The code patching code wants to get the value of a struct ppc_inst as
a u64 when the instruction is prefixed, so we can pass the u64 down to
__put_user_asm() and write it with a single store.
The optprobes code wants to load a struct ppc_inst as an immediate
into a register so it is useful to have it as a u64 to use the
existing helper function.
Currently this is a bit awkward because the value differs based on the
CPU endianness, so add a helper to do the conversion.
This fixes the usage in arch_prepare_optimized_kprobe() which was
previously incorrect on big endian.
Fixes: 650b55b707fd ("powerpc: Add prefixed instructions to instruction data
type")
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Tested-by: Jordan Niethe <jniet...@gmail.com>
Link: https://lore.kernel.org/r/20200525055004.2182328-1-...@ellerman.id.au
---
arch/powerpc/include/asm/inst.h | 9 +++++++++
arch/powerpc/kernel/optprobes.c | 3 +--
arch/powerpc/lib/code-patching.c | 8 +-------
3 files changed, 11 insertions(+), 9 deletions(-)
v2: Update the commit message as noted by Jordan.
Add a Fixes tag.
diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
index 5b756ba77ed2..45f3ec868258 100644
--- a/arch/powerpc/include/asm/inst.h
+++ b/arch/powerpc/include/asm/inst.h
@@ -113,6 +113,15 @@ static inline struct ppc_inst *ppc_inst_next(void
*location, struct ppc_inst *va
return location + ppc_inst_len(tmp);
}
+static inline u64 ppc_inst_as_u64(struct ppc_inst x)
+{
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+ return (u64)ppc_inst_suffix(x) << 32 | ppc_inst_val(x);
+#else
+ return (u64)ppc_inst_val(x) << 32 | ppc_inst_suffix(x);
+#endif
+}
+
int probe_user_read_inst(struct ppc_inst *inst,
struct ppc_inst __user *nip);
diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index 3ac105e7faae..69bfe96884e2 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -283,8 +283,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe
*op, struct kprobe *p)
* 3. load instruction to be emulated into relevant register, and
*/
temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
- patch_imm64_load_insns(ppc_inst_val(temp) | ((u64)ppc_inst_suffix(temp)
<< 32),
- 4, buff + TMPL_INSN_IDX);
+ patch_imm64_load_insns(ppc_inst_as_u64(temp), 4, buff + TMPL_INSN_IDX);
/*
* 4. branch back from trampoline
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 64cf621e5b00..5ecf0d635a8d 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -27,13 +27,7 @@ static int __patch_instruction(struct ppc_inst *exec_addr,
struct ppc_inst instr
if (!ppc_inst_prefixed(instr)) {
__put_user_asm(ppc_inst_val(instr), patch_addr, err, "stw");
} else {
-#ifdef CONFIG_CPU_LITTLE_ENDIAN
- __put_user_asm((u64)ppc_inst_suffix(instr) << 32 |
- ppc_inst_val(instr), patch_addr, err, "std");
-#else
- __put_user_asm((u64)ppc_inst_val(instr) << 32 |
- ppc_inst_suffix(instr), patch_addr, err, "std");
-#endif
+ __put_user_asm(ppc_inst_as_u64(instr), patch_addr, err, "std");
}
if (err)
--
2.25.1
