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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, He Zhe <zhe.he@windriver.com>,
        Will Deacon <will@kernel.org>
Subject: [PATCH 4.19 215/247] arm64: uprobe: Return EOPNOTSUPP for AARCH32 instruction probing
Date:   Mon,  1 Mar 2021 17:13:55 +0100
Message-Id: <20210301161042.196645943@linuxfoundation.org>
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From: He Zhe <zhe.he@windriver.com>

commit d47422d953e258ad587b5edf2274eb95d08bdc7d upstream.

As stated in linux/errno.h, ENOTSUPP should never be seen by user programs.
When we set up uprobe with 32-bit perf and arm64 kernel, we would see the
following vague error without useful hint.

The sys_perf_event_open() syscall returned with 524 (INTERNAL ERROR:
strerror_r(524, [buf], 128)=22)

Use EOPNOTSUPP instead to indicate such cases.

Signed-off-by: He Zhe <zhe.he@windriver.com>
Link: https://lore.kernel.org/r/20210223082535.48730-1-zhe.he@windriver.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm64/kernel/probes/uprobes.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm64/kernel/probes/uprobes.c
+++ b/arch/arm64/kernel/probes/uprobes.c
@@ -41,7 +41,7 @@ int arch_uprobe_analyze_insn(struct arch
 
 	/* TODO: Currently we do not support AARCH32 instruction probing */
 	if (mm->context.flags & MMCF_AARCH32)
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 	else if (!IS_ALIGNED(addr, AARCH64_INSN_SIZE))
 		return -EINVAL;