kernel.git/arch/s390/net, branch linux-4.14.y

s390/bpf: Fix optimizing out zero-extensions

2021-09-26T11:37:27Z

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

s390/bpf: Fix 64-bit subtraction of the -0x80000000 constant

2021-09-22T09:45:35Z

commit 6e61dc9da0b7a0d91d57c2e20b5ea4fd2d4e7e53 upstream. The JIT uses agfi for subtracting constants, but -(-0x80000000) cannot be represented as a 32-bit signed binary integer. Fix by using algfi in this particular case. 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

s390/bpf: Perform r1 range checking before accessing jit->seen_reg[r1]

2021-07-28T09:12:17Z

[ Upstream commit 91091656252f5d6d8c476e0c92776ce9fae7b445 ] Currently array jit->seen_reg[r1] is being accessed before the range checking of index r1. The range changing on r1 should be performed first since it will avoid any potential out-of-range accesses on the array seen_reg[] and also it is more optimal to perform checks on r1 before fetching data from the array. Fix this by swapping the order of the checks before the array access. Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Colin Ian King Signed-off-by: Daniel Borkmann Tested-by: Ilya Leoshkevich Acked-by: Ilya Leoshkevich Link: https://lore.kernel.org/bpf/20210715125712.24690-1-colin.king@canonical.com Signed-off-by: Sasha Levin

s390/bpf: use 32-bit index for tail calls

2019-09-21T05:15:31Z

[ Upstream commit 91b4db5313a2c793aabc2143efb8ed0cf0fdd097 ] "p runtime/jit: pass > 32bit index to tail_call" fails when bpf_jit_enable=1, because the tail call is not executed. This in turn is because the generated code assumes index is 64-bit, while it must be 32-bit, and as a result prog array bounds check fails, while it should pass. Even if bounds check would have passed, the code that follows uses 64-bit index to compute prog array offset. Fix by using clrj instead of clgrj for comparing index with array size, and also by using llgfr for truncating index to 32 bits before using it to compute prog array offset. Fixes: 6651ee070b31 ("s390/bpf: implement bpf_tail_call() helper") Reported-by: Yauheni Kaliuta Acked-by: Vasily Gorbik Signed-off-by: Ilya Leoshkevich Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin

s390/bpf: fix lcgr instruction encoding

2019-09-21T05:15:30Z

[ Upstream commit bb2d267c448f4bc3a3389d97c56391cb779178ae ] "masking, test in bounds 3" fails on s390, because BPF_ALU64_IMM(BPF_NEG, BPF_REG_2, 0) ignores the top 32 bits of BPF_REG_2. The reason is that JIT emits lcgfr instead of lcgr. The associated comment indicates that the code was intended to emit lcgr in the first place, it's just that the wrong opcode was used. Fix by using the correct opcode. Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Ilya Leoshkevich Acked-by: Vasily Gorbik Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin

bpf: get rid of pure_initcall dependency to enable jits

2019-08-25T08:50:02Z

commit fa9dd599b4dae841924b022768354cfde9affecb upstream. Having a pure_initcall() callback just to permanently enable BPF JITs under CONFIG_BPF_JIT_ALWAYS_ON is unnecessary and could leave a small race window in future where JIT is still disabled on boot. Since we know about the setting at compilation time anyway, just initialize it properly there. Also consolidate all the individual bpf_jit_enable variables into a single one and move them under one location. Moreover, don't allow for setting unspecified garbage values on them. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov [bwh: Backported to 4.14 as dependency of commit 2e4a30983b0f "bpf: restrict access to core bpf sysctls": - Adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

s390: fix br_r1_trampoline for machines without exrl

2018-09-05T07:26:40Z

commit 26f843848bae973817b3587780ce6b7b0200d3e4 upstream. For machines without the exrl instruction the BFP jit generates code that uses an "br %r1" instruction located in the lowcore page. Unfortunately there is a cut & paste error that puts an additional "larl %r1,.+14" instruction in the code that clobbers the branch target address in %r1. Remove the larl instruction. Cc: # v4.17+ Fixes: de5cb6eb51 ("s390: use expoline thunks in the BPF JIT") Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

bpf, s390: fix potential memleak when later bpf_jit_prog fails

2018-08-24T11:09:09Z

[ Upstream commit f605ce5eb26ac934fb8106d75d46a2c875a2bf23 ] If we would ever fail in the bpf_jit_prog() pass that writes the actual insns to the image after we got header via bpf_jit_binary_alloc() then we also need to make sure to free it through bpf_jit_binary_free() again when bailing out. Given we had prior bpf_jit_prog() passes to initially probe for clobbered registers, program size and to fill in addrs arrray for jump targets, this is more of a theoretical one, but at least make sure this doesn't break with future changes. Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Daniel Borkmann Cc: Martin Schwidefsky Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

s390: use expoline thunks in the BPF JIT

2018-05-25T14:17:33Z

[ Upstream commit de5cb6eb514ebe241e3edeb290cb41deb380b81d ] The BPF JIT need safe guarding against spectre v2 in the sk_load_xxx assembler stubs and the indirect branches generated by the JIT itself need to be converted to expolines. Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

bpf, s390x: do not reload skb pointers in non-skb context

2017-12-25T13:26:31Z

[ Upstream commit 6d59b7dbf72ed20d0138e2f9b75ca3d4a9d4faca ] The assumption of unconditionally reloading skb pointers on BPF helper calls where bpf_helper_changes_pkt_data() holds true is wrong. There can be different contexts where the BPF helper would enforce a reload such as in case of XDP. Here, we do have a struct xdp_buff instead of struct sk_buff as context, thus this will access garbage. JITs only ever need to deal with cached skb pointer reload when ld_abs/ind was seen, therefore guard the reload behind SEEN_SKB only. Tested on s390x. Fixes: 9db7f2b81880 ("s390/bpf: recache skb->data/hlen for skb_vlan_push/pop") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Cc: Michael Holzheu Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman