On Sun, 13 Apr 2014, Liu hua wrote: > Hi Nicolas. > > Sure, your suggestion made my patch looks better. How about that : > > Thanks, > Liu Hua
There is something else that bothers me. > ------------------------------------------------- > > Changes from v2: > moved new codes to highmem.c as more as possible. > unchanged Document/arm/memory.txt. > > > In 32-bit ARM systems, the fixmap mapping region can support > no more than 14 CPUs(total: 896k; one CPU: 64K). And we can > configure NR_CPUS up to 32. So there is a mismatch. > > This patch moves fixmapping region downwards to region > 0xffc00000-0xffe00000 . Then the fixmap mapping region can > support up to 32 CPUs > > Acked-by: Nicolas Pitre <[email protected]> > Signed-off-by: Liu Hua <[email protected]> > --- > arch/arm/include/asm/fixmap.h | 4 ++-- > arch/arm/include/asm/highmem.h | 1 + > arch/arm/mm/highmem.c | 28 ++++++++++++++++++++++------ > arch/arm/mm/mmu.c | 4 ++++ > 4 files changed, 29 insertions(+), 8 deletions(-) > > diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h > index bbae919..014a70d 100644 > --- a/arch/arm/include/asm/fixmap.h > +++ b/arch/arm/include/asm/fixmap.h > @@ -13,8 +13,8 @@ > * 0xfffe0000 and 0xfffeffff. > */ > > -#define FIXADDR_START 0xfff00000UL > -#define FIXADDR_TOP 0xfffe0000UL > +#define FIXADDR_START 0xffc00000UL > +#define FIXADDR_TOP 0xffe00000UL > #define FIXADDR_SIZE (FIXADDR_TOP - FIXADDR_START) > > #define FIX_KMAP_BEGIN 0 > diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h > index 91b99ab..5355795 100644 > --- a/arch/arm/include/asm/highmem.h > +++ b/arch/arm/include/asm/highmem.h > @@ -18,6 +18,7 @@ > } while (0) > > extern pte_t *pkmap_page_table; > +extern pte_t *fixmap_page_table; > > extern void *kmap_high(struct page *page); > extern void kunmap_high(struct page *page); > diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c > index 21b9e1b..fa97896 100644 > --- a/arch/arm/mm/highmem.c > +++ b/arch/arm/mm/highmem.c > @@ -18,6 +18,22 @@ > #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(FIX_KMAP_BEGIN + idx); > + set_pte_ext(fixmap_page_table + idx, 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 -= FIX_KMAP_BEGIN; > + return *(fixmap_page_table + idx); FIX_KMAP_BEGIN represents the starting point for mapping fixmap indices to page table entries. So here you should _add_ the FIX_KMAP_BEGIN offset to the page table index not substract it. Currently FIX_KMAP_BEGIN is defined to 0 but still. > +} > + > void *kmap(struct page *page) > { > might_sleep(); > @@ -69,14 +85,14 @@ void *kmap_atomic(struct page *page) > * With debugging enabled, kunmap_atomic forces that entry to 0. > * Make sure it was indeed properly unmapped. > */ > - BUG_ON(!pte_none(get_top_pte(vaddr))); > + BUG_ON(!pte_none(*(fixmap_page_table + idx))); This is therefore also wrong. It should be fixmap_page_table + idx + FIX_KMAP_BEGIN. > #endif > /* > * When debugging is off, kunmap_atomic leaves the previous mapping > * in place, so the contained TLB flush ensures the TLB is updated > * with the new mapping. > */ > - set_top_pte(vaddr, mk_pte(page, kmap_prot)); > + set_fixmap_pte(idx, mk_pte(page, kmap_prot)); > > return (void *)vaddr; > } > @@ -95,7 +111,7 @@ void __kunmap_atomic(void *kvaddr) > __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE); > #ifdef CONFIG_DEBUG_HIGHMEM > BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); > - set_top_pte(vaddr, __pte(0)); > + set_fixmap_pte(idx, __pte(0)); > #else > (void) idx; /* to kill a warning */ > #endif > @@ -119,9 +135,9 @@ void *kmap_atomic_pfn(unsigned long pfn) > idx = type + KM_TYPE_NR * smp_processor_id(); > vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); > #ifdef CONFIG_DEBUG_HIGHMEM > - BUG_ON(!pte_none(get_top_pte(vaddr))); > + BUG_ON(!pte_none(*(fixmap_page_table + idx))); Ditto here. In fact, this FIX_KMAP_BEGIN is only creating more confusing code for nothing as we define it to 0 anyway, and it is not used by non architecture specific code. So I'd suggest you create a patch to be applied before this one that simply gets rid of FIX_KMAP_BEGIN and FIX_KMAP_END altogether. We could reintroduce them back if ever they're needed. Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
