Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
x86: kdump: use generic interface to simplify crashkernel reservation code
With the help of newly changed function parse_crashkernel() and generic
reserve_crashkernel_generic(), crashkernel reservation can be simplified
by steps:
1) Add a new header file <asm/crash_core.h>, and define CRASH_ALIGN,
CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX and
DEFAULT_CRASH_KERNEL_LOW_SIZE in <asm/crash_core.h>;
2) Add arch_reserve_crashkernel() to call parse_crashkernel() and
reserve_crashkernel_generic(), and do the ARCH specific work if
needed.
3) Add ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION Kconfig in
arch/x86/Kconfig.
When adding DEFAULT_CRASH_KERNEL_LOW_SIZE, add crash_low_size_default() to
calculate crashkernel low memory because x86_64 has special requirement.
The old reserve_crashkernel_low() and reserve_crashkernel() can be
removed.
[bhe@redhat.com: move crash_low_size_default() code into <asm/crash_core.h>]
Link: https://lkml.kernel.org/r/ZQpeAjOmuMJBFw1/@MiWiFi-R3L-srv
Link: https://lkml.kernel.org/r/20230914033142.676708-7-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Jiahao <chenjiahao16@huawei.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
authored by
Baoquan He
and committed by
Andrew Morton
9c08a2a1
b631b95d
+56
-137
+3
arch/x86/Kconfig
+3
arch/x86/Kconfig
···
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config ARCH_SUPPORTS_CRASH_HOTPLUG
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def_bool y
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+
config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
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def_bool CRASH_CORE
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+
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config PHYSICAL_START
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hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
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default "0x1000000"
+42
arch/x86/include/asm/crash_core.h
+42
arch/x86/include/asm/crash_core.h
···
1
+
/* SPDX-License-Identifier: GPL-2.0 */
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+
#ifndef _X86_CRASH_CORE_H
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#define _X86_CRASH_CORE_H
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+
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/* 16M alignment for crash kernel regions */
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#define CRASH_ALIGN SZ_16M
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+
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/*
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* Keep the crash kernel below this limit.
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*
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* Earlier 32-bits kernels would limit the kernel to the low 512 MB range
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* due to mapping restrictions.
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*
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* 64-bit kdump kernels need to be restricted to be under 64 TB, which is
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* the upper limit of system RAM in 4-level paging mode. Since the kdump
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* jump could be from 5-level paging to 4-level paging, the jump will fail if
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* the kernel is put above 64 TB, and during the 1st kernel bootup there's
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* no good way to detect the paging mode of the target kernel which will be
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* loaded for dumping.
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*/
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extern unsigned long swiotlb_size_or_default(void);
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+
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#ifdef CONFIG_X86_32
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# define CRASH_ADDR_LOW_MAX SZ_512M
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# define CRASH_ADDR_HIGH_MAX SZ_512M
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#else
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# define CRASH_ADDR_LOW_MAX SZ_4G
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# define CRASH_ADDR_HIGH_MAX SZ_64T
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#endif
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+
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# define DEFAULT_CRASH_KERNEL_LOW_SIZE crash_low_size_default()
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+
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static inline unsigned long crash_low_size_default(void)
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{
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#ifdef CONFIG_X86_64
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return max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
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#else
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return 0;
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#endif
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}
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#endif /* _X86_CRASH_CORE_H */
+11
-137
arch/x86/kernel/setup.c
+11
-137
arch/x86/kernel/setup.c
···
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}
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}
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-
/*
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* --------- Crashkernel reservation ------------------------------
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*/
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-
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/* 16M alignment for crash kernel regions */
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#define CRASH_ALIGN SZ_16M
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-
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/*
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* Keep the crash kernel below this limit.
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*
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* Earlier 32-bits kernels would limit the kernel to the low 512 MB range
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* due to mapping restrictions.
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*
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* 64-bit kdump kernels need to be restricted to be under 64 TB, which is
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* the upper limit of system RAM in 4-level paging mode. Since the kdump
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* jump could be from 5-level paging to 4-level paging, the jump will fail if
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* the kernel is put above 64 TB, and during the 1st kernel bootup there's
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* no good way to detect the paging mode of the target kernel which will be
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* loaded for dumping.
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*/
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#ifdef CONFIG_X86_32
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# define CRASH_ADDR_LOW_MAX SZ_512M
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# define CRASH_ADDR_HIGH_MAX SZ_512M
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-
#else
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# define CRASH_ADDR_LOW_MAX SZ_4G
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# define CRASH_ADDR_HIGH_MAX SZ_64T
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#endif
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-
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static int __init reserve_crashkernel_low(void)
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+
static void __init arch_reserve_crashkernel(void)
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{
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#ifdef CONFIG_X86_64
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unsigned long long base, low_base = 0, low_size = 0;
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unsigned long low_mem_limit;
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int ret;
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low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
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/* crashkernel=Y,low */
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ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
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if (ret) {
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/*
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* two parts from kernel/dma/swiotlb.c:
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* -swiotlb size: user-specified with swiotlb= or default.
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*
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* -swiotlb overflow buffer: now hardcoded to 32k. We round it
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* to 8M for other buffers that may need to stay low too. Also
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* make sure we allocate enough extra low memory so that we
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* don't run out of DMA buffers for 32-bit devices.
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*/
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low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
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} else {
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/* passed with crashkernel=0,low ? */
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if (!low_size)
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return 0;
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}
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-
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low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
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if (!low_base) {
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pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
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(unsigned long)(low_size >> 20));
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return -ENOMEM;
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}
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pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
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(unsigned long)(low_size >> 20),
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(unsigned long)(low_base >> 20),
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(unsigned long)(low_mem_limit >> 20));
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-
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crashk_low_res.start = low_base;
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crashk_low_res.end = low_base + low_size - 1;
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insert_resource(&iomem_resource, &crashk_low_res);
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#endif
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return 0;
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}
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-
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static void __init reserve_crashkernel(void)
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{
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unsigned long long crash_size, crash_base, total_mem;
471
+
unsigned long long crash_base, crash_size, low_size = 0;
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char *cmdline = boot_command_line;
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bool high = false;
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int ret;
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if (!IS_ENABLED(CONFIG_KEXEC_CORE))
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return;
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478
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-
total_mem = memblock_phys_mem_size();
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-
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/* crashkernel=XM */
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ret = parse_crashkernel(boot_command_line, total_mem,
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&crash_size, &crash_base, NULL, NULL);
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if (ret != 0 || crash_size <= 0) {
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/* crashkernel=X,high */
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ret = parse_crashkernel_high(boot_command_line, total_mem,
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&crash_size, &crash_base);
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if (ret != 0 || crash_size <= 0)
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return;
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high = true;
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}
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ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
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&crash_size, &crash_base,
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&low_size, &high);
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if (ret)
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return;
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if (xen_pv_domain()) {
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pr_info("Ignoring crashkernel for a Xen PV domain\n");
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return;
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}
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/* 0 means: find the address automatically */
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if (!crash_base) {
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/*
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* Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
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* crashkernel=x,high reserves memory over 4G, also allocates
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* 256M extra low memory for DMA buffers and swiotlb.
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* But the extra memory is not required for all machines.
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* So try low memory first and fall back to high memory
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* unless "crashkernel=size[KMG],high" is specified.
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*/
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if (!high)
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crash_base = memblock_phys_alloc_range(crash_size,
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CRASH_ALIGN, CRASH_ALIGN,
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CRASH_ADDR_LOW_MAX);
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if (!crash_base)
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crash_base = memblock_phys_alloc_range(crash_size,
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CRASH_ALIGN, CRASH_ALIGN,
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CRASH_ADDR_HIGH_MAX);
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if (!crash_base) {
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pr_info("crashkernel reservation failed - No suitable area found.\n");
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return;
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}
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} else {
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unsigned long long start;
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-
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start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
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-
crash_base + crash_size);
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if (start != crash_base) {
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pr_info("crashkernel reservation failed - memory is in use.\n");
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return;
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}
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}
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-
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if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
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memblock_phys_free(crash_base, crash_size);
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return;
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}
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-
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pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
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(unsigned long)(crash_size >> 20),
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(unsigned long)(crash_base >> 20),
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-
(unsigned long)(total_mem >> 20));
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-
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crashk_res.start = crash_base;
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crashk_res.end = crash_base + crash_size - 1;
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insert_resource(&iomem_resource, &crashk_res);
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+
reserve_crashkernel_generic(cmdline, crash_size, crash_base,
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+
low_size, high);
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}
619
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static struct resource standard_io_resources[] = {
···
1102
1228
* Reserve memory for crash kernel after SRAT is parsed so that it
1103
1229
* won't consume hotpluggable memory.
1104
1230
*/
1105
-
reserve_crashkernel();
1231
+
arch_reserve_crashkernel();
1106
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1107
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memblock_find_dma_reserve();
1108
1234