[PATCH 3/7] arm: mm: reduce fixmap kmap from 32 to 16 CPUS
From: Kees Cook <hidden>
Date: 2014-08-06 19:35:45
Also in:
lkml
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
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 <redacted> --- 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 45aeaaca9052..cbbef0b533d6 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 b005a3337bc1..8dbdadc42d75 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