| Message ID | 1083d7e4a6285c39d2955fb99dc9fa4c345d00fa.1457977403.git.geoff@infradead.org |
|---|---|
| State | Superseded |
| Headers | show |
On Fri, Mar 18, 2016 at 06:08:30PM +0000, James Morse wrote: > Hi! > > On 14/03/16 17:48, Geoff Levand wrote: > > From: AKASHI Takahiro <takahiro.akashi@linaro.org> > > > > 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. > > [NB: Re-ordered diff hunks ] > > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > > index 7802f21..4edf181 100644 > > --- a/arch/arm64/mm/init.c > > +++ b/arch/arm64/mm/init.c > > @@ -171,6 +229,8 @@ void __init arm64_memblock_init(void) > > memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start); > > #endif > > > > + reserve_crashkernel(); > > + > > early_init_fdt_scan_reserved_mem(); > > > > /* 4GB maximum for 32-bit only capable devices */ > > > > > This is 'nit' territory, but if you were to make this: > > if (IS_ENABLED(CONFIG_KEXEC_CORE)) > > reserve_crashkernel(); > > then the #ifdefs around reserve_crashkernel() can go, and the compiler will work > out that this static function can be optimised out. It also means the > compiler performs its checks, even if CONFIG_KEXEC_CORE isn't selected. The same > trick can be applied in patch 18 (around reserve_elfcorehdr()). It will also make the code more understandable. Thanks, -Takahiro AKASHI > > @@ -66,6 +67,63 @@ 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); > > + if (ret) > > + return; > > + > > + if (crash_base == 0) { > > + crash_base = memblock_find_in_range(0, > > + MEMBLOCK_ALLOC_ACCESSIBLE, crash_size, 1 << 21); > > + if (crash_base == 0) { > > + pr_warn("Unable to allocate crashkernel (size:%llx)\n", > > + crash_size); > > + return; > > + } > > + memblock_reserve(crash_base, crash_size); > > + > > + } 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; > > +} > > +#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 > > > Thanks, > > James > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On 03/31/2016 02:19 PM, AKASHI Takahiro wrote: > On Fri, Mar 18, 2016 at 06:08:30PM +0000, James Morse wrote: >> Hi! >> >> On 14/03/16 17:48, Geoff Levand wrote: >>> From: AKASHI Takahiro <takahiro.akashi@linaro.org> >>> >>> 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. >> >> [NB: Re-ordered diff hunks ] >> >>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c >>> index 7802f21..4edf181 100644 >>> --- a/arch/arm64/mm/init.c >>> +++ b/arch/arm64/mm/init.c >>> @@ -171,6 +229,8 @@ void __init arm64_memblock_init(void) >>> memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start); >>> #endif >>> >>> + reserve_crashkernel(); >>> + >>> early_init_fdt_scan_reserved_mem(); >>> >>> /* 4GB maximum for 32-bit only capable devices */ >>> >> >> >> This is 'nit' territory, but if you were to make this: >>> if (IS_ENABLED(CONFIG_KEXEC_CORE)) >>> reserve_crashkernel(); >> >> then the #ifdefs around reserve_crashkernel() can go, and the compiler will work >> out that this static function can be optimised out. It also means the >> compiler performs its checks, even if CONFIG_KEXEC_CORE isn't selected. The same >> trick can be applied in patch 18 (around reserve_elfcorehdr()). > > It will also make the code more understandable. I tried this change, but unfortunately, preserve_crashkernel() calls an external function, parse_crashkernel(), which is defined only if CONFIG_KEXEC_CORE. So we will see a compiler error in !CONFIG_KEXEC_CORE if we take #ifdef out around perserve_crashkernel(). -Takahiro AKASHI > Thanks, > -Takahiro AKASHI > >>> @@ -66,6 +67,63 @@ 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); >>> + if (ret) >>> + return; >>> + >>> + if (crash_base == 0) { >>> + crash_base = memblock_find_in_range(0, >>> + MEMBLOCK_ALLOC_ACCESSIBLE, crash_size, 1 << 21); >>> + if (crash_base == 0) { >>> + pr_warn("Unable to allocate crashkernel (size:%llx)\n", >>> + crash_size); >>> + return; >>> + } >>> + memblock_reserve(crash_base, crash_size); >>> + >>> + } 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; >>> +} >>> +#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 >> >> >> Thanks, >> >> James >> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 8119479..293cee2 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> @@ -221,6 +220,12 @@ 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 } #ifdef CONFIG_BLK_DEV_INITRD diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 7802f21..4edf181 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 +67,63 @@ 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); + if (ret) + return; + + if (crash_base == 0) { + crash_base = memblock_find_in_range(0, + MEMBLOCK_ALLOC_ACCESSIBLE, crash_size, 1 << 21); + if (crash_base == 0) { + pr_warn("Unable to allocate crashkernel (size:%llx)\n", + crash_size); + return; + } + memblock_reserve(crash_base, crash_size); + + } 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; +} +#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 @@ -171,6 +229,8 @@ void __init arm64_memblock_init(void) memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start); #endif + reserve_crashkernel(); + early_init_fdt_scan_reserved_mem(); /* 4GB maximum for 32-bit only capable devices */