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From:   He Zhe <zhe.he@windriver.com>
To:     catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com,
        alexander.shishkin@linux.intel.com, jolsa@redhat.com,
        namhyung@kernel.org, linux-arm-kernel@lists.infradead.org,
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Subject: [PATCH 1/2] arm64: uprobe: Return EOPNOTSUPP for AARCH32 instruction probing
Date:   Tue, 23 Feb 2021 16:25:34 +0800
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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>
---
 arch/arm64/kernel/probes/uprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/probes/uprobes.c b/arch/arm64/kernel/probes/uprobes.c
index a412d8edbcd2..2c247634552b 100644
--- a/arch/arm64/kernel/probes/uprobes.c
+++ b/arch/arm64/kernel/probes/uprobes.c
@@ -38,7 +38,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
 
 	/* 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;
 
-- 
2.17.1