| Message ID | 20160706075226.27609-2-takahiro.akashi@linaro.org |
|---|---|
| State | New |
| Headers | show |
Geoff, Thank you for your reviewing. On Wed, Jul 06, 2016 at 10:00:18AM -0700, Geoff Levand wrote: > On Wed, 2016-07-06 at 16:52 +0900, AKASHI Takahiro wrote: > > > > +#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 (ret || !crash_size) > > +> > > return; > > + > > +> > 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); > > + > > +> > } 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)) { > > +> > > > 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 */ > > + I know that this is just a matter of preference, but I can see more use cases of the above than the below that you mentioned under arm64 directory. So I want to keep the current style unchanged unless the maintainers don't like it. Thanks, -Takahiro AKASHI > I think it is a bit cleaner if you move this conditional > into the function and have something like: > > static void __init reserve_crashkernel(void) > { > #ifdef CONFIG_KEXEC_CORE > #else > #endif > } > > -Geoff > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Wed, Jul 06, 2016 at 03:11:45PM -0300, Thiago Jung Bauermann wrote: > Am Mittwoch, 06 Juli 2016, 16:52:19 schrieb AKASHI Takahiro: > > 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. > > On powerpc, userspace tools get everything from the device tree (exposed to > userspace in /proc/device-tree/), not /proc/iomem. I started my kdump patches with arm (not arm64) implementation, and so /proc/iomem is used for consistency. Since my kexec-tools (for arm64) have to access /proc/iomem to identify usable memory regions on *UEFI* systems anyway, I didn't think it was odd. (Please note that UEFI won't expose memory regions information via a device tree, but via ACPI table.) > In the case of the crashkernel reserved region, that information is in > /chosen/linux,crashkernel-base and /chosen/linux,crashkernel-size. > > Either way is fine I think. I'm just mentioning this for reference in case > you want the ARM implementation to be closer to another arch which is also > based on the device tree. Adding those properties to a device tree is quite easy (and it won't conflict with /proc/iomem), so I'd like to defer to arm64 maintainers. Thanks, -Takahiro AKASHI > -- > []'s > Thiago Jung Bauermann > IBM Linux Technology Center > _______________________________________________ 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 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 } u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID }; diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 2ade7a6..e1134fb 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 (ret || !crash_size) + return; + + 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); + + } 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)) { + 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 @@ -289,6 +349,8 @@ void __init arm64_memblock_init(void) } #endif + reserve_crashkernel(); + early_init_fdt_scan_reserved_mem(); /* 4GB maximum for 32-bit only capable devices */