linux-kernel - [PATCH] arm64: print additional fault message when executing non-exec memory

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Date:   Mon, 28 Oct 2019 17:08:37 +0800
From:   Xiang Zheng <zhengxiang9@...wei.com>
To:     <catalin.marinas@....com>, <will@...nel.org>
CC:     <james.morse@....com>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <wanghaibin.wang@...wei.com>
Subject: [PATCH] arm64: print additional fault message when executing non-exec memory

When attempting to executing non-executable memory, the fault message
shows:

  Unable to handle kernel read from unreadable memory at virtual address
  ffff802dac469000

This may confuse someone, so add a new fault message for instruction
abort.

Signed-off-by: Xiang Zheng <zhengxiang9@...wei.com>
---
 arch/arm64/mm/fault.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 9fc6db0bcbad..68bf4ec376d0 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -318,6 +318,8 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr,
 	if (is_el1_permission_fault(addr, esr, regs)) {
 		if (esr & ESR_ELx_WNR)
 			msg = "write to read-only memory";
+		else if (is_el1_instruction_abort(esr))
+			msg = "execute non-executable memory";
 		else
 			msg = "read from unreadable memory";
 	} else if (addr < PAGE_SIZE) {
-- 
2.19.1