From 14a2de5c16f3da3fdb28398a5119d6fc911aade3 Mon Sep 17 00:00:00 2001
From: Guo Ren <guoren@linux.alibaba.com>
Date: Sat, 4 Feb 2023 01:35:31 -0500
Subject: [PATCH] riscv: kprobe: Fixup misaligned load text
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[ Upstream commit eb7423273cc9922ee2d05bf660c034d7d515bb91 ]
The current kprobe would cause a misaligned load for the probe point.
This patch fixup it with two half-word loads instead.
Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/linux-riscv/878rhig9zj.fsf@all.your.base.are.belong.to.us/
Reported-by: Bjorn Topel <bjorn.topel@gmail.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20230204063531.740220-1-guoren@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/riscv/kernel/probes/kprobes.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index b53aa0209e07..7548b1d62509 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -65,16 +65,18 @@ static bool __kprobes arch_check_kprobe(struct kprobe *p)
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
- unsigned long probe_addr = (unsigned long)p->addr;
+ u16 *insn = (u16 *)p->addr;
- if (probe_addr & 0x1)
+ if ((unsigned long)insn & 0x1)
return -EILSEQ;
if (!arch_check_kprobe(p))
return -EILSEQ;
/* copy instruction */
- p->opcode = *p->addr;
+ p->opcode = (kprobe_opcode_t)(*insn++);
+ if (GET_INSN_LENGTH(p->opcode) == 4)
+ p->opcode |= (kprobe_opcode_t)(*insn) << 16;
/* decode instruction */
switch (riscv_probe_decode_insn(p->addr, &p->ainsn.api)) {