On Mon, Apr 15, 2019 at 10:27:30AM +0800, Chen Zhou wrote: > 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 for the clarification! > Thanks, > Chen Zhou > > > > >> Signed-off-by: Chen Zhou <chenzhou10@xxxxxxxxxx> > >> --- > >> 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 > >> > > > -- Sincerely yours, Mike.
