From 19ab5d6d6b8c9dc25b6cccba582fbd0a6211297a Mon Sep 17 00:00:00 2001 From: Chen Zhou Date: Wed, 17 Apr 2019 16:22:02 +0800 Subject: [PATCH] arm64: kdump: support reserving crashkernel above 4G hulk inclusion category: feature bugzilla: 12800 CVE: NA ------------------------------------------------- When crashkernel is reserved above 4G in memory, kernel should reserve some amount of low memory for swiotlb and some DMA buffers. Kernel would try to allocate at least 256M below 4G automatically as x86_64 if crashkernel is above 4G. Meanwhile, support crashkernel=X,[high,low] in arm64. Signed-off-by: Chen Zhou Reviewed-by: Yang Yingliang Signed-off-by: Yang Yingliang --- arch/arm64/include/asm/kexec.h | 3 +++ arch/arm64/kernel/setup.c | 3 +++ arch/arm64/mm/init.c | 25 ++++++++++++++++++++----- 3 files changed, 26 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h index e17f0529a882..87e75d0579f8 100644 --- a/arch/arm64/include/asm/kexec.h +++ b/arch/arm64/include/asm/kexec.h @@ -28,6 +28,9 @@ #define KEXEC_ARCH KEXEC_ARCH_AARCH64 +/* 2M alignment for crash kernel regions */ +#define CRASH_ALIGN SZ_2M + #ifndef __ASSEMBLY__ /** diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 97f993bc6224..ec75d203b5ff 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -253,6 +253,9 @@ static void __init request_standard_resources(void) request_resource(res, &kernel_data); #ifdef CONFIG_KEXEC_CORE /* Userspace will find "Crash kernel" region in /proc/iomem. */ + if (crashk_low_res.end && crashk_low_res.start >= res->start && + crashk_low_res.end <= res->end) + request_resource(res, &crashk_low_res); if (crashk_res.end && crashk_res.start >= res->start && crashk_res.end <= res->end) request_resource(res, &crashk_res); diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 71df283f933a..b0a47048c4ad 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -94,20 +94,30 @@ early_param("initrd", early_initrd); static void __init reserve_crashkernel(void) { unsigned long long crash_base, crash_size; + bool high = false; 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 (ret || !crash_size) { + /* crashkernel=X,high */ + ret = parse_crashkernel_high(boot_command_line, + memblock_phys_mem_size(), + &crash_size, &crash_base); + if (ret || !crash_size) + return; + high = true; + } crash_size = PAGE_ALIGN(crash_size); if (crash_base == 0) { /* Current arm64 boot protocol requires 2MB alignment */ - crash_base = memblock_find_in_range(0, ARCH_LOW_ADDRESS_LIMIT, - crash_size, SZ_2M); + crash_base = memblock_find_in_range(0, + high ? memblock_end_of_DRAM() + : ARCH_LOW_ADDRESS_LIMIT, + crash_size, CRASH_ALIGN); if (crash_base == 0) { pr_warn("cannot allocate crashkernel (size:0x%llx)\n", crash_size); @@ -125,13 +135,18 @@ static void __init reserve_crashkernel(void) return; } - if (!IS_ALIGNED(crash_base, SZ_2M)) { + if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) { pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n"); return; } } memblock_reserve(crash_base, crash_size); + if (crash_base >= SZ_4G && reserve_crashkernel_low()) { + memblock_free(crash_base, crash_size); + return; + } + pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", crash_base, crash_base + crash_size, crash_size >> 20); -- GitLab