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MIPS: ftrace: Fix icache flush range error

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In 32-bit mode, the start address passed to flush_icache_range is
shifted by 4 bytes before the second safe_store_code() call.

This causes system crash from time to time because the first 4 bytes
might not be flushed properly. This bug exists since linux-3.8.

Also remove obsoleted comment while at it.

Signed-off-by: Viller Hsiao <villerhsiao@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: rostedt@goodmis.org
Cc: fweisbec@gmail.com
Cc: mingo@redhat.com
Cc: Qais.Yousef@imgtec.com
Patchwork: https://patchwork.linux-mips.org/patch/6586/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Viller Hsiao 2014-02-22 15:46:49 +08:00 committed by Ralf Baechle
parent 86ca57b5a5
commit a467109422
1 changed files with 2 additions and 3 deletions
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5
arch/mips/kernel/ftrace.c
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@ -111,11 +111,10 @@ static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1,
safe_store_code(new_code1, ip, faulted);
if (unlikely(faulted))
return -EFAULT;
ip += 4;
safe_store_code(new_code2, ip, faulted);
safe_store_code(new_code2, ip + 4, faulted);
if (unlikely(faulted))
return -EFAULT;
flush_icache_range(ip, ip + 8); /* original ip + 12 */
flush_icache_range(ip, ip + 8);
return 0;
}
#endif