM0
 	def_bool y
 	depends on XEN
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
new file mode 100644
index 0000000..46d63cd
--- /dev/null
+++ b/arch/arm64/include/asm/kexec.h
@@ -0,0 +1,48 @@
+/*
+ * kexec for arm64
+ *
+ * Copyright (C) Linaro.
+ * Copyright (C) Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#if !defined(_ARM64_KEXEC_H)
+#define _ARM64_KEXEC_H
+
+/* Maximum physical address we can use pages from */
+
+#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
+
+/* Maximum address we can reach in physical address mode */
+
+#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
+
+/* Maximum address we can use for the control code buffer */
+
+#define KEXEC_CONTROL_MEMORY_LIMIT (-1UL)
+
+#define KEXEC_CONTROL_PAGE_SIZE	4096
+
+#define KEXEC_ARCH KEXEC_ARCH_ARM64
+
+#if !defined(__ASSEMBLY__)
+
+/**
+ * crash_setup_regs() - save registers for the panic kernel
+ *
+ * @newregs: registers are saved here
+ * @oldregs: registers to be saved (may be %NULL)
+ */
+
+static inline void crash_setup_regs(struct pt_regs *newregs,
+				    struct pt_regs *oldregs)
+{
+	/* Empty routine needed to avoid build errors. */
+}
+
+#endif /* !defined(__ASSEMBLY__) */
+
+#endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 22dc9bc..989ccd7 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -36,6 +36,8 @@ arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
 arm64-obj-$(CONFIG_PCI)			+= pci.o
 arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
 arm64-obj-$(CONFIG_ACPI)		+= acpi.o
+arm64-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o	\
+					   cpu-reset.o
 
 obj-y					+= $(arm64-obj-y) vdso/
 obj-m					+= $(arm64-obj-m)
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
new file mode 100644
index 0000000..8b990b8
--- /dev/null
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -0,0 +1,152 @@
+/*
+ * kexec for arm64
+ *
+ * Copyright (C) Linaro.
+ * Copyright (C) Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kexec.h>
+#include <linux/of_fdt.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include <asm/cacheflush.h>
+#include <asm/system_misc.h>
+
+#include "cpu-reset.h"
+
+/* Global variables for the arm64_relocate_new_kernel routine. */
+extern const unsigned char arm64_relocate_new_kernel[];
+extern const unsigned long arm64_relocate_new_kernel_size;
+
+static unsigned long kimage_start;
+
+void machine_kexec_cleanup(struct kimage *kimage)
+{
+	/* Empty routine needed to avoid build errors. */
+}
+
+/**
+ * machine_kexec_prepare - Prepare for a kexec reboot.
+ *
+ * Called from the core kexec code when a kernel image is loaded.
+ */
+int machine_kexec_prepare(struct kimage *kimage)
+{
+	kimage_start = kimage->start;
+	return 0;
+}
+
+/**
+ * kexec_list_flush - Helper to flush the kimage list to PoC.
+ */
+static void kexec_list_flush(unsigned long kimage_head)
+{
+	unsigned long *entry;
+
+	for (entry = &kimage_head; ; entry++) {
+		unsigned int flag = *entry & IND_FLAGS;
+		void *addr = phys_to_virt(*entry & PAGE_MASK);
+
+		switch (flag) {
+		case IND_INDIRECTION:
+			entry = (unsigned long *)addr - 1;
+			__flush_dcache_area(addr, PAGE_SIZE);
+			break;
+		case IND_DESTINATION:
+			break;
+		case IND_SOURCE:
+			__flush_dcache_area(addr, PAGE_SIZE);
+			break;
+		case IND_DONE:
+			return;
+		default:
+			BUG();
+		}
+	}
+}
+
+/**
+ * kexec_segment_flush - Helper to flush the kimage segments to PoC.
+ */
+static void kexec_segment_flush(const struct kimage *kimage)
+{
+	unsigned long i;
+
+	pr_devel("%s:\n", __func__);
+
+	for (i = 0; i < kimage->nr_segments; i++) {
+		pr_devel("  segment[%lu]: %016lx - %016lx, %lx bytes, %lu pages\n",
+			i,
+			kimage->segment[i].mem,
+			kimage->segment[i].mem + kimage->segment[i].memsz,
+			kimage->segment[i].memsz,
+			kimage->segment[i].memsz /  PAGE_SIZE);
+
+		__flush_dcache_area(phys_to_virt(kimage->segment[i].mem),
+			kimage->segment[i].memsz);
+	}
+}
+
+/**
+ * machine_kexec - Do the kexec reboot.
+ *
+ * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC.
+ */
+void machine_kexec(struct kimage *kimage)
+{
+	phys_addr_t reboot_code_buffer_phys;
+	void *reboot_code_buffer;
+
+	BUG_ON(num_online_cpus() > 1);
+
+	reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
+	reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
+
+	/*
+	 * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
+	 * after the kernel is shut down.
+	 */
+	memcpy(reboot_code_buffer, arm64_relocate_new_kernel,
+		arm64_relocate_new_kernel_size);
+
+	/* Flush the reboot_code_buffer in preparation for its execution. */
+	__flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);
+
+	/* Flush the new image. */
+	kexec_segment_flush(kimage);
+
+	/* Flush the kimage list. */
+	kexec_list_flush(kimage->head);
+
+	pr_info("Bye!\n");
+
+	/* Disable all DAIF exceptions. */
+	asm volatile ("msr daifset, #0xf" : : : "memory");
+
+	setup_mm_for_reboot();
+
+	/*
+	 * cpu_soft_restart will shutdown the MMU, disable data caches, then
+	 * transfer control to the reboot_code_buffer which contains a copy of
+	 * the arm64_relocate_new_kernel routine.  arm64_relocate_new_kernel
+	 * uses physical addressing to relocate the new image to its final
+	 * position and transfers control to the image entry point when the
+	 * relocation is complete.
+	 */
+
+	cpu_soft_restart(virt_to_phys(cpu_reset),
+		is_hyp_mode_available(),
+		reboot_code_buffer_phys, kimage->head, kimage_start);
+
+	BUG(); /* Should never get here. */
+}
+
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+	/* Empty routine needed to avoid build errors. */
+}
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
new file mode 100644
index 0000000..71cab0e
--- /dev/null
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -0,0 +1,131 @@
+/*
+ * kexec for arm64
+ *
+ * Copyright (C) Linaro.
+ * Copyright (C) Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kexec.h>
+
+#include <asm/assembler.h>
+#include <asm/kexec.h>
+#include <asm/kvm_arm.h>
+#include <asm/page.h>
+
+/*
+ * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
+ *
+ * The memory that the old kernel occupies may be overwritten when coping the
+ * new image to its final location.  To assure that the
+ * arm64_relocate_new_kernel routine which does that copy is not overwritten,
+ * all code and data needed by arm64_relocate_new_kernel must be between the
+ * symbols arm64_relocate_new_kernel and arm64_relocate_new_kernel_end.  The
+ * machine_kexec() routine will copy arm64_relocate_new_kernel to the kexec
+ * control_code_page, a special page which has been set up to be preserved
+ * during the copy operation.
+ */
+.globl arm64_relocate_new_kernel
+arm64_relocate_new_kernel:
+
+	/* Setup the list loop variables. */
+	mov	x18, x0				/* x18 = kimage_head */
+	mov	x17, x1				/* x17 = kimage_start */
+	dcache_line_size x16, x0		/* x16 = dcache line size */
+	mov	x15, xzr			/* x15 = segment start */
+	mov	x14, xzr			/* x14 = entry ptr */
+	mov	x13, xzr			/* x13 = copy dest */
+
+	/* Clear the sctlr_el2 flags. */
+	mrs	x0, CurrentEL
+	cmp	x0, #CurrentEL_EL2
+	b.ne	1f
+	mrs	x0, sctlr_el2
+	ldr	x1, =SCTLR_EL2_FLAGS
+	bic	x0, x0, x1
+	msr	sctlr_el2, x0
+	isb
+1:
+
+	/* Check if the new image needs relocation. */
+	cbz	x18, .Ldone
+	tbnz	x18, IND_DONE_BIT, .Ldone
+
+.Lloop:
+	and	x12, x18, PAGE_MASK		/* x12 = addr */
+
+	/* Test the entry flags. */
+.Ltest_source:
+	tbz	x18, IND_SOURCE_BIT, .Ltest_indirection
+
+	mov x20, x13				/*  x20 = copy dest */
+	mov x21, x12				/*  x21 = copy src */
+
+	/* Copy page. */
+1:	ldp	x22, x23, [x21]
+	ldp	x24, x25, [x21, #16]
+	ldp	x26, x27, [x21, #32]
+	ldp	x28, x29, [x21, #48]
+	add	x21, x21, #64
+	stnp	x22, x23, [x20]
+	stnp	x24, x25, [x20, #16]
+	stnp	x26, x27, [x20, #32]
+	stnp	x28, x29, [x20, #48]
+	add	x20, x20, #64
+	tst	x21, #(PAGE_SIZE - 1)
+	b.ne	1b
+
+	/* dest += PAGE_SIZE */
+	add	x13, x13, PAGE_SIZE
+	b	.Lnext
+
+.Ltest_indirection:
+	tbz	x18, IND_INDIRECTION_BIT, .Ltest_destination
+
+	/* ptr = addr */
+	mov	x14, x12
+	b	.Lnext
+
+.Ltest_destination:
+	tbz	x18, IND_DESTINATION_BIT, .Lnext
+
+	mov	x15, x12
+
+	/* dest = addr */
+	mov	x13, x12
+
+.Lnext:
+	/* entry = *ptr++ */
+	ldr	x18, [x14], #8
+
+	/* while (!(entry & DONE)) */
+	tbz	x18, IND_DONE_BIT, .Lloop
+
+.Ldone:
+	dsb	sy
+	ic	ialluis
+	dsb	sy
+	isb
+
+	/* Start new image. */
+	mov	x0, xzr
+	mov	x1, xzr
+	mov	x2, xzr
+	mov	x3, xzr
+	br	x17
+
+.align 3	/* To keep the 64-bit values below naturally aligned. */
+
+.Lcopy_end:
+.org	KEXEC_CONTROL_PAGE_SIZE
+
+/*
+ * arm64_relocate_new_kernel_size - Number of bytes to copy to the
+ * control_code_page.
+ */
+.globl arm64_relocate_new_kernel_size
+arm64_relocate_new_kernel_size:
+	.quad	.Lcopy_end - arm64_relocate_new_kernel
diff --git a/include/uapi/linux/kexec.h b/include/uapi/linux/kexec.h
index 99048e5..ccec467 100644
--- a/include/uapi/linux/kexec.h
+++ b/include/uapi/linux/kexec.h
@@ -39,6 +39,7 @@
 #define KEXEC_ARCH_SH      (42 << 16)
 #define KEXEC_ARCH_MIPS_LE (10 << 16)
 #define KEXEC_ARCH_MIPS    ( 8 << 16)
+#define KEXEC_ARCH_ARM64   (183 << 16)
 
 /* The artificial cap on the number of segments passed to kexec_load. */
 #define KEXEC_SEGMENT_MAX 16
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 06/15] Revert "arm64: remove dead code"
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

This reverts commit b08d4640a3dca68670fc5af2fe9205b395a02388.

Add back the setup_mm_for_reboot() needed for kexec.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/include/asm/mmu.h |  1 +
 arch/arm64/mm/mmu.c          | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 0302087..79fcfb0 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -28,6 +28,7 @@ typedef struct {
 #define ASID(mm)	((mm)->context.id & 0xffff)
 
 extern void paging_init(void);
+extern void setup_mm_for_reboot(void);
 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
 extern void init_mem_pgprot(void);
 extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 9211b85..8cffad9 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -461,6 +461,17 @@ void __init paging_init(void)
 }
 
 /*
+ * Enable the identity mapping to allow the MMU disabling.
+ */
+void setup_mm_for_reboot(void)
+{
+	cpu_set_reserved_ttbr0();
+	flush_tlb_all();
+	cpu_set_idmap_tcr_t0sz();
+	cpu_switch_mm(idmap_pg_dir, &init_mm);
+}
+
+/*
  * Check whether a kernel address is valid (derived from arch/x86/).
  */
 int kern_addr_valid(unsigned long addr)
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 09/15] arm64/kexec: Enable kexec in the arm64 defconfig
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 34d71dd..c80d8a4 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -55,6 +55,7 @@ CONFIG_PREEMPT=y
 CONFIG_KSM=y
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_CMA=y
+CONFIG_KEXEC=y
 CONFIG_CMDLINE="console=ttyAMA0"
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_COMPAT=y
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 02/15] arm64: Convert hcalls to use HVC immediate value
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

The existing arm64 hcall implementations are limited in that they only allow
for two distinct hcalls; with the x0 register either zero or not zero.  Also,
the API of the hyp-stub exception vector routines and the KVM exception vector
routines differ; hyp-stub uses a non-zero value in x0 to implement
__hyp_set_vectors, whereas KVM uses it to implement kvm_call_hyp.

To allow for additional hcalls to be defined and to make the arm64 hcall API
more consistent across exception vector routines, change the hcall
implementations to use the 16 bit immediate value of the HVC instruction to
specify the hcall type.

Define three new preprocessor macros HVC_CALL_HYP, HVC_GET_VECTORS, and
HVC_SET_VECTORS to be used as hcall type specifiers and convert the
existing __hyp_get_vectors(), __hyp_set_vectors() and kvm_call_hyp() routines
to use these new macros when executing an HVC call.  Also, change the
corresponding hyp-stub and KVM el1_sync exception vector routines to use these
new macros.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/include/asm/virt.h | 27 +++++++++++++++++++++++++++
 arch/arm64/kernel/hyp-stub.S  | 32 +++++++++++++++++++++-----------
 arch/arm64/kvm/hyp.S          | 16 +++++++++-------
 3 files changed, 57 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 7a5df52..eb10368 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -18,6 +18,33 @@
 #ifndef __ASM__VIRT_H
 #define __ASM__VIRT_H
 
+/*
+ * The arm64 hcall implementation uses the ISS field of the ESR_EL2 register to
+ * specify the hcall type.  The exception handlers are allowed to use registers
+ * x17 and x18 in their implementation.  Any routine issuing an hcall must not
+ * expect these registers to be preserved.
+ */
+
+/*
+ * HVC_CALL_HYP - Execute a hyp routine.
+ */
+
+#define HVC_CALL_HYP 0
+
+/*
+ * HVC_GET_VECTORS - Return the value of the vbar_el2 register.
+ */
+
+#define HVC_GET_VECTORS 1
+
+/*
+ * HVC_SET_VECTORS - Set the value of the vbar_el2 register.
+ *
+ * @x0: Physical address of the new vector table.
+ */
+
+#define HVC_SET_VECTORS 2
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index a272f33..017ab519 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -22,6 +22,7 @@
 #include <linux/irqchip/arm-gic-v3.h>
 
 #include <asm/assembler.h>
+#include <asm/kvm_arm.h>
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
@@ -53,14 +54,22 @@ ENDPROC(__hyp_stub_vectors)
 	.align 11
 
 el1_sync:
-	mrs	x1, esr_el2
-	lsr	x1, x1, #26
-	cmp	x1, #0x16
+	mrs	x18, esr_el2
+	lsr	x17, x18, #ESR_ELx_EC_SHIFT
+	and	x18, x18, #ESR_ELx_ISS_MASK
+
+	cmp	x17, #ESR_ELx_EC_HVC64
 	b.ne	2f				// Not an HVC trap
-	cbz	x0, 1f
-	msr	vbar_el2, x0			// Set vbar_el2
+
+	cmp	x18, #HVC_GET_VECTORS
+	b.ne	1f
+	mrs	x0, vbar_el2
 	b	2f
-1:	mrs	x0, vbar_el2			// Return vbar_el2
+
+1:	cmp	x18, #HVC_SET_VECTORS
+	b.ne	2f
+	msr	vbar_el2, x0
+
 2:	eret
 ENDPROC(el1_sync)
 
@@ -100,11 +109,12 @@ ENDPROC(\label)
  * initialisation entry point.
  */
 
-ENTRY(__hyp_get_vectors)
-	mov	x0, xzr
-	// fall through
 ENTRY(__hyp_set_vectors)
-	hvc	#0
+	hvc	#HVC_SET_VECTORS
 	ret
-ENDPROC(__hyp_get_vectors)
 ENDPROC(__hyp_set_vectors)
+
+ENTRY(__hyp_get_vectors)
+	hvc	#HVC_GET_VECTORS
+	ret
+ENDPROC(__hyp_get_vectors)
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index e583613..073b8bf 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -29,6 +29,7 @@
 #include <asm/kvm_asm.h>
 #include <asm/kvm_mmu.h>
 #include <asm/memory.h>
+#include <asm/virt.h>
 
 #define CPU_GP_REG_OFFSET(x)	(CPU_GP_REGS + x)
 #define CPU_XREG_OFFSET(x)	CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)
@@ -924,12 +925,9 @@ __hyp_panic_str:
  * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
  * passed in r0 and r1.
  *
- * A function pointer with a value of 0 has a special meaning, and is
- * used to implement __hyp_get_vectors in the same way as in
- * arch/arm64/kernel/hyp_stub.S.
  */
 ENTRY(kvm_call_hyp)
-	hvc	#0
+	hvc	#HVC_CALL_HYP
 	ret
 ENDPROC(kvm_call_hyp)
 
@@ -960,6 +958,7 @@ el1_sync:					// Guest trapped into EL2
 
 	mrs	x1, esr_el2
 	lsr	x2, x1, #ESR_ELx_EC_SHIFT
+	and	x0, x1, #ESR_ELx_ISS_MASK
 
 	cmp	x2, #ESR_ELx_EC_HVC64
 	b.ne	el1_trap
@@ -968,15 +967,18 @@ el1_sync:					// Guest trapped into EL2
 	cbnz	x3, el1_trap			// called HVC
 
 	/* Here, we're pretty sure the host called HVC. */
+	mov	x18, x0
 	pop	x2, x3
 	pop	x0, x1
 
-	/* Check for __hyp_get_vectors */
-	cbnz	x0, 1f
+	cmp	x18, #HVC_GET_VECTORS
+	b.ne	1f
 	mrs	x0, vbar_el2
 	b	2f
 
-1:	push	lr, xzr
+1:	/* Default to HVC_CALL_HYP. */
+
+	push	lr, xzr
 
 	/*
 	 * Compute the function address in EL2, and shuffle the parameters.
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 04/15] arm64: kvm: allows kvm cpu hotplug
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

The current kvm implementation on arm64 does cpu-specific initialization
at system boot, and has no way to gracefully shutdown a core in terms of
kvm. This prevents, especially, kexec from rebooting the system on a boot
core in EL2.

This patch adds a cpu tear-down function and also puts an existing cpu-init
code into a separate function, kvm_arch_hardware_disable() and
kvm_arch_hardware_enable() respectively.
We don't need arm64-specific cpu hotplug hook any more.

Since this patch modifies common part of code between arm and arm64, one
stub definition, __cpu_reset_hyp_mode(), is added on arm side to avoid
compiling errors.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm/include/asm/kvm_host.h   | 10 ++++-
 arch/arm/include/asm/kvm_mmu.h    |  1 +
 arch/arm/kvm/arm.c                | 79 ++++++++++++++++++---------------------
 arch/arm/kvm/mmu.c                |  5 +++
 arch/arm64/include/asm/kvm_host.h | 16 +++++++-
 arch/arm64/include/asm/kvm_mmu.h  |  1 +
 arch/arm64/include/asm/virt.h     |  9 +++++
 arch/arm64/kvm/hyp-init.S         | 33 ++++++++++++++++
 arch/arm64/kvm/hyp.S              | 32 ++++++++++++++--
 9 files changed, 138 insertions(+), 48 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index c4072d9..4c6a38c 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -211,6 +211,15 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
 	kvm_call_hyp((void*)hyp_stack_ptr, vector_ptr, pgd_ptr);
 }
 
+static inline void __cpu_reset_hyp_mode(phys_addr_t boot_pgd_ptr,
+					phys_addr_t phys_idmap_start)
+{
+	/*
+	 * TODO
+	 * kvm_call_reset(boot_pgd_ptr, phys_idmap_start);
+	 */
+}
+
 static inline int kvm_arch_dev_ioctl_check_extension(long ext)
 {
 	return 0;
@@ -223,7 +232,6 @@ void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
 
 struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
 
-static inline void kvm_arch_hardware_disable(void) {}
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 405aa18..dc6fadf 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -66,6 +66,7 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_mmu_get_boot_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
+phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 78b2869..5005e6e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -16,7 +16,6 @@
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-#include <linux/cpu.h>
 #include <linux/cpu_pm.h>
 #include <linux/errno.h>
 #include <linux/err.h>
@@ -61,6 +60,8 @@ static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
 static u8 kvm_next_vmid;
 static DEFINE_SPINLOCK(kvm_vmid_lock);
 
+static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);
+
 static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
 {
 	BUG_ON(preemptible());
@@ -85,11 +86,6 @@ struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
 	return &kvm_arm_running_vcpu;
 }
 
-int kvm_arch_hardware_enable(void)
-{
-	return 0;
-}
-
 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
 	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
@@ -915,7 +911,7 @@ long kvm_arch_vm_ioctl(struct file *filp,
 	}
 }
 
-static void cpu_init_hyp_mode(void *dummy)
+int kvm_arch_hardware_enable(void)
 {
 	phys_addr_t boot_pgd_ptr;
 	phys_addr_t pgd_ptr;
@@ -923,6 +919,9 @@ static void cpu_init_hyp_mode(void *dummy)
 	unsigned long stack_page;
 	unsigned long vector_ptr;
 
+	if (__hyp_get_vectors() != hyp_default_vectors)
+		return 0;
+
 	/* Switch from the HYP stub to our own HYP init vector */
 	__hyp_set_vectors(kvm_get_idmap_vector());
 
@@ -935,38 +934,50 @@ static void cpu_init_hyp_mode(void *dummy)
 	__cpu_init_hyp_mode(boot_pgd_ptr, pgd_ptr, hyp_stack_ptr, vector_ptr);
 
 	kvm_arm_init_debug();
+
+	return 0;
 }
 
-static int hyp_init_cpu_notify(struct notifier_block *self,
-			       unsigned long action, void *cpu)
+void kvm_arch_hardware_disable(void)
 {
-	switch (action) {
-	case CPU_STARTING:
-	case CPU_STARTING_FROZEN:
-		if (__hyp_get_vectors() == hyp_default_vectors)
-			cpu_init_hyp_mode(NULL);
-		break;
-	}
+	phys_addr_t boot_pgd_ptr;
+	phys_addr_t phys_idmap_start;
 
-	return NOTIFY_OK;
-}
+	if (__hyp_get_vectors() == hyp_default_vectors)
+		return;
 
-static struct notifier_block hyp_init_cpu_nb = {
-	.notifier_call = hyp_init_cpu_notify,
-};
+	boot_pgd_ptr = kvm_mmu_get_boot_httbr();
+	phys_idmap_start = kvm_get_idmap_start();
+
+	__cpu_reset_hyp_mode(boot_pgd_ptr, phys_idmap_start);
+}
 
 #ifdef CONFIG_CPU_PM
 static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
 				    unsigned long cmd,
 				    void *v)
 {
-	if (cmd == CPU_PM_EXIT &&
-	    __hyp_get_vectors() == hyp_default_vectors) {
-		cpu_init_hyp_mode(NULL);
+	switch (cmd) {
+	case CPU_PM_ENTER:
+		if (__hyp_get_vectors() != hyp_default_vectors)
+			__this_cpu_write(kvm_arm_hardware_enabled, 1);
+		else
+			__this_cpu_write(kvm_arm_hardware_enabled, 0);
+		/*
+		 * don't call kvm_arch_hardware_disable() in case of
+		 * CPU_PM_ENTER because it does't actually save any state.
+		 */
+
+		return NOTIFY_OK;
+	case CPU_PM_EXIT:
+		if (__this_cpu_read(kvm_arm_hardware_enabled))
+			kvm_arch_hardware_enable();
+
 		return NOTIFY_OK;
-	}
 
-	return NOTIFY_DONE;
+	default:
+		return NOTIFY_DONE;
+	}
 }
 
 static struct notifier_block hyp_init_cpu_pm_nb = {
@@ -1064,11 +1075,6 @@ static int init_hyp_mode(void)
 	}
 
 	/*
-	 * Execute the init code on each CPU.
-	 */
-	on_each_cpu(cpu_init_hyp_mode, NULL, 1);
-
-	/*
 	 * Init HYP view of VGIC
 	 */
 	err = kvm_vgic_hyp_init();
@@ -1142,26 +1148,15 @@ int kvm_arch_init(void *opaque)
 		}
 	}
 
-	cpu_notifier_register_begin();
-
 	err = init_hyp_mode();
 	if (err)
 		goto out_err;
 
-	err = __register_cpu_notifier(&hyp_init_cpu_nb);
-	if (err) {
-		kvm_err("Cannot register HYP init CPU notifier (%d)\n", err);
-		goto out_err;
-	}
-
-	cpu_notifier_register_done();
-
 	hyp_cpu_pm_init();
 
 	kvm_coproc_table_init();
 	return 0;
 out_err:
-	cpu_notifier_register_done();
 	return err;
 }
 
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 6984342..69b4a33 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1644,6 +1644,11 @@ phys_addr_t kvm_get_idmap_vector(void)
 	return hyp_idmap_vector;
 }
 
+phys_addr_t kvm_get_idmap_start(void)
+{
+	return hyp_idmap_start;
+}
+
 int kvm_mmu_init(void)
 {
 	int err;
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index ed03968..e86421a 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -220,6 +220,7 @@ struct kvm_vcpu *kvm_arm_get_running_vcpu(void);
 struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);
 
 u64 kvm_call_hyp(void *hypfn, ...);
+void kvm_call_reset(phys_addr_t boot_pgd_ptr, phys_addr_t phys_idmap_start);
 void force_vm_exit(const cpumask_t *mask);
 void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
 
@@ -244,7 +245,20 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
 		     hyp_stack_ptr, vector_ptr);
 }
 
-static inline void kvm_arch_hardware_disable(void) {}
+static inline void __cpu_reset_hyp_mode(phys_addr_t boot_pgd_ptr,
+					phys_addr_t phys_idmap_start)
+{
+	/*
+	 * Call reset code, and switch back to stub hyp vectors.
+	 */
+	kvm_call_reset(boot_pgd_ptr, phys_idmap_start);
+}
+
+struct vgic_sr_vectors {
+	void	*save_vgic;
+	void	*restore_vgic;
+};
+
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 6150567..ff5a087 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -98,6 +98,7 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_mmu_get_boot_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
+phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 3070096..bca79f9 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -58,9 +58,18 @@
 
 #define HVC_CALL_FUNC 3
 
+/*
+ * HVC_RESET_CPU - Reset cpu in EL2 to initial state.
+ *
+ * @x0: entry address in trampoline code in va
+ * @x1: identical mapping page table in pa
+ */
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
+#define HVC_RESET_CPU 4
+
 #ifndef __ASSEMBLY__
 
 /*
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 2e67a48..1925163 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -139,6 +139,39 @@ merged:
 	eret
 ENDPROC(__kvm_hyp_init)
 
+	/*
+	 * x0: HYP boot pgd
+	 * x1: HYP phys_idmap_start
+	 */
+ENTRY(__kvm_hyp_reset)
+	/* We're in trampoline code in VA, switch back to boot page tables */
+	msr	ttbr0_el2, x0
+	isb
+
+	/* Invalidate the old TLBs */
+	tlbi	alle2
+	dsb	sy
+
+	/* Branch into PA space */
+	adr	x0, 1f
+	bfi	x1, x0, #0, #PAGE_SHIFT
+	br	x1
+
+	/* We're now in idmap, disable MMU */
+1:	mrs	x0, sctlr_el2
+	ldr	x1, =SCTLR_EL2_FLAGS
+	bic	x0, x0, x1		// Clear SCTL_M and etc
+	msr	sctlr_el2, x0
+	isb
+
+	/* Install stub vectors */
+	adrp	x0, __hyp_stub_vectors
+	add	x0, x0, #:lo12:__hyp_stub_vectors
+	msr	vbar_el2, x0
+
+	eret
+ENDPROC(__kvm_hyp_reset)
+
 	.ltorg
 
 	.popsection
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 073b8bf..c9804ac 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -931,6 +931,11 @@ ENTRY(kvm_call_hyp)
 	ret
 ENDPROC(kvm_call_hyp)
 
+ENTRY(kvm_call_reset)
+	hvc	#HVC_RESET_CPU
+	ret
+ENDPROC(kvm_call_reset)
+
 .macro invalid_vector	label, target
 	.align	2
 \label:
@@ -974,10 +979,27 @@ el1_sync:					// Guest trapped into EL2
 	cmp	x18, #HVC_GET_VECTORS
 	b.ne	1f
 	mrs	x0, vbar_el2
-	b	2f
-
-1:	/* Default to HVC_CALL_HYP. */
+	b	do_eret
 
+	/* jump into trampoline code */
+1:	cmp	x18, #HVC_RESET_CPU
+	b.ne	2f
+	/*
+	 * Entry point is:
+	 *	TRAMPOLINE_VA
+	 *	+ (__kvm_hyp_reset - (__hyp_idmap_text_start & PAGE_MASK))
+	 */
+	adrp	x2, __kvm_hyp_reset
+	add	x2, x2, #:lo12:__kvm_hyp_reset
+	adrp	x3, __hyp_idmap_text_start
+	add	x3, x3, #:lo12:__hyp_idmap_text_start
+	and	x3, x3, PAGE_MASK
+	sub	x2, x2, x3
+	ldr	x3, =TRAMPOLINE_VA
+	add	x2, x2, x3
+	br	x2				// no return
+
+2:	/* Default to HVC_CALL_HYP. */
 	push	lr, xzr
 
 	/*
@@ -991,7 +1013,9 @@ el1_sync:					// Guest trapped into EL2
 	blr	lr
 
 	pop	lr, xzr
-2:	eret
+
+do_eret:
+	eret
 
 el1_trap:
 	/*
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 03/15] arm64: Add new hcall HVC_CALL_FUNC
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

Add the new hcall HVC_CALL_FUNC that allows execution of a function at EL2.
During CPU reset the CPU must be brought to the exception level it had on
entry to the kernel.  The HVC_CALL_FUNC hcall will provide the mechanism
needed for this exception level switch.

To allow the HVC_CALL_FUNC exception vector to work without a stack, which is
needed to support an hcall at CPU reset, this implementation uses register x18
to store the link register across the caller provided function.  This dictates
that the caller provided function must preserve the contents of register x18.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/include/asm/virt.h | 13 +++++++++++++
 arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index eb10368..3070096 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -45,6 +45,19 @@
 
 #define HVC_SET_VECTORS 2
 
+/*
+ * HVC_CALL_FUNC - Execute a function at EL2.
+ *
+ * @x0: Physical address of the function to be executed.
+ * @x1: Passed as the first argument to the function.
+ * @x2: Passed as the second argument to the function.
+ * @x3: Passed as the third argument to the function.
+ *
+ * The called function must preserve the contents of register x18.
+ */
+
+#define HVC_CALL_FUNC 3
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 017ab519..e8febe9 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -67,8 +67,19 @@ el1_sync:
 	b	2f
 
 1:	cmp	x18, #HVC_SET_VECTORS
-	b.ne	2f
+	b.ne	1f
 	msr	vbar_el2, x0
+	b	2f
+
+1:	cmp	x18, #HVC_CALL_FUNC
+	b.ne	2f
+	mov	x18, lr
+	mov	lr, x0
+	mov	x0, x1
+	mov	x1, x2
+	mov	x2, x3
+	blr	lr
+	mov	lr, x18
 
 2:	eret
 ENDPROC(el1_sync)
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 08/15] arm64/kexec: Add pr_devel output
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

To aid in debugging kexec problems or when adding new functionality to kexec add
a new routine kexec_image_info() and several inline pr_devel statements.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/kernel/machine_kexec.c | 63 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 8b990b8..da28a26 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -25,6 +25,48 @@ extern const unsigned long arm64_relocate_new_kernel_size;
 
 static unsigned long kimage_start;
 
+/**
+ * kexec_is_dtb - Helper routine to check the device tree header signature.
+ */
+static bool kexec_is_dtb(const void *dtb)
+{
+	__be32 magic;
+
+	return get_user(magic, (__be32 *)dtb) ? false :
+		(be32_to_cpu(magic) == OF_DT_HEADER);
+}
+
+/**
+ * kexec_image_info - For debugging output.
+ */
+#define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i)
+static void _kexec_image_info(const char *func, int line,
+	const struct kimage *kimage)
+{
+	unsigned long i;
+
+#if !defined(DEBUG)
+	return;
+#endif
+	pr_devel("%s:%d:\n", func, line);
+	pr_devel("  kexec kimage info:\n");
+	pr_devel("    type:        %d\n", kimage->type);
+	pr_devel("    start:       %lx\n", kimage->start);
+	pr_devel("    head:        %lx\n", kimage->head);
+	pr_devel("    nr_segments: %lu\n", kimage->nr_segments);
+
+	for (i = 0; i < kimage->nr_segments; i++) {
+		pr_devel("      segment[%lu]: %016lx - %016lx, %lx bytes, %lu pages%s\n",
+			i,
+			kimage->segment[i].mem,
+			kimage->segment[i].mem + kimage->segment[i].memsz,
+			kimage->segment[i].memsz,
+			kimage->segment[i].memsz /  PAGE_SIZE,
+			(kexec_is_dtb(kimage->segment[i].buf) ?
+				", dtb segment" : ""));
+	}
+}
+
 void machine_kexec_cleanup(struct kimage *kimage)
 {
 	/* Empty routine needed to avoid build errors. */
@@ -38,6 +80,8 @@ void machine_kexec_cleanup(struct kimage *kimage)
 int machine_kexec_prepare(struct kimage *kimage)
 {
 	kimage_start = kimage->start;
+	kexec_image_info(kimage);
+
 	return 0;
 }
 
@@ -107,6 +151,25 @@ void machine_kexec(struct kimage *kimage)
 	reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
 	reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
 
+	kexec_image_info(kimage);
+
+	pr_devel("%s:%d: control_code_page:        %p\n", __func__, __LINE__,
+		kimage->control_code_page);
+	pr_devel("%s:%d: reboot_code_buffer_phys:  %pa\n", __func__, __LINE__,
+		&reboot_code_buffer_phys);
+	pr_devel("%s:%d: reboot_code_buffer:       %p\n", __func__, __LINE__,
+		reboot_code_buffer);
+	pr_devel("%s:%d: relocate_new_kernel:      %p\n", __func__, __LINE__,
+		arm64_relocate_new_kernel);
+	pr_devel("%s:%d: relocate_new_kernel_size: 0x%lx(%lu) bytes\n",
+		__func__, __LINE__, arm64_relocate_new_kernel_size,
+		arm64_relocate_new_kernel_size);
+
+	pr_devel("%s:%d: kimage_head:              %lx\n", __func__, __LINE__,
+		kimage->head);
+	pr_devel("%s:%d: kimage_start:             %lx\n", __func__, __LINE__,
+		kimage_start);
+
 	/*
 	 * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
 	 * after the kernel is shut down.
-- 
2.5.0



_______________________________________________
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http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 05/15] arm64: Add back cpu_reset routines
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

Commit 68234df4ea7939f98431aa81113fbdce10c4a84b (arm64: kill flush_cache_all())
removed the global arm64 routines cpu_reset() and cpu_soft_restart() needed by
the arm64 kexec and kdump support.  Add simplified versions of those two
routines back with some changes needed for kexec in the new files cpu_reset.S,
and cpu_reset.h.

When a CPU is reset it needs to be put into the exception level it had
when it entered the kernel. Update cpu_reset() to accept an argument
which signals if the reset address needs to be entered at EL1 or EL2.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/kernel/cpu-reset.S | 84 +++++++++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/cpu-reset.h | 22 ++++++++++++
 2 files changed, 106 insertions(+)
 create mode 100644 arch/arm64/kernel/cpu-reset.S
 create mode 100644 arch/arm64/kernel/cpu-reset.h

diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S
new file mode 100644
index 0000000..0423f27
--- /dev/null
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -0,0 +1,84 @@
+/*
+ * cpu reset routines
+ *
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2015 Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/virt.h>
+
+#define SCTLR_ELx_I	(1 << 12)
+#define SCTLR_ELx_SA	(1 << 3)
+#define SCTLR_ELx_C	(1 << 2)
+#define SCTLR_ELx_A	(1 << 1)
+#define SCTLR_ELx_M	1
+#define SCTLR_ELx_FLAGS	(SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C |	\
+			 SCTLR_ELx_SA | SCTLR_ELx_I)
+
+.text
+.pushsection    .idmap.text, "ax"
+
+.align 5
+
+/*
+ * cpu_soft_restart(cpu_reset, el2_switch, entry, arg0, arg1) - Perform a cpu
+ * soft reset.
+ *
+ * @cpu_reset: Physical address of the cpu_reset routine.
+ * @el2_switch: Flag to indicate a swich to EL2 is needed, passed to cpu_reset.
+ * @entry: Location to jump to for soft reset, passed to cpu_reset.
+ * arg0: First argument passed to @entry.
+ * arg1: Second argument passed to @entry.
+ */
+
+ENTRY(cpu_soft_restart)
+	mov	x18, x0				// cpu_reset
+	mov	x0, x1				// el2_switch
+	mov	x1, x2				// entry
+	mov	x2, x3				// arg0
+	mov	x3, x4				// arg1
+	ret	x18
+ENDPROC(cpu_soft_restart)
+
+/*
+ * cpu_reset(el2_switch, entry, arg0, arg1) - Helper for cpu_soft_restart.
+ *
+ * @el2_switch: Flag to indicate a swich to EL2 is needed.
+ * @entry: Location to jump to for soft reset.
+ * arg0: First argument passed to @entry.
+ * arg1: Second argument passed to @entry.
+ *
+ * Put the CPU into the same state as it would be if it had been reset, and
+ * branch to what would be the reset vector. It must be executed with the
+ * flat identity mapping.
+ */
+
+ENTRY(cpu_reset)
+	/* Clear sctlr_el1 flags. */
+	mrs	x12, sctlr_el1
+	ldr	x13, =SCTLR_ELx_FLAGS
+	bic	x12, x12, x13
+	msr	sctlr_el1, x12
+	isb
+
+	cbz	x0, 1f				// el2_switch?
+
+	mov	x0, x1				// entry
+	mov	x1, x2				// arg0
+	mov	x2, x3				// arg1
+	hvc	#HVC_CALL_FUNC			// no return
+
+1:	mov	x18, x1				// entry
+	mov	x0, x2				// arg0
+	mov	x1, x3				// arg1
+	ret	x18
+ENDPROC(cpu_reset)
+
+.popsection
diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h
new file mode 100644
index 0000000..79816b6
--- /dev/null
+++ b/arch/arm64/kernel/cpu-reset.h
@@ -0,0 +1,22 @@
+/*
+ * cpu reset routines
+ *
+ * Copyright (C) 2015 Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#if !defined(_ARM64_CPU_RESET_H)
+#define _ARM64_CPU_RESET_H
+
+#include <asm/virt.h>
+
+void __attribute__((noreturn)) cpu_reset(unsigned long el2_switch,
+	unsigned long entry, unsigned long arg0, unsigned long arg1);
+void __attribute__((noreturn)) cpu_soft_restart(phys_addr_t cpu_reset,
+	unsigned long el2_switch, unsigned long entry, unsigned long arg0,
+	unsigned long arg1);
+
+#endif
-- 
2.5.0



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http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 01/15] arm64: Fold proc-macros.S into assembler.h
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

To allow the assembler macros defined in arch/arm64/mm/proc-macros.S to be used
outside the mm code move the contents of proc-macros.S to asm/assembler.h.  Also,
delete proc-macros.S, and fix up all references to proc-macros.S.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 arch/arm64/include/asm/assembler.h | 48 +++++++++++++++++++++++++++-
 arch/arm64/kernel/head.S           |  1 -
 arch/arm64/kvm/hyp-init.S          |  1 -
 arch/arm64/mm/cache.S              |  2 --
 arch/arm64/mm/proc-macros.S        | 64 --------------------------------------
 arch/arm64/mm/proc.S               |  3 --
 6 files changed, 47 insertions(+), 72 deletions(-)
 delete mode 100644 arch/arm64/mm/proc-macros.S

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index b51f2cc..3b46501 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -1,5 +1,5 @@
 /*
- * Based on arch/arm/include/asm/assembler.h
+ * Based on arch/arm/include/asm/assembler.h, arch/arm/mm/proc-macros.S
  *
  * Copyright (C) 1996-2000 Russell King
  * Copyright (C) 2012 ARM Ltd.
@@ -23,6 +23,8 @@
 #ifndef __ASM_ASSEMBLER_H
 #define __ASM_ASSEMBLER_H
 
+#include <asm/asm-offsets.h>
+#include <asm/pgtable-hwdef.h>
 #include <asm/ptrace.h>
 #include <asm/thread_info.h>
 
@@ -193,4 +195,48 @@ lr	.req	x30		// link register
 	str	\src, [\tmp, :lo12:\sym]
 	.endm
 
+/*
+ * vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
+ */
+	.macro	vma_vm_mm, rd, rn
+	ldr	\rd, [\rn, #VMA_VM_MM]
+	.endm
+
+/*
+ * mmid - get context id from mm pointer (mm->context.id)
+ */
+	.macro	mmid, rd, rn
+	ldr	\rd, [\rn, #MM_CONTEXT_ID]
+	.endm
+
+/*
+ * dcache_line_size - get the minimum D-cache line size from the CTR register.
+ */
+	.macro	dcache_line_size, reg, tmp
+	mrs	\tmp, ctr_el0			// read CTR
+	ubfm	\tmp, \tmp, #16, #19		// cache line size encoding
+	mov	\reg, #4			// bytes per word
+	lsl	\reg, \reg, \tmp		// actual cache line size
+	.endm
+
+/*
+ * icache_line_size - get the minimum I-cache line size from the CTR register.
+ */
+	.macro	icache_line_size, reg, tmp
+	mrs	\tmp, ctr_el0			// read CTR
+	and	\tmp, \tmp, #0xf		// cache line size encoding
+	mov	\reg, #4			// bytes per word
+	lsl	\reg, \reg, \tmp		// actual cache line size
+	.endm
+
+/*
+ * tcr_set_idmap_t0sz - update TCR.T0SZ so that we can load the ID map
+ */
+	.macro	tcr_set_idmap_t0sz, valreg, tmpreg
+#ifndef CONFIG_ARM64_VA_BITS_48
+	ldr_l	\tmpreg, idmap_t0sz
+	bfi	\valreg, \tmpreg, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
+#endif
+	.endm
+
 #endif	/* __ASM_ASSEMBLER_H */
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 90d09ed..9ad8b1f 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -31,7 +31,6 @@
 #include <asm/cputype.h>
 #include <asm/memory.h>
 #include <asm/thread_info.h>
-#include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
 #include <asm/page.h>
 #include <asm/virt.h>
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 178ba22..2e67a48 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -20,7 +20,6 @@
 #include <asm/assembler.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_mmu.h>
-#include <asm/pgtable-hwdef.h>
 
 	.text
 	.pushsection	.hyp.idmap.text, "ax"
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index eb48d5d..9e13cb5 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -24,8 +24,6 @@
 #include <asm/cpufeature.h>
 #include <asm/alternative.h>
 
-#include "proc-macros.S"
-
 /*
  *	flush_icache_range(start,end)
  *
diff --git a/arch/arm64/mm/proc-macros.S b/arch/arm64/mm/proc-macros.S
deleted file mode 100644
index 4c4d93c..0000000
--- a/arch/arm64/mm/proc-macros.S
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * Based on arch/arm/mm/proc-macros.S
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <asm/asm-offsets.h>
-#include <asm/thread_info.h>
-
-/*
- * vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
- */
-	.macro	vma_vm_mm, rd, rn
-	ldr	\rd, [\rn, #VMA_VM_MM]
-	.endm
-
-/*
- * mmid - get context id from mm pointer (mm->context.id)
- */
-	.macro	mmid, rd, rn
-	ldr	\rd, [\rn, #MM_CONTEXT_ID]
-	.endm
-
-/*
- * dcache_line_size - get the minimum D-cache line size from the CTR register.
- */
-	.macro	dcache_line_size, reg, tmp
-	mrs	\tmp, ctr_el0			// read CTR
-	ubfm	\tmp, \tmp, #16, #19		// cache line size encoding
-	mov	\reg, #4			// bytes per word
-	lsl	\reg, \reg, \tmp		// actual cache line size
-	.endm
-
-/*
- * icache_line_size - get the minimum I-cache line size from the CTR register.
- */
-	.macro	icache_line_size, reg, tmp
-	mrs	\tmp, ctr_el0			// read CTR
-	and	\tmp, \tmp, #0xf		// cache line size encoding
-	mov	\reg, #4			// bytes per word
-	lsl	\reg, \reg, \tmp		// actual cache line size
-	.endm
-
-/*
- * tcr_set_idmap_t0sz - update TCR.T0SZ so that we can load the ID map
- */
-	.macro	tcr_set_idmap_t0sz, valreg, tmpreg
-#ifndef CONFIG_ARM64_VA_BITS_48
-	ldr_l	\tmpreg, idmap_t0sz
-	bfi	\valreg, \tmpreg, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
-#endif
-	.endm
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index e4ee7bd..456c1c5 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -23,11 +23,8 @@
 #include <asm/assembler.h>
 #include <asm/asm-offsets.h>
 #include <asm/hwcap.h>
-#include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
 
-#include "proc-macros.S"
-
 #ifdef CONFIG_ARM64_64K_PAGES
 #define TCR_TG_FLAGS	TCR_TG0_64K | TCR_TG1_64K
 #else
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 14/15] arm64: kdump: enable kdump in the arm64 defconfig
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index c80d8a4..94ec44e 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -56,6 +56,7 @@ CONFIG_KSM=y
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_CMA=y
 CONFIG_KEXEC=y
+CONFIG_CRASH_DUMP=y
 CONFIG_CMDLINE="console=ttyAMA0"
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_COMPAT=y
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 13/15] arm64: kdump: update a kernel doc
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

This patch adds arch specific descriptions about kdump usage on arm64
to kdump.txt.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 Documentation/kdump/kdump.txt | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index bc4bd5a..7d3fad0 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -18,7 +18,7 @@ memory image to a dump file on the local disk, or across the network to
 a remote system.
 
 Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64,
-s390x and arm architectures.
+s390x, arm and arm64 architectures.
 
 When the system kernel boots, it reserves a small section of memory for
 the dump-capture kernel. This ensures that ongoing Direct Memory Access
@@ -249,6 +249,29 @@ Dump-capture kernel config options (Arch Dependent, arm)
 
     AUTO_ZRELADDR=y
 
+Dump-capture kernel config options (Arch Dependent, arm64)
+----------------------------------------------------------
+
+1) Disable symmetric multi-processing support under "Processor type and
+   features":
+
+   CONFIG_SMP=n
+
+   (If CONFIG_SMP=y, then specify maxcpus=1 on the kernel command line
+   when loading the dump-capture kernel, see section "Load the Dump-capture
+   Kernel".)
+
+2) The maximum memory size on the dump-capture kernel must be limited by
+   specifying:
+
+   mem=X[MG]
+
+   where X should be less than or equal to the size in "crashkernel="
+   boot parameter. Kexec-tools will automatically add this.
+
+3) Currently, kvm will not be enabled on the dump-capture kernel even
+   if it is configured.
+
 Extended crashkernel syntax
 ===========================
 
@@ -312,6 +335,8 @@ Boot into System Kernel
    any space below the alignment point may be overwritten by the dump-capture kernel,
    which means it is possible that the vmcore is not that precise as expected.
 
+   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
+   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
 
 Load the Dump-capture Kernel
 ============================
@@ -334,6 +359,8 @@ For s390x:
 	- Use image or bzImage
 For arm:
 	- Use zImage
+For arm64:
+	- Use vmlinux
 
 If you are using a uncompressed vmlinux image then use following command
 to load dump-capture kernel.
@@ -377,6 +404,9 @@ For s390x:
 For arm:
 	"1 maxcpus=1 reset_devices"
 
+For arm64:
+	"1 mem=X[MG] maxcpus=1 reset_devices"
+
 Notes on loading the dump-capture kernel:
 
 * By default, the ELF headers are stored in ELF64 format to support
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 12/15] arm64: kdump: add kdump support
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

On crash dump kernel, all the information about primary kernel's core
image is available in elf core header specified by "elfcorehdr=" boot
parameter. reserve_elfcorehdr() will set aside the region to avoid any
corruption by crash dump kernel.

Crash dump kernel will access the system memory of primary kernel via
copy_oldmem_page(), which reads one page by ioremap'ing it since it does
not reside in linear mapping on crash dump kernel.
Please note that we should add "mem=X[MG]" boot parameter to limit the
memory size and avoid the following assertion at ioremap():
	if (WARN_ON(pfn_valid(__phys_to_pfn(phys_addr))))
		return NULL;
when accessing any pages beyond the usable memories of crash dump kernel.

We also need our own elfcorehdr_read() here since the weak definition of
elfcorehdr_read() utilizes copy_oldmem_page() and will hit the assertion
above on arm64.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm64/Kconfig             | 12 +++++++
 arch/arm64/kernel/Makefile     |  1 +
 arch/arm64/kernel/crash_dump.c | 71 ++++++++++++++++++++++++++++++++++++++++++
 arch/arm64/mm/init.c           | 29 +++++++++++++++++
 4 files changed, 113 insertions(+)
 create mode 100644 arch/arm64/kernel/crash_dump.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index d9631ac..48b787b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -501,6 +501,18 @@ config KEXEC
 	  but it is independent of the system firmware.   And like a reboot
 	  you can start any kernel with it, not just Linux.
 
+config CRASH_DUMP
+	bool "Build kdump crash kernel"
+	help
+	  Generate crash dump after being started by kexec. This should
+	  be normally only set in special crash dump kernels which are
+	  loaded in the main kernel with kexec-tools into a specially
+	  reserved region and then later executed after a crash by
+	  kdump/kexec. The crash dump kernel must be compiled to a
+	  memory address not used by the main kernel.
+
+	  For more details see Documentation/kdump/kdump.txt
+
 config XEN_DOM0
 	def_bool y
 	depends on XEN
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 989ccd7..7ef9fa4 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -38,6 +38,7 @@ arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
 arm64-obj-$(CONFIG_ACPI)		+= acpi.o
 arm64-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o	\
 					   cpu-reset.o
+arm64-obj-$(CONFIG_CRASH_DUMP)		+= crash_dump.o
 
 obj-y					+= $(arm64-obj-y) vdso/
 obj-m					+= $(arm64-obj-m)
diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c
new file mode 100644
index 0000000..3d86c0a
--- /dev/null
+++ b/arch/arm64/kernel/crash_dump.c
@@ -0,0 +1,71 @@
+/*
+ * Routines for doing kexec-based kdump
+ *
+ * Copyright (C) 2014 Linaro Limited
+ * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/crash_dump.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+#include <linux/uaccess.h>
+#include <asm/memory.h>
+
+/**
+ * copy_oldmem_page() - copy one page from old kernel memory
+ * @pfn: page frame number to be copied
+ * @buf: buffer where the copied page is placed
+ * @csize: number of bytes to copy
+ * @offset: offset in bytes into the page
+ * @userbuf: if set, @buf is in a user address space
+ *
+ * This function copies one page from old kernel memory into buffer pointed by
+ * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
+ * copied or negative error in case of failure.
+ */
+ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+			 size_t csize, unsigned long offset,
+			 int userbuf)
+{
+	void *vaddr;
+
+	if (!csize)
+		return 0;
+
+	vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
+	if (!vaddr)
+		return -ENOMEM;
+
+	if (userbuf) {
+		if (copy_to_user(buf, vaddr + offset, csize)) {
+			iounmap(vaddr);
+			return -EFAULT;
+		}
+	} else {
+		memcpy(buf, vaddr + offset, csize);
+	}
+
+	iounmap(vaddr);
+
+	return csize;
+}
+
+/**
+ * elfcorehdr_read - read from ELF core header
+ * @buf: buffer where the data is placed
+ * @csize: number of bytes to read
+ * @ppos: address in the memory
+ *
+ * This function reads @count bytes from elf core header which exists
+ * on crash dump kernel's memory.
+ */
+ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
+{
+	memcpy(buf, phys_to_virt((phys_addr_t)*ppos), count);
+	return count;
+}
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index f33f201..ff8eeb4 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -35,6 +35,7 @@
 #include <linux/efi.h>
 #include <linux/swiotlb.h>
 #include <linux/kexec.h>
+#include <linux/crash_dump.h>
 
 #include <asm/fixmap.h>
 #include <asm/memory.h>
@@ -116,6 +117,31 @@ static void __init reserve_crashkernel(void)
 }
 #endif /* CONFIG_KEXEC */
 
+#ifdef CONFIG_CRASH_DUMP
+/*
+ * reserve_elfcorehdr() - reserves memory for elf core header
+ *
+ * This function reserves elf core header given in "elfcorehdr=" kernel
+ * command line parameter. This region contains all the information about
+ * primary kernel's core image and is used by a dump capture kernel to
+ * access the system memory on primary kernel.
+ */
+static void __init reserve_elfcorehdr(void)
+{
+	if (!elfcorehdr_size)
+		return;
+
+	if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
+		pr_warn("elfcorehdr is overlapped\n");
+		return;
+	}
+
+	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
+
+	pr_info("Reserving %lldKB of memory at %lldMB for elfcorehdr\n",
+		elfcorehdr_size >> 10, elfcorehdr_addr >> 20);
+}
+#endif /* CONFIG_CRASH_DUMP */
 /*
  * Return the maximum physical address for ZONE_DMA (DMA_BIT_MASK(32)). It
  * currently assumes that for memory starting above 4G, 32-bit devices will
@@ -223,6 +249,9 @@ void __init arm64_memblock_init(void)
 #ifdef CONFIG_KEXEC
 	reserve_crashkernel();
 #endif
+#ifdef CONFIG_CRASH_DUMP
+	reserve_elfcorehdr();
+#endif
 
 	early_init_fdt_scan_reserved_mem();
 
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 11/15] arm64: kdump: implement machine_crash_shutdown()
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

kdump calls machine_crash_shutdown() to shut down non-boot cpus and
save registers' status in per-cpu ELF notes before starting the crash
dump kernel. See kernel_kexec().

ipi_cpu_stop() is a bit modified and used to support this behavior.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm64/include/asm/kexec.h    | 34 +++++++++++++++++++++++++++++++++-
 arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++--
 arch/arm64/kernel/smp.c           | 16 ++++++++++++++--
 3 files changed, 76 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 46d63cd..555a955 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -30,6 +30,8 @@
 
 #if !defined(__ASSEMBLY__)
 
+extern bool in_crash_kexec;
+
 /**
  * crash_setup_regs() - save registers for the panic kernel
  *
@@ -40,7 +42,37 @@
 static inline void crash_setup_regs(struct pt_regs *newregs,
 				    struct pt_regs *oldregs)
 {
-	/* Empty routine needed to avoid build errors. */
+	if (oldregs) {
+		memcpy(newregs, oldregs, sizeof(*newregs));
+	} else {
+		__asm__ __volatile__ (
+			"stp	 x0,   x1, [%3, #16 *  0]\n"
+			"stp	 x2,   x3, [%3, #16 *  1]\n"
+			"stp	 x4,   x5, [%3, #16 *  2]\n"
+			"stp	 x6,   x7, [%3, #16 *  3]\n"
+			"stp	 x8,   x9, [%3, #16 *  4]\n"
+			"stp	x10,  x11, [%3, #16 *  5]\n"
+			"stp	x12,  x13, [%3, #16 *  6]\n"
+			"stp	x14,  x15, [%3, #16 *  7]\n"
+			"stp	x16,  x17, [%3, #16 *  8]\n"
+			"stp	x18,  x19, [%3, #16 *  9]\n"
+			"stp	x20,  x21, [%3, #16 * 10]\n"
+			"stp	x22,  x23, [%3, #16 * 11]\n"
+			"stp	x24,  x25, [%3, #16 * 12]\n"
+			"stp	x26,  x27, [%3, #16 * 13]\n"
+			"stp	x28,  x29, [%3, #16 * 14]\n"
+			"str	x30,	   [%3, #16 * 15]\n"
+			"mov	%0, sp\n"
+			"adr	%1, 1f\n"
+			"mrs	%2, spsr_el1\n"
+		"1:"
+			: "=r" (newregs->sp),
+			  "=r" (newregs->pc),
+			  "=r" (newregs->pstate)
+			: "r"  (&newregs->regs)
+			: "memory"
+		);
+	}
 }
 
 #endif /* !defined(__ASSEMBLY__) */
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index da28a26..d2d7e90 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -9,6 +9,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/kernel.h>
 #include <linux/kexec.h>
 #include <linux/of_fdt.h>
 #include <linux/slab.h>
@@ -23,6 +24,7 @@
 extern const unsigned char arm64_relocate_new_kernel[];
 extern const unsigned long arm64_relocate_new_kernel_size;
 
+bool in_crash_kexec;
 static unsigned long kimage_start;
 
 /**
@@ -203,13 +205,38 @@ void machine_kexec(struct kimage *kimage)
 	 */
 
 	cpu_soft_restart(virt_to_phys(cpu_reset),
-		is_hyp_mode_available(),
+		in_crash_kexec ? 0 : is_hyp_mode_available(),
 		reboot_code_buffer_phys, kimage->head, kimage_start);
 
 	BUG(); /* Should never get here. */
 }
 
+/**
+ * machine_crash_shutdown - shutdown non-boot cpus and save registers
+ */
 void machine_crash_shutdown(struct pt_regs *regs)
 {
-	/* Empty routine needed to avoid build errors. */
+	struct pt_regs dummy_regs;
+	int cpu;
+
+	local_irq_disable();
+
+	in_crash_kexec = true;
+
+	/*
+	 * clear and initialize the per-cpu info. This is necessary
+	 * because, otherwise, slots for offline cpus would never be
+	 * filled up. See smp_send_stop().
+	 */
+	memset(&dummy_regs, 0, sizeof(dummy_regs));
+	for_each_possible_cpu(cpu)
+		crash_save_cpu(&dummy_regs, cpu);
+
+	/* shutdown non-boot cpus */
+	smp_send_stop();
+
+	/* for boot cpu */
+	crash_save_cpu(regs, smp_processor_id());
+
+	pr_info("Starting crashdump kernel...\n");
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index dbdaacd..88aec66 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -37,6 +37,7 @@
 #include <linux/completion.h>
 #include <linux/of.h>
 #include <linux/irq_work.h>
+#include <linux/kexec.h>
 
 #include <asm/alternative.h>
 #include <asm/atomic.h>
@@ -54,6 +55,8 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
+#include "cpu-reset.h"
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
@@ -679,8 +682,12 @@ static DEFINE_RAW_SPINLOCK(stop_lock);
 /*
  * ipi_cpu_stop - handle IPI from smp_send_stop()
  */
-static void ipi_cpu_stop(unsigned int cpu)
+static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
 {
+#ifdef CONFIG_KEXEC
+	/* printing messages may slow down the shutdown. */
+	if (!in_crash_kexec)
+#endif
 	if (system_state == SYSTEM_BOOTING ||
 	    system_state == SYSTEM_RUNNING) {
 		raw_spin_lock(&stop_lock);
@@ -693,6 +700,11 @@ static void ipi_cpu_stop(unsigned int cpu)
 
 	local_irq_disable();
 
+#ifdef CONFIG_KEXEC
+	if (in_crash_kexec)
+		crash_save_cpu(regs, cpu);
+#endif /* CONFIG_KEXEC */
+
 	while (1)
 		cpu_relax();
 }
@@ -723,7 +735,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 
 	case IPI_CPU_STOP:
 		irq_enter();
-		ipi_cpu_stop(cpu);
+		ipi_cpu_stop(cpu, regs);
 		irq_exit();
 		break;
 
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 15/15] arm64: kdump: relax BUG_ON() if more than one cpus are still active
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

We should try best in case of kdump.
So even if not all secondary cpus have shut down, we do kdump anyway.
---
 arch/arm64/kernel/machine_kexec.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index d2d7e90..482aae7 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -148,7 +148,13 @@ void machine_kexec(struct kimage *kimage)
 	phys_addr_t reboot_code_buffer_phys;
 	void *reboot_code_buffer;
 
-	BUG_ON(num_online_cpus() > 1);
+	if (num_online_cpus() > 1) {
+		if (in_crash_kexec)
+			pr_warn("kdump might fail because %d cpus are still online\n",
+					num_online_cpus());
+		else
+			BUG();
+	}
 
 	reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
 	reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 10/15] arm64: kdump: reserve memory for crash dump kernel
  2015-11-06 19:14 ` Geoff Levand
@ 2015-11-06 19:14   ` Geoff Levand
  -1 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

On primary kernel, the memory region used by crash dump kernel must be
specified by "crashkernel=" boot parameter. reserve_crashkernel()
will allocate and reserve the region for later use.

User space tools will be able to find the region marked as "Crash kernel"
in /proc/iomem.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm64/kernel/setup.c |  7 +++++-
 arch/arm64/mm/init.c      | 54 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 2322479..9d085ac 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -32,7 +32,6 @@
 #include <linux/screen_info.h>
 #include <linux/init.h>
 #include <linux/kexec.h>
-#include <linux/crash_dump.h>
 #include <linux/root_dev.h>
 #include <linux/cpu.h>
 #include <linux/interrupt.h>
@@ -337,6 +336,12 @@ static void __init request_standard_resources(void)
 		    kernel_data.end <= res->end)
 			request_resource(res, &kernel_data);
 	}
+
+#ifdef CONFIG_KEXEC
+	/* User space tools will find "Crash kernel" region in /proc/iomem. */
+	if (crashk_res.end)
+		insert_resource(&iomem_resource, &crashk_res);
+#endif
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index f5c0680..f33f201 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -34,6 +34,7 @@
 #include <linux/dma-contiguous.h>
 #include <linux/efi.h>
 #include <linux/swiotlb.h>
+#include <linux/kexec.h>
 
 #include <asm/fixmap.h>
 #include <asm/memory.h>
@@ -66,6 +67,55 @@ static int __init early_initrd(char *p)
 early_param("initrd", early_initrd);
 #endif
 
+#ifdef CONFIG_KEXEC
+/*
+ * reserve_crashkernel() - reserves memory for crash kernel
+ *
+ * This function reserves memory area given in "crashkernel=" kernel command
+ * line parameter. The memory reserved is used by dump capture kernel when
+ * primary kernel is crashing.
+ */
+static void __init reserve_crashkernel(void)
+{
+	unsigned long long crash_size = 0, crash_base = 0;
+	int ret;
+
+	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
+				&crash_size, &crash_base);
+	if (ret)
+		return;
+
+	if (crash_base == 0) {
+		crash_base = memblock_alloc(crash_size, 1 << 21);
+		if (crash_base == 0) {
+			pr_warn("Unable to allocate crashkernel (size:%llx)\n",
+				crash_size);
+			return;
+		}
+	} else {
+		/* User specifies base address explicitly. */
+		if (!memblock_is_region_memory(crash_base, crash_size) ||
+			memblock_is_region_reserved(crash_base, crash_size)) {
+			pr_warn("crashkernel has wrong address or size\n");
+			return;
+		}
+
+		if (crash_base & ((1 << 21) - 1)) {
+			pr_warn("crashkernel base address is not 2MB aligned\n");
+			return;
+		}
+
+		memblock_reserve(crash_base, crash_size);
+	}
+
+	pr_info("Reserving %lldMB of memory@%lldMB for crashkernel\n",
+		crash_size >> 20, crash_base >> 20);
+
+	crashk_res.start = crash_base;
+	crashk_res.end = crash_base + crash_size - 1;
+}
+#endif /* CONFIG_KEXEC */
+
 /*
  * Return the maximum physical address for ZONE_DMA (DMA_BIT_MASK(32)). It
  * currently assumes that for memory starting above 4G, 32-bit devices will
@@ -170,6 +220,10 @@ void __init arm64_memblock_init(void)
 		memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
 #endif
 
+#ifdef CONFIG_KEXEC
+	reserve_crashkernel();
+#endif
+
 	early_init_fdt_scan_reserved_mem();
 
 	/* 4GB maximum for 32-bit only capable devices */
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 14/15] arm64: kdump: enable kdump in the arm64 defconfig
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index c80d8a4..94ec44e 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -56,6 +56,7 @@ CONFIG_KSM=y
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_CMA=y
 CONFIG_KEXEC=y
+CONFIG_CRASH_DUMP=y
 CONFIG_CMDLINE="console=ttyAMA0"
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_COMPAT=y
-- 
2.5.0



_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 13/15] arm64: kdump: update a kernel doc
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

This patch adds arch specific descriptions about kdump usage on arm64
to kdump.txt.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 Documentation/kdump/kdump.txt | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index bc4bd5a..7d3fad0 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -18,7 +18,7 @@ memory image to a dump file on the local disk, or across the network to
 a remote system.
 
 Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64,
-s390x and arm architectures.
+s390x, arm and arm64 architectures.
 
 When the system kernel boots, it reserves a small section of memory for
 the dump-capture kernel. This ensures that ongoing Direct Memory Access
@@ -249,6 +249,29 @@ Dump-capture kernel config options (Arch Dependent, arm)
 
     AUTO_ZRELADDR=y
 
+Dump-capture kernel config options (Arch Dependent, arm64)
+----------------------------------------------------------
+
+1) Disable symmetric multi-processing support under "Processor type and
+   features":
+
+   CONFIG_SMP=n
+
+   (If CONFIG_SMP=y, then specify maxcpus=1 on the kernel command line
+   when loading the dump-capture kernel, see section "Load the Dump-capture
+   Kernel".)
+
+2) The maximum memory size on the dump-capture kernel must be limited by
+   specifying:
+
+   mem=X[MG]
+
+   where X should be less than or equal to the size in "crashkernel="
+   boot parameter. Kexec-tools will automatically add this.
+
+3) Currently, kvm will not be enabled on the dump-capture kernel even
+   if it is configured.
+
 Extended crashkernel syntax
 ===========================
 
@@ -312,6 +335,8 @@ Boot into System Kernel
    any space below the alignment point may be overwritten by the dump-capture kernel,
    which means it is possible that the vmcore is not that precise as expected.
 
+   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
+   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
 
 Load the Dump-capture Kernel
 ============================
@@ -334,6 +359,8 @@ For s390x:
 	- Use image or bzImage
 For arm:
 	- Use zImage
+For arm64:
+	- Use vmlinux
 
 If you are using a uncompressed vmlinux image then use following command
 to load dump-capture kernel.
@@ -377,6 +404,9 @@ For s390x:
 For arm:
 	"1 maxcpus=1 reset_devices"
 
+For arm64:
+	"1 mem=X[MG] maxcpus=1 reset_devices"
+
 Notes on loading the dump-capture kernel:
 
 * By default, the ELF headers are stored in ELF64 format to support
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 12/15] arm64: kdump: add kdump support
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

On crash dump kernel, all the information about primary kernel's core
image is available in elf core header specified by "elfcorehdr=" boot
parameter. reserve_elfcorehdr() will set aside the region to avoid any
corruption by crash dump kernel.

Crash dump kernel will access the system memory of primary kernel via
copy_oldmem_page(), which reads one page by ioremap'ing it since it does
not reside in linear mapping on crash dump kernel.
Please note that we should add "mem=X[MG]" boot parameter to limit the
memory size and avoid the following assertion at ioremap():
	if (WARN_ON(pfn_valid(__phys_to_pfn(phys_addr))))
		return NULL;
when accessing any pages beyond the usable memories of crash dump kernel.

We also need our own elfcorehdr_read() here since the weak definition of
elfcorehdr_read() utilizes copy_oldmem_page() and will hit the assertion
above on arm64.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm64/Kconfig             | 12 +++++++
 arch/arm64/kernel/Makefile     |  1 +
 arch/arm64/kernel/crash_dump.c | 71 ++++++++++++++++++++++++++++++++++++++++++
 arch/arm64/mm/init.c           | 29 +++++++++++++++++
 4 files changed, 113 insertions(+)
 create mode 100644 arch/arm64/kernel/crash_dump.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index d9631ac..48b787b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -501,6 +501,18 @@ config KEXEC
 	  but it is independent of the system firmware.   And like a reboot
 	  you can start any kernel with it, not just Linux.
 
+config CRASH_DUMP
+	bool "Build kdump crash kernel"
+	help
+	  Generate crash dump after being started by kexec. This should
+	  be normally only set in special crash dump kernels which are
+	  loaded in the main kernel with kexec-tools into a specially
+	  reserved region and then later executed after a crash by
+	  kdump/kexec. The crash dump kernel must be compiled to a
+	  memory address not used by the main kernel.
+
+	  For more details see Documentation/kdump/kdump.txt
+
 config XEN_DOM0
 	def_bool y
 	depends on XEN
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 989ccd7..7ef9fa4 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -38,6 +38,7 @@ arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o
 arm64-obj-$(CONFIG_ACPI)		+= acpi.o
 arm64-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o	\
 					   cpu-reset.o
+arm64-obj-$(CONFIG_CRASH_DUMP)		+= crash_dump.o
 
 obj-y					+= $(arm64-obj-y) vdso/
 obj-m					+= $(arm64-obj-m)
diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c
new file mode 100644
index 0000000..3d86c0a
--- /dev/null
+++ b/arch/arm64/kernel/crash_dump.c
@@ -0,0 +1,71 @@
+/*
+ * Routines for doing kexec-based kdump
+ *
+ * Copyright (C) 2014 Linaro Limited
+ * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/crash_dump.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+#include <linux/uaccess.h>
+#include <asm/memory.h>
+
+/**
+ * copy_oldmem_page() - copy one page from old kernel memory
+ * @pfn: page frame number to be copied
+ * @buf: buffer where the copied page is placed
+ * @csize: number of bytes to copy
+ * @offset: offset in bytes into the page
+ * @userbuf: if set, @buf is in a user address space
+ *
+ * This function copies one page from old kernel memory into buffer pointed by
+ * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
+ * copied or negative error in case of failure.
+ */
+ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+			 size_t csize, unsigned long offset,
+			 int userbuf)
+{
+	void *vaddr;
+
+	if (!csize)
+		return 0;
+
+	vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
+	if (!vaddr)
+		return -ENOMEM;
+
+	if (userbuf) {
+		if (copy_to_user(buf, vaddr + offset, csize)) {
+			iounmap(vaddr);
+			return -EFAULT;
+		}
+	} else {
+		memcpy(buf, vaddr + offset, csize);
+	}
+
+	iounmap(vaddr);
+
+	return csize;
+}
+
+/**
+ * elfcorehdr_read - read from ELF core header
+ * @buf: buffer where the data is placed
+ * @csize: number of bytes to read
+ * @ppos: address in the memory
+ *
+ * This function reads @count bytes from elf core header which exists
+ * on crash dump kernel's memory.
+ */
+ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
+{
+	memcpy(buf, phys_to_virt((phys_addr_t)*ppos), count);
+	return count;
+}
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index f33f201..ff8eeb4 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -35,6 +35,7 @@
 #include <linux/efi.h>
 #include <linux/swiotlb.h>
 #include <linux/kexec.h>
+#include <linux/crash_dump.h>
 
 #include <asm/fixmap.h>
 #include <asm/memory.h>
@@ -116,6 +117,31 @@ static void __init reserve_crashkernel(void)
 }
 #endif /* CONFIG_KEXEC */
 
+#ifdef CONFIG_CRASH_DUMP
+/*
+ * reserve_elfcorehdr() - reserves memory for elf core header
+ *
+ * This function reserves elf core header given in "elfcorehdr=" kernel
+ * command line parameter. This region contains all the information about
+ * primary kernel's core image and is used by a dump capture kernel to
+ * access the system memory on primary kernel.
+ */
+static void __init reserve_elfcorehdr(void)
+{
+	if (!elfcorehdr_size)
+		return;
+
+	if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
+		pr_warn("elfcorehdr is overlapped\n");
+		return;
+	}
+
+	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
+
+	pr_info("Reserving %lldKB of memory at %lldMB for elfcorehdr\n",
+		elfcorehdr_size >> 10, elfcorehdr_addr >> 20);
+}
+#endif /* CONFIG_CRASH_DUMP */
 /*
  * Return the maximum physical address for ZONE_DMA (DMA_BIT_MASK(32)). It
  * currently assumes that for memory starting above 4G, 32-bit devices will
@@ -223,6 +249,9 @@ void __init arm64_memblock_init(void)
 #ifdef CONFIG_KEXEC
 	reserve_crashkernel();
 #endif
+#ifdef CONFIG_CRASH_DUMP
+	reserve_elfcorehdr();
+#endif
 
 	early_init_fdt_scan_reserved_mem();
 
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 11/15] arm64: kdump: implement machine_crash_shutdown()
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

kdump calls machine_crash_shutdown() to shut down non-boot cpus and
save registers' status in per-cpu ELF notes before starting the crash
dump kernel. See kernel_kexec().

ipi_cpu_stop() is a bit modified and used to support this behavior.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm64/include/asm/kexec.h    | 34 +++++++++++++++++++++++++++++++++-
 arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++--
 arch/arm64/kernel/smp.c           | 16 ++++++++++++++--
 3 files changed, 76 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 46d63cd..555a955 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -30,6 +30,8 @@
 
 #if !defined(__ASSEMBLY__)
 
+extern bool in_crash_kexec;
+
 /**
  * crash_setup_regs() - save registers for the panic kernel
  *
@@ -40,7 +42,37 @@
 static inline void crash_setup_regs(struct pt_regs *newregs,
 				    struct pt_regs *oldregs)
 {
-	/* Empty routine needed to avoid build errors. */
+	if (oldregs) {
+		memcpy(newregs, oldregs, sizeof(*newregs));
+	} else {
+		__asm__ __volatile__ (
+			"stp	 x0,   x1, [%3, #16 *  0]\n"
+			"stp	 x2,   x3, [%3, #16 *  1]\n"
+			"stp	 x4,   x5, [%3, #16 *  2]\n"
+			"stp	 x6,   x7, [%3, #16 *  3]\n"
+			"stp	 x8,   x9, [%3, #16 *  4]\n"
+			"stp	x10,  x11, [%3, #16 *  5]\n"
+			"stp	x12,  x13, [%3, #16 *  6]\n"
+			"stp	x14,  x15, [%3, #16 *  7]\n"
+			"stp	x16,  x17, [%3, #16 *  8]\n"
+			"stp	x18,  x19, [%3, #16 *  9]\n"
+			"stp	x20,  x21, [%3, #16 * 10]\n"
+			"stp	x22,  x23, [%3, #16 * 11]\n"
+			"stp	x24,  x25, [%3, #16 * 12]\n"
+			"stp	x26,  x27, [%3, #16 * 13]\n"
+			"stp	x28,  x29, [%3, #16 * 14]\n"
+			"str	x30,	   [%3, #16 * 15]\n"
+			"mov	%0, sp\n"
+			"adr	%1, 1f\n"
+			"mrs	%2, spsr_el1\n"
+		"1:"
+			: "=r" (newregs->sp),
+			  "=r" (newregs->pc),
+			  "=r" (newregs->pstate)
+			: "r"  (&newregs->regs)
+			: "memory"
+		);
+	}
 }
 
 #endif /* !defined(__ASSEMBLY__) */
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index da28a26..d2d7e90 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -9,6 +9,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/kernel.h>
 #include <linux/kexec.h>
 #include <linux/of_fdt.h>
 #include <linux/slab.h>
@@ -23,6 +24,7 @@
 extern const unsigned char arm64_relocate_new_kernel[];
 extern const unsigned long arm64_relocate_new_kernel_size;
 
+bool in_crash_kexec;
 static unsigned long kimage_start;
 
 /**
@@ -203,13 +205,38 @@ void machine_kexec(struct kimage *kimage)
 	 */
 
 	cpu_soft_restart(virt_to_phys(cpu_reset),
-		is_hyp_mode_available(),
+		in_crash_kexec ? 0 : is_hyp_mode_available(),
 		reboot_code_buffer_phys, kimage->head, kimage_start);
 
 	BUG(); /* Should never get here. */
 }
 
+/**
+ * machine_crash_shutdown - shutdown non-boot cpus and save registers
+ */
 void machine_crash_shutdown(struct pt_regs *regs)
 {
-	/* Empty routine needed to avoid build errors. */
+	struct pt_regs dummy_regs;
+	int cpu;
+
+	local_irq_disable();
+
+	in_crash_kexec = true;
+
+	/*
+	 * clear and initialize the per-cpu info. This is necessary
+	 * because, otherwise, slots for offline cpus would never be
+	 * filled up. See smp_send_stop().
+	 */
+	memset(&dummy_regs, 0, sizeof(dummy_regs));
+	for_each_possible_cpu(cpu)
+		crash_save_cpu(&dummy_regs, cpu);
+
+	/* shutdown non-boot cpus */
+	smp_send_stop();
+
+	/* for boot cpu */
+	crash_save_cpu(regs, smp_processor_id());
+
+	pr_info("Starting crashdump kernel...\n");
 }
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index dbdaacd..88aec66 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -37,6 +37,7 @@
 #include <linux/completion.h>
 #include <linux/of.h>
 #include <linux/irq_work.h>
+#include <linux/kexec.h>
 
 #include <asm/alternative.h>
 #include <asm/atomic.h>
@@ -54,6 +55,8 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
+#include "cpu-reset.h"
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>
 
@@ -679,8 +682,12 @@ static DEFINE_RAW_SPINLOCK(stop_lock);
 /*
  * ipi_cpu_stop - handle IPI from smp_send_stop()
  */
-static void ipi_cpu_stop(unsigned int cpu)
+static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
 {
+#ifdef CONFIG_KEXEC
+	/* printing messages may slow down the shutdown. */
+	if (!in_crash_kexec)
+#endif
 	if (system_state == SYSTEM_BOOTING ||
 	    system_state == SYSTEM_RUNNING) {
 		raw_spin_lock(&stop_lock);
@@ -693,6 +700,11 @@ static void ipi_cpu_stop(unsigned int cpu)
 
 	local_irq_disable();
 
+#ifdef CONFIG_KEXEC
+	if (in_crash_kexec)
+		crash_save_cpu(regs, cpu);
+#endif /* CONFIG_KEXEC */
+
 	while (1)
 		cpu_relax();
 }
@@ -723,7 +735,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 
 	case IPI_CPU_STOP:
 		irq_enter();
-		ipi_cpu_stop(cpu);
+		ipi_cpu_stop(cpu, regs);
 		irq_exit();
 		break;
 
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 10/15] arm64: kdump: reserve memory for crash dump kernel
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

On primary kernel, the memory region used by crash dump kernel must be
specified by "crashkernel=" boot parameter. reserve_crashkernel()
will allocate and reserve the region for later use.

User space tools will be able to find the region marked as "Crash kernel"
in /proc/iomem.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 arch/arm64/kernel/setup.c |  7 +++++-
 arch/arm64/mm/init.c      | 54 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 2322479..9d085ac 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -32,7 +32,6 @@
 #include <linux/screen_info.h>
 #include <linux/init.h>
 #include <linux/kexec.h>
-#include <linux/crash_dump.h>
 #include <linux/root_dev.h>
 #include <linux/cpu.h>
 #include <linux/interrupt.h>
@@ -337,6 +336,12 @@ static void __init request_standard_resources(void)
 		    kernel_data.end <= res->end)
 			request_resource(res, &kernel_data);
 	}
+
+#ifdef CONFIG_KEXEC
+	/* User space tools will find "Crash kernel" region in /proc/iomem. */
+	if (crashk_res.end)
+		insert_resource(&iomem_resource, &crashk_res);
+#endif
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index f5c0680..f33f201 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -34,6 +34,7 @@
 #include <linux/dma-contiguous.h>
 #include <linux/efi.h>
 #include <linux/swiotlb.h>
+#include <linux/kexec.h>
 
 #include <asm/fixmap.h>
 #include <asm/memory.h>
@@ -66,6 +67,55 @@ static int __init early_initrd(char *p)
 early_param("initrd", early_initrd);
 #endif
 
+#ifdef CONFIG_KEXEC
+/*
+ * reserve_crashkernel() - reserves memory for crash kernel
+ *
+ * This function reserves memory area given in "crashkernel=" kernel command
+ * line parameter. The memory reserved is used by dump capture kernel when
+ * primary kernel is crashing.
+ */
+static void __init reserve_crashkernel(void)
+{
+	unsigned long long crash_size = 0, crash_base = 0;
+	int ret;
+
+	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
+				&crash_size, &crash_base);
+	if (ret)
+		return;
+
+	if (crash_base == 0) {
+		crash_base = memblock_alloc(crash_size, 1 << 21);
+		if (crash_base == 0) {
+			pr_warn("Unable to allocate crashkernel (size:%llx)\n",
+				crash_size);
+			return;
+		}
+	} else {
+		/* User specifies base address explicitly. */
+		if (!memblock_is_region_memory(crash_base, crash_size) ||
+			memblock_is_region_reserved(crash_base, crash_size)) {
+			pr_warn("crashkernel has wrong address or size\n");
+			return;
+		}
+
+		if (crash_base & ((1 << 21) - 1)) {
+			pr_warn("crashkernel base address is not 2MB aligned\n");
+			return;
+		}
+
+		memblock_reserve(crash_base, crash_size);
+	}
+
+	pr_info("Reserving %lldMB of memory at %lldMB for crashkernel\n",
+		crash_size >> 20, crash_base >> 20);
+
+	crashk_res.start = crash_base;
+	crashk_res.end = crash_base + crash_size - 1;
+}
+#endif /* CONFIG_KEXEC */
+
 /*
  * Return the maximum physical address for ZONE_DMA (DMA_BIT_MASK(32)). It
  * currently assumes that for memory starting above 4G, 32-bit devices will
@@ -170,6 +220,10 @@ void __init arm64_memblock_init(void)
 		memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
 #endif
 
+#ifdef CONFIG_KEXEC
+	reserve_crashkernel();
+#endif
+
 	early_init_fdt_scan_reserved_mem();
 
 	/* 4GB maximum for 32-bit only capable devices */
-- 
2.5.0



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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 15/15] arm64: kdump: relax BUG_ON() if more than one cpus are still active
@ 2015-11-06 19:14   ` Geoff Levand
  0 siblings, 0 replies; 36+ messages in thread
From: Geoff Levand @ 2015-11-06 19:14 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: Mark Rutland, marc.zyngier, kexec, AKASHI Takahiro,
	christoffer.dall, linux-arm-kernel

From: AKASHI Takahiro <takahiro.akashi@linaro.org>

We should try best in case of kdump.
So even if not all secondary cpus have shut down, we do kdump anyway.
---
 arch/arm64/kernel/machine_kexec.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index d2d7e90..482aae7 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -148,7 +148,13 @@ void machine_kexec(struct kimage *kimage)
 	phys_addr_t reboot_code_buffer_phys;
 	void *reboot_code_buffer;
 
-	BUG_ON(num_online_cpus() > 1);
+	if (num_online_cpus() > 1) {
+		if (in_crash_kexec)
+			pr_warn("kdump might fail because %d cpus are still online\n",
+					num_online_cpus());
+		else
+			BUG();
+	}
 
 	reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
 	reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
-- 
2.5.0


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^ permalink raw reply related	[flat|nested] 36+ messages in thread
* [PATCH 11/15] arm64: kdump: implement machine_crash_shutdown()
  2015-11-06 19:14   ` Geoff Levand
@ 2015-11-10  1:23     ` AKASHI Takahiro
  -1 siblings, 0 replies; 36+ messages in thread
From: AKASHI Takahiro @ 2015-11-10  1:23 UTC (permalink / raw)
  To: linux-arm-kernel

On 11/07/2015 04:14 AM, Geoff Levand wrote:
> From: AKASHI Takahiro <takahiro.akashi@linaro.org>
>
> kdump calls machine_crash_shutdown() to shut down non-boot cpus and
> save registers' status in per-cpu ELF notes before starting the crash
> dump kernel. See kernel_kexec().
>
> ipi_cpu_stop() is a bit modified and used to support this behavior.

I've got some concerns of using ipi_cpu_stop().

> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
>   arch/arm64/include/asm/kexec.h    | 34 +++++++++++++++++++++++++++++++++-
>   arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++--
>   arch/arm64/kernel/smp.c           | 16 ++++++++++++++--
>   3 files changed, 76 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index 46d63cd..555a955 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -30,6 +30,8 @@
>
>   #if !defined(__ASSEMBLY__)
>
> +extern bool in_crash_kexec;
> +
>   /**
>    * crash_setup_regs() - save registers for the panic kernel
>    *
> @@ -40,7 +42,37 @@
>   static inline void crash_setup_regs(struct pt_regs *newregs,
>   				    struct pt_regs *oldregs)
>   {
> -	/* Empty routine needed to avoid build errors. */
> +	if (oldregs) {
> +		memcpy(newregs, oldregs, sizeof(*newregs));
> +	} else {
> +		__asm__ __volatile__ (
> +			"stp	 x0,   x1, [%3, #16 *  0]\n"
> +			"stp	 x2,   x3, [%3, #16 *  1]\n"
> +			"stp	 x4,   x5, [%3, #16 *  2]\n"
> +			"stp	 x6,   x7, [%3, #16 *  3]\n"
> +			"stp	 x8,   x9, [%3, #16 *  4]\n"
> +			"stp	x10,  x11, [%3, #16 *  5]\n"
> +			"stp	x12,  x13, [%3, #16 *  6]\n"
> +			"stp	x14,  x15, [%3, #16 *  7]\n"
> +			"stp	x16,  x17, [%3, #16 *  8]\n"
> +			"stp	x18,  x19, [%3, #16 *  9]\n"
> +			"stp	x20,  x21, [%3, #16 * 10]\n"
> +			"stp	x22,  x23, [%3, #16 * 11]\n"
> +			"stp	x24,  x25, [%3, #16 * 12]\n"
> +			"stp	x26,  x27, [%3, #16 * 13]\n"
> +			"stp	x28,  x29, [%3, #16 * 14]\n"
> +			"str	x30,	   [%3, #16 * 15]\n"
> +			"mov	%0, sp\n"
> +			"adr	%1, 1f\n"
> +			"mrs	%2, spsr_el1\n"
> +		"1:"
> +			: "=r" (newregs->sp),
> +			  "=r" (newregs->pc),
> +			  "=r" (newregs->pstate)
> +			: "r"  (&newregs->regs)
> +			: "memory"
> +		);
> +	}
>   }
>
>   #endif /* !defined(__ASSEMBLY__) */
> diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
> index da28a26..d2d7e90 100644
> --- a/arch/arm64/kernel/machine_kexec.c
> +++ b/arch/arm64/kernel/machine_kexec.c
> @@ -9,6 +9,7 @@
>    * published by the Free Software Foundation.
>    */
>
> +#include <linux/kernel.h>
>   #include <linux/kexec.h>
>   #include <linux/of_fdt.h>
>   #include <linux/slab.h>
> @@ -23,6 +24,7 @@
>   extern const unsigned char arm64_relocate_new_kernel[];
>   extern const unsigned long arm64_relocate_new_kernel_size;
>
> +bool in_crash_kexec;
>   static unsigned long kimage_start;
>
>   /**
> @@ -203,13 +205,38 @@ void machine_kexec(struct kimage *kimage)
>   	 */
>
>   	cpu_soft_restart(virt_to_phys(cpu_reset),
> -		is_hyp_mode_available(),
> +		in_crash_kexec ? 0 : is_hyp_mode_available(),
>   		reboot_code_buffer_phys, kimage->head, kimage_start);
>
>   	BUG(); /* Should never get here. */
>   }
>
> +/**
> + * machine_crash_shutdown - shutdown non-boot cpus and save registers
> + */
>   void machine_crash_shutdown(struct pt_regs *regs)
>   {
> -	/* Empty routine needed to avoid build errors. */
> +	struct pt_regs dummy_regs;
> +	int cpu;
> +
> +	local_irq_disable();
> +
> +	in_crash_kexec = true;
> +
> +	/*
> +	 * clear and initialize the per-cpu info. This is necessary
> +	 * because, otherwise, slots for offline cpus would never be
> +	 * filled up. See smp_send_stop().
> +	 */
> +	memset(&dummy_regs, 0, sizeof(dummy_regs));
> +	for_each_possible_cpu(cpu)
> +		crash_save_cpu(&dummy_regs, cpu);
> +
> +	/* shutdown non-boot cpus */
> +	smp_send_stop();
> +
> +	/* for boot cpu */
> +	crash_save_cpu(regs, smp_processor_id());
> +
> +	pr_info("Starting crashdump kernel...\n");
>   }
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index dbdaacd..88aec66 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -37,6 +37,7 @@
>   #include <linux/completion.h>
>   #include <linux/of.h>
>   #include <linux/irq_work.h>
> +#include <linux/kexec.h>
>
>   #include <asm/alternative.h>
>   #include <asm/atomic.h>
> @@ -54,6 +55,8 @@
>   #include <asm/ptrace.h>
>   #include <asm/virt.h>
>
> +#include "cpu-reset.h"
> +
>   #define CREATE_TRACE_POINTS
>   #include <trace/events/ipi.h>
>
> @@ -679,8 +682,12 @@ static DEFINE_RAW_SPINLOCK(stop_lock);
>   /*
>    * ipi_cpu_stop - handle IPI from smp_send_stop()
>    */
> -static void ipi_cpu_stop(unsigned int cpu)
> +static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
>   {
> +#ifdef CONFIG_KEXEC
> +	/* printing messages may slow down the shutdown. */
> +	if (!in_crash_kexec)
> +#endif
>   	if (system_state == SYSTEM_BOOTING ||
>   	    system_state == SYSTEM_RUNNING) {
>   		raw_spin_lock(&stop_lock);
> @@ -693,6 +700,11 @@ static void ipi_cpu_stop(unsigned int cpu)
>
>   	local_irq_disable();
>
> +#ifdef CONFIG_KEXEC
> +	if (in_crash_kexec)
> +		crash_save_cpu(regs, cpu);
> +#endif /* CONFIG_KEXEC */
> +
>   	while (1)
>   		cpu_relax();
>   }

cpu_relax() is defined as asm("yield"), and this puts all but boot cpu into
a infinite loop of nop (actually, whether nop or other depends on hw implementation).
Thus all the secondary cpus are still running busy loop even after crash dump kernel
has started up, and the chip can potentially get overheated.
I ran into this situation when I tested the code on Hikey, and the system was
forced to be shut down by thermal driver.

So I'd like to modify the code a bit like:
if (in_crash_kernel {
     crash_save_cpu(regs, cpu);
     while (1)
         asm("wfi"); /* irq is disabled here. */
}

Does this make sense?

-Takahiro AKASHI

> @@ -723,7 +735,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
>
>   	case IPI_CPU_STOP:
>   		irq_enter();
> -		ipi_cpu_stop(cpu);
> +		ipi_cpu_stop(cpu, regs);
>   		irq_exit();
>   		break;
>
>

^ permalink raw reply	[flat|nested] 36+ messages in thread
* Re: [PATCH 11/15] arm64: kdump: implement machine_crash_shutdown()
@ 2015-11-10  1:23     ` AKASHI Takahiro
  0 siblings, 0 replies; 36+ messages in thread
From: AKASHI Takahiro @ 2015-11-10  1:23 UTC (permalink / raw)
  To: Geoff Levand, Catalin Marinas, Will Deacon
  Cc: marc.zyngier, Mark Rutland, kexec, linux-arm-kernel, christoffer.dall

On 11/07/2015 04:14 AM, Geoff Levand wrote:
> From: AKASHI Takahiro <takahiro.akashi@linaro.org>
>
> kdump calls machine_crash_shutdown() to shut down non-boot cpus and
> save registers' status in per-cpu ELF notes before starting the crash
> dump kernel. See kernel_kexec().
>
> ipi_cpu_stop() is a bit modified and used to support this behavior.

I've got some concerns of using ipi_cpu_stop().

> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
>   arch/arm64/include/asm/kexec.h    | 34 +++++++++++++++++++++++++++++++++-
>   arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++--
>   arch/arm64/kernel/smp.c           | 16 ++++++++++++++--
>   3 files changed, 76 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index 46d63cd..555a955 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -30,6 +30,8 @@
>
>   #if !defined(__ASSEMBLY__)
>
> +extern bool in_crash_kexec;
> +
>   /**
>    * crash_setup_regs() - save registers for the panic kernel
>    *
> @@ -40,7 +42,37 @@
>   static inline void crash_setup_regs(struct pt_regs *newregs,
>   				    struct pt_regs *oldregs)
>   {
> -	/* Empty routine needed to avoid build errors. */
> +	if (oldregs) {
> +		memcpy(newregs, oldregs, sizeof(*newregs));
> +	} else {
> +		__asm__ __volatile__ (
> +			"stp	 x0,   x1, [%3, #16 *  0]\n"
> +			"stp	 x2,   x3, [%3, #16 *  1]\n"
> +			"stp	 x4,   x5, [%3, #16 *  2]\n"
> +			"stp	 x6,   x7, [%3, #16 *  3]\n"
> +			"stp	 x8,   x9, [%3, #16 *  4]\n"
> +			"stp	x10,  x11, [%3, #16 *  5]\n"
> +			"stp	x12,  x13, [%3, #16 *  6]\n"
> +			"stp	x14,  x15, [%3, #16 *  7]\n"
> +			"stp	x16,  x17, [%3, #16 *  8]\n"
> +			"stp	x18,  x19, [%3, #16 *  9]\n"
> +			"stp	x20,  x21, [%3, #16 * 10]\n"
> +			"stp	x22,  x23, [%3, #16 * 11]\n"
> +			"stp	x24,  x25, [%3, #16 * 12]\n"
> +			"stp	x26,  x27, [%3, #16 * 13]\n"
> +			"stp	x28,  x29, [%3, #16 * 14]\n"
> +			"str	x30,	   [%3, #16 * 15]\n"
> +			"mov	%0, sp\n"
> +			"adr	%1, 1f\n"
> +			"mrs	%2, spsr_el1\n"
> +		"1:"
> +			: "=r" (newregs->sp),
> +			  "=r" (newregs->pc),
> +			  "=r" (newregs->pstate)
> +			: "r"  (&newregs->regs)
> +			: "memory"
> +		);
> +	}
>   }
>
>   #endif /* !defined(__ASSEMBLY__) */
> diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
> index da28a26..d2d7e90 100644
> --- a/arch/arm64/kernel/machine_kexec.c
> +++ b/arch/arm64/kernel/machine_kexec.c
> @@ -9,6 +9,7 @@
>    * published by the Free Software Foundation.
>    */
>
> +#include <linux/kernel.h>
>   #include <linux/kexec.h>
>   #include <linux/of_fdt.h>
>   #include <linux/slab.h>
> @@ -23,6 +24,7 @@
>   extern const unsigned char arm64_relocate_new_kernel[];
>   extern const unsigned long arm64_relocate_new_kernel_size;
>
> +bool in_crash_kexec;
>   static unsigned long kimage_start;
>
>   /**
> @@ -203,13 +205,38 @@ void machine_kexec(struct kimage *kimage)
>   	 */
>
>   	cpu_soft_restart(virt_to_phys(cpu_reset),
> -		is_hyp_mode_available(),
> +		in_crash_kexec ? 0 : is_hyp_mode_available(),
>   		reboot_code_buffer_phys, kimage->head, kimage_start);
>
>   	BUG(); /* Should never get here. */
>   }
>
> +/**
> + * machine_crash_shutdown - shutdown non-boot cpus and save registers
> + */
>   void machine_crash_shutdown(struct pt_regs *regs)
>   {
> -	/* Empty routine needed to avoid build errors. */
> +	struct pt_regs dummy_regs;
> +	int cpu;
> +
> +	local_irq_disable();
> +
> +	in_crash_kexec = true;
> +
> +	/*
> +	 * clear and initialize the per-cpu info. This is necessary
> +	 * because, otherwise, slots for offline cpus would never be
> +	 * filled up. See smp_send_stop().
> +	 */
> +	memset(&dummy_regs, 0, sizeof(dummy_regs));
> +	for_each_possible_cpu(cpu)
> +		crash_save_cpu(&dummy_regs, cpu);
> +
> +	/* shutdown non-boot cpus */
> +	smp_send_stop();
> +
> +	/* for boot cpu */
> +	crash_save_cpu(regs, smp_processor_id());
> +
> +	pr_info("Starting crashdump kernel...\n");
>   }
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index dbdaacd..88aec66 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -37,6 +37,7 @@
>   #include <linux/completion.h>
>   #include <linux/of.h>
>   #include <linux/irq_work.h>
> +#include <linux/kexec.h>
>
>   #include <asm/alternative.h>
>   #include <asm/atomic.h>
> @@ -54,6 +55,8 @@
>   #include <asm/ptrace.h>
>   #include <asm/virt.h>
>
> +#include "cpu-reset.h"
> +
>   #define CREATE_TRACE_POINTS
>   #include <trace/events/ipi.h>
>
> @@ -679,8 +682,12 @@ static DEFINE_RAW_SPINLOCK(stop_lock);
>   /*
>    * ipi_cpu_stop - handle IPI from smp_send_stop()
>    */
> -static void ipi_cpu_stop(unsigned int cpu)
> +static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
>   {
> +#ifdef CONFIG_KEXEC
> +	/* printing messages may slow down the shutdown. */
> +	if (!in_crash_kexec)
> +#endif
>   	if (system_state == SYSTEM_BOOTING ||
>   	    system_state == SYSTEM_RUNNING) {
>   		raw_spin_lock(&stop_lock);
> @@ -693,6 +700,11 @@ static void ipi_cpu_stop(unsigned int cpu)
>
>   	local_irq_disable();
>
> +#ifdef CONFIG_KEXEC
> +	if (in_crash_kexec)
> +		crash_save_cpu(regs, cpu);
> +#endif /* CONFIG_KEXEC */
> +
>   	while (1)
>   		cpu_relax();
>   }

cpu_relax() is defined as asm("yield"), and this puts all but boot cpu into
a infinite loop of nop (actually, whether nop or other depends on hw implementation).
Thus all the secondary cpus are still running busy loop even after crash dump kernel
has started up, and the chip can potentially get overheated.
I ran into this situation when I tested the code on Hikey, and the system was
forced to be shut down by thermal driver.

So I'd like to modify the code a bit like:
if (in_crash_kernel {
     crash_save_cpu(regs, cpu);
     while (1)
         asm("wfi"); /* irq is disabled here. */
}

Does this make sense?

-Takahiro AKASHI

> @@ -723,7 +735,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
>
>   	case IPI_CPU_STOP:
>   		irq_enter();
> -		ipi_cpu_stop(cpu);
> +		ipi_cpu_stop(cpu, regs);
>   		irq_exit();
>   		break;
>
>

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 36+ messages in thread
* [PATCH 11/15] arm64: kdump: implement machine_crash_shutdown()
  2015-11-10  1:23     ` AKASHI Takahiro
@ 2015-11-10  9:54       ` Will Deacon
  -1 siblings, 0 replies; 36+ messages in thread
From: Will Deacon @ 2015-11-10  9:54 UTC (permalink / raw)
  To: linux-arm-kernel

On Tue, Nov 10, 2015 at 10:23:56AM +0900, AKASHI Takahiro wrote:
> On 11/07/2015 04:14 AM, Geoff Levand wrote:
> >From: AKASHI Takahiro <takahiro.akashi@linaro.org>
> >
> >kdump calls machine_crash_shutdown() to shut down non-boot cpus and
> >save registers' status in per-cpu ELF notes before starting the crash
> >dump kernel. See kernel_kexec().
> >
> >ipi_cpu_stop() is a bit modified and used to support this behavior.
> 
> I've got some concerns of using ipi_cpu_stop().
> 
> >Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> >---
> >  arch/arm64/include/asm/kexec.h    | 34 +++++++++++++++++++++++++++++++++-
> >  arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++--
> >  arch/arm64/kernel/smp.c           | 16 ++++++++++++++--
> >  3 files changed, 76 insertions(+), 5 deletions(-)

[...]

> >diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> >index dbdaacd..88aec66 100644
> >--- a/arch/arm64/kernel/smp.c
> >+++ b/arch/arm64/kernel/smp.c
> >@@ -37,6 +37,7 @@
> >  #include <linux/completion.h>
> >  #include <linux/of.h>
> >  #include <linux/irq_work.h>
> >+#include <linux/kexec.h>
> >
> >  #include <asm/alternative.h>
> >  #include <asm/atomic.h>
> >@@ -54,6 +55,8 @@
> >  #include <asm/ptrace.h>
> >  #include <asm/virt.h>
> >
> >+#include "cpu-reset.h"
> >+
> >  #define CREATE_TRACE_POINTS
> >  #include <trace/events/ipi.h>
> >
> >@@ -679,8 +682,12 @@ static DEFINE_RAW_SPINLOCK(stop_lock);
> >  /*
> >   * ipi_cpu_stop - handle IPI from smp_send_stop()
> >   */
> >-static void ipi_cpu_stop(unsigned int cpu)
> >+static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
> >  {
> >+#ifdef CONFIG_KEXEC
> >+	/* printing messages may slow down the shutdown. */
> >+	if (!in_crash_kexec)
> >+#endif
> >  	if (system_state == SYSTEM_BOOTING ||
> >  	    system_state == SYSTEM_RUNNING) {
> >  		raw_spin_lock(&stop_lock);
> >@@ -693,6 +700,11 @@ static void ipi_cpu_stop(unsigned int cpu)
> >
> >  	local_irq_disable();
> >
> >+#ifdef CONFIG_KEXEC
> >+	if (in_crash_kexec)
> >+		crash_save_cpu(regs, cpu);
> >+#endif /* CONFIG_KEXEC */
> >+
> >  	while (1)
> >  		cpu_relax();
> >  }
> 
> cpu_relax() is defined as asm("yield"), and this puts all but boot cpu into
> a infinite loop of nop (actually, whether nop or other depends on hw implementation).
> Thus all the secondary cpus are still running busy loop even after crash dump kernel
> has started up, and the chip can potentially get overheated.
> I ran into this situation when I tested the code on Hikey, and the system was
> forced to be shut down by thermal driver.
> 
> So I'd like to modify the code a bit like:
> if (in_crash_kernel {
>     crash_save_cpu(regs, cpu);
>     while (1)
>         asm("wfi"); /* irq is disabled here. */
> }
> 
> Does this make sense?

It would be even better if we could hotplug them off.

Will

^ permalink raw reply	[flat|nested] 36+ messages in thread
* Re: [PATCH 11/15] arm64: kdump: implement machine_crash_shutdown()
@ 2015-11-10  9:54       ` Will Deacon
  0 siblings, 0 replies; 36+ messages in thread
From: Will Deacon @ 2015-11-10  9:54 UTC (permalink / raw)
  To: AKASHI Takahiro
  Cc: Mark Rutland, Geoff Levand, Catalin Marinas, kexec, marc.zyngier,
	linux-arm-kernel, christoffer.dall

On Tue, Nov 10, 2015 at 10:23:56AM +0900, AKASHI Takahiro wrote:
> On 11/07/2015 04:14 AM, Geoff Levand wrote:
> >From: AKASHI Takahiro <takahiro.akashi@linaro.org>
> >
> >kdump calls machine_crash_shutdown() to shut down non-boot cpus and
> >save registers' status in per-cpu ELF notes before starting the crash
> >dump kernel. See kernel_kexec().
> >
> >ipi_cpu_stop() is a bit modified and used to support this behavior.
> 
> I've got some concerns of using ipi_cpu_stop().
> 
> >Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> >---
> >  arch/arm64/include/asm/kexec.h    | 34 +++++++++++++++++++++++++++++++++-
> >  arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++--
> >  arch/arm64/kernel/smp.c           | 16 ++++++++++++++--
> >  3 files changed, 76 insertions(+), 5 deletions(-)

[...]

> >diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> >index dbdaacd..88aec66 100644
> >--- a/arch/arm64/kernel/smp.c
> >+++ b/arch/arm64/kernel/smp.c
> >@@ -37,6 +37,7 @@
> >  #include <linux/completion.h>
> >  #include <linux/of.h>
> >  #include <linux/irq_work.h>
> >+#include <linux/kexec.h>
> >
> >  #include <asm/alternative.h>
> >  #include <asm/atomic.h>
> >@@ -54,6 +55,8 @@
> >  #include <asm/ptrace.h>
> >  #include <asm/virt.h>
> >
> >+#include "cpu-reset.h"
> >+
> >  #define CREATE_TRACE_POINTS
> >  #include <trace/events/ipi.h>
> >
> >@@ -679,8 +682,12 @@ static DEFINE_RAW_SPINLOCK(stop_lock);
> >  /*
> >   * ipi_cpu_stop - handle IPI from smp_send_stop()
> >   */
> >-static void ipi_cpu_stop(unsigned int cpu)
> >+static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
> >  {
> >+#ifdef CONFIG_KEXEC
> >+	/* printing messages may slow down the shutdown. */
> >+	if (!in_crash_kexec)
> >+#endif
> >  	if (system_state == SYSTEM_BOOTING ||
> >  	    system_state == SYSTEM_RUNNING) {
> >  		raw_spin_lock(&stop_lock);
> >@@ -693,6 +700,11 @@ static void ipi_cpu_stop(unsigned int cpu)
> >
> >  	local_irq_disable();
> >
> >+#ifdef CONFIG_KEXEC
> >+	if (in_crash_kexec)
> >+		crash_save_cpu(regs, cpu);
> >+#endif /* CONFIG_KEXEC */
> >+
> >  	while (1)
> >  		cpu_relax();
> >  }
> 
> cpu_relax() is defined as asm("yield"), and this puts all but boot cpu into
> a infinite loop of nop (actually, whether nop or other depends on hw implementation).
> Thus all the secondary cpus are still running busy loop even after crash dump kernel
> has started up, and the chip can potentially get overheated.
> I ran into this situation when I tested the code on Hikey, and the system was
> forced to be shut down by thermal driver.
> 
> So I'd like to modify the code a bit like:
> if (in_crash_kernel {
>     crash_save_cpu(regs, cpu);
>     while (1)
>         asm("wfi"); /* irq is disabled here. */
> }
> 
> Does this make sense?

It would be even better if we could hotplug them off.

Will

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^ permalink raw reply	[flat|nested] 36+ messages in thread
end of thread, other threads:[~2015-11-10  9:54 UTC | newest]

Thread overview: 36+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-11-06 19:14 [PATCH 00/15] arm64 kexec kernel patches v11 Geoff Levand
2015-11-06 19:14 ` Geoff Levand
2015-11-06 19:14 ` [PATCH 07/15] arm64/kexec: Add core kexec support Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 01/15] arm64: Fold proc-macros.S into assembler.h Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 09/15] arm64/kexec: Enable kexec in the arm64 defconfig Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 04/15] arm64: kvm: allows kvm cpu hotplug Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 05/15] arm64: Add back cpu_reset routines Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 06/15] Revert "arm64: remove dead code" Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 02/15] arm64: Convert hcalls to use HVC immediate value Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 03/15] arm64: Add new hcall HVC_CALL_FUNC Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 08/15] arm64/kexec: Add pr_devel output Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 15/15] arm64: kdump: relax BUG_ON() if more than one cpus are still active Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 10/15] arm64: kdump: reserve memory for crash dump kernel Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 13/15] arm64: kdump: update a kernel doc Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 12/15] arm64: kdump: add kdump support Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-06 19:14 ` [PATCH 11/15] arm64: kdump: implement machine_crash_shutdown() Geoff Levand
2015-11-06 19:14   ` Geoff Levand
2015-11-10  1:23   ` AKASHI Takahiro
2015-11-10  1:23     ` AKASHI Takahiro
2015-11-10  9:54     ` Will Deacon
2015-11-10  9:54       ` Will Deacon
2015-11-06 19:14 ` [PATCH 14/15] arm64: kdump: enable kdump in the arm64 defconfig Geoff Levand
2015-11-06 19:14   ` Geoff Levand

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