[PATCH v22 1/8] arm64: kdump: reserve memory for crash dump kernel
From: Suzuki.Poulose@arm.com (Suzuki K Poulose)
Date: 2016-07-13 09:12:12
Also in:
kexec
On 12/07/16 06:05, AKASHI Takahiro wrote:
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 as - "Crash kernel" in /proc/iomem, or - "linux,crashkernel-base" and "linux,crashkernel-size" under /sys/firmware/devicetree/base/chosen Signed-off-by: AKASHI Takahiro <redacted> Signed-off-by: Mark Salter <redacted> Signed-off-by: Pratyush Anand <redacted> Reviewed-by: James Morse <james.morse@arm.com>
Minor nits below.
quoted hunk ↗ jump to hunk
--- arch/arm64/kernel/setup.c | 7 ++- arch/arm64/mm/init.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 121 insertions(+), 1 deletion(-)diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index c1509e6..cb5eee0 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>@@ -222,6 +221,12 @@ static void __init request_standard_resources(void) kernel_data.end <= res->end) request_resource(res, &kernel_data); } + +#ifdef CONFIG_KEXEC_CORE + /* User space tools will find "Crash kernel" region in /proc/iomem. */ + if (crashk_res.end) + insert_resource(&iomem_resource, &crashk_res); +#endif
nit: Could we not do this from reserve_crashkernel() ?
quoted hunk ↗ jump to hunk
#include <asm/boot.h> #include <asm/fixmap.h>@@ -76,6 +78,117 @@ static int __init early_initrd(char *p) early_param("initrd", early_initrd); #endif +#ifdef CONFIG_KEXEC_CORE +static unsigned long long crash_size, crash_base; +static struct property crash_base_prop = { + .name = "linux,crashkernel-base", + .length = sizeof(u64), + .value = &crash_base +}; +static struct property crash_size_prop = { + .name = "linux,crashkernel-size", + .length = sizeof(u64), + .value = &crash_size, +}; +
+
+/*
+ * 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)
+{
+ 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;
+
+ if (crash_base == 0) {...
+ memblock_reserve(crash_base, crash_size);
+
+ } else {...
+ + memblock_reserve(crash_base, crash_size);
+ }
Nit: you could move the memblock_reserve() here to a single place.
+
+ 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;As mentioned above, may be we could move the insert_resource() here, which would keep the generic setup.c code cleaner and is a bit more reader friendly.
+} +#else
Suzuki