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authorCatalin Marinas <catalin.marinas@arm.com>2012-11-15 17:21:16 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2012-11-16 15:50:25 +0000
commit8e620b0476696e9428442d3551f3dad47df0e28f (patch)
tree259e48a52e0d3725b3f77167b6195066fe26d455 /arch/arm64/include/asm/pgtable-hwdef.h
parent77b67063bb6bce6d475e910d3b886a606d0d91f7 (diff)
downloadlinux-8e620b0476696e9428442d3551f3dad47df0e28f.tar.gz
arm64: Distinguish between user and kernel XN bits
On AArch64, the meaning of the XN bit has changed to UXN (user). The PXN (privileged) bit must be set to prevent kernel execution. Without the PXN bit set, the CPU may speculatively access device memory. This patch ensures that all the mappings that the kernel must not execute from (including user mappings) have the PXN bit set. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/pgtable-hwdef.h')
-rw-r--r--arch/arm64/include/asm/pgtable-hwdef.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index 0f3b4581d92..75fd13d289b 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -38,7 +38,8 @@
#define PMD_SECT_S (_AT(pmdval_t, 3) << 8)
#define PMD_SECT_AF (_AT(pmdval_t, 1) << 10)
#define PMD_SECT_NG (_AT(pmdval_t, 1) << 11)
-#define PMD_SECT_XN (_AT(pmdval_t, 1) << 54)
+#define PMD_SECT_PXN (_AT(pmdval_t, 1) << 53)
+#define PMD_SECT_UXN (_AT(pmdval_t, 1) << 54)
/*
* AttrIndx[2:0] encoding (mapping attributes defined in the MAIR* registers).
@@ -57,7 +58,8 @@
#define PTE_SHARED (_AT(pteval_t, 3) << 8) /* SH[1:0], inner shareable */
#define PTE_AF (_AT(pteval_t, 1) << 10) /* Access Flag */
#define PTE_NG (_AT(pteval_t, 1) << 11) /* nG */
-#define PTE_XN (_AT(pteval_t, 1) << 54) /* XN */
+#define PTE_PXN (_AT(pteval_t, 1) << 53) /* Privileged XN */
+#define PTE_UXN (_AT(pteval_t, 1) << 54) /* User XN */
/*
* AttrIndx[2:0] encoding (mapping attributes defined in the MAIR* registers).