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From: takahiro.akashi@linaro.org (AKASHI Takahiro)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v35 04/14] arm64: kdump: reserve memory for crash dump kernel
Date: Mon,  3 Apr 2017 11:24:32 +0900	[thread overview]
Message-ID: <20170403022440.12515-2-takahiro.akashi@linaro.org> (raw)
In-Reply-To: <20170403022139.12383-1-takahiro.akashi@linaro.org>

"crashkernel=" kernel parameter specifies the size (and optionally
the start address) of the system ram to be used by crash dump kernel.
reserve_crashkernel() will allocate and reserve that memory at boot time
of primary kernel.

The memory range will be exposed to userspace as a resource named
"Crash kernel" in /proc/iomem.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Pratyush Anand <panand@redhat.com>
Reviewed-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/kernel/setup.c |  7 ++++-
 arch/arm64/mm/init.c      | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 42274bda0ccb..28855ec1be95 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -31,7 +31,6 @@
 #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>
@@ -226,6 +225,12 @@ static void __init request_standard_resources(void)
 		if (kernel_data.start >= res->start &&
 		    kernel_data.end <= res->end)
 			request_resource(res, &kernel_data);
+#ifdef CONFIG_KEXEC_CORE
+		/* Userspace will find "Crash kernel" region in /proc/iomem. */
+		if (crashk_res.end && crashk_res.start >= res->start &&
+		    crashk_res.end <= res->end)
+			request_resource(res, &crashk_res);
+#endif
 	}
 }
 
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 290794b1a0f1..09d19207362d 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -30,6 +30,7 @@
 #include <linux/gfp.h>
 #include <linux/memblock.h>
 #include <linux/sort.h>
+#include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/dma-mapping.h>
 #include <linux/dma-contiguous.h>
@@ -37,6 +38,7 @@
 #include <linux/swiotlb.h>
 #include <linux/vmalloc.h>
 #include <linux/mm.h>
+#include <linux/kexec.h>
 
 #include <asm/boot.h>
 #include <asm/fixmap.h>
@@ -77,6 +79,67 @@ static int __init early_initrd(char *p)
 early_param("initrd", early_initrd);
 #endif
 
+#ifdef CONFIG_KEXEC_CORE
+/*
+ * 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_base, crash_size;
+	int ret;
+
+	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
+				&crash_size, &crash_base);
+	/* no crashkernel= or invalid value specified */
+	if (ret || !crash_size)
+		return;
+
+	crash_size = PAGE_ALIGN(crash_size);
+
+	if (crash_base == 0) {
+		/* Current arm64 boot protocol requires 2MB alignment */
+		crash_base = memblock_find_in_range(0, ARCH_LOW_ADDRESS_LIMIT,
+				crash_size, SZ_2M);
+		if (crash_base == 0) {
+			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
+				crash_size);
+			return;
+		}
+	} else {
+		/* User specifies base address explicitly. */
+		if (!memblock_is_region_memory(crash_base, crash_size)) {
+			pr_warn("cannot reserve crashkernel: region is not memory\n");
+			return;
+		}
+
+		if (memblock_is_region_reserved(crash_base, crash_size)) {
+			pr_warn("cannot reserve crashkernel: region overlaps reserved memory\n");
+			return;
+		}
+
+		if (!IS_ALIGNED(crash_base, SZ_2M)) {
+			pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
+			return;
+		}
+	}
+	memblock_reserve(crash_base, crash_size);
+
+	pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
+		crash_base, crash_base + crash_size, crash_size >> 20);
+
+	crashk_res.start = crash_base;
+	crashk_res.end = crash_base + crash_size - 1;
+}
+#else
+static void __init reserve_crashkernel(void)
+{
+}
+#endif /* CONFIG_KEXEC_CORE */
+
 /*
  * 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
@@ -332,6 +395,9 @@ void __init arm64_memblock_init(void)
 		arm64_dma_phys_limit = max_zone_dma_phys();
 	else
 		arm64_dma_phys_limit = PHYS_MASK + 1;
+
+	reserve_crashkernel();
+
 	dma_contiguous_reserve(arm64_dma_phys_limit);
 
 	memblock_allow_resize();
-- 
2.11.1

  parent reply	other threads:[~2017-04-03  2:24 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-03  2:21 [PATCH v35 00/14] arm64: add kdump support AKASHI Takahiro
2017-04-03  2:23 ` [PATCH v35 01/14] memblock: add memblock_clear_nomap() AKASHI Takahiro
2017-04-03  2:23 ` [PATCH v35 02/14] memblock: add memblock_cap_memory_range() AKASHI Takahiro
2017-04-05 17:20   ` Catalin Marinas
2017-04-03  2:24 ` [PATCH v35 03/14] arm64: limit memory regions based on DT property, usable-memory-range AKASHI Takahiro
2017-04-03  2:24 ` AKASHI Takahiro [this message]
2017-04-03  2:24 ` [PATCH v35 05/14] arm64: mm: add set_memory_valid() AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 06/14] arm64: kdump: protect crash dump kernel memory AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 07/14] arm64: hibernate: preserve kdump image around hibernation AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 08/14] arm64: kdump: implement machine_crash_shutdown() AKASHI Takahiro
2017-04-03  9:21   ` David Woodhouse
2017-04-04  7:29     ` AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 09/14] arm64: kdump: add VMCOREINFO's for user-space tools AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 10/14] arm64: kdump: provide /proc/vmcore file AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 11/14] arm64: kdump: enable kdump in defconfig AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 12/14] Documentation: kdump: describe arm64 port AKASHI Takahiro
2017-04-03  2:26 ` [PATCH v35 13/14] Documentation: dt: chosen properties for arm64 kdump AKASHI Takahiro
2017-04-03  2:26 ` [PATCH v35 14/14] efi/libstub/arm*: Set default address and size cells values for an empty dtb AKASHI Takahiro
2017-05-22  0:25 ` [PATCH v35 00/14] arm64: add kdump support AKASHI Takahiro

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