| From | Greg Kroah-Hartman <> | Subject | [ 29/73] arm64: Ignore the write ESR flag on cache maintenance faults | Date | Thu, 9 May 2013 15:31:52 -0700 |
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3.8-stable review patch. If anyone has any objections, please let me know.
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From: Catalin Marinas <catalin.marinas@arm.com>
commit 0e7f7bcc3fc87489cda5aa6aff8ce40eed912279 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/arm64/mm/fault.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -148,6 +148,7 @@ void do_bad_area(unsigned long addr, uns #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(unsig 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);
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