Hi! On 14/03/16 17:48, Geoff Levand wrote: > From: AKASHI Takahiro <takahiro.akashi at 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()). > @@ -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