BMC/Intel-BMC/linux.git/arch/s390/net, branch dev

s390/bpf: clear correct BPF accumulator register

2015-07-27T07:08:11+00:00

Currently we assumed the following BPF to eBPF register mapping: - BPF_REG_A -> BPF_REG_7 - BPF_REG_X -> BPF_REG_8 Unfortunately this mapping is wrong. The correct mapping is: - BPF_REG_A -> BPF_REG_0 - BPF_REG_X -> BPF_REG_7 So clear the correct registers and use the BPF_REG_A and BPF_REG_X macros instead of BPF_REG_0/7. Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Cc: stable@vger.kernel.org # 4.0+ Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky

s390/bpf: Fix backward jumps

2015-06-25T07:39:18+00:00

Currently all backward jumps crash for JITed s390x eBPF programs with an illegal instruction program check and kernel panic. Because for negative values the opcode of the jump instruction is overriden by the negative branch offset an illegal instruction is generated by the JIT: 000003ff802da378: c01100000002 lgfi %r1,2 000003ff802da37e: fffffff52065 unknown <-- illegal instruction 000003ff802da384: b904002e lgr %r2,%r14 So fix this and mask the offset in order not to damage the opcode. Cc: stable@vger.kernel.org # 4.0+ Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky

s390/bpf: implement bpf_tail_call() helper

2015-06-09T18:47:10+00:00

bpf_tail_call() arguments: - ctx......: Context pointer - jmp_table: One of BPF_MAP_TYPE_PROG_ARRAY maps used as the jump table - index....: Index in the jump table In this implementation s390x JIT does stack unwinding and jumps into the callee program prologue. Caller and callee use the same stack. With this patch a tail call generates the following code on s390x: if (index >= array->map.max_entries) goto out 000003ff8001c7e4: e31030100016 llgf %r1,16(%r3) 000003ff8001c7ea: ec41001fa065 clgrj %r4,%r1,10,3ff8001c828 if (tail_call_cnt++ > MAX_TAIL_CALL_CNT) goto out; 000003ff8001c7f0: a7080001 lhi %r0,1 000003ff8001c7f4: eb10f25000fa laal %r1,%r0,592(%r15) 000003ff8001c7fa: ec120017207f clij %r1,32,2,3ff8001c828 prog = array->prog[index]; if (prog == NULL) goto out; 000003ff8001c800: eb140003000d sllg %r1,%r4,3 000003ff8001c806: e31310800004 lg %r1,128(%r3,%r1) 000003ff8001c80c: ec18000e007d clgij %r1,0,8,3ff8001c828 Restore registers before calling function 000003ff8001c812: eb68f2980004 lmg %r6,%r8,664(%r15) 000003ff8001c818: ebbff2c00004 lmg %r11,%r15,704(%r15) goto *(prog->bpf_func + tail_call_start); 000003ff8001c81e: e31100200004 lg %r1,32(%r1,%r0) 000003ff8001c824: 47f01006 bc 15,6(%r1) Reviewed-by: Martin Schwidefsky Signed-off-by: Michael Holzheu Acked-by: Heiko Carstens Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller

s390/bpf: fix bpf frame pointer setup

2015-06-04T02:31:39+00:00

Currently the bpf frame pointer is set to the old r15. This is wrong because of packed stack. Fix this and adjust the frame pointer to respect packed stack. This now generates a prolog like the following: 3ff8001c3fa: eb67f0480024 stmg %r6,%r7,72(%r15) 3ff8001c400: ebcff0780024 stmg %r12,%r15,120(%r15) 3ff8001c406: b904001f lgr %r1,%r15 <- load backchain 3ff8001c40a: 41d0f048 la %r13,72(%r15) <- load adjusted bfp 3ff8001c40e: a7fbfd98 aghi %r15,-616 3ff8001c412: e310f0980024 stg %r1,152(%r15) <- save backchain Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Michael Holzheu Acked-by: Heiko Carstens Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller

s390/bpf: fix stack allocation

2015-06-04T02:31:39+00:00

On s390x we have to provide 160 bytes stack space before we can call the next function. From the 160 bytes that we got from the previous function we only use 11 * 8 bytes and have 160 - 11 * 8 bytes left. Currently for BPF we allocate additional 160 - 11 * 8 bytes for the next function. This is wrong because then the next function only gets: (160 - 11 * 8) + (160 - 11 * 8) = 2 * 72 = 144 bytes Fix this and allocate enough memory for the next function. Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Michael Holzheu Acked-by: Heiko Carstens Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller

s390/bpf: Fix gcov stack space problem

2015-04-30T11:50:36+00:00

When compiling the kernel for GCOV (CONFIG_GCOV_KERNEL,-fprofile-arcs), gcc allocates a lot of stack space because of the large switch statement in bpf_jit_insn(). This leads to the following compile warning: arch/s390/net/bpf_jit_comp.c: In function 'bpf_jit_prog': arch/s390/net/bpf_jit_comp.c:1144:1: warning: frame size of function 'bpf_jit_prog' is 12592 bytes which is more than half the stack size. The dynamic check would not be reliable. No check emitted for this function. arch/s390/net/bpf_jit_comp.c:1144:1: warning: the frame size of 12504 bytes is larger than 1024 bytes [-Wframe-larger-than=] And indead gcc allocates 12592 bytes of stack space: # objdump -d arch/s390/net/bpf_jit_comp.o ... 0000000000000c60 : c60: eb 6f f0 48 00 24 stmg %r6,%r15,72(%r15) c66: b9 04 00 ef lgr %r14,%r15 c6a: e3 f0 fe d0 fc 71 lay %r15,-12592(%r15) As a workaround of that problem we now define bpf_jit_insn() as noinline which then reduces the stack space. # objdump -d arch/s390/net/bpf_jit_comp.o ... 0000000000000070 : 70: eb 6f f0 48 00 24 stmg %r6,%r15,72(%r15) 76: c0 d0 00 00 00 00 larl %r13,76 7c: a7 f1 3f 80 tmll %r15,16256 80: b9 04 00 ef lgr %r14,%r15 84: e3 f0 ff a0 ff 71 lay %r15,-96(%r15) Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky

s390/bpf: Adjust ALU64_DIV/MOD to match interpreter change

2015-04-30T11:50:34+00:00

The s390x ALU64_DIV/MOD has been implemented according to the eBPF interpreter specification that used do_div(). This function does a 64-bit by 32-bit divide. It turned out that this was wrong and now the interpreter uses div64_u64_rem() for full 64-bit division. So fix this and use full 64-bit division in the s390x eBPF backend code. Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky

s390/bpf: Add s390x eBPF JIT compiler backend

2015-04-15T10:23:49+00:00

Replace 32 bit BPF JIT backend with new 64 bit eBPF backend. Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky

s390/bpf: Zero extend parameters before calling C function

2015-01-15T10:10:41+00:00

The s390x ABI requires to zero extend parameters before functions are called. Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky

s390/bpf: Fix sk_load_byte_msh()

2015-01-15T10:10:37+00:00

In sk_load_byte_msh() sk_load_byte_slow() is called instead of sk_load_byte_msh_slow(). Fix this and call the correct function. Besides of this load only one byte instead of two and fix the comment. Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky