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.biesheu...@linaro.org>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poul...@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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