From mboxrd@z Thu Jan 1 00:00:00 1970 From: minchan@kernel.org (Minchan Kim) Date: Wed, 23 May 2012 17:35:42 +0900 Subject: [PATCH] arm: limit memblock base address for early_pte_alloc Message-ID: <1337762142-17318-1-git-send-email-minchan@kernel.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org If we do arm_memblock_steal with a page which is not aligned with section size, panic can happen during boot by page fault in map_lowmem. Detail: 1) mdesc->reserve can steal a page which is allocated at 0x1ffff000 by memblock which prefers tail pages of regions. 2) map_lowmem maps 0x00000000 - 0x1fe00000 3) map_lowmem try to map 0x1fe00000 but it's not aligned by section due to 1. 4) calling alloc_init_pte allocates a new page for new pte by memblock_alloc 5) allocated memory for pte is 0x1fffe000 -> it's not mapped yet. 6) memset(ptr, 0, sz) in early_alloc_aligned got PANICed! This patch fix it by limiting memblock to mapped memory range. Reported-by: Jongsung Kim Suggested-by: Chanho Min Signed-off-by: Minchan Kim --- This patch is based on v3.4. arch/arm/mm/mmu.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index aa78de8..82820c2 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -586,7 +586,7 @@ static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr, static void __init alloc_init_section(pud_t *pud, unsigned long addr, unsigned long end, phys_addr_t phys, - const struct mem_type *type) + const struct mem_type *type, bool lowmem) { pmd_t *pmd = pmd_offset(pud, addr); @@ -611,6 +611,8 @@ static void __init alloc_init_section(pud_t *pud, unsigned long addr, flush_pmd_entry(p); } else { + if (lowmem) + memblock_set_current_limit(__pa(addr)); /* * No need to loop; pte's aren't interested in the * individual L1 entries. @@ -620,14 +622,15 @@ static void __init alloc_init_section(pud_t *pud, unsigned long addr, } static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr, - unsigned long end, unsigned long phys, const struct mem_type *type) + unsigned long end, unsigned long phys, + const struct mem_type *type, bool lowmem) { pud_t *pud = pud_offset(pgd, addr); unsigned long next; do { next = pud_addr_end(addr, end); - alloc_init_section(pud, addr, next, phys, type); + alloc_init_section(pud, addr, next, phys, type, lowmem); phys += next - addr; } while (pud++, addr = next, addr != end); } @@ -694,14 +697,7 @@ static void __init create_36bit_mapping(struct map_desc *md, } #endif /* !CONFIG_ARM_LPAE */ -/* - * Create the page directory entries and any necessary - * page tables for the mapping specified by `md'. We - * are able to cope here with varying sizes and address - * offsets, and we take full advantage of sections and - * supersections. - */ -static void __init create_mapping(struct map_desc *md) +static inline void __create_mapping(struct map_desc *md, bool lowmem) { unsigned long addr, length, end; phys_addr_t phys; @@ -751,7 +747,7 @@ static void __init create_mapping(struct map_desc *md) do { unsigned long next = pgd_addr_end(addr, end); - alloc_init_pud(pgd, addr, next, phys, type); + alloc_init_pud(pgd, addr, next, phys, type, lowmem); phys += next - addr; addr = next; @@ -759,6 +755,18 @@ static void __init create_mapping(struct map_desc *md) } /* + * Create the page directory entries and any necessary + * page tables for the mapping specified by `md'. We + * are able to cope here with varying sizes and address + * offsets, and we take full advantage of sections and + * supersections. + */ +static void __init create_mapping(struct map_desc *md) +{ + __create_mapping(md, false); +} + +/* * Create the architecture specific mappings */ void __init iotable_init(struct map_desc *io_desc, int nr) @@ -1103,7 +1111,7 @@ static void __init map_lowmem(void) map.length = end - start; map.type = MT_MEMORY; - create_mapping(&map); + __create_mapping(&map, true); } } @@ -1115,11 +1123,10 @@ void __init paging_init(struct machine_desc *mdesc) { void *zero_page; - memblock_set_current_limit(lowmem_limit); - build_mem_type_table(); prepare_page_table(); map_lowmem(); + memblock_set_current_limit(lowmem_limit); devicemaps_init(mdesc); kmap_init(); -- 1.7.9.5