[PATCH 2/2] x86/mm/KASLR: Correct the upper boundary of KALSR mm regions if adjacent to EFI
From: Baoquan He
Date: Wed Mar 08 2017 - 02:47:58 EST
EFI allocates runtime services regions top-down, starting from EFI_VA_START
to EFI_VA_END. So EFI_VA_START is bigger than EFI_VA_END and is the end of
EFI region. The upper boundary of memory regions randomized by KASLR should
be EFI_VA_END if it's adjacent to EFI region, but not EFI_VA_START.
Correct it in this patch.
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
---
arch/x86/mm/kaslr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 887e571..aed2064 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -48,7 +48,7 @@ static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
#if defined(CONFIG_X86_ESPFIX64)
static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
#elif defined(CONFIG_EFI)
-static const unsigned long vaddr_end = EFI_VA_START;
+static const unsigned long vaddr_end = EFI_VA_END;
#else
static const unsigned long vaddr_end = __START_KERNEL_map;
#endif
@@ -105,7 +105,7 @@ void __init kernel_randomize_memory(void)
*/
BUILD_BUG_ON(vaddr_start >= vaddr_end);
BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_ESPFIX64) &&
- vaddr_end >= EFI_VA_START);
+ vaddr_end >= EFI_VA_END);
BUILD_BUG_ON((IS_ENABLED(CONFIG_X86_ESPFIX64) ||
IS_ENABLED(CONFIG_EFI)) &&
vaddr_end >= __START_KERNEL_map);
--
2.5.5