Messages in this thread Patch in this message | | | Subject | Re: [PATCHv3 02/11] arm64: Handle section maps for swapper/idmap | From | "Suzuki K. Poulose" <> | Date | Wed, 14 Oct 2015 14:21:24 +0100 |
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On 14/10/15 13:06, Mark Rutland wrote: > On Wed, Oct 14, 2015 at 12:20:25PM +0100, Suzuki K. Poulose wrote: >> We use section maps with 4K page size to create the swapper/idmaps. >> So far we have used !64K or 4K checks to handle the case where we >> use the section maps. >> This patch adds a new symbol, ARM64_SWAPPER_USES_SECTION_MAPS, to >> handle cases where we use section maps, instead of using the page size >> symbols. >> >> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Will Deacon <will.deacon@arm.com> >> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com> >> --- >> arch/arm64/include/asm/kernel-pgtable.h | 31 ++++++++----- >> arch/arm64/mm/mmu.c | 72 ++++++++++++++----------------- >> 2 files changed, 52 insertions(+), 51 deletions(-) >> >> diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h >> index 622929d..5876a36 100644 >> --- a/arch/arm64/include/asm/kernel-pgtable.h >> +++ b/arch/arm64/include/asm/kernel-pgtable.h >> @@ -19,6 +19,13 @@ >> #ifndef __ASM_KERNEL_PGTABLE_H >> #define __ASM_KERNEL_PGTABLE_H >> >> +/* With 4K pages, we use section maps. */ >> +#ifdef CONFIG_ARM64_4K_PAGES >> +#define ARM64_SWAPPER_USES_SECTION_MAPS 1 >> +#else >> +#define ARM64_SWAPPER_USES_SECTION_MAPS 0 >> +#endif > > The comment is somewhat redunant. It would be better to state why we do > this for 4K and not 64K (or 16K).
Something like :
/* * ARM64 kernel is guaranteed to be loaded at 2M aligned * address (as per booting requirements). Hence we can use * section mapping with 4K (section size = 2M) and not with * 16K(section size = 32M) or 64K (section size = 512M). */
>> + * us PUD_SIZE (with SECTION maps, i.e, 4K) or PMD_SIZE (without >> + * SECTION maps, i.e, 64K pages) memory starting from PHYS_OFFSET >> + * (which must be aligned to 2MB as per Documentation/arm64/booting.txt). > > This didn't seem to get updated for 16K later in the series, unless I > missed something. > > Perhaps drop the mention of 4K / 64K entirely here?
You are right, I missed it. We can drop the pagesize info entirely.
> >> @@ -551,7 +552,7 @@ int kern_addr_valid(unsigned long addr) >> return pfn_valid(pte_pfn(*pte)); >> } >> #ifdef CONFIG_SPARSEMEM_VMEMMAP >> -#ifdef CONFIG_ARM64_64K_PAGES >> +#if !ARM64_SWAPPER_USES_SECTION_MAPS > > This leaves the comments on the #else and #endif stale. Please update > those too.
Done.
Thanks Suzuki
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