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linux/arch/x86/include/asm/crash_reserve.h
Baoquan He 32fbe52465 crash: use macro to add crashk_res into iomem early for specific arch
There are regression reports[1][2] that crashkernel region on x86_64 can't
be added into iomem tree sometime.  This causes the later failure of kdump
loading.

This happened after commit 4a693ce65b ("kdump: defer the insertion of
crashkernel resources") was merged.

Even though, these reported issues are proved to be related to other
component, they are just exposed after above commmit applied, I still
would like to keep crashk_res and crashk_low_res being added into iomem
early as before because the early adding has been always there on x86_64
and working very well.  For safety of kdump, Let's change it back.

Here, add a macro HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY to limit that
only ARCH defining the macro can have the early adding
crashk_res/_low_res into iomem. Then define
HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY on x86 to enable it.

Note: In reserve_crashkernel_low(), there's a remnant of crashk_low_res
handling which was mistakenly added back in commit 85fcde402d ("kexec:
split crashkernel reservation code out from crash_core.c").

[1]
[PATCH V2] x86/kexec: do not update E820 kexec table for setup_data
https://lore.kernel.org/all/Zfv8iCL6CT2JqLIC@darkstar.users.ipa.redhat.com/T/#u

[2]
Question about Address Range Validation in Crash Kernel Allocation
https://lore.kernel.org/all/4eeac1f733584855965a2ea62fa4da58@huawei.com/T/#u

Link: https://lkml.kernel.org/r/ZgDYemRQ2jxjLkq+@MiWiFi-R3L-srv
Fixes: 4a693ce65b ("kdump: defer the insertion of crashkernel resources")
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-26 11:14:12 -07:00

44 lines
1.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _X86_CRASH_RESERVE_H
#define _X86_CRASH_RESERVE_H
/* 16M alignment for crash kernel regions */
#define CRASH_ALIGN SZ_16M
/*
* Keep the crash kernel below this limit.
*
* Earlier 32-bits kernels would limit the kernel to the low 512 MB range
* due to mapping restrictions.
*
* 64-bit kdump kernels need to be restricted to be under 64 TB, which is
* the upper limit of system RAM in 4-level paging mode. Since the kdump
* jump could be from 5-level paging to 4-level paging, the jump will fail if
* the kernel is put above 64 TB, and during the 1st kernel bootup there's
* no good way to detect the paging mode of the target kernel which will be
* loaded for dumping.
*/
extern unsigned long swiotlb_size_or_default(void);
#ifdef CONFIG_X86_32
# define CRASH_ADDR_LOW_MAX SZ_512M
# define CRASH_ADDR_HIGH_MAX SZ_512M
#else
# define CRASH_ADDR_LOW_MAX SZ_4G
# define CRASH_ADDR_HIGH_MAX SZ_64T
#endif
# define DEFAULT_CRASH_KERNEL_LOW_SIZE crash_low_size_default()
static inline unsigned long crash_low_size_default(void)
{
#ifdef CONFIG_X86_64
return max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
#else
return 0;
#endif
}
#define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
#endif /* _X86_CRASH_RESERVE_H */