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From: Alexandru Elisei <alexandru.elisei@arm.com>
To: drjones@redhat.com, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Cc: andre.przywara@arm.com
Subject: [kvm-unit-tests PATCH v2 2/6] arm/arm64: Remove dcache_line_size global variable
Date: Mon, 22 Mar 2021 15:06:37 +0000	[thread overview]
Message-ID: <20210322150641.58878-3-alexandru.elisei@arm.com> (raw)
In-Reply-To: <20210322150641.58878-1-alexandru.elisei@arm.com>

Compute the dcache line size when doing dcache maintenance instead of using
a global variable computed in setup(), which allows us to do dcache
maintenance at any point in the boot process. This will be useful for
running as an EFI app and it also aligns our implementation to that of the
Linux kernel. As a result, the dcache_by_line_op assembly has been modified
to take a range described by start address and size, instead of start and
end addresses.

For consistency, the arm code has been similary modified.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
 lib/arm/asm/assembler.h   | 53 ++++++++++++++++++++++++++++++++++++++
 lib/arm/asm/processor.h   |  7 -----
 lib/arm64/asm/assembler.h | 54 +++++++++++++++++++++++++++++++++++++++
 lib/arm64/asm/processor.h |  7 -----
 lib/arm/setup.c           |  7 -----
 arm/cstart.S              | 18 +++----------
 arm/cstart64.S            | 16 ++----------
 7 files changed, 112 insertions(+), 50 deletions(-)
 create mode 100644 lib/arm/asm/assembler.h
 create mode 100644 lib/arm64/asm/assembler.h

diff --git a/lib/arm/asm/assembler.h b/lib/arm/asm/assembler.h
new file mode 100644
index 000000000000..dfd3c51bf6ad
--- /dev/null
+++ b/lib/arm/asm/assembler.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Based on several files from Linux version v5.10: arch/arm/mm/proc-macros.S,
+ * arch/arm/mm/proc-v7.S.
+ */
+
+#ifndef __ASSEMBLY__
+#error "Only include this from assembly code"
+#endif
+
+#ifndef __ASM_ASSEMBLER_H
+#define __ASM_ASSEMBLER_H
+
+/*
+ * dcache_line_size - get the minimum D-cache line size from the CTR register
+ * on ARMv7.
+ */
+	.macro	dcache_line_size, reg, tmp
+	mrc	p15, 0, \tmp, c0, c0, 1		// read ctr
+	lsr	\tmp, \tmp, #16
+	and	\tmp, \tmp, #0xf		// cache line size encoding
+	mov	\reg, #4			// bytes per word
+	mov	\reg, \reg, lsl \tmp		// actual cache line size
+	.endm
+
+/*
+ * Macro to perform a data cache maintenance for the interval
+ * [addr, addr + size).
+ *
+ * 	op:		operation to execute
+ * 	domain		domain used in the dsb instruction
+ * 	addr:		starting virtual address of the region
+ * 	size:		size of the region
+ * 	Corrupts:	addr, size, tmp1, tmp2
+ */
+	.macro dcache_by_line_op op, domain, addr, size, tmp1, tmp2
+	dcache_line_size \tmp1, \tmp2
+	add	\size, \addr, \size
+	sub	\tmp2, \tmp1, #1
+	bic	\addr, \addr, \tmp2
+9998:
+	.ifc	\op, dccimvac
+	mcr	p15, 0, \addr, c7, c14, 1
+	.else
+	.err
+	.endif
+	add	\addr, \addr, \tmp1
+	cmp	\addr, \size
+	blo	9998b
+	dsb	\domain
+	.endm
+
+#endif	/* __ASM_ASSEMBLER_H */
diff --git a/lib/arm/asm/processor.h b/lib/arm/asm/processor.h
index 273366d1fe1c..3c36eac903f0 100644
--- a/lib/arm/asm/processor.h
+++ b/lib/arm/asm/processor.h
@@ -9,11 +9,6 @@
 #include <asm/sysreg.h>
 #include <asm/barrier.h>
 
-#define CTR_DMINLINE_SHIFT	16
-#define CTR_DMINLINE_MASK	(0xf << 16)
-#define CTR_DMINLINE(x)	\
-	(((x) & CTR_DMINLINE_MASK) >> CTR_DMINLINE_SHIFT)
-
 enum vector {
 	EXCPTN_RST,
 	EXCPTN_UND,
@@ -89,6 +84,4 @@ static inline u32 get_ctr(void)
 	return read_sysreg(CTR);
 }
 
-extern unsigned long dcache_line_size;
-
 #endif /* _ASMARM_PROCESSOR_H_ */
diff --git a/lib/arm64/asm/assembler.h b/lib/arm64/asm/assembler.h
new file mode 100644
index 000000000000..0a6ab9720bdd
--- /dev/null
+++ b/lib/arm64/asm/assembler.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Based on the file arch/arm64/include/asm/assembled.h from Linux v5.10, which
+ * in turn is based on arch/arm/include/asm/assembler.h and
+ * arch/arm/mm/proc-macros.S
+ *
+ * Copyright (C) 1996-2000 Russell King
+ * Copyright (C) 2012 ARM Ltd.
+ */
+
+#ifndef __ASSEMBLY__
+#error "Only include this from assembly code"
+#endif
+
+#ifndef __ASM_ASSEMBLER_H
+#define __ASM_ASSEMBLER_H
+
+/*
+ * raw_dcache_line_size - get the minimum D-cache line size on this CPU
+ * from the CTR register.
+ */
+	.macro	raw_dcache_line_size, reg, tmp
+	mrs	\tmp, ctr_el0			// read CTR
+	ubfx	\tmp, \tmp, #16, #4		// cache line size encoding
+	mov	\reg, #4			// bytes per word
+	lsl	\reg, \reg, \tmp		// actual cache line size
+	.endm
+
+/*
+ * Macro to perform a data cache maintenance for the interval
+ * [addr, addr + size). Use the raw value for the dcache line size because
+ * kvm-unit-tests has no concept of scheduling.
+ *
+ * 	op:		operation passed to dc instruction
+ * 	domain:		domain used in dsb instruciton
+ * 	addr:		starting virtual address of the region
+ * 	size:		size of the region
+ * 	Corrupts:	addr, size, tmp1, tmp2
+ */
+
+	.macro dcache_by_line_op op, domain, addr, size, tmp1, tmp2
+	raw_dcache_line_size \tmp1, \tmp2
+	add	\size, \addr, \size
+	sub	\tmp2, \tmp1, #1
+	bic	\addr, \addr, \tmp2
+9998:
+	dc	\op, \addr
+	add	\addr, \addr, \tmp1
+	cmp	\addr, \size
+	b.lo	9998b
+	dsb	\domain
+	.endm
+
+#endif	/* __ASM_ASSEMBLER_H */
diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h
index 771b2d1e0c94..cdc2463e1981 100644
--- a/lib/arm64/asm/processor.h
+++ b/lib/arm64/asm/processor.h
@@ -16,11 +16,6 @@
 #define SCTLR_EL1_A	(1 << 1)
 #define SCTLR_EL1_M	(1 << 0)
 
-#define CTR_DMINLINE_SHIFT	16
-#define CTR_DMINLINE_MASK	(0xf << 16)
-#define CTR_DMINLINE(x)	\
-	(((x) & CTR_DMINLINE_MASK) >> CTR_DMINLINE_SHIFT)
-
 #ifndef __ASSEMBLY__
 #include <asm/ptrace.h>
 #include <asm/esr.h>
@@ -115,8 +110,6 @@ static inline u64 get_ctr(void)
 	return read_sysreg(ctr_el0);
 }
 
-extern unsigned long dcache_line_size;
-
 static inline unsigned long get_id_aa64mmfr0_el1(void)
 {
 	return read_sysreg(id_aa64mmfr0_el1);
diff --git a/lib/arm/setup.c b/lib/arm/setup.c
index 066524f8bf61..751ba980000a 100644
--- a/lib/arm/setup.c
+++ b/lib/arm/setup.c
@@ -42,8 +42,6 @@ static struct mem_region __initial_mem_regions[NR_INITIAL_MEM_REGIONS + 1];
 struct mem_region *mem_regions = __initial_mem_regions;
 phys_addr_t __phys_offset, __phys_end;
 
-unsigned long dcache_line_size;
-
 int mpidr_to_cpu(uint64_t mpidr)
 {
 	int i;
@@ -72,11 +70,6 @@ static void cpu_init(void)
 	ret = dt_for_each_cpu_node(cpu_set, NULL);
 	assert(ret == 0);
 	set_cpu_online(0, true);
-	/*
-	 * DminLine is log2 of the number of words in the smallest cache line; a
-	 * word is 4 bytes.
-	 */
-	dcache_line_size = 1 << (CTR_DMINLINE(get_ctr()) + 2);
 }
 
 unsigned int mem_region_get_flags(phys_addr_t paddr)
diff --git a/arm/cstart.S b/arm/cstart.S
index ef936ae2f874..954748b00f64 100644
--- a/arm/cstart.S
+++ b/arm/cstart.S
@@ -7,6 +7,7 @@
  */
 #define __ASSEMBLY__
 #include <auxinfo.h>
+#include <asm/assembler.h>
 #include <asm/thread_info.h>
 #include <asm/asm-offsets.h>
 #include <asm/pgtable-hwdef.h>
@@ -197,20 +198,6 @@ asm_mmu_enable:
 
 	mov     pc, lr
 
-.macro dcache_clean_inval domain, start, end, tmp1, tmp2
-	ldr	\tmp1, =dcache_line_size
-	ldr	\tmp1, [\tmp1]
-	sub	\tmp2, \tmp1, #1
-	bic	\start, \start, \tmp2
-9998:
-	/* DCCIMVAC */
-	mcr	p15, 0, \start, c7, c14, 1
-	add	\start, \start, \tmp1
-	cmp	\start, \end
-	blo	9998b
-	dsb	\domain
-.endm
-
 .globl asm_mmu_disable
 asm_mmu_disable:
 	/* SCTLR */
@@ -223,7 +210,8 @@ asm_mmu_disable:
 	ldr	r0, [r0]
 	ldr	r1, =__phys_end
 	ldr	r1, [r1]
-	dcache_clean_inval sy, r0, r1, r2, r3
+	sub	r1, r1, r0
+	dcache_by_line_op dccimvac, sy, r0, r1, r2, r3
 	isb
 
 	mov     pc, lr
diff --git a/arm/cstart64.S b/arm/cstart64.S
index fc1930bcdb53..046bd3914098 100644
--- a/arm/cstart64.S
+++ b/arm/cstart64.S
@@ -8,6 +8,7 @@
 #define __ASSEMBLY__
 #include <auxinfo.h>
 #include <asm/asm-offsets.h>
+#include <asm/assembler.h>
 #include <asm/ptrace.h>
 #include <asm/processor.h>
 #include <asm/page.h>
@@ -204,20 +205,6 @@ asm_mmu_enable:
 
 	ret
 
-/* Taken with small changes from arch/arm64/incluse/asm/assembler.h */
-.macro dcache_by_line_op op, domain, start, end, tmp1, tmp2
-	adrp	\tmp1, dcache_line_size
-	ldr	\tmp1, [\tmp1, :lo12:dcache_line_size]
-	sub	\tmp2, \tmp1, #1
-	bic	\start, \start, \tmp2
-9998:
-	dc	\op , \start
-	add	\start, \start, \tmp1
-	cmp	\start, \end
-	b.lo	9998b
-	dsb	\domain
-.endm
-
 .globl asm_mmu_disable
 asm_mmu_disable:
 	mrs	x0, sctlr_el1
@@ -230,6 +217,7 @@ asm_mmu_disable:
 	ldr	x0, [x0, :lo12:__phys_offset]
 	adrp	x1, __phys_end
 	ldr	x1, [x1, :lo12:__phys_end]
+	sub	x1, x1, x0
 	dcache_by_line_op civac, sy, x0, x1, x2, x3
 	isb
 
-- 
2.31.0


  parent reply	other threads:[~2021-03-22 15:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-22 15:06 [kvm-unit-tests PATCH v2 0/6] Misc assembly fixes and cleanups Alexandru Elisei
2021-03-22 15:06 ` [kvm-unit-tests PATCH v2 1/6] arm64: Remove unnecessary ISB when writing to SPSel Alexandru Elisei
2021-03-22 15:06 ` Alexandru Elisei [this message]
2021-03-23 16:32   ` [kvm-unit-tests PATCH v2 2/6] arm/arm64: Remove dcache_line_size global variable Andre Przywara
2021-03-22 15:06 ` [kvm-unit-tests PATCH v2 3/6] arm/arm64: Remove unnecessary ISB when doing dcache maintenance Alexandru Elisei
2021-03-22 15:06 ` [kvm-unit-tests PATCH v2 4/6] lib: arm64: Consolidate register definitions to sysreg.h Alexandru Elisei
2021-03-22 15:06 ` [kvm-unit-tests PATCH v2 5/6] arm64: Configure SCTLR_EL1 at boot Alexandru Elisei
2021-03-22 15:06 ` [kvm-unit-tests PATCH v2 6/6] arm64: Disable TTBR1_EL1 translation table walks Alexandru Elisei
2021-03-25 15:31 ` [kvm-unit-tests PATCH v2 0/6] Misc assembly fixes and cleanups Andrew Jones

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