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Date: Thu, 7 Aug 2014 08:01:48 -0700 From: Kees Cook <keescook@...omium.org> To: linux-kernel@...r.kernel.org Cc: Kees Cook <keescook@...omium.org>, Liu hua <sdu.liu@...wei.com>, Mark Salter <msalter@...hat.com>, Rabin Vincent <rabin@....in>, Nikolay Borisov <Nikolay.Borisov@....com>, Nicolas Pitre <nicolas.pitre@...aro.org>, Leif Lindholm <leif.lindholm@...aro.org>, Tomasz Figa <t.figa@...sung.com>, Rob Herring <robh@...nel.org>, Doug Anderson <dianders@...gle.com>, Jason Wessel <jason.wessel@...driver.com>, Will Deacon <will.deacon@....com>, Laura Abbott <lauraa@...eaurora.org>, Catalin Marinas <catalin.marinas@....com>, Russell King - ARM Linux <linux@....linux.org.uk>, linux-arm-kernel@...ts.infradead.org Subject: [PATCH 3/8] arm: mm: reduce fixmap kmap from 32 to 16 CPUS More room is needed in the fixmap range for non-kmap fixmap entries. This reduces the kmap range from 32 to 16 CPUs. Additionally, add PTE entry for fixmap regardless of CONFIG_HIGHMEM. Signed-off-by: Kees Cook <keescook@...omium.org> --- arch/arm/include/asm/fixmap.h | 12 ++++++++++-- arch/arm/mm/highmem.c | 2 -- arch/arm/mm/mm.h | 3 +++ arch/arm/mm/mmu.c | 5 ++++- 4 files changed, 17 insertions(+), 5 deletions(-) diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h index 8ee7cb4f62ca..3ed08232be55 100644 --- a/arch/arm/include/asm/fixmap.h +++ b/arch/arm/include/asm/fixmap.h @@ -1,16 +1,24 @@ #ifndef _ASM_FIXMAP_H #define _ASM_FIXMAP_H +/* + * The fixmap uses 2MB. The KMAP fixmap needs 64k per CPU, so make room for + * 16 CPUs (taking 1MB) and leave the rest for additional fixmap areas. + */ #define FIXADDR_START 0xffc00000UL #define FIXADDR_END 0xffe00000UL #define FIXADDR_TOP (FIXADDR_END - PAGE_SIZE) #define FIXADDR_SIZE (FIXADDR_END - FIXADDR_START) -#define FIX_KMAP_NR_PTES (FIXADDR_SIZE >> PAGE_SHIFT) +/* 16 PTEs per CPU (64k of 4k pages). */ +#define FIX_KMAP_NR_PTES 16 +#define FIX_KMAP_NR_CPUS 16 enum fixed_addresses { + /* Support 16 CPUs for kmap as the first region of fixmap entries. */ FIX_KMAP_BEGIN, - FIX_KMAP_END = FIX_KMAP_NR_PTES - 1, + FIX_KMAP_END = (FIX_KMAP_NR_PTES * FIX_KMAP_NR_CPUS) - 1, + __end_of_fixed_addresses }; diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c index a1241ee8425e..adf264fb700b 100644 --- a/arch/arm/mm/highmem.c +++ b/arch/arm/mm/highmem.c @@ -18,8 +18,6 @@ #include <asm/tlbflush.h> #include "mm.h" -pte_t *fixmap_page_table; - static inline void set_fixmap_pte(int idx, pte_t pte) { unsigned long vaddr = __fix_to_virt(idx); diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h index ce727d47275c..c8b5b2d05b55 100644 --- a/arch/arm/mm/mm.h +++ b/arch/arm/mm/mm.h @@ -7,6 +7,9 @@ /* the upper-most page table pointer */ extern pmd_t *top_pmd; +/* The fixmap PTE. */ +extern pte_t *fixmap_page_table; + /* * 0xffff8000 to 0xffffffff is reserved for any ARM architecture * specific hacks for copying pages efficiently, while 0xffff4000 diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index e881ed817a8b..a7a756603775 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -53,6 +53,9 @@ EXPORT_SYMBOL(empty_zero_page); */ pmd_t *top_pmd; +/* The fixmap PTE. */ +pte_t *fixmap_page_table; + #define CPOLICY_UNCACHED 0 #define CPOLICY_BUFFERED 1 #define CPOLICY_WRITETHROUGH 2 @@ -1342,10 +1345,10 @@ static void __init kmap_init(void) #ifdef CONFIG_HIGHMEM pkmap_page_table = early_pte_alloc(pmd_off_k(PKMAP_BASE), PKMAP_BASE, _PAGE_KERNEL_TABLE); +#endif fixmap_page_table = early_pte_alloc(pmd_off_k(FIXADDR_START), FIXADDR_START, _PAGE_KERNEL_TABLE); -#endif } static void __init map_lowmem(void) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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