* [PATCH] powerpc/bpf: Use bctrl for making function calls
@ 2021-06-09 9:00 ` Naveen N. Rao
0 siblings, 0 replies; 6+ messages in thread
From: Naveen N. Rao @ 2021-06-09 9:00 UTC (permalink / raw)
To: linuxppc-dev, bpf; +Cc: Michael Ellerman, Anton Blanchard
blrl corrupts the link stack. Instead use bctrl when making function
calls from BPF programs.
Reported-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/ppc-opcode.h | 1 +
arch/powerpc/net/bpf_jit_comp32.c | 4 ++--
arch/powerpc/net/bpf_jit_comp64.c | 12 ++++++------
3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index ac41776661e963..1abacb8417d562 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -451,6 +451,7 @@
#define PPC_RAW_MTLR(r) (0x7c0803a6 | ___PPC_RT(r))
#define PPC_RAW_MFLR(t) (PPC_INST_MFLR | ___PPC_RT(t))
#define PPC_RAW_BCTR() (PPC_INST_BCTR)
+#define PPC_RAW_BCTRL() (PPC_INST_BCTRL)
#define PPC_RAW_MTCTR(r) (PPC_INST_MTCTR | ___PPC_RT(r))
#define PPC_RAW_ADDI(d, a, i) (PPC_INST_ADDI | ___PPC_RT(d) | ___PPC_RA(a) | IMM_L(i))
#define PPC_RAW_LI(r, i) PPC_RAW_ADDI(r, 0, i)
diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index bbb16099e8c7fa..40ab50bea61c02 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -195,8 +195,8 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
/* Load function address into r0 */
EMIT(PPC_RAW_LIS(__REG_R0, IMM_H(func)));
EMIT(PPC_RAW_ORI(__REG_R0, __REG_R0, IMM_L(func)));
- EMIT(PPC_RAW_MTLR(__REG_R0));
- EMIT(PPC_RAW_BLRL());
+ EMIT(PPC_RAW_MTCTR(__REG_R0));
+ EMIT(PPC_RAW_BCTRL());
}
}
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 57a8c1153851a0..ae9a6532be6ad4 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -153,8 +153,8 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
PPC_LI64(b2p[TMP_REG_2], func);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
- /* ... and move it to LR */
- EMIT(PPC_RAW_MTLR(b2p[TMP_REG_1]));
+ /* ... and move it to CTR */
+ EMIT(PPC_RAW_MTCTR(b2p[TMP_REG_1]));
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
@@ -165,9 +165,9 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
#else
/* We can clobber r12 */
PPC_FUNC_ADDR(12, func);
- EMIT(PPC_RAW_MTLR(12));
+ EMIT(PPC_RAW_MTCTR(12));
#endif
- EMIT(PPC_RAW_BLRL());
+ EMIT(PPC_RAW_BCTRL());
}
void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
@@ -202,8 +202,8 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
PPC_BPF_LL(12, 12, 0);
#endif
- EMIT(PPC_RAW_MTLR(12));
- EMIT(PPC_RAW_BLRL());
+ EMIT(PPC_RAW_MTCTR(12));
+ EMIT(PPC_RAW_BCTRL());
}
static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out)
base-commit: 112f47a1484ddca610b70cbe4a99f0d0f1701daf
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] powerpc/bpf: Use bctrl for making function calls
@ 2021-06-09 9:00 ` Naveen N. Rao
0 siblings, 0 replies; 6+ messages in thread
From: Naveen N. Rao @ 2021-06-09 9:00 UTC (permalink / raw)
To: linuxppc-dev, bpf
blrl corrupts the link stack. Instead use bctrl when making function
calls from BPF programs.
Reported-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/ppc-opcode.h | 1 +
arch/powerpc/net/bpf_jit_comp32.c | 4 ++--
arch/powerpc/net/bpf_jit_comp64.c | 12 ++++++------
3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index ac41776661e963..1abacb8417d562 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -451,6 +451,7 @@
#define PPC_RAW_MTLR(r) (0x7c0803a6 | ___PPC_RT(r))
#define PPC_RAW_MFLR(t) (PPC_INST_MFLR | ___PPC_RT(t))
#define PPC_RAW_BCTR() (PPC_INST_BCTR)
+#define PPC_RAW_BCTRL() (PPC_INST_BCTRL)
#define PPC_RAW_MTCTR(r) (PPC_INST_MTCTR | ___PPC_RT(r))
#define PPC_RAW_ADDI(d, a, i) (PPC_INST_ADDI | ___PPC_RT(d) | ___PPC_RA(a) | IMM_L(i))
#define PPC_RAW_LI(r, i) PPC_RAW_ADDI(r, 0, i)
diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index bbb16099e8c7fa..40ab50bea61c02 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -195,8 +195,8 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
/* Load function address into r0 */
EMIT(PPC_RAW_LIS(__REG_R0, IMM_H(func)));
EMIT(PPC_RAW_ORI(__REG_R0, __REG_R0, IMM_L(func)));
- EMIT(PPC_RAW_MTLR(__REG_R0));
- EMIT(PPC_RAW_BLRL());
+ EMIT(PPC_RAW_MTCTR(__REG_R0));
+ EMIT(PPC_RAW_BCTRL());
}
}
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 57a8c1153851a0..ae9a6532be6ad4 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -153,8 +153,8 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
PPC_LI64(b2p[TMP_REG_2], func);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
- /* ... and move it to LR */
- EMIT(PPC_RAW_MTLR(b2p[TMP_REG_1]));
+ /* ... and move it to CTR */
+ EMIT(PPC_RAW_MTCTR(b2p[TMP_REG_1]));
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
@@ -165,9 +165,9 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
#else
/* We can clobber r12 */
PPC_FUNC_ADDR(12, func);
- EMIT(PPC_RAW_MTLR(12));
+ EMIT(PPC_RAW_MTCTR(12));
#endif
- EMIT(PPC_RAW_BLRL());
+ EMIT(PPC_RAW_BCTRL());
}
void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
@@ -202,8 +202,8 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
PPC_BPF_LL(12, 12, 0);
#endif
- EMIT(PPC_RAW_MTLR(12));
- EMIT(PPC_RAW_BLRL());
+ EMIT(PPC_RAW_MTCTR(12));
+ EMIT(PPC_RAW_BCTRL());
}
static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out)
base-commit: 112f47a1484ddca610b70cbe4a99f0d0f1701daf
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc/bpf: Use bctrl for making function calls
2021-06-09 9:00 ` Naveen N. Rao
(?)
@ 2021-06-09 9:42 ` Christophe Leroy
2021-06-09 13:11 ` Naveen N. Rao
-1 siblings, 1 reply; 6+ messages in thread
From: Christophe Leroy @ 2021-06-09 9:42 UTC (permalink / raw)
To: Naveen N. Rao, linuxppc-dev, bpf
Le 09/06/2021 à 11:00, Naveen N. Rao a écrit :
> blrl corrupts the link stack. Instead use bctrl when making function
> calls from BPF programs.
What's the link stack ? Is it the PPC64 branch predictor stack ?
>
> Reported-by: Anton Blanchard <anton@ozlabs.org>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> ---
> arch/powerpc/include/asm/ppc-opcode.h | 1 +
> arch/powerpc/net/bpf_jit_comp32.c | 4 ++--
> arch/powerpc/net/bpf_jit_comp64.c | 12 ++++++------
> 3 files changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
> index ac41776661e963..1abacb8417d562 100644
> --- a/arch/powerpc/include/asm/ppc-opcode.h
> +++ b/arch/powerpc/include/asm/ppc-opcode.h
> @@ -451,6 +451,7 @@
> #define PPC_RAW_MTLR(r) (0x7c0803a6 | ___PPC_RT(r))
> #define PPC_RAW_MFLR(t) (PPC_INST_MFLR | ___PPC_RT(t))
> #define PPC_RAW_BCTR() (PPC_INST_BCTR)
> +#define PPC_RAW_BCTRL() (PPC_INST_BCTRL)
Can you use the numeric value instead of the PPC_INST_BCTRL, to avoid conflict with
https://patchwork.ozlabs.org/project/linuxppc-dev/patch/4ca2bfdca2f47a293d05f61eb3c4e487ee170f1f.1621506159.git.christophe.leroy@csgroup.eu/
> #define PPC_RAW_MTCTR(r) (PPC_INST_MTCTR | ___PPC_RT(r))
> #define PPC_RAW_ADDI(d, a, i) (PPC_INST_ADDI | ___PPC_RT(d) | ___PPC_RA(a) | IMM_L(i))
> #define PPC_RAW_LI(r, i) PPC_RAW_ADDI(r, 0, i)
> diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
> index bbb16099e8c7fa..40ab50bea61c02 100644
> --- a/arch/powerpc/net/bpf_jit_comp32.c
> +++ b/arch/powerpc/net/bpf_jit_comp32.c
> @@ -195,8 +195,8 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
> /* Load function address into r0 */
> EMIT(PPC_RAW_LIS(__REG_R0, IMM_H(func)));
> EMIT(PPC_RAW_ORI(__REG_R0, __REG_R0, IMM_L(func)));
> - EMIT(PPC_RAW_MTLR(__REG_R0));
> - EMIT(PPC_RAW_BLRL());
> + EMIT(PPC_RAW_MTCTR(__REG_R0));
> + EMIT(PPC_RAW_BCTRL());
> }
> }
>
> diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> index 57a8c1153851a0..ae9a6532be6ad4 100644
> --- a/arch/powerpc/net/bpf_jit_comp64.c
> +++ b/arch/powerpc/net/bpf_jit_comp64.c
> @@ -153,8 +153,8 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
> PPC_LI64(b2p[TMP_REG_2], func);
> /* Load actual entry point from function descriptor */
> PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
> - /* ... and move it to LR */
> - EMIT(PPC_RAW_MTLR(b2p[TMP_REG_1]));
> + /* ... and move it to CTR */
> + EMIT(PPC_RAW_MTCTR(b2p[TMP_REG_1]));
> /*
> * Load TOC from function descriptor at offset 8.
> * We can clobber r2 since we get called through a
> @@ -165,9 +165,9 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
> #else
> /* We can clobber r12 */
> PPC_FUNC_ADDR(12, func);
> - EMIT(PPC_RAW_MTLR(12));
> + EMIT(PPC_RAW_MTCTR(12));
> #endif
> - EMIT(PPC_RAW_BLRL());
> + EMIT(PPC_RAW_BCTRL());
> }
>
> void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
> @@ -202,8 +202,8 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
> PPC_BPF_LL(12, 12, 0);
> #endif
>
> - EMIT(PPC_RAW_MTLR(12));
> - EMIT(PPC_RAW_BLRL());
> + EMIT(PPC_RAW_MTCTR(12));
> + EMIT(PPC_RAW_BCTRL());
> }
>
> static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out)
>
> base-commit: 112f47a1484ddca610b70cbe4a99f0d0f1701daf
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc/bpf: Use bctrl for making function calls
2021-06-09 9:42 ` Christophe Leroy
@ 2021-06-09 13:11 ` Naveen N. Rao
0 siblings, 0 replies; 6+ messages in thread
From: Naveen N. Rao @ 2021-06-09 13:11 UTC (permalink / raw)
To: bpf, Christophe Leroy, linuxppc-dev
Christophe Leroy wrote:
>
>
> Le 09/06/2021 à 11:00, Naveen N. Rao a écrit :
>> blrl corrupts the link stack. Instead use bctrl when making function
>> calls from BPF programs.
>
> What's the link stack ? Is it the PPC64 branch predictor stack ?
c974809a26a13e ("powerpc/vdso: Avoid link stack corruption in
__get_datapage()") has a good write up on the link stack.
>
>>
>> Reported-by: Anton Blanchard <anton@ozlabs.org>
>> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
>> ---
>> arch/powerpc/include/asm/ppc-opcode.h | 1 +
>> arch/powerpc/net/bpf_jit_comp32.c | 4 ++--
>> arch/powerpc/net/bpf_jit_comp64.c | 12 ++++++------
>> 3 files changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
>> index ac41776661e963..1abacb8417d562 100644
>> --- a/arch/powerpc/include/asm/ppc-opcode.h
>> +++ b/arch/powerpc/include/asm/ppc-opcode.h
>> @@ -451,6 +451,7 @@
>> #define PPC_RAW_MTLR(r) (0x7c0803a6 | ___PPC_RT(r))
>> #define PPC_RAW_MFLR(t) (PPC_INST_MFLR | ___PPC_RT(t))
>> #define PPC_RAW_BCTR() (PPC_INST_BCTR)
>> +#define PPC_RAW_BCTRL() (PPC_INST_BCTRL)
>
> Can you use the numeric value instead of the PPC_INST_BCTRL, to avoid conflict with
> https://patchwork.ozlabs.org/project/linuxppc-dev/patch/4ca2bfdca2f47a293d05f61eb3c4e487ee170f1f.1621506159.git.christophe.leroy@csgroup.eu/
Sure. I'll post a v2.
- Naveen
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc/bpf: Use bctrl for making function calls
2021-06-09 9:00 ` Naveen N. Rao
@ 2021-06-26 10:37 ` Michael Ellerman
-1 siblings, 0 replies; 6+ messages in thread
From: Michael Ellerman @ 2021-06-26 10:37 UTC (permalink / raw)
To: linuxppc-dev, bpf, Naveen N. Rao; +Cc: Michael Ellerman, Anton Blanchard
On Wed, 9 Jun 2021 14:30:24 +0530, Naveen N. Rao wrote:
> blrl corrupts the link stack. Instead use bctrl when making function
> calls from BPF programs.
Applied to powerpc/next.
[1/1] powerpc/bpf: Use bctrl for making function calls
https://git.kernel.org/powerpc/c/20ccb004bad659c186f9091015a956da220d615d
cheers
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-06-26 10:43 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-09 9:00 [PATCH] powerpc/bpf: Use bctrl for making function calls Naveen N. Rao
2021-06-09 9:00 ` Naveen N. Rao
2021-06-09 9:42 ` Christophe Leroy
2021-06-09 13:11 ` Naveen N. Rao
2021-06-26 10:37 ` Michael Ellerman
2021-06-26 10:37 ` Michael Ellerman
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.