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authorCatalin Marinas <catalin.marinas@arm.com>2013-05-07 16:57:06 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2013-05-08 10:33:16 +0100
commit0e7f7bcc3fc87489cda5aa6aff8ce40eed912279 (patch)
tree42256e2678fc1c4a53686cb6f701560c3d86781b /arch/arm64/mm
parented1f23637a4916112800df2779c160be520d1525 (diff)
downloadlinux-0e7f7bcc3fc87489cda5aa6aff8ce40eed912279.tar.gz
arm64: Ignore the 'write' ESR flag on cache maintenance faults
ESR.WnR bit is always set on data cache maintenance faults even though the page is not required to have write permission. If a translation fault (page not yet mapped) happens for read-only user address range, Linux incorrectly assumes a permission fault. This patch adds the check of the ESR.CM bit during the page fault handling to ignore the 'write' flag. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Tim Northover <Tim.Northover@arm.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'arch/arm64/mm')
-rw-r--r--arch/arm64/mm/fault.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 52638171d6f..98af6e760cc 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -148,6 +148,7 @@ void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)
#define VM_FAULT_BADACCESS 0x020000
#define ESR_WRITE (1 << 6)
+#define ESR_CM (1 << 8)
#define ESR_LNX_EXEC (1 << 24)
/*
@@ -206,7 +207,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
struct task_struct *tsk;
struct mm_struct *mm;
int fault, sig, code;
- int write = esr & ESR_WRITE;
+ bool write = (esr & ESR_WRITE) && !(esr & ESR_CM);
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
(write ? FAULT_FLAG_WRITE : 0);