linux-kernel - [PATCH Resend v2 2/3] ARM: mm: Provide is_write

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Message-ID: <20211115134848.171098-3-wangkefeng.wang@huawei.com>
Date:   Mon, 15 Nov 2021 21:48:47 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     <linux@...linux.org.uk>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
CC:     <glider@...gle.com>, <elver@...gle.com>, <dvyukov@...gle.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH Resend v2 2/3] ARM: mm: Provide is_write_fault()

The function will check whether the fault is caused by a write access,
it will be called in die_kernel_fault() too in next patch, so put it
before the function of die_kernel_fault().

Acked-by: Marco Elver <elver@...gle.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 arch/arm/mm/fault.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index bc8779d54a64..1207ed925039 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -99,6 +99,11 @@ void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr)
 { }
 #endif					/* CONFIG_MMU */
 
+static inline bool is_write_fault(unsigned int fsr)
+{
+	return (fsr & FSR_WRITE) && !(fsr & FSR_CM);
+}
+
 static void die_kernel_fault(const char *msg, struct mm_struct *mm,
 			     unsigned long addr, unsigned int fsr,
 			     struct pt_regs *regs)
@@ -261,7 +266,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	if (user_mode(regs))
 		flags |= FAULT_FLAG_USER;
 
-	if ((fsr & FSR_WRITE) && !(fsr & FSR_CM)) {
+	if (is_write_fault(fsr)) {
 		flags |= FAULT_FLAG_WRITE;
 		vm_flags = VM_WRITE;
 	}
-- 
2.26.2