On systems where CTR_EL0.DIC is set, we don't need to perform
icache invalidation to guarantee that we'll fetch the right
instruction stream.
This also means that taking a permission fault to invalidate the
icache is an unnecessary overhead.
On such systems, we can safely leave the page as being executable.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm64/include/asm/pgtable-prot.h | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index c66c3047400e..78b942c1bea4 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -77,8 +77,18 @@
__val; \
})
-#define PAGE_S2 __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PTE_S2_XN)
-#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_S2_XN)
+#define PAGE_S2_XN \
+ ({ \
+ u64 __val; \
+ if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) \
+ __val = 0; \
+ else \
+ __val = PTE_S2_XN; \
+ __val; \
+ })
+
+#define PAGE_S2 __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PAGE_S2_XN)
+#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PAGE_S2_XN)
#define PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
#define PAGE_SHARED __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
--
2.14.2
