| Message ID | 53E2E354.6020902@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Aug 6, 2014 at 7:24 PM, Laura Abbott <lauraa@codeaurora.org> wrote: > On 8/6/2014 12:32 PM, 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"] >> Signed-off-by: Kees Cook <keescook@chromium.org> >> --- >> arch/arm/include/asm/fixmap.h | 27 +++++++++------------------ >> arch/arm/mm/init.c | 2 +- >> 2 files changed, 10 insertions(+), 19 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/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 >> > > I'm working off of a 3.14 kernel and with this backported > kmap_atomic does not actually map properly for me. This was > > my quick fix (not sure if we should be using __set_fixmap?). Or did > I fail at backportery? > > -----8<----- > From ea11b54704aa0a311ab3d05fd70072679bfe1a0b Mon Sep 17 00:00:00 2001 > From: Laura Abbott <lauraa@codeaurora.org> > Date: Wed, 6 Aug 2014 19:20:46 -0700 > Subject: [PATCH] arm: Get proper pte for fixmaps > > The generic fixmap.h gets indexes from high to low instead > of low to high so the fixmap idx does not correspond to > the array entry in fixmap_page_table. Get the proper pte > to update. > > Signed-off-by: Laura Abbott <lauraa@codeaurora.org> > --- > arch/arm/mm/highmem.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c > index bedca3a..7f08e64 100644 > --- a/arch/arm/mm/highmem.c > +++ b/arch/arm/mm/highmem.c > @@ -22,14 +22,18 @@ > 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); > - return *(fixmap_page_table + idx); > + pte_t *ppte = pte_offset_kernel(pmd_off_k(FIXADDR_START), vaddr); > + > + return *ppte; > } IIUC, what you have is correct: it matches what I had to do for __set_fixmap and flips the high/low indexing. Thanks! I'll merge this with the "use generic fixmap" patch, since it's what flips around the ordering. -Kees
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c index bedca3a..7f08e64 100644 --- a/arch/arm/mm/highmem.c +++ b/arch/arm/mm/highmem.c @@ -22,14 +22,18 @@ 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); - return *(fixmap_page_table + idx); + pte_t *ppte = pte_offset_kernel(pmd_off_k(FIXADDR_START), vaddr); + + return *ppte; } void *kmap(struct page *page)