From mboxrd@z Thu Jan 1 00:00:00 1970 From: msalter@redhat.com (Mark Salter) Date: Tue, 19 Jul 2016 08:48:57 -0400 Subject: [PATCH v22 1/8] arm64: kdump: reserve memory for crash dump kernel In-Reply-To: <20160719104103.GB20990@arm.com> References: <20160712050514.22307-1-takahiro.akashi@linaro.org> <20160712050514.22307-2-takahiro.akashi@linaro.org> <20160719093906.GA20732@arm.com> <20160719102815.GE20774@linaro.org> <20160719104103.GB20990@arm.com> Message-ID: <1468932537.27473.6.camel@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 2016-07-19 at 18:41 +0800, Dennis Chen wrote: > On Tue, Jul 19, 2016 at 07:28:16PM +0900, AKASHI Takahiro wrote: > > > > On Tue, Jul 19, 2016 at 05:39:07PM +0800, Dennis Chen wrote: > > > > > > Hello AKASHI, > > > > > > On Tue, Jul 12, 2016 at 02:05:07PM +0900, 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 > > > > Signed-off-by: Mark Salter > > > > Signed-off-by: Pratyush Anand > > > > Reviewed-by: James Morse > > > > --- > > > > ?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 > > > > ?#include > > > > ?#include > > > > -#include > > > > ?#include > > > > ?#include > > > > ?#include > > > > @@ -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..51b1302 100644 > > > > --- a/arch/arm64/mm/init.c > > > > +++ b/arch/arm64/mm/init.c > > > > @@ -29,11 +29,13 @@ > > > > ?#include > > > > ?#include > > > > ?#include > > > > +#include > > > > ?#include > > > > ?#include > > > > ?#include > > > > ?#include > > > > ?#include > > > > +#include > > > > > > > > ?#include > > > > ?#include > > > > @@ -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, > > > > +}; > > > > + > > > > +static int __init export_crashkernel(void) > > > > +{ > > > > +?????struct device_node *node; > > > > +?????int ret; > > > > + > > > > +?????if (!crashk_res.end) > > > > +?????????????return 0; > > > > + > > > > +?????crash_base = cpu_to_be64(crashk_res.start); > > > > +?????crash_size = cpu_to_be64(crashk_res.end - crashk_res.start + 1); > > > > + > > > > +?????/* Add /chosen/linux,crashkernel-* properties */ > > > > +?????node = of_find_node_by_path("/chosen"); > > > > +?????if (!node) > > > > +?????????????return -ENOENT; > > > > + > > > > +?????/* > > > > +??????* There might be existing crash kernel properties, but we can't > > > > +??????* be sure what's in them, so remove them. > > > > +??????*/ > > > > +?????of_remove_property(node, of_find_property(node, > > > > +?????????????????????????????"linux,crashkernel-base", NULL)); > > > > +?????of_remove_property(node, of_find_property(node, > > > > +?????????????????????????????"linux,crashkernel-size", NULL)); > > > > + > > > > +?????ret = of_add_property(node, &crash_base_prop); > > > > +?????if (ret) > > > > +?????????????goto ret_err; > > > > + > > > > +?????ret = of_add_property(node, &crash_size_prop); > > > > +?????if (ret) > > > > +?????????????goto ret_err; > > > > + > > > > +?????return 0; > > > > + > > > > +ret_err: > > > > +?????pr_warn("Exporting crashkernel region to device tree failed\n"); > > > > +?????return ret; > > > > +} > > > > +late_initcall(export_crashkernel); > > > > + > > > > +/* > > > > + * 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) { > > > > +?????????????/* 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); > > > > > > > I am not pretty sure the context here, but > > > can we use below code piece instead of the above lines? > > > ????????if (crash_base == 0) > > > ????????????????memblock_alloc(crash_size, SZ_2M); > > Either would be fine here. > > > Hello AKASHI, maybe you can succeed to find the base with memblock_find_in_range(),? > but that doesn't mean you will also succeed to reserve them with memblock_reserve followed. We avoid memblock_alloc() here because it panics on failure. This could happen if user asks for an unusually large crashkernel size. Better to print a message and keep booting. Checking the return value of memblock_reserve() seems like a good thing to do though. > > Thanks, > Dennis > > > > > > Thanks, > > -Takahiro AKASHI > > > > > > > > Thanks, > > > Dennis > > > > > > > > > > > + > > > > +?????} 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 +402,8 @@ void __init arm64_memblock_init(void) > > > > ??????} > > > > ?#endif > > > > > > > > +?????reserve_crashkernel(); > > > > + > > > > ??????early_init_fdt_scan_reserved_mem(); > > > > > > > > ??????/* 4GB maximum for 32-bit only capable devices */ > > > > -- > > > > 2.9.0 > > > > > > > > > > > > _______________________________________________ > > > > linux-arm-kernel mailing list > > > > linux-arm-kernel at lists.infradead.org > > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > >