1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _X86_CRASH_RESERVE_H 3 #define _X86_CRASH_RESERVE_H 4 5 /* 16M alignment for crash kernel regions */ 6 #define CRASH_ALIGN SZ_16M 7 8 /* 9 * Keep the crash kernel below this limit. 10 * 11 * Earlier 32-bits kernels would limit the kernel to the low 512 MB range 12 * due to mapping restrictions. 13 * 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 19 * loaded for dumping. 20 */ 21 extern unsigned long swiotlb_size_or_default(void); 22 23 #ifdef CONFIG_X86_32 24 # define CRASH_ADDR_LOW_MAX SZ_512M 25 # define CRASH_ADDR_HIGH_MAX SZ_512M 26 #else 27 # define CRASH_ADDR_LOW_MAX SZ_4G 28 # define CRASH_ADDR_HIGH_MAX SZ_64T 29 #endif 30 31 # define DEFAULT_CRASH_KERNEL_LOW_SIZE crash_low_size_default() 32 33 static inline unsigned long crash_low_size_default(void) 34 { 35 #ifdef CONFIG_X86_64 36 return max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20); 37 #else 38 return 0; 39 #endif 40 } 41 42 #define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY 43 44 #endif /* _X86_CRASH_RESERVE_H */ 45