Messages in this thread | | | Date | Thu, 7 Aug 2014 10:47:30 -0700 | Subject | Re: [PATCH 1/8] arm: use generic fixmap.h | From | Kees Cook <> |
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On Thu, Aug 7, 2014 at 10:38 AM, Leif Lindholm <leif.lindholm@linaro.org> wrote: > On Thu, Aug 07, 2014 at 08:01:46AM -0700, Kees Cook wrote: >> From: Mark Salter <msalter@redhat.com> >> >> ARM is different from other architectures in that fixmap pages are indexed >> with a positive offset from FIXADDR_START. Other architectures index with >> a negative offset from FIXADDR_TOP. In order to use the generic fixmap.h >> definitions, this patch redefines FIXADDR_TOP to be inclusive of the >> useable range. That is, FIXADDR_TOP is the virtual address of the topmost >> fixed page. The newly defined FIXADDR_END is the first virtual address >> past the fixed mappings. >> >> Signed-off-by: Mark Salter <msalter@redhat.com> >> Reviewed-by: Doug Anderson <dianders@chromium.org> >> [update for "ARM: 8031/2: change fixmap mapping region to support 32 CPUs"] >> [flipped highmem order, thanks to Laura Abbott] >> Signed-off-by: Kees Cook <keescook@chromium.org> >> Cc: Laura Abbott <lauraa@codeaurora.org> >> --- >> arch/arm/include/asm/fixmap.h | 27 +++++++++------------------ >> arch/arm/mm/highmem.c | 8 ++++++-- >> arch/arm/mm/init.c | 2 +- >> 3 files changed, 16 insertions(+), 21 deletions(-) >> >> diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h >> index 74124b0d0d79..190142d174ee 100644 >> --- a/arch/arm/include/asm/fixmap.h >> +++ b/arch/arm/include/asm/fixmap.h >> @@ -2,27 +2,18 @@ >> #define _ASM_FIXMAP_H >> >> #define FIXADDR_START 0xffc00000UL >> -#define FIXADDR_TOP 0xffe00000UL >> -#define FIXADDR_SIZE (FIXADDR_TOP - FIXADDR_START) >> +#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) >> >> -#define __fix_to_virt(x) (FIXADDR_START + ((x) << PAGE_SHIFT)) >> -#define __virt_to_fix(x) (((x) - FIXADDR_START) >> PAGE_SHIFT) >> +enum fixed_addresses { >> + FIX_KMAP_BEGIN, >> + FIX_KMAP_END = FIX_KMAP_NR_PTES - 1, >> + __end_of_fixed_addresses >> +}; >> >> -extern void __this_fixmap_does_not_exist(void); >> - >> -static inline unsigned long fix_to_virt(const unsigned int idx) >> -{ >> - if (idx >= FIX_KMAP_NR_PTES) >> - __this_fixmap_does_not_exist(); >> - return __fix_to_virt(idx); >> -} >> - >> -static inline unsigned int virt_to_fix(const unsigned long vaddr) >> -{ >> - BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); >> - return __virt_to_fix(vaddr); >> -} >> +#include <asm-generic/fixmap.h> >> >> #endif >> diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c >> index 45aeaaca9052..a1241ee8425e 100644 >> --- a/arch/arm/mm/highmem.c >> +++ b/arch/arm/mm/highmem.c >> @@ -23,14 +23,18 @@ pte_t *fixmap_page_table; >> static inline void set_fixmap_pte(int idx, pte_t pte) >> { >> unsigned long vaddr = __fix_to_virt(idx); >> - set_pte_ext(fixmap_page_table + idx, pte, 0); >> + pte_t *ppte = pte_offset_kernel(pmd_off_k(FIXADDR_START), vaddr); >> + >> + set_pte_ext(ppte, pte, 0); >> local_flush_tlb_kernel_page(vaddr); >> } >> >> static inline pte_t get_fixmap_pte(unsigned long vaddr) >> { >> unsigned long idx = __virt_to_fix(vaddr); > > idx is now "unused variable".
Ah! Yes, thanks. I'll add HIGHMEM to my build cycles.
> >> - return *(fixmap_page_table + idx); >> + pte_t *ppte = pte_offset_kernel(pmd_off_k(FIXADDR_START), vaddr); >> + >> + return *ppte; >> } >> >> void *kmap(struct page *page) >> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c >> index 659c75d808dc..ad82c05bfc3a 100644 >> --- a/arch/arm/mm/init.c >> +++ b/arch/arm/mm/init.c >> @@ -570,7 +570,7 @@ void __init mem_init(void) >> MLK(DTCM_OFFSET, (unsigned long) dtcm_end), >> MLK(ITCM_OFFSET, (unsigned long) itcm_end), >> #endif >> - MLK(FIXADDR_START, FIXADDR_TOP), >> + MLK(FIXADDR_START, FIXADDR_END), >> MLM(VMALLOC_START, VMALLOC_END), >> MLM(PAGE_OFFSET, (unsigned long)high_memory), >> #ifdef CONFIG_HIGHMEM >> -- >> 1.9.1 > > Apart from that, verified with early_ioremap/UEFI patches on TC2. > > Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Thanks! I've added this and fixed idx above for the future v3 of this series.
-Kees
-- Kees Cook Chrome OS Security
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