Re: [PATCH v2 10/10] powerpc/bpf ppc32: Fix BPF_SUB when imm == 0x80000000

[Christophe Leroy]

Le 05/10/2021 à 22:25, Naveen N. Rao a écrit :

Special case handling of the smallest 32-bit negative number for BPF_SUB.

Fixes: 51c66ad849a703 ("powerpc/bpf: Implement extended BPF on PPC32")
Signed-off-by: Naveen N. Rao 


Reviewed-by: Christophe Leroy 


---
  arch/powerpc/net/bpf_jit_comp32.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_jit_comp32.c 
b/arch/powerpc/net/bpf_jit_comp32.c
index 68dc8a8231de04..0da31d41d41310 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -357,7 +357,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, 
struct codegen_context *
PPC_LI32(_R0, imm);
EMIT(PPC_RAW_ADDC(dst_reg, dst_reg, _R0));
}
-   if (imm >= 0)
+   if (imm >= 0 || (BPF_OP(code) == BPF_SUB && imm == 
0x8000))
EMIT(PPC_RAW_ADDZE(dst_reg_h, dst_reg_h));
else
EMIT(PPC_RAW_ADDME(dst_reg_h, dst_reg_h));

[PATCH v2 10/10] powerpc/bpf ppc32: Fix BPF_SUB when imm == 0x80000000

[Naveen N. Rao]

Special case handling of the smallest 32-bit negative number for BPF_SUB.

Fixes: 51c66ad849a703 ("powerpc/bpf: Implement extended BPF on PPC32")
Signed-off-by: Naveen N. Rao 
---
 arch/powerpc/net/bpf_jit_comp32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_jit_comp32.c 
b/arch/powerpc/net/bpf_jit_comp32.c
index 68dc8a8231de04..0da31d41d41310 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -357,7 +357,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, 
struct codegen_context *
PPC_LI32(_R0, imm);
EMIT(PPC_RAW_ADDC(dst_reg, dst_reg, _R0));
}
-   if (imm >= 0)
+   if (imm >= 0 || (BPF_OP(code) == BPF_SUB && imm == 
0x8000))
EMIT(PPC_RAW_ADDZE(dst_reg_h, dst_reg_h));
else
EMIT(PPC_RAW_ADDME(dst_reg_h, dst_reg_h));
-- 
2.33.0