From 96d8348d45aa268440bfc5a3159f75c3a2e6e3ca Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 22 Sep 2021 16:38:29 +0200 Subject: [PATCH] 4.14-stable patches added patches: s390-bpf-fix-optimizing-out-zero-extensions.patch --- ...f-fix-optimizing-out-zero-extensions.patch | 128 ++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 queue-4.14/s390-bpf-fix-optimizing-out-zero-extensions.patch diff --git a/queue-4.14/s390-bpf-fix-optimizing-out-zero-extensions.patch b/queue-4.14/s390-bpf-fix-optimizing-out-zero-extensions.patch new file mode 100644 index 00000000000..0fdf2a19c66 --- /dev/null +++ b/queue-4.14/s390-bpf-fix-optimizing-out-zero-extensions.patch @@ -0,0 +1,128 @@ +From db7bee653859ef7179be933e7d1384644f795f26 Mon Sep 17 00:00:00 2001 +From: Ilya Leoshkevich +Date: Mon, 6 Sep 2021 15:04:14 +0200 +Subject: s390/bpf: Fix optimizing out zero-extensions + +From: Ilya Leoshkevich + +commit db7bee653859ef7179be933e7d1384644f795f26 upstream. + +Currently the JIT completely removes things like `reg32 += 0`, +however, the BPF_ALU semantics requires the target register to be +zero-extended in such cases. + +Fix by optimizing out only the arithmetic operation, but not the +subsequent zero-extension. + +Reported-by: Johan Almbladh +Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") +Reviewed-by: Heiko Carstens +Signed-off-by: Ilya Leoshkevich +Signed-off-by: Vasily Gorbik +Signed-off-by: Greg Kroah-Hartman + +--- + arch/s390/net/bpf_jit_comp.c | 50 ++++++++++++++++++++++--------------------- + 1 file changed, 26 insertions(+), 24 deletions(-) + +--- a/arch/s390/net/bpf_jit_comp.c ++++ b/arch/s390/net/bpf_jit_comp.c +@@ -592,10 +592,10 @@ static noinline int bpf_jit_insn(struct + EMIT4(0xb9080000, dst_reg, src_reg); + break; + case BPF_ALU | BPF_ADD | BPF_K: /* dst = (u32) dst + (u32) imm */ +- if (!imm) +- break; +- /* alfi %dst,imm */ +- EMIT6_IMM(0xc20b0000, dst_reg, imm); ++ if (imm != 0) { ++ /* alfi %dst,imm */ ++ EMIT6_IMM(0xc20b0000, dst_reg, imm); ++ } + EMIT_ZERO(dst_reg); + break; + case BPF_ALU64 | BPF_ADD | BPF_K: /* dst = dst + imm */ +@@ -617,10 +617,10 @@ static noinline int bpf_jit_insn(struct + EMIT4(0xb9090000, dst_reg, src_reg); + break; + case BPF_ALU | BPF_SUB | BPF_K: /* dst = (u32) dst - (u32) imm */ +- if (!imm) +- break; +- /* alfi %dst,-imm */ +- EMIT6_IMM(0xc20b0000, dst_reg, -imm); ++ if (imm != 0) { ++ /* alfi %dst,-imm */ ++ EMIT6_IMM(0xc20b0000, dst_reg, -imm); ++ } + EMIT_ZERO(dst_reg); + break; + case BPF_ALU64 | BPF_SUB | BPF_K: /* dst = dst - imm */ +@@ -647,10 +647,10 @@ static noinline int bpf_jit_insn(struct + EMIT4(0xb90c0000, dst_reg, src_reg); + break; + case BPF_ALU | BPF_MUL | BPF_K: /* dst = (u32) dst * (u32) imm */ +- if (imm == 1) +- break; +- /* msfi %r5,imm */ +- EMIT6_IMM(0xc2010000, dst_reg, imm); ++ if (imm != 1) { ++ /* msfi %r5,imm */ ++ EMIT6_IMM(0xc2010000, dst_reg, imm); ++ } + EMIT_ZERO(dst_reg); + break; + case BPF_ALU64 | BPF_MUL | BPF_K: /* dst = dst * imm */ +@@ -711,6 +711,8 @@ static noinline int bpf_jit_insn(struct + if (BPF_OP(insn->code) == BPF_MOD) + /* lhgi %dst,0 */ + EMIT4_IMM(0xa7090000, dst_reg, 0); ++ else ++ EMIT_ZERO(dst_reg); + break; + } + /* lhi %w0,0 */ +@@ -803,10 +805,10 @@ static noinline int bpf_jit_insn(struct + EMIT4(0xb9820000, dst_reg, src_reg); + break; + case BPF_ALU | BPF_XOR | BPF_K: /* dst = (u32) dst ^ (u32) imm */ +- if (!imm) +- break; +- /* xilf %dst,imm */ +- EMIT6_IMM(0xc0070000, dst_reg, imm); ++ if (imm != 0) { ++ /* xilf %dst,imm */ ++ EMIT6_IMM(0xc0070000, dst_reg, imm); ++ } + EMIT_ZERO(dst_reg); + break; + case BPF_ALU64 | BPF_XOR | BPF_K: /* dst = dst ^ imm */ +@@ -827,10 +829,10 @@ static noinline int bpf_jit_insn(struct + EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, src_reg, 0); + break; + case BPF_ALU | BPF_LSH | BPF_K: /* dst = (u32) dst << (u32) imm */ +- if (imm == 0) +- break; +- /* sll %dst,imm(%r0) */ +- EMIT4_DISP(0x89000000, dst_reg, REG_0, imm); ++ if (imm != 0) { ++ /* sll %dst,imm(%r0) */ ++ EMIT4_DISP(0x89000000, dst_reg, REG_0, imm); ++ } + EMIT_ZERO(dst_reg); + break; + case BPF_ALU64 | BPF_LSH | BPF_K: /* dst = dst << imm */ +@@ -852,10 +854,10 @@ static noinline int bpf_jit_insn(struct + EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, src_reg, 0); + break; + case BPF_ALU | BPF_RSH | BPF_K: /* dst = (u32) dst >> (u32) imm */ +- if (imm == 0) +- break; +- /* srl %dst,imm(%r0) */ +- EMIT4_DISP(0x88000000, dst_reg, REG_0, imm); ++ if (imm != 0) { ++ /* srl %dst,imm(%r0) */ ++ EMIT4_DISP(0x88000000, dst_reg, REG_0, imm); ++ } + EMIT_ZERO(dst_reg); + break; + case BPF_ALU64 | BPF_RSH | BPF_K: /* dst = dst >> imm */ -- 2.47.3