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* bpf: fix x64 JIT code generation for jmp to 1st insnAlexei Starovoitov2019-08-011-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | Introduction of bounded loops exposed old bug in x64 JIT. JIT maintains the array of offsets to the end of all instructions to compute jmp offsets. addrs[0] - offset of the end of the 1st insn (that includes prologue). addrs[1] - offset of the end of the 2nd insn. JIT didn't keep the offset of the beginning of the 1st insn, since classic BPF didn't have backward jumps and valid extended BPF couldn't have a branch to 1st insn, because it didn't allow loops. With bounded loops it's possible to construct a valid program that jumps backwards to the 1st insn. Fix JIT by computing: addrs[0] - offset of the end of prologue == start of the 1st insn. addrs[1] - offset of the end of 1st insn. v1->v2: - Yonghong noticed a bug in jit linfo. Fix it by passing 'addrs + 1' to bpf_prog_fill_jited_linfo(), since it expects insn_to_jit_off array to be offsets to last byte. Reported-by: syzbot+35101610ff3e83119b1b@syzkaller.appspotmail.com Fixes: 2589726d12a1 ("bpf: introduce bounded loops") Fixes: 0a14842f5a3c ("net: filter: Just In Time compiler for x86-64") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds2019-06-181-53/+21Star
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking fixes from David Miller: "Lots of bug fixes here: 1) Out of bounds access in __bpf_skc_lookup, from Lorenz Bauer. 2) Fix rate reporting in cfg80211_calculate_bitrate_he(), from John Crispin. 3) Use after free in psock backlog workqueue, from John Fastabend. 4) Fix source port matching in fdb peer flow rule of mlx5, from Raed Salem. 5) Use atomic_inc_not_zero() in fl6_sock_lookup(), from Eric Dumazet. 6) Network header needs to be set for packet redirect in nfp, from John Hurley. 7) Fix udp zerocopy refcnt, from Willem de Bruijn. 8) Don't assume linear buffers in vxlan and geneve error handlers, from Stefano Brivio. 9) Fix TOS matching in mlxsw, from Jiri Pirko. 10) More SCTP cookie memory leak fixes, from Neil Horman. 11) Fix VLAN filtering in rtl8366, from Linus Walluij. 12) Various TCP SACK payload size and fragmentation memory limit fixes from Eric Dumazet. 13) Use after free in pneigh_get_next(), also from Eric Dumazet. 14) LAPB control block leak fix from Jeremy Sowden" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (145 commits) lapb: fixed leak of control-blocks. tipc: purge deferredq list for each grp member in tipc_group_delete ax25: fix inconsistent lock state in ax25_destroy_timer neigh: fix use-after-free read in pneigh_get_next tcp: fix compile error if !CONFIG_SYSCTL hv_sock: Suppress bogus "may be used uninitialized" warnings be2net: Fix number of Rx queues used for flow hashing net: handle 802.1P vlan 0 packets properly tcp: enforce tcp_min_snd_mss in tcp_mtu_probing() tcp: add tcp_min_snd_mss sysctl tcp: tcp_fragment() should apply sane memory limits tcp: limit payload size of sacked skbs Revert "net: phylink: set the autoneg state in phylink_phy_change" bpf: fix nested bpf tracepoints with per-cpu data bpf: Fix out of bounds memory access in bpf_sk_storage vsock/virtio: set SOCK_DONE on peer shutdown net: dsa: rtl8366: Fix up VLAN filtering net: phylink: set the autoneg state in phylink_phy_change net: add high_order_alloc_disable sysctl/static key tcp: add tcp_tx_skb_cache sysctl ...
| * bpf, x64: fix stack layout of JITed bpf codeAlexei Starovoitov2019-06-151-53/+21Star
| | | | | | | | | | | | | | | | | | | | | | Since commit 177366bf7ceb the %rbp stopped pointing to %rbp of the previous stack frame. That broke frame pointer based stack unwinding. This commit is a partial revert of it. Note that the location of tail_call_cnt is fixed, since the verifier enforces MAX_BPF_STACK stack size for programs with tail calls. Fixes: 177366bf7ceb ("bpf: change x86 JITed program stack layout") Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441Thomas Gleixner2019-06-051-5/+1Star
|/ | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 315 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* x86_64: bpf: implement jitting of JMP32Jiong Wang2019-01-261-6/+40
| | | | | | | | | This patch implements code-gen for new JMP32 instructions on x86_64. Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* bpf: Add bpf_line_info supportMartin KaFai Lau2018-12-091-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds bpf_line_info support. It accepts an array of bpf_line_info objects during BPF_PROG_LOAD. The "line_info", "line_info_cnt" and "line_info_rec_size" are added to the "union bpf_attr". The "line_info_rec_size" makes bpf_line_info extensible in the future. The new "check_btf_line()" ensures the userspace line_info is valid for the kernel to use. When the verifier is translating/patching the bpf_prog (through "bpf_patch_insn_single()"), the line_infos' insn_off is also adjusted by the newly added "bpf_adj_linfo()". If the bpf_prog is jited, this patch also provides the jited addrs (in aux->jited_linfo) for the corresponding line_info.insn_off. "bpf_prog_fill_jited_linfo()" is added to fill the aux->jited_linfo. It is currently called by the x86 jit. Other jits can also use "bpf_prog_fill_jited_linfo()" and it will be done in the followup patches. In the future, if it deemed necessary, a particular jit could also provide its own "bpf_prog_fill_jited_linfo()" implementation. A few "*line_info*" fields are added to the bpf_prog_info such that the user can get the xlated line_info back (i.e. the line_info with its insn_off reflecting the translated prog). The jited_line_info is available if the prog is jited. It is an array of __u64. If the prog is not jited, jited_line_info_cnt is 0. The verifier's verbose log with line_info will be done in a follow up patch. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* treewide: kmalloc() -> kmalloc_array()Kees Cook2018-06-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kmalloc() function has a 2-factor argument form, kmalloc_array(). This patch replaces cases of: kmalloc(a * b, gfp) with: kmalloc_array(a * b, gfp) as well as handling cases of: kmalloc(a * b * c, gfp) with: kmalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kmalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kmalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The tools/ directory was manually excluded, since it has its own implementation of kmalloc(). The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(char) * COUNT + COUNT , ...) | kmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kmalloc + kmalloc_array ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kmalloc(C1 * C2 * C3, ...) | kmalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kmalloc(sizeof(THING) * C2, ...) | kmalloc(sizeof(TYPE) * C2, ...) | kmalloc(C1 * C2 * C3, ...) | kmalloc(C1 * C2, ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - (E1) * E2 + E1, E2 , ...) | - kmalloc + kmalloc_array ( - (E1) * (E2) + E1, E2 , ...) | - kmalloc + kmalloc_array ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller2018-05-081-223/+120Star
|\ | | | | | | | | | | | | | | Minor conflict, a CHECK was placed into an if() statement in net-next, whilst a newline was added to that CHECK call in 'net'. Thanks to Daniel for the merge resolution. Signed-off-by: David S. Miller <davem@davemloft.net>
| * bpf, x64: remove ld_abs/ld_indDaniel Borkmann2018-05-041-140/+4Star
| | | | | | | | | | | | | | | | | | | | Since LD_ABS/LD_IND instructions are now removed from the core and reimplemented through a combination of inlined BPF instructions and a slow-path helper, we can get rid of the complexity from x64 JIT. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| * x86/bpf: Clean up non-standard comments, to make the code more readableIngo Molnar2018-05-021-100/+133
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | So by chance I looked into x86 assembly in arch/x86/net/bpf_jit_comp.c and noticed the weird and inconsistent comment style it mistakenly learned from the networking code: /* Multi-line comment ... * ... looks like this. */ Fix this to use the standard comment style specified in Documentation/CodingStyle and used in arch/x86/ as well: /* * Multi-line comment ... * ... looks like this. */ Also, to quote Linus's ... more explicit views about this: http://article.gmane.org/gmane.linux.kernel.cryptoapi/21066 > But no, the networking code picked *none* of the above sane formats. > Instead, it picked these two models that are just half-arsed > shit-for-brains: > > (no) > /* This is disgusting drug-induced > * crap, and should die > */ > > (no-no-no) > /* This is also very nasty > * and visually unbalanced */ > > Please. The networking code actually has the *worst* possible comment > style. You can literally find that (no-no-no) style, which is just > really horribly disgusting and worse than the otherwise fairly similar > (d) in pretty much every way. Also improve the comments and some other details while at it: - Don't mix same-line and previous-line comment style on otherwise identical code patterns within the same function, - capitalize 'BPF' and x86 register names consistently, - capitalize sentences consistently, - instead of 'x64' use 'x86-64': x64 is a Microsoft specific term, - use more consistent punctuation, - use standard coding style in macros as well, - fix typos and a few other minor details. Consistent coding style is not optional, at least in arch/x86/. No change in functionality. ( In case this commit causes conflicts with pending development code I'll be glad to help resolve any conflicts! ) Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: David S. Miller <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@fb.com> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
* | bpf, x64: fix memleak when not converging on callsDaniel Borkmann2018-05-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The JIT logic in jit_subprogs() is as follows: for all subprogs we allocate a bpf_prog_alloc(), populate it (prog->is_func = 1 here), and pass it to bpf_int_jit_compile(). If a failure occurred during JIT and prog->jited is not set, then we bail out from attempting to JIT the whole program, and punt to the interpreter instead. In case JITing went successful, we fixup BPF call offsets and do another pass to bpf_int_jit_compile() (extra_pass is true at that point) to complete JITing calls. Given that requires to pass JIT context around addrs and jit_data from x86 JIT are freed in the extra_pass in bpf_int_jit_compile() when calls are involved (if not, they can be freed immediately). However, if in the original pass, the JIT image didn't converge then we leak addrs and jit_data since image itself is NULL, the prog->is_func is set and extra_pass is false in that case, meaning both will become unreachable and are never cleaned up, therefore we need to free as well on !image. Only x64 JIT is affected. Fixes: 1c2a088a6626 ("bpf: x64: add JIT support for multi-function programs") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | bpf, x64: fix memleak when not converging after imageDaniel Borkmann2018-05-021-2/+2
|/ | | | | | | | | | | | | | | | While reviewing x64 JIT code, I noticed that we leak the prior allocated JIT image in the case where proglen != oldproglen during the JIT passes. Prior to the commit e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT compiler") we would just break out of the loop, and using the image as the JITed prog since it could only shrink in size anyway. After e0ee9c12157d, we would bail out to out_addrs label where we free addrs and jit_data but not the image coming from bpf_jit_binary_alloc(). Fixes: e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT compiler") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* bpf, x64: fix JIT emission for dead codeGianluca Borello2018-04-251-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 2a5418a13fcf ("bpf: improve dead code sanitizing") replaced dead code with a series of ja-1 instructions, for safety. That made JIT compilation much more complex for some BPF programs. One instance of such programs is, for example: bool flag = false ... /* A bunch of other code */ ... if (flag) do_something() In some cases llvm is not able to remove at compile time the code for do_something(), so the generated BPF program ends up with a large amount of dead instructions. In one specific real life example, there are two series of ~500 and ~1000 dead instructions in the program. When the verifier replaces them with a series of ja-1 instructions, it causes an interesting behavior at JIT time. During the first pass, since all the instructions are estimated at 64 bytes, the ja-1 instructions end up being translated as 5 bytes JMP instructions (0xE9), since the jump offsets become increasingly large (> 127) as each instruction gets discovered to be 5 bytes instead of the estimated 64. Starting from the second pass, the first N instructions of the ja-1 sequence get translated into 2 bytes JMPs (0xEB) because the jump offsets become <= 127 this time. In particular, N is defined as roughly 127 / (5 - 2) ~= 42. So, each further pass will make the subsequent N JMP instructions shrink from 5 to 2 bytes, making the image shrink every time. This means that in order to have the entire program converge, there need to be, in the real example above, at least ~1000 / 42 ~= 24 passes just for translating the dead code. If we add this number to the passes needed to translate the other non dead code, it brings such program to 40+ passes, and JIT doesn't complete. Ultimately the userspace loader fails because such BPF program was supposed to be part of a prog array owner being JITed. While it is certainly possible to try to refactor such programs to help the compiler remove dead code, the behavior is not really intuitive and it puts further burden on the BPF developer who is not expecting such behavior. To make things worse, such programs are working just fine in all the kernel releases prior to the ja-1 fix. A possible approach to mitigate this behavior consists into noticing that for ja-1 instructions we don't really need to rely on the estimated size of the previous and current instructions, we know that a -1 BPF jump offset can be safely translated into a 0xEB instruction with a jump offset of -2. Such fix brings the BPF program in the previous example to complete again in ~9 passes. Fixes: 2a5418a13fcf ("bpf: improve dead code sanitizing") Signed-off-by: Gianluca Borello <g.borello@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2018-03-231-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fun set of conflict resolutions here... For the mac80211 stuff, these were fortunately just parallel adds. Trivially resolved. In drivers/net/phy/phy.c we had a bug fix in 'net' that moved the function phy_disable_interrupts() earlier in the file, whilst in 'net-next' the phy_error() call from this function was removed. In net/ipv4/xfrm4_policy.c, David Ahern's changes to remove the 'rt_table_id' member of rtable collided with a bug fix in 'net' that added a new struct member "rt_mtu_locked" which needs to be copied over here. The mlxsw driver conflict consisted of net-next separating the span code and definitions into separate files, whilst a 'net' bug fix made some changes to that moved code. The mlx5 infiniband conflict resolution was quite non-trivial, the RDMA tree's merge commit was used as a guide here, and here are their notes: ==================== Due to bug fixes found by the syzkaller bot and taken into the for-rc branch after development for the 4.17 merge window had already started being taken into the for-next branch, there were fairly non-trivial merge issues that would need to be resolved between the for-rc branch and the for-next branch. This merge resolves those conflicts and provides a unified base upon which ongoing development for 4.17 can be based. Conflicts: drivers/infiniband/hw/mlx5/main.c - Commit 42cea83f9524 (IB/mlx5: Fix cleanup order on unload) added to for-rc and commit b5ca15ad7e61 (IB/mlx5: Add proper representors support) add as part of the devel cycle both needed to modify the init/de-init functions used by mlx5. To support the new representors, the new functions added by the cleanup patch needed to be made non-static, and the init/de-init list added by the representors patch needed to be modified to match the init/de-init list changes made by the cleanup patch. Updates: drivers/infiniband/hw/mlx5/mlx5_ib.h - Update function prototypes added by representors patch to reflect new function names as changed by cleanup patch drivers/infiniband/hw/mlx5/ib_rep.c - Update init/de-init stage list to match new order from cleanup patch ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
| * bpf, x64: increase number of passesDaniel Borkmann2018-03-071-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In Cilium some of the main programs we run today are hitting 9 passes on x64's JIT compiler, and we've had cases already where we surpassed the limit where the JIT then punts the program to the interpreter instead, leading to insertion failures due to CONFIG_BPF_JIT_ALWAYS_ON or insertion failures due to the prog array owner being JITed but the program to insert not (both must have the same JITed/non-JITed property). One concrete case the program image shrunk from 12,767 bytes down to 10,288 bytes where the image converged after 16 steps. I've measured that this took 340us in the JIT until it converges on my i7-6600U. Thus, increase the original limit we had from day one where the JIT covered cBPF only back then before we run into the case (as similar with the complexity limit) where we trip over this and hit program rejections. Also add a cond_resched() into the compilation loop, the JIT process runs without any locks and may sleep anyway. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | bpf, x64: remove bpf_flush_icacheDaniel Borkmann2018-02-271-13/+2Star
| | | | | | | | | | | | | | | | | | | | | | Unlike other archs flush_icache_range() is a noop on x64, therefore remove the JIT's bpf_flush_icache() altogether since not needed. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Eric Dumazet <edumazet@google.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller2018-02-261-87/+132
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Daniel Borkmann says: ==================== pull-request: bpf-next 2018-02-26 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Various improvements for BPF kselftests: i) skip unprivileged tests when kernel.unprivileged_bpf_disabled sysctl knob is set, ii) count the number of skipped tests from unprivileged, iii) when a test case had an unexpected error then print the actual but also the unexpected one for better comparison, from Joe. 2) Add a sample program for collecting CPU state statistics with regards to how long the CPU resides in cstate and pstate levels. Based on cpu_idle and cpu_frequency trace points, from Leo. 3) Various x64 BPF JIT optimizations to further shrink the generated image size in order to make it more icache friendly. When tested on the Cilium generated programs, image size reduced by approx 4-5% in best case mainly due to how LLVM emits unsigned 32 bit constants, from Daniel. 4) Improvements and fixes on the BPF sockmap sample programs: i) fix the sockmap's Makefile to include nlattr.o for libbpf, ii) detach the sock ops programs from the cgroup before exit, from Prashant. 5) Avoid including xdp.h in filter.h by just forward declaring the struct xdp_rxq_info in filter.h, from Jesper. 6) Fix the BPF kselftests Makefile for cgroup_helpers.c by only declaring it a dependency for test_dev_cgroup.c but not every other test case where it is not needed, from Jesper. 7) Adjust rlimit RLIMIT_MEMLOCK for test_tcpbpf_user selftest since the default is insufficient for creating the 'global_map' used in the corresponding BPF program, from Yonghong. 8) Likewise, for the xdp_redirect sample, Tushar ran into the same when invoking xdp_redirect and xdp_monitor at the same time, therefore in order to have the sample generically work bump the limit here, too. Fix from Tushar. 9) Avoid an unnecessary NULL check in BPF_CGROUP_RUN_PROG_INET_SOCK() since sk is always guaranteed to be non-NULL, from Yafang. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
| * bpf, x64: save 5 bytes in prologue when ebpf insns came from cbpfDaniel Borkmann2018-02-241-12/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | While it's rather cumbersome to reduce prologue for cBPF->eBPF migrations wrt spill/fill for r15 which is callee saved register due to bpf_error path in bpf_jit.S that is both used by migrations as well as native eBPF, we can still trivially save 5 bytes in prologue for the former since tail calls can never be used there. cBPF->eBPF migrations also have their own custom prologue in BPF asm that xors A and X reg anyway, so it's fine we skip this here. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| * bpf, x64: save few bytes when mul is in alu32Daniel Borkmann2018-02-241-15/+28
| | | | | | | | | | | | | | | | | | Add a generic emit_mov_reg() helper in order to reuse it in BPF multiplication to load the src into rax, we can save a few bytes in alu32 while doing so. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| * bpf, x64: save several bytes when mul dest is r0/r3 anywayDaniel Borkmann2018-02-241-10/+11
| | | | | | | | | | | | | | | | | | | | Instead of unconditionally performing push/pop on rax/rdx in case of multiplication, we can save a few bytes in case of dest register being either BPF r0 (rax) or r3 (rdx) since the result is written in there anyway. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| * bpf, x64: save several bytes by using mov over movabsq when possibleDaniel Borkmann2018-02-241-51/+74
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While analyzing some of the more complex BPF programs from Cilium, I found that LLVM generally prefers to emit LD_IMM64 instead of MOV32 BPF instructions for loading unsigned 32-bit immediates into a register. Given we cannot change the current/stable LLVM versions that are already out there, lets optimize this case such that the JIT prefers to emit 'mov %eax, imm32' over 'movabsq %rax, imm64' whenever suitable in order to reduce the image size by 4-5 bytes per such load in the typical case, reducing image size on some of the bigger programs by up to 4%. emit_mov_imm32() and emit_mov_imm64() have been added as helpers. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| * bpf, x64: save one byte per shl/shr/sar when imm is 1Daniel Borkmann2018-02-241-1/+5
| | | | | | | | | | | | | | | | When we shift by one, we can use a different encoding where imm is not explicitly needed, which saves 1 byte per such op. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* | bpf, x64: implement retpoline for tail callDaniel Borkmann2018-02-231-4/+5
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement a retpoline [0] for the BPF tail call JIT'ing that converts the indirect jump via jmp %rax that is used to make the long jump into another JITed BPF image. Since this is subject to speculative execution, we need to control the transient instruction sequence here as well when CONFIG_RETPOLINE is set, and direct it into a pause + lfence loop. The latter aligns also with what gcc / clang emits (e.g. [1]). JIT dump after patch: # bpftool p d x i 1 0: (18) r2 = map[id:1] 2: (b7) r3 = 0 3: (85) call bpf_tail_call#12 4: (b7) r0 = 2 5: (95) exit With CONFIG_RETPOLINE: # bpftool p d j i 1 [...] 33: cmp %edx,0x24(%rsi) 36: jbe 0x0000000000000072 |* 38: mov 0x24(%rbp),%eax 3e: cmp $0x20,%eax 41: ja 0x0000000000000072 | 43: add $0x1,%eax 46: mov %eax,0x24(%rbp) 4c: mov 0x90(%rsi,%rdx,8),%rax 54: test %rax,%rax 57: je 0x0000000000000072 | 59: mov 0x28(%rax),%rax 5d: add $0x25,%rax 61: callq 0x000000000000006d |+ 66: pause | 68: lfence | 6b: jmp 0x0000000000000066 | 6d: mov %rax,(%rsp) | 71: retq | 72: mov $0x2,%eax [...] * relative fall-through jumps in error case + retpoline for indirect jump Without CONFIG_RETPOLINE: # bpftool p d j i 1 [...] 33: cmp %edx,0x24(%rsi) 36: jbe 0x0000000000000063 |* 38: mov 0x24(%rbp),%eax 3e: cmp $0x20,%eax 41: ja 0x0000000000000063 | 43: add $0x1,%eax 46: mov %eax,0x24(%rbp) 4c: mov 0x90(%rsi,%rdx,8),%rax 54: test %rax,%rax 57: je 0x0000000000000063 | 59: mov 0x28(%rax),%rax 5d: add $0x25,%rax 61: jmpq *%rax |- 63: mov $0x2,%eax [...] * relative fall-through jumps in error case - plain indirect jump as before [0] https://support.google.com/faqs/answer/7625886 [1] https://github.com/gcc-mirror/gcc/commit/a31e654fa107be968b802786d747e962c2fcdb2b Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* bpf, x86_64: remove obsolete exception handling from div/modDaniel Borkmann2018-01-271-20/+0Star
| | | | | | | | | Since we've changed div/mod exception handling for src_reg in eBPF verifier itself, remove the leftovers from x86_64 JIT. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* bpf, x86: small optimization in alu ops with immDaniel Borkmann2018-01-201-5/+30
| | | | | | | | | | | | For the BPF_REG_0 (BPF_REG_A in cBPF, respectively), we can use the short form of the opcode as dst mapping is on eax/rax and thus save a byte per such operation. Added to add/sub/and/or/xor for 32/64 bit when K immediate is used. There may be more such low-hanging fruit to add in future as well. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* bpf: get rid of pure_initcall dependency to enable jitsDaniel Borkmann2018-01-201-2/+0Star
| | | | | | | | | | | | | | | 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 <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* bpf: x64: add JIT support for multi-function programsAlexei Starovoitov2017-12-171-3/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Typical JIT does several passes over bpf instructions to compute total size and relative offsets of jumps and calls. With multitple bpf functions calling each other all relative calls will have invalid offsets intially therefore we need to additional last pass over the program to emit calls with correct offsets. For example in case of three bpf functions: main: call foo call bpf_map_lookup exit foo: call bar exit bar: exit We will call bpf_int_jit_compile() indepedently for main(), foo() and bar() x64 JIT typically does 4-5 passes to converge. After these initial passes the image for these 3 functions will be good except call targets, since start addresses of foo() and bar() are unknown when we were JITing main() (note that call bpf_map_lookup will be resolved properly during initial passes). Once start addresses of 3 functions are known we patch call_insn->imm to point to right functions and call bpf_int_jit_compile() again which needs only one pass. Additional safety checks are done to make sure this last pass doesn't produce image that is larger or smaller than previous pass. When constant blinding is on it's applied to all functions at the first pass, since doing it once again at the last pass can change size of the JITed code. Tested on x64 and arm64 hw with JIT on/off, blinding on/off. x64 jits bpf-to-bpf calls correctly while arm64 falls back to interpreter. All other JITs that support normal BPF_CALL will behave the same way since bpf-to-bpf call is equivalent to bpf-to-kernel call from JITs point of view. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
* bpf: fix net.core.bpf_jit_enable raceAlexei Starovoitov2017-12-171-1/+1
| | | | | | | | | | | | global bpf_jit_enable variable is tested multiple times in JITs, blinding and verifier core. The malicious root can try to toggle it while loading the programs. This race condition was accounted for and there should be no issues, but it's safer to avoid this race condition. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
* bpf: fix bpf_tail_call() x64 JITAlexei Starovoitov2017-10-041-2/+2
| | | | | | | | | | | | | | | | | | | | - bpf prog_array just like all other types of bpf array accepts 32-bit index. Clarify that in the comment. - fix x64 JIT of bpf_tail_call which was incorrectly loading 8 instead of 4 bytes - tighten corresponding check in the interpreter to stay consistent The JIT bug can be triggered after introduction of BPF_F_NUMA_NODE flag in commit 96eabe7a40aa in 4.14. Before that the map_flags would stay zero and though JIT code is wrong it will check bounds correctly. Hence two fixes tags. All other JITs don't have this problem. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Fixes: 96eabe7a40aa ("bpf: Allow selecting numa node during map creation") Fixes: b52f00e6a715 ("x86: bpf_jit: implement bpf_tail_call() helper") Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* x86: bpf_jit: small optimization in emit_bpf_tail_call()Eric Dumazet2017-08-311-5/+4Star
| | | | | | | | | | | | | | | | | | | | Saves 4 bytes replacing following instructions : lea rax, [rsi + rdx * 8 + offsetof(...)] mov rax, qword ptr [rax] cmp rax, 0 by : mov rax, [rsi + rdx * 8 + offsetof(...)] test rax, rax Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf, x86: implement jiting of BPF_J{LT,LE,SLT,SLE}Daniel Borkmann2017-08-101-0/+26
| | | | | | | | | This work implements jiting of BPF_J{LT,LE,SLT,SLE} instructions with BPF_X/BPF_K variants for the x86_64 eBPF JIT. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Add jited_len to struct bpf_progMartin KaFai Lau2017-06-061-0/+1
| | | | | | | | | | | Add jited_len to struct bpf_prog. It will be useful for the struct bpf_prog_info which will be added in the later patch. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: take advantage of stack_depth tracking in x64 JITAlexei Starovoitov2017-06-011-4/+5
| | | | | | | | | | Take advantage of stack_depth tracking in x64 JIT. Round up allocated stack by 8 bytes to make sure it stays aligned for functions called from JITed bpf program. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: change x86 JITed program stack layoutAlexei Starovoitov2017-06-011-27/+31
| | | | | | | | | | | | | in order to JIT programs with different stack sizes we need to make epilogue and exception path to be stack size independent, hence move auxiliary stack space from the bottom of the stack to the top of the stack. Nice side effect is that JITed function prologue becomes shorter due to imm8 offset encoding vs imm32. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: free up BPF_JMP | BPF_CALL | BPF_X opcodeAlexei Starovoitov2017-06-011-1/+1
| | | | | | | | | | free up BPF_JMP | BPF_CALL | BPF_X opcode to be used by actual indirect call by register and use kernel internal opcode to mark call instruction into bpf_tail_call() helper. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* x86: use set_memory.h headerLaura Abbott2017-05-091-0/+1
| | | | | | | | | | | set_memory_* functions have moved to set_memory.h. Switch to this explicitly. Link: http://lkml.kernel.org/r/1488920133-27229-6-git-send-email-labbott@redhat.com Signed-off-by: Laura Abbott <labbott@redhat.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* bpf, x86_64/arm64: remove old ldimm64 artifacts from jitsDaniel Borkmann2017-04-281-7/+0Star
| | | | | | | | | | | For both cases, the verifier is already rejecting such invalid formed instructions. Thus, remove these artifacts from old times and align it with ppc64, sparc64 and s390x JITs that don't have them in the first place. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: fix unlocking of jited image when module ronx not setDaniel Borkmann2017-02-211-1/+1
| | | | | | | | | | | | | | | | | | | Eric and Willem reported that they recently saw random crashes when JIT was in use and bisected this to 74451e66d516 ("bpf: make jited programs visible in traces"). Issue was that the consolidation part added bpf_jit_binary_unlock_ro() that would unlock previously made read-only memory back to read-write. However, DEBUG_SET_MODULE_RONX cannot be used for this to test for presence of set_memory_*() functions. We need to use ARCH_HAS_SET_MEMORY instead to fix this; also add the corresponding bpf_jit_binary_lock_ro() to filter.h. Fixes: 74451e66d516 ("bpf: make jited programs visible in traces") Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: Willem de Bruijn <willemb@google.com> Bisected-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: make jited programs visible in tracesDaniel Borkmann2017-02-171-15/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Long standing issue with JITed programs is that stack traces from function tracing check whether a given address is kernel code through {__,}kernel_text_address(), which checks for code in core kernel, modules and dynamically allocated ftrace trampolines. But what is still missing is BPF JITed programs (interpreted programs are not an issue as __bpf_prog_run() will be attributed to them), thus when a stack trace is triggered, the code walking the stack won't see any of the JITed ones. The same for address correlation done from user space via reading /proc/kallsyms. This is read by tools like perf, but the latter is also useful for permanent live tracing with eBPF itself in combination with stack maps when other eBPF types are part of the callchain. See offwaketime example on dumping stack from a map. This work tries to tackle that issue by making the addresses and symbols known to the kernel. The lookup from *kernel_text_address() is implemented through a latched RB tree that can be read under RCU in fast-path that is also shared for symbol/size/offset lookup for a specific given address in kallsyms. The slow-path iteration through all symbols in the seq file done via RCU list, which holds a tiny fraction of all exported ksyms, usually below 0.1 percent. Function symbols are exported as bpf_prog_<tag>, in order to aide debugging and attribution. This facility is currently enabled for root-only when bpf_jit_kallsyms is set to 1, and disabled if hardening is active in any mode. The rationale behind this is that still a lot of systems ship with world read permissions on kallsyms thus addresses should not get suddenly exposed for them. If that situation gets much better in future, we always have the option to change the default on this. Likewise, unprivileged programs are not allowed to add entries there either, but that is less of a concern as most such programs types relevant in this context are for root-only anyway. If enabled, call graphs and stack traces will then show a correct attribution; one example is illustrated below, where the trace is now visible in tooling such as perf script --kallsyms=/proc/kallsyms and friends. Before: 7fff8166889d bpf_clone_redirect+0x80007f0020ed (/lib/modules/4.9.0-rc8+/build/vmlinux) f5d80 __sendmsg_nocancel+0xffff006451f1a007 (/usr/lib64/libc-2.18.so) After: 7fff816688b7 bpf_clone_redirect+0x80007f002107 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fffa0575728 bpf_prog_33c45a467c9e061a+0x8000600020fb (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fffa07ef1fc cls_bpf_classify+0x8000600020dc (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff81678b68 tc_classify+0x80007f002078 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164d40b __netif_receive_skb_core+0x80007f0025fb (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164d718 __netif_receive_skb+0x80007f002018 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164e565 process_backlog+0x80007f002095 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164dc71 net_rx_action+0x80007f002231 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff81767461 __softirqentry_text_start+0x80007f0020d1 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff817658ac do_softirq_own_stack+0x80007f00201c (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff810a2c20 do_softirq+0x80007f002050 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff810a2cb5 __local_bh_enable_ip+0x80007f002085 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168d452 ip_finish_output2+0x80007f002152 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168ea3d ip_finish_output+0x80007f00217d (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168f2af ip_output+0x80007f00203f (/lib/modules/4.9.0-rc8+/build/vmlinux) [...] 7fff81005854 do_syscall_64+0x80007f002054 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff817649eb return_from_SYSCALL_64+0x80007f002000 (/lib/modules/4.9.0-rc8+/build/vmlinux) f5d80 __sendmsg_nocancel+0xffff01c484812007 (/usr/lib64/libc-2.18.so) Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: remove stubs for cBPF from arch codeDaniel Borkmann2017-02-171-6/+2Star
| | | | | | | | | | | Remove the dummy bpf_jit_compile() stubs for eBPF JITs and make that a single __weak function in the core that can be overridden similarly to the eBPF one. Also remove stale pr_err() mentions of bpf_jit_compile. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: change back to orig prog on too many passesDaniel Borkmann2017-01-081-0/+2
| | | | | | | | | | | If after too many passes still no image could be emitted, then swap back to the original program as we do in all other cases and don't use the one with blinding. Fixes: 959a75791603 ("bpf, x86: add support for constant blinding") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: xdp: Allow head adjustment in XDP progMartin KaFai Lau2016-12-081-1/+1
| | | | | | | | | | | | | | | | | | | | | This patch allows XDP prog to extend/remove the packet data at the head (like adding or removing header). It is done by adding a new XDP helper bpf_xdp_adjust_head(). It also renames bpf_helper_changes_skb_data() to bpf_helper_changes_pkt_data() to better reflect that XDP prog does not work on skb. This patch adds one "xdp_adjust_head" bit to bpf_prog for the XDP-capable driver to check if the XDP prog requires bpf_xdp_adjust_head() support. The driver can then decide to error out during XDP_SETUP_PROG. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf, x86: add support for constant blindingDaniel Borkmann2016-05-161-13/+53
| | | | | | | | | | | | | | | | This patch adds recently added constant blinding helpers into the x86 eBPF JIT. In the bpf_int_jit_compile() path, requirements are to utilize bpf_jit_blind_constants()/bpf_jit_prog_release_other() pair for rewriting the program into a blinded one, and to map the BPF_REG_AX register to a CPU register. The mapping of BPF_REG_AX is at non-callee saved register r10, and thus shared with cached skb->data used for ld_abs/ind and not in every program type needed. When blinding is not used, there's zero additional overhead in the generated image. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: prepare bpf_int_jit_compile/bpf_prog_select_runtime apisDaniel Borkmann2016-05-161-3/+4
| | | | | | | | | | | | | Since the blinding is strictly only called from inside eBPF JITs, we need to change signatures for bpf_int_jit_compile() and bpf_prog_select_runtime() first in order to prepare that the eBPF program we're dealing with can change underneath. Hence, for call sites, we need to return the latest prog. No functional change in this patch. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf, x86/arm64: remove useless checks on progDaniel Borkmann2016-05-161-3/+0Star
| | | | | | | | | | | There is never such a situation, where bpf_int_jit_compile() is called with either prog as NULL or len as 0, so the tests are unnecessary and confusing as people would just copy them. s390 doesn't have them, so no change is needed there. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf, x86: detect/optimize loading 0 immediatesDaniel Borkmann2015-12-181-0/+26
| | | | | | | | | | | | When sometimes structs or variables need to be initialized/'memset' to 0 in an eBPF C program, the x86 BPF JIT converts this to use immediates. We can however save a couple of bytes (f.e. even up to 7 bytes on a single emmission of BPF_LD | BPF_IMM | BPF_DW) in the image by detecting such case and use xor on the dst register instead. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: move clearing of A/X into classic to eBPF migration prologueDaniel Borkmann2015-12-181-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Back in the days where eBPF (or back then "internal BPF" ;->) was not exposed to user space, and only the classic BPF programs internally translated into eBPF programs, we missed the fact that for classic BPF A and X needed to be cleared. It was fixed back then via 83d5b7ef99c9 ("net: filter: initialize A and X registers"), and thus classic BPF specifics were added to the eBPF interpreter core to work around it. This added some confusion for JIT developers later on that take the eBPF interpreter code as an example for deriving their JIT. F.e. in f75298f5c3fe ("s390/bpf: clear correct BPF accumulator register"), at least X could leak stack memory. Furthermore, since this is only needed for classic BPF translations and not for eBPF (verifier takes care that read access to regs cannot be done uninitialized), more complexity is added to JITs as they need to determine whether they deal with migrations or native eBPF where they can just omit clearing A/X in their prologue and thus reduce image size a bit, see f.e. cde66c2d88da ("s390/bpf: Only clear A and X for converted BPF programs"). In other cases (x86, arm64), A and X is being cleared in the prologue also for eBPF case, which is unnecessary. Lets move this into the BPF migration in bpf_convert_filter() where it actually belongs as long as the number of eBPF JITs are still few. It can thus be done generically; allowing us to remove the quirk from __bpf_prog_run() and to slightly reduce JIT image size in case of eBPF, while reducing code duplication on this matter in current(/future) eBPF JITs. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Zi Shen Lim <zlim.lnx@gmail.com> Cc: Yang Shi <yang.shi@linaro.org> Acked-by: Yang Shi <yang.shi@linaro.org> Acked-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ebpf: migrate bpf_prog's flags to bitfieldDaniel Borkmann2015-10-031-1/+1
| | | | | | | | | | | | | | As we need to add further flags to the bpf_prog structure, lets migrate both bools to a bitfield representation. The size of the base structure (excluding insns) remains unchanged at 40 bytes. Add also tags for the kmemchecker, so that it doesn't throw false positives. Even in case gcc would generate suboptimal code, it's not being accessed in performance critical paths. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Make the bpf_prog_array_map more genericWang Nan2015-08-101-3/+3
| | | | | | | | | | | | All the map backends are of generic nature. In order to avoid adding much special code into the eBPF core, rewrite part of the bpf_prog_array map code and make it more generic. So the new perf_event_array map type can reuse most of code with bpf_prog_array map and add fewer lines of special code. Signed-off-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: Kaixu Xia <xiakaixu@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2015-08-011-4/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/s390/net/bpf_jit_comp.c drivers/net/ethernet/ti/netcp_ethss.c net/bridge/br_multicast.c net/ipv4/ip_fragment.c All four conflicts were cases of simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
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