Hi Mike, On 2019/4/14 20:13, Mike Rapoport wrote: > Hi, > > On Tue, Apr 09, 2019 at 06:28:18PM +0800, Chen Zhou wrote: >> After commit (arm64: kdump: support reserving crashkernel above 4G), >> there may be two crash kernel regions, one is below 4G, the other is >> above 4G. >> >> Crash dump kernel reads more than one crash kernel regions via a dtb >> property under node /chosen, >> linux,usable-memory-range = <BASE1 SIZE1 [BASE2 SIZE2]> > > Somehow I've missed that previously, but how is this supposed to work on > EFI systems?
Whatever the way in which the systems work, there is FDT pointer(__fdt_pointer) in arm64 kernel and file /sys/firmware/fdt will be created in late_initcall. Kexec-tools read and update file /sys/firmware/fdt in EFI systems to support kdump to boot capture kernel. For supporting more than one crash kernel regions, kexec-tools make changes accordingly. Details are in below: http://lists.infradead.org/pipermail/kexec/2019-April/022792.html Thanks, Chen Zhou > >> Signed-off-by: Chen Zhou <chenzho...@huawei.com> >> --- >> arch/arm64/mm/init.c | 66 >> ++++++++++++++++++++++++++++++++++++++++-------- >> include/linux/memblock.h | 6 +++++ >> mm/memblock.c | 7 ++--- >> 3 files changed, 66 insertions(+), 13 deletions(-) >> >> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c >> index 3bebddf..0f18665 100644 >> --- a/arch/arm64/mm/init.c >> +++ b/arch/arm64/mm/init.c >> @@ -65,6 +65,11 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init; >> >> #ifdef CONFIG_KEXEC_CORE >> >> +/* at most two crash kernel regions, low_region and high_region */ >> +#define CRASH_MAX_USABLE_RANGES 2 >> +#define LOW_REGION_IDX 0 >> +#define HIGH_REGION_IDX 1 >> + >> /* >> * reserve_crashkernel() - reserves memory for crash kernel >> * >> @@ -297,8 +302,8 @@ static int __init early_init_dt_scan_usablemem(unsigned >> long node, >> const char *uname, int depth, void *data) >> { >> struct memblock_region *usablemem = data; >> - const __be32 *reg; >> - int len; >> + const __be32 *reg, *endp; >> + int len, nr = 0; >> >> if (depth != 1 || strcmp(uname, "chosen") != 0) >> return 0; >> @@ -307,22 +312,63 @@ static int __init >> early_init_dt_scan_usablemem(unsigned long node, >> if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells))) >> return 1; >> >> - usablemem->base = dt_mem_next_cell(dt_root_addr_cells, ®); >> - usablemem->size = dt_mem_next_cell(dt_root_size_cells, ®); >> + endp = reg + (len / sizeof(__be32)); >> + while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) { >> + usablemem[nr].base = dt_mem_next_cell(dt_root_addr_cells, ®); >> + usablemem[nr].size = dt_mem_next_cell(dt_root_size_cells, ®); >> + >> + if (++nr >= CRASH_MAX_USABLE_RANGES) >> + break; >> + } >> >> return 1; >> } >> >> static void __init fdt_enforce_memory_region(void) >> { >> - struct memblock_region reg = { >> - .size = 0, >> - }; >> + int i, cnt = 0; >> + struct memblock_region regs[CRASH_MAX_USABLE_RANGES]; >> + >> + memset(regs, 0, sizeof(regs)); >> + of_scan_flat_dt(early_init_dt_scan_usablemem, regs); >> + >> + for (i = 0; i < CRASH_MAX_USABLE_RANGES; i++) >> + if (regs[i].size) >> + cnt++; >> + else >> + break; >> + >> + if (cnt - 1 == LOW_REGION_IDX) >> + memblock_cap_memory_range(regs[LOW_REGION_IDX].base, >> + regs[LOW_REGION_IDX].size); >> + else if (cnt - 1 == HIGH_REGION_IDX) { >> + /* >> + * Two crash kernel regions, cap the memory range >> + * [regs[LOW_REGION_IDX].base, regs[HIGH_REGION_IDX].end] >> + * and then remove the memory range in the middle. >> + */ >> + int start_rgn, end_rgn, i, ret; >> + phys_addr_t mid_base, mid_size; >> + >> + mid_base = regs[LOW_REGION_IDX].base + >> regs[LOW_REGION_IDX].size; >> + mid_size = regs[HIGH_REGION_IDX].base - mid_base; >> + ret = memblock_isolate_range(&memblock.memory, mid_base, >> + mid_size, &start_rgn, &end_rgn); >> >> - of_scan_flat_dt(early_init_dt_scan_usablemem, ®); >> + if (ret) >> + return; >> >> - if (reg.size) >> - memblock_cap_memory_range(reg.base, reg.size); >> + memblock_cap_memory_range(regs[LOW_REGION_IDX].base, >> + regs[HIGH_REGION_IDX].base - >> + regs[LOW_REGION_IDX].base + >> + regs[HIGH_REGION_IDX].size); >> + for (i = end_rgn - 1; i >= start_rgn; i--) { >> + if (!memblock_is_nomap(&memblock.memory.regions[i])) >> + memblock_remove_region(&memblock.memory, i); >> + } >> + memblock_remove_range(&memblock.reserved, mid_base, >> + mid_base + mid_size); >> + } >> } >> >> void __init arm64_memblock_init(void) >> diff --git a/include/linux/memblock.h b/include/linux/memblock.h >> index 294d5d8..787d252 100644 >> --- a/include/linux/memblock.h >> +++ b/include/linux/memblock.h >> @@ -110,9 +110,15 @@ void memblock_discard(void); >> >> phys_addr_t memblock_find_in_range(phys_addr_t start, phys_addr_t end, >> phys_addr_t size, phys_addr_t align); >> +void memblock_remove_region(struct memblock_type *type, unsigned long r); >> void memblock_allow_resize(void); >> int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid); >> int memblock_add(phys_addr_t base, phys_addr_t size); >> +int memblock_isolate_range(struct memblock_type *type, >> + phys_addr_t base, phys_addr_t size, >> + int *start_rgn, int *end_rgn); >> +int memblock_remove_range(struct memblock_type *type, >> + phys_addr_t base, phys_addr_t size); >> int memblock_remove(phys_addr_t base, phys_addr_t size); >> int memblock_free(phys_addr_t base, phys_addr_t size); >> int memblock_reserve(phys_addr_t base, phys_addr_t size); >> diff --git a/mm/memblock.c b/mm/memblock.c >> index e7665cf..1846e2d 100644 >> --- a/mm/memblock.c >> +++ b/mm/memblock.c >> @@ -357,7 +357,8 @@ phys_addr_t __init_memblock >> memblock_find_in_range(phys_addr_t start, >> return ret; >> } >> >> -static void __init_memblock memblock_remove_region(struct memblock_type >> *type, unsigned long r) >> +void __init_memblock memblock_remove_region(struct memblock_type *type, >> + unsigned long r) >> { >> type->total_size -= type->regions[r].size; >> memmove(&type->regions[r], &type->regions[r + 1], >> @@ -724,7 +725,7 @@ int __init_memblock memblock_add(phys_addr_t base, >> phys_addr_t size) >> * Return: >> * 0 on success, -errno on failure. >> */ >> -static int __init_memblock memblock_isolate_range(struct memblock_type >> *type, >> +int __init_memblock memblock_isolate_range(struct memblock_type *type, >> phys_addr_t base, phys_addr_t size, >> int *start_rgn, int *end_rgn) >> { >> @@ -784,7 +785,7 @@ static int __init_memblock memblock_isolate_range(struct >> memblock_type *type, >> return 0; >> } >> >> -static int __init_memblock memblock_remove_range(struct memblock_type *type, >> +int __init_memblock memblock_remove_range(struct memblock_type *type, >> phys_addr_t base, phys_addr_t size) >> { >> int start_rgn, end_rgn; >> -- >> 2.7.4 >> >
