This is a note to let you know that I've just added the patch titled
powerpc/bpf ppc32: Fix BPF_SUB when imm == 0x80000000
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-bpf-ppc32-fix-bpf_sub-when-imm-0x80000000.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 82e3935490e27117aad613222f792125159071f0
Author: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Date: Wed Oct 6 01:55:29 2021 +0530
powerpc/bpf ppc32: Fix BPF_SUB when imm == 0x80000000
[ Upstream commit 548b762763b885b81850db676258df47c55dd5f9 ]
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 <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/7135360a0cdf70adedbccf9863128b8daef18764.1633464148.git.naveen.n.rao@xxxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index c48de048c8ce..a7759aa8043d 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -355,7 +355,7 @@ 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 == 0x80000000))
EMIT(PPC_RAW_ADDZE(dst_reg_h, dst_reg_h));
else
EMIT(PPC_RAW_ADDME(dst_reg_h, dst_reg_h));
