From: Catalin Marinas Date: Tue, 7 May 2013 15:57:06 +0000 (+0100) Subject: arm64: Ignore the 'write' ESR flag on cache maintenance faults X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=0e7f7bcc3fc87489cda5aa6aff8ce40eed912279;p=openwrt%2Fstaging%2Fblogic.git 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 Reported-by: Tim Northover Cc: stable@vger.kernel.org --- diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 52638171d6fd..98af6e760cce 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);