Patrick Georgi (pgeorgi@google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/11722
-gerrit
commit 5d78f70ff7bbe0b8886b2410f72b051683093a60 Author: Jimmy Huang jimmy.huang@mediatek.com Date: Tue Sep 15 15:29:10 2015 +0800
arm64: mmu: Prevent CPU prefetch instructions from device memory
Set XN bit of block upper attribute to device memory in mmu. CPU may speculatively prefetch instructions from device memory, but the IO subsystem of some implementation may not support this operation. Set this attribute to device memory mmu entries can prevent CPU from prefetching device memory.
BRANCH=none BUG=none TEST=build and booted to kernel on oak-rev3 with dcm enabled.
Change-Id: I52ac7d7c84220624aaf6a48d64b9110d7afeb293 Signed-off-by: Patrick Georgi pgeorgi@chromium.org Original-Commit-Id: 7b01a4157cb046a5e75ea7625060a602e7a63c3c Original-Change-Id: Id535e990a23b6c89123b5a4e64d7ed21eebed607 Original-Signed-off-by: Jimmy Huang jimmy.huang@mediatek.com Original-Reviewed-on: https://chromium-review.googlesource.com/302301 Original-Commit-Ready: Yidi Lin yidi.lin@mediatek.com Original-Tested-by: Yidi Lin yidi.lin@mediatek.com Original-Reviewed-by: Aaron Durbin adurbin@chromium.org Original-Reviewed-by: Julius Werner jwerner@chromium.org --- payloads/libpayload/arch/arm64/mmu.c | 1 + payloads/libpayload/include/arm64/arch/mmu.h | 2 ++ src/arch/arm64/armv8/mmu.c | 1 + src/arch/arm64/include/armv8/arch/mmu.h | 2 ++ 4 files changed, 6 insertions(+)
diff --git a/payloads/libpayload/arch/arm64/mmu.c b/payloads/libpayload/arch/arm64/mmu.c index e2a0cb1..f07e4c4 100644 --- a/payloads/libpayload/arch/arm64/mmu.c +++ b/payloads/libpayload/arch/arm64/mmu.c @@ -91,6 +91,7 @@ static uint64_t get_block_attr(unsigned long tag) break; case TYPE_DEV_MEM: attr |= BLOCK_INDEX_MEM_DEV_NGNRNE << BLOCK_INDEX_SHIFT; + attr |= BLOCK_XN; break; case TYPE_DMA_MEM: attr |= BLOCK_INDEX_MEM_NORMAL_NC << BLOCK_INDEX_SHIFT; diff --git a/payloads/libpayload/include/arm64/arch/mmu.h b/payloads/libpayload/include/arm64/arch/mmu.h index 30a1973..2f87d09 100644 --- a/payloads/libpayload/include/arm64/arch/mmu.h +++ b/payloads/libpayload/include/arm64/arch/mmu.h @@ -72,6 +72,8 @@ extern char _start[], _end[];
#define BLOCK_ACCESS (1 << 10)
+#define BLOCK_XN (1UL << 54) + #define BLOCK_SH_SHIFT (8) #define BLOCK_SH_NON_SHAREABLE (0 << BLOCK_SH_SHIFT) #define BLOCK_SH_UNPREDICTABLE (1 << BLOCK_SH_SHIFT) diff --git a/src/arch/arm64/armv8/mmu.c b/src/arch/arm64/armv8/mmu.c index a3e8d77..5c95e96 100644 --- a/src/arch/arm64/armv8/mmu.c +++ b/src/arch/arm64/armv8/mmu.c @@ -76,6 +76,7 @@ static uint64_t get_block_attr(unsigned long tag) attr |= BLOCK_INDEX_MEM_NORMAL << BLOCK_INDEX_SHIFT; } else { attr |= BLOCK_INDEX_MEM_DEV_NGNRNE << BLOCK_INDEX_SHIFT; + attr |= BLOCK_XN; }
return attr; diff --git a/src/arch/arm64/include/armv8/arch/mmu.h b/src/arch/arm64/include/armv8/arch/mmu.h index f5111ae..f697ddb 100644 --- a/src/arch/arm64/include/armv8/arch/mmu.h +++ b/src/arch/arm64/include/armv8/arch/mmu.h @@ -56,6 +56,8 @@
#define BLOCK_ACCESS (1 << 10)
+#define BLOCK_XN (1UL << 54) + #define BLOCK_SH_SHIFT (8) #define BLOCK_SH_NON_SHAREABLE (0 << BLOCK_SH_SHIFT) #define BLOCK_SH_UNPREDICTABLE (1 << BLOCK_SH_SHIFT)