| Message ID | b7024b63a5501bbb67699da2345250deeea03d7e.1633104510.git.naveen.n.rao@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc/bpf: Various fixes | expand |
On Fri, Oct 1, 2021 at 11:15 PM Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> wrote: > > Johan reported the below crash with test_bpf on ppc64 e5500: > > test_bpf: #296 ALU_END_FROM_LE 64: 0x0123456789abcdef -> 0x67452301 jited:1 > Oops: Exception in kernel mode, sig: 4 [#1] > BE PAGE_SIZE=4K SMP NR_CPUS=24 QEMU e500 > Modules linked in: test_bpf(+) > CPU: 0 PID: 76 Comm: insmod Not tainted 5.14.0-03771-g98c2059e008a-dirty #1 > NIP: 8000000000061c3c LR: 80000000006dea64 CTR: 8000000000061c18 > REGS: c0000000032d3420 TRAP: 0700 Not tainted (5.14.0-03771-g98c2059e008a-dirty) > MSR: 0000000080089000 <EE,ME> CR: 88002822 XER: 20000000 IRQMASK: 0 > <...> > NIP [8000000000061c3c] 0x8000000000061c3c > LR [80000000006dea64] .__run_one+0x104/0x17c [test_bpf] > Call Trace: > .__run_one+0x60/0x17c [test_bpf] (unreliable) > .test_bpf_init+0x6a8/0xdc8 [test_bpf] > .do_one_initcall+0x6c/0x28c > .do_init_module+0x68/0x28c > .load_module+0x2460/0x2abc > .__do_sys_init_module+0x120/0x18c > .system_call_exception+0x110/0x1b8 > system_call_common+0xf0/0x210 > --- interrupt: c00 at 0x101d0acc > <...> > ---[ end trace 47b2bf19090bb3d0 ]--- > > Illegal instruction > > The illegal instruction turned out to be 'ldbrx' emitted for > BPF_FROM_[L|B]E, which was only introduced in ISA v2.06. Guard use of > the same and implement an alternative approach for older processors. > > Fixes: 156d0e290e969c ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF") > Reported-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Tested-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> > --- > arch/powerpc/include/asm/ppc-opcode.h | 1 + > arch/powerpc/net/bpf_jit_comp64.c | 22 +++++++++++++--------- > 2 files changed, 14 insertions(+), 9 deletions(-) > > diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h > index baea657bc8687e..bca31a61e57f88 100644 > --- a/arch/powerpc/include/asm/ppc-opcode.h > +++ b/arch/powerpc/include/asm/ppc-opcode.h > @@ -498,6 +498,7 @@ > #define PPC_RAW_LDX(r, base, b) (0x7c00002a | ___PPC_RT(r) | ___PPC_RA(base) | ___PPC_RB(b)) > #define PPC_RAW_LHZ(r, base, i) (0xa0000000 | ___PPC_RT(r) | ___PPC_RA(base) | IMM_L(i)) > #define PPC_RAW_LHBRX(r, base, b) (0x7c00062c | ___PPC_RT(r) | ___PPC_RA(base) | ___PPC_RB(b)) > +#define PPC_RAW_LWBRX(r, base, b) (0x7c00042c | ___PPC_RT(r) | ___PPC_RA(base) | ___PPC_RB(b)) > #define PPC_RAW_LDBRX(r, base, b) (0x7c000428 | ___PPC_RT(r) | ___PPC_RA(base) | ___PPC_RB(b)) > #define PPC_RAW_STWCX(s, a, b) (0x7c00012d | ___PPC_RS(s) | ___PPC_RA(a) | ___PPC_RB(b)) > #define PPC_RAW_CMPWI(a, i) (0x2c000000 | ___PPC_RA(a) | IMM_L(i)) > diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c > index 4641a50e82d50d..097d1ecfb9f562 100644 > --- a/arch/powerpc/net/bpf_jit_comp64.c > +++ b/arch/powerpc/net/bpf_jit_comp64.c > @@ -601,17 +601,21 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * > EMIT(PPC_RAW_MR(dst_reg, b2p[TMP_REG_1])); > break; > case 64: > - /* > - * Way easier and faster(?) to store the value > - * into stack and then use ldbrx > - * > - * ctx->seen will be reliable in pass2, but > - * the instructions generated will remain the > - * same across all passes > - */ > + /* Store the value to stack and then use byte-reverse loads */ > PPC_BPF_STL(dst_reg, 1, bpf_jit_stack_local(ctx)); > EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], 1, bpf_jit_stack_local(ctx))); > - EMIT(PPC_RAW_LDBRX(dst_reg, 0, b2p[TMP_REG_1])); > + if (cpu_has_feature(CPU_FTR_ARCH_206)) { > + EMIT(PPC_RAW_LDBRX(dst_reg, 0, b2p[TMP_REG_1])); > + } else { > + EMIT(PPC_RAW_LWBRX(dst_reg, 0, b2p[TMP_REG_1])); > + if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN)) > + EMIT(PPC_RAW_SLDI(dst_reg, dst_reg, 32)); > + EMIT(PPC_RAW_LI(b2p[TMP_REG_2], 4)); > + EMIT(PPC_RAW_LWBRX(b2p[TMP_REG_2], b2p[TMP_REG_2], b2p[TMP_REG_1])); > + if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) > + EMIT(PPC_RAW_SLDI(b2p[TMP_REG_2], b2p[TMP_REG_2], 32)); > + EMIT(PPC_RAW_OR(dst_reg, dst_reg, b2p[TMP_REG_2])); > + } > break; > } > break; > -- > 2.33.0 >
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h index baea657bc8687e..bca31a61e57f88 100644 --- a/arch/powerpc/include/asm/ppc-opcode.h +++ b/arch/powerpc/include/asm/ppc-opcode.h @@ -498,6 +498,7 @@ #define PPC_RAW_LDX(r, base, b) (0x7c00002a | ___PPC_RT(r) | ___PPC_RA(base) | ___PPC_RB(b)) #define PPC_RAW_LHZ(r, base, i) (0xa0000000 | ___PPC_RT(r) | ___PPC_RA(base) | IMM_L(i)) #define PPC_RAW_LHBRX(r, base, b) (0x7c00062c | ___PPC_RT(r) | ___PPC_RA(base) | ___PPC_RB(b)) +#define PPC_RAW_LWBRX(r, base, b) (0x7c00042c | ___PPC_RT(r) | ___PPC_RA(base) | ___PPC_RB(b)) #define PPC_RAW_LDBRX(r, base, b) (0x7c000428 | ___PPC_RT(r) | ___PPC_RA(base) | ___PPC_RB(b)) #define PPC_RAW_STWCX(s, a, b) (0x7c00012d | ___PPC_RS(s) | ___PPC_RA(a) | ___PPC_RB(b)) #define PPC_RAW_CMPWI(a, i) (0x2c000000 | ___PPC_RA(a) | IMM_L(i)) diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 4641a50e82d50d..097d1ecfb9f562 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -601,17 +601,21 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * EMIT(PPC_RAW_MR(dst_reg, b2p[TMP_REG_1])); break; case 64: - /* - * Way easier and faster(?) to store the value - * into stack and then use ldbrx - * - * ctx->seen will be reliable in pass2, but - * the instructions generated will remain the - * same across all passes - */ + /* Store the value to stack and then use byte-reverse loads */ PPC_BPF_STL(dst_reg, 1, bpf_jit_stack_local(ctx)); EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], 1, bpf_jit_stack_local(ctx))); - EMIT(PPC_RAW_LDBRX(dst_reg, 0, b2p[TMP_REG_1])); + if (cpu_has_feature(CPU_FTR_ARCH_206)) { + EMIT(PPC_RAW_LDBRX(dst_reg, 0, b2p[TMP_REG_1])); + } else { + EMIT(PPC_RAW_LWBRX(dst_reg, 0, b2p[TMP_REG_1])); + if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN)) + EMIT(PPC_RAW_SLDI(dst_reg, dst_reg, 32)); + EMIT(PPC_RAW_LI(b2p[TMP_REG_2], 4)); + EMIT(PPC_RAW_LWBRX(b2p[TMP_REG_2], b2p[TMP_REG_2], b2p[TMP_REG_1])); + if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) + EMIT(PPC_RAW_SLDI(b2p[TMP_REG_2], b2p[TMP_REG_2], 32)); + EMIT(PPC_RAW_OR(dst_reg, dst_reg, b2p[TMP_REG_2])); + } break; } break;
Johan reported the below crash with test_bpf on ppc64 e5500: test_bpf: #296 ALU_END_FROM_LE 64: 0x0123456789abcdef -> 0x67452301 jited:1 Oops: Exception in kernel mode, sig: 4 [#1] BE PAGE_SIZE=4K SMP NR_CPUS=24 QEMU e500 Modules linked in: test_bpf(+) CPU: 0 PID: 76 Comm: insmod Not tainted 5.14.0-03771-g98c2059e008a-dirty #1 NIP: 8000000000061c3c LR: 80000000006dea64 CTR: 8000000000061c18 REGS: c0000000032d3420 TRAP: 0700 Not tainted (5.14.0-03771-g98c2059e008a-dirty) MSR: 0000000080089000 <EE,ME> CR: 88002822 XER: 20000000 IRQMASK: 0 <...> NIP [8000000000061c3c] 0x8000000000061c3c LR [80000000006dea64] .__run_one+0x104/0x17c [test_bpf] Call Trace: .__run_one+0x60/0x17c [test_bpf] (unreliable) .test_bpf_init+0x6a8/0xdc8 [test_bpf] .do_one_initcall+0x6c/0x28c .do_init_module+0x68/0x28c .load_module+0x2460/0x2abc .__do_sys_init_module+0x120/0x18c .system_call_exception+0x110/0x1b8 system_call_common+0xf0/0x210 --- interrupt: c00 at 0x101d0acc <...> ---[ end trace 47b2bf19090bb3d0 ]--- Illegal instruction The illegal instruction turned out to be 'ldbrx' emitted for BPF_FROM_[L|B]E, which was only introduced in ISA v2.06. Guard use of the same and implement an alternative approach for older processors. Fixes: 156d0e290e969c ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF") Reported-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> 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_comp64.c | 22 +++++++++++++--------- 2 files changed, 14 insertions(+), 9 deletions(-)