[PATCH v19 06/13] arm64: kdump: reserve memory for crash dump kernel
From: james.morse@arm.com (James Morse)
Date: 2016-06-20 16:07:11
Also in:
kexec
Hi, On 17/06/16 00:48, Geoff Levand wrote:
From: AKASHI Takahiro <redacted> On the startup of primary kernel, the memory region used by crash dump kernel must be specified by "crashkernel=" kernel parameter. reserve_crashkernel() will allocate and reserve the region for later use. User space tools, like kexec-tools, will be able to find that region marked as "Crash kernel" in /proc/iomem.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index d45f862..45f1319 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/boot.h> #include <asm/fixmap.h>@@ -76,6 +77,65 @@ 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_size = 0, crash_base = 0; + int ret; + + ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), + &crash_size, &crash_base); + /* no crashkernel= or invalid value specified */ + if (!crash_size) + return;
Should we check ret too?
+
+ if (crash_base == 0) {
+ /* Current arm64 boot protocol requires 2MB alignment */
+ crash_base = memblock_find_in_range(0,
+ MEMBLOCK_ALLOC_ACCESSIBLE, crash_size, SZ_2M);
+ if (crash_base == 0) {
+ pr_warn("Unable to allocate crashkernel (size:%llx)\n",
+ crash_size);
+ return;
+ }
+ memblock_reserve(crash_base, crash_size);What if memblock_reserve() fails?
+
+ } 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 (IS_ALIGNED(crash_base, SZ_2M)) {!IS_ALIGNED()...
+ pr_warn("crashkernel base address is not 2MB aligned\n");
+ return;
+ }
+
+ memblock_reserve(crash_base, crash_size);What if memblock_reserve() fails?
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+ } + + 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; +} +#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@@ -291,6 +351,8 @@ void __init arm64_memblock_init(void) } #endif + reserve_crashkernel(); + early_init_fdt_scan_reserved_mem(); /* 4GB maximum for 32-bit only capable devices */
With those, Reviewed-by: James Morse <james.morse@arm.com> Thanks, James