From: Catalin Marinas catalin.marinas@arm.com
commit 2687275a5843d1089687f08fc64eb3f3b026a169 upstream.
mem_init() currently relies on knowing the boundaries of the crashkernel reservation to map such region with page granularity for later unmapping via set_memory_valid(..., 0). If the crashkernel reservation is deferred, such boundaries are not known when the linear mapping is created. Simply parse the command line for "crashkernel" and, if found, create the linear map with NO_BLOCK_MAPPINGS.
Signed-off-by: Catalin Marinas catalin.marinas@arm.com Tested-by: Nicolas Saenz Julienne nsaenzjulienne@suse.de Reviewed-by: Nicolas Saenz Julienne nsaenzjulienne@suse.de Acked-by: James Morse james.morse@arm.com Cc: James Morse james.morse@arm.com Cc: Nicolas Saenz Julienne nsaenzjulienne@suse.de Link: https://lore.kernel.org/r/20201119175556.18681-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/mm/mmu.c | 37 ++++++++++++++++--------------------- 1 file changed, 16 insertions(+), 21 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index afdad7607850..58dc93e56617 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -469,6 +469,21 @@ void __init mark_linear_text_alias_ro(void) PAGE_KERNEL_RO); }
+static bool crash_mem_map __initdata; + +static int __init enable_crash_mem_map(char *arg) +{ + /* + * Proper parameter parsing is done by reserve_crashkernel(). We only + * need to know if the linear map has to avoid block mappings so that + * the crashkernel reservations can be unmapped later. + */ + crash_mem_map = true; + + return 0; +} +early_param("crashkernel", enable_crash_mem_map); + static void __init map_mem(pgd_t *pgdp) { phys_addr_t kernel_start = __pa_symbol(_text); @@ -477,7 +492,7 @@ static void __init map_mem(pgd_t *pgdp) int flags = 0; u64 i;
- if (rodata_full || debug_pagealloc_enabled()) + if (rodata_full || crash_mem_map || debug_pagealloc_enabled()) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
/* @@ -487,11 +502,6 @@ static void __init map_mem(pgd_t *pgdp) * the following for-loop */ memblock_mark_nomap(kernel_start, kernel_end - kernel_start); -#ifdef CONFIG_KEXEC_CORE - if (crashk_res.end) - memblock_mark_nomap(crashk_res.start, - resource_size(&crashk_res)); -#endif
/* map all the memory banks */ for_each_mem_range(i, &start, &end) { @@ -519,21 +529,6 @@ static void __init map_mem(pgd_t *pgdp) __map_memblock(pgdp, kernel_start, kernel_end, PAGE_KERNEL, NO_CONT_MAPPINGS); memblock_clear_nomap(kernel_start, kernel_end - kernel_start); - -#ifdef CONFIG_KEXEC_CORE - /* - * Use page-level mappings here so that we can shrink the region - * in page granularity and put back unused memory to buddy system - * through /sys/kernel/kexec_crash_size interface. - */ - if (crashk_res.end) { - __map_memblock(pgdp, crashk_res.start, crashk_res.end + 1, - PAGE_KERNEL, - NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); - memblock_clear_nomap(crashk_res.start, - resource_size(&crashk_res)); - } -#endif }
void mark_rodata_ro(void)