From: Palmer Dabbelt <palmer@dabbelt.com>
To: linux-riscv@lists.infradead.org
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
aou@eecs.berkeley.edu, penberg@kernel.org,
guoren@linux.alibaba.com, me@packi.ch, mhiramat@kernel.org,
mingo@kernel.org, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org, kernel-team@android.com,
Palmer Dabbelt <palmerdabbelt@google.com>,
kernel test robot <lkp@intel.com>
Subject: [PATCH] RISC-V: probes: Treat the instruction stream as host-endian
Date: Fri, 22 Jan 2021 19:34:29 -0800 [thread overview]
Message-ID: <20210123033429.2072716-1-palmer@dabbelt.com> (raw)
From: Palmer Dabbelt <palmerdabbelt@google.com>
Neither of these are actually correct: the instruction stream is defined
(for versions of the ISA manual newer than 2.2) as a stream of 16-bit
little-endian parcels, which is different than just being little-endian.
In theory we should represent this as a type, but we don't have any
concrete plans for the big endian stuff so it doesn't seem worth the
time -- we've got variants of this all over the place.
Instead I'm just dropping the unnecessary type conversion, which is a
NOP on LE systems but causes an sparse error as the types are all mixed
up.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
arch/riscv/kernel/probes/decode-insn.c | 2 +-
arch/riscv/kernel/probes/kprobes.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/kernel/probes/decode-insn.c b/arch/riscv/kernel/probes/decode-insn.c
index 0876c304ca77..0ed043acc882 100644
--- a/arch/riscv/kernel/probes/decode-insn.c
+++ b/arch/riscv/kernel/probes/decode-insn.c
@@ -16,7 +16,7 @@
enum probe_insn __kprobes
riscv_probe_decode_insn(probe_opcode_t *addr, struct arch_probe_insn *api)
{
- probe_opcode_t insn = le32_to_cpu(*addr);
+ probe_opcode_t insn = *addr;
/*
* Reject instructions list:
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index e60893bd87db..a2ec18662fee 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -57,7 +57,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
}
/* copy instruction */
- p->opcode = le32_to_cpu(*p->addr);
+ p->opcode = *p->addr;
/* decode instruction */
switch (riscv_probe_decode_insn(p->addr, &p->ainsn.api)) {
--
2.30.0.280.ga3ce27912f-goog
next reply other threads:[~2021-01-23 3:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-23 3:34 Palmer Dabbelt [this message]
2021-01-23 7:33 ` Guo Ren
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