Re: [PATCH] powerpc: Add ppc_inst_as_u64()
On Mon, 25 May 2020 15:50:04 +1000, Michael Ellerman wrote: > 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. > > This is a bit awkward because the value differs based on the CPU > endianness, so add a helper to do the conversion. Applied to powerpc/next. [1/1] powerpc: Add ppc_inst_as_u64() https://git.kernel.org/powerpc/c/16ef9767e4dc5cf03a71ae7bc2bc588dbbe7983e cheers
Re: [PATCH] powerpc: Add ppc_inst_as_u64()
On Mon, May 25, 2020 at 3:49 PM Michael Ellerman wrote:
>
> The code patching code wants to get the value of a struct ppc_inst as
Might need to change the wording here as it also gets used in
arch_prepare_optimized_kprobe()
> 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.
>
> This is a bit awkward because the value differs based on the CPU
> endianness, so add a helper to do the conversion.
>
> Signed-off-by: Michael Ellerman
> ---
> 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(-)
>
> diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
> index d82e0c99cfa1..d61e07fb2937 100644
> --- a/arch/powerpc/include/asm/inst.h
> +++ b/arch/powerpc/include/asm/inst.h
> @@ -100,6 +100,15 @@ static inline int ppc_inst_len(struct ppc_inst x)
> return ppc_inst_prefixed(x) ? 8 : 4;
> }
>
> +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
>
I booted a BE and LE kernel - test_prefixed_patching() worked on both.
Also on BE and LE kernels I put optprobes on prefixed and non prefixed
instructions.
The correct value was passed via r4 to emulate_step().
Tested-by: Jordan Niethe
[PATCH] powerpc: Add ppc_inst_as_u64()
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.
This is a bit awkward because the value differs based on the CPU
endianness, so add a helper to do the conversion.
Signed-off-by: Michael Ellerman
---
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(-)
diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
index d82e0c99cfa1..d61e07fb2937 100644
--- a/arch/powerpc/include/asm/inst.h
+++ b/arch/powerpc/include/asm/inst.h
@@ -100,6 +100,15 @@ static inline int ppc_inst_len(struct ppc_inst x)
return ppc_inst_prefixed(x) ? 8 : 4;
}
+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
