1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _X86_CRASH_RESERVE_H
3 #define _X86_CRASH_RESERVE_H
5 /* 16M alignment for crash kernel regions */
6 #define CRASH_ALIGN SZ_16M
9 * Keep the crash kernel below this limit.
11 * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
12 * due to mapping restrictions.
14 * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
15 * the upper limit of system RAM in 4-level paging mode. Since the kdump
16 * jump could be from 5-level paging to 4-level paging, the jump will fail if
17 * the kernel is put above 64 TB, and during the 1st kernel bootup there's
18 * no good way to detect the paging mode of the target kernel which will be
21 extern unsigned long swiotlb_size_or_default(void);
24 # define CRASH_ADDR_LOW_MAX SZ_512M
25 # define CRASH_ADDR_HIGH_MAX SZ_512M
27 # define CRASH_ADDR_LOW_MAX SZ_4G
28 # define CRASH_ADDR_HIGH_MAX SZ_64T
31 # define DEFAULT_CRASH_KERNEL_LOW_SIZE crash_low_size_default()
33 static inline unsigned long crash_low_size_default(void)
36 return max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
42 #define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
44 #endif /* _X86_CRASH_RESERVE_H */