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2019-07-03bpf, arm64: use more scalable stadd over ldxr / stxr loop in xaddDaniel Borkmann2-9/+23
commit 34b8ab091f9ef57a2bb3c8c8359a0a03a8abf2f9 upstream. Since ARMv8.1 supplement introduced LSE atomic instructions back in 2016, lets add support for STADD and use that in favor of LDXR / STXR loop for the XADD mapping if available. STADD is encoded as an alias for LDADD with XZR as the destination register, therefore add LDADD to the instruction encoder along with STADD as special case and use it in the JIT for CPUs that advertise LSE atomics in CPUID register. If immediate offset in the BPF XADD insn is 0, then use dst register directly instead of temporary one. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-22bpf, arm64: remove prefetch insn in xadd mappingDaniel Borkmann2-7/+0
commit 8968c67a82ab7501bc3b9439c3624a49b42fe54c upstream. Prefetch-with-intent-to-write is currently part of the XADD mapping in the AArch64 JIT and follows the kernel's implementation of atomic_add. This may interfere with other threads executing the LDXR/STXR loop, leading to potential starvation and fairness issues. Drop the optional prefetch instruction. Fixes: 85f68fe89832 ("bpf, arm64: implement jiting of BPF_XADD") Reported-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-15bpf, arm64: save 4 bytes in prologue when ebpf insns came from cbpfDaniel Borkmann1-10/+13
We can trivially save 4 bytes in prologue for cBPF since tail calls can never be used from there. The register push/pop is pairwise, here, x25 (fp) and x26 (tcc), so no point in changing that, only reset to zero is not needed. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-15bpf, arm64: optimize 32/64 immediate emissionDaniel Borkmann1-31/+54
Improve the JIT to emit 64 and 32 bit immediates, the current algorithm is not optimal and we often emit more instructions than actually needed. arm64 has movz, movn, movk variants but for the current 64 bit immediates we only use movz with a series of movk when needed. For example loading ffffffffffffabab emits the following 4 instructions in the JIT today: * movz: abab, shift: 0, result: 000000000000abab * movk: ffff, shift: 16, result: 00000000ffffabab * movk: ffff, shift: 32, result: 0000ffffffffabab * movk: ffff, shift: 48, result: ffffffffffffabab Whereas after the patch the same load only needs a single instruction: * movn: 5454, shift: 0, result: ffffffffffffabab Another example where two extra instructions can be saved: * movz: abab, shift: 0, result: 000000000000abab * movk: 1f2f, shift: 16, result: 000000001f2fabab * movk: ffff, shift: 32, result: 0000ffff1f2fabab * movk: ffff, shift: 48, result: ffffffff1f2fabab After the patch: * movn: e0d0, shift: 16, result: ffffffff1f2fffff * movk: abab, shift: 0, result: ffffffff1f2fabab Another example with movz, before: * movz: 0000, shift: 0, result: 0000000000000000 * movk: fea0, shift: 32, result: 0000fea000000000 After: * movz: fea0, shift: 32, result: 0000fea000000000 Moreover, reuse emit_a64_mov_i() for 32 bit immediates that are loaded via emit_a64_mov_i64() which is a similar optimization as done in 6fe8b9c1f41d ("bpf, x64: save several bytes by using mov over movabsq when possible"). On arm64, the latter allows to use a single instruction with movn due to zero extension where otherwise two would be needed. And last but not least add a missing optimization in emit_a64_mov_i() where movn is used but the subsequent movk not needed. With some of the Cilium programs in use, this shrinks the needed instructions by about three percent. Tested on Cavium ThunderX CN8890. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-15bpf, arm64: save 4 bytes of unneeded stack spaceDaniel Borkmann1-5/+2
Follow-up to 816d9ef32a8b ("bpf, arm64: remove ld_abs/ld_ind") in that the extra 4 byte JIT scratchpad is not needed anymore since it was in ld_abs/ld_ind as stack buffer for bpf_load_pointer(). Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-04bpf, arm64: remove ld_abs/ld_indDaniel Borkmann1-65/+0
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 arm64 JIT. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-02-23bpf, arm64: fix out of bounds access in tail callDaniel Borkmann1-2/+3
I recently noticed a crash on arm64 when feeding a bogus index into BPF tail call helper. The crash would not occur when the interpreter is used, but only in case of JIT. Output looks as follows: [ 347.007486] Unable to handle kernel paging request at virtual address fffb850e96492510 [...] [ 347.043065] [fffb850e96492510] address between user and kernel address ranges [ 347.050205] Internal error: Oops: 96000004 [#1] SMP [...] [ 347.190829] x13: 0000000000000000 x12: 0000000000000000 [ 347.196128] x11: fffc047ebe782800 x10: ffff808fd7d0fd10 [ 347.201427] x9 : 0000000000000000 x8 : 0000000000000000 [ 347.206726] x7 : 0000000000000000 x6 : 001c991738000000 [ 347.212025] x5 : 0000000000000018 x4 : 000000000000ba5a [ 347.217325] x3 : 00000000000329c4 x2 : ffff808fd7cf0500 [ 347.222625] x1 : ffff808fd7d0fc00 x0 : ffff808fd7cf0500 [ 347.227926] Process test_verifier (pid: 4548, stack limit = 0x000000007467fa61) [ 347.235221] Call trace: [ 347.237656] 0xffff000002f3a4fc [ 347.240784] bpf_test_run+0x78/0xf8 [ 347.244260] bpf_prog_test_run_skb+0x148/0x230 [ 347.248694] SyS_bpf+0x77c/0x1110 [ 347.251999] el0_svc_naked+0x30/0x34 [ 347.255564] Code: 9100075a d280220a 8b0a002a d37df04b (f86b694b) [...] In this case the index used in BPF r3 is the same as in r1 at the time of the call, meaning we fed a pointer as index; here, it had the value 0xffff808fd7cf0500 which sits in x2. While I found tail calls to be working in general (also for hitting the error cases), I noticed the following in the code emission: # bpftool p d j i 988 [...] 38: ldr w10, [x1,x10] 3c: cmp w2, w10 40: b.ge 0x000000000000007c <-- signed cmp 44: mov x10, #0x20 // #32 48: cmp x26, x10 4c: b.gt 0x000000000000007c 50: add x26, x26, #0x1 54: mov x10, #0x110 // #272 58: add x10, x1, x10 5c: lsl x11, x2, #3 60: ldr x11, [x10,x11] <-- faulting insn (f86b694b) 64: cbz x11, 0x000000000000007c [...] Meaning, the tests passed because commit ddb55992b04d ("arm64: bpf: implement bpf_tail_call() helper") was using signed compares instead of unsigned which as a result had the test wrongly passing. Change this but also the tail call count test both into unsigned and cap the index as u32. Latter we did as well in 90caccdd8cc0 ("bpf: fix bpf_tail_call() x64 JIT") and is needed in addition here, too. Tested on HiSilicon Hi1616. Result after patch: # bpftool p d j i 268 [...] 38: ldr w10, [x1,x10] 3c: add w2, w2, #0x0 40: cmp w2, w10 44: b.cs 0x0000000000000080 48: mov x10, #0x20 // #32 4c: cmp x26, x10 50: b.hi 0x0000000000000080 54: add x26, x26, #0x1 58: mov x10, #0x110 // #272 5c: add x10, x1, x10 60: lsl x11, x2, #3 64: ldr x11, [x10,x11] 68: cbz x11, 0x0000000000000080 [...] Fixes: ddb55992b04d ("arm64: bpf: implement bpf_tail_call() helper") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-27bpf, arm64: remove obsolete exception handling from div/modDaniel Borkmann1-13/+0
Since we've changed div/mod exception handling for src_reg in eBPF verifier itself, remove the leftovers from arm64 JIT. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller1-2/+0
Alexei Starovoitov says: ==================== pull-request: bpf-next 2018-01-19 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) bpf array map HW offload, from Jakub. 2) support for bpf_get_next_key() for LPM map, from Yonghong. 3) test_verifier now runs loaded programs, from Alexei. 4) xdp cpumap monitoring, from Jesper. 5) variety of tests, cleanups and small x64 JIT optimization, from Daniel. 6) user space can now retrieve HW JITed program, from Jiong. Note there is a minor conflict between Russell's arm32 JIT fixes and removal of bpf_jit_enable variable by Daniel which should be resolved by keeping Russell's comment and removing that variable. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-20Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-9/+11
The BPF verifier conflict was some minor contextual issue. The TUN conflict was less trivial. Cong Wang fixed a memory leak of tfile->tx_array in 'net'. This is an skb_array. But meanwhile in net-next tun changed tfile->tx_arry into tfile->tx_ring which is a ptr_ring. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-20bpf: get rid of pure_initcall dependency to enable jitsDaniel Borkmann1-2/+0
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>
2018-01-16bpf, arm64: fix stack_depth tracking in combination with tail callsDaniel Borkmann1-9/+11
Using dynamic stack_depth tracking in arm64 JIT is currently broken in combination with tail calls. In prologue, we cache ctx->stack_size and adjust SP reg for setting up function call stack, and tearing it down again in epilogue. Problem is that when doing a tail call, the cached ctx->stack_size might not be the same. One way to fix the problem with minimal overhead is to re-adjust SP in emit_bpf_tail_call() and properly adjust it to the current program's ctx->stack_size. Tested on Cavium ThunderX ARMv8. Fixes: f1c9eed7f437 ("bpf, arm64: take advantage of stack_depth tracking") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2017-12-19bpf: arm64: fix uninitialized variableAlexei Starovoitov1-0/+1
fix the following issue: arch/arm64/net/bpf_jit_comp.c: In function 'bpf_int_jit_compile': arch/arm64/net/bpf_jit_comp.c:982:18: error: 'image_size' may be used uninitialized in this function [-Werror=maybe-uninitialized] Fixes: db496944fdaa ("bpf: arm64: add JIT support for multi-function programs") Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2017-12-17bpf: arm64: add JIT support for multi-function programsAlexei Starovoitov1-4/+64
similar to x64 add support for bpf-to-bpf calls. When program has calls to in-kernel helpers the target call offset is known at JIT time and arm64 architecture needs 2 passes. With bpf-to-bpf calls the dynamically allocated function start is unknown until all functions of the program are JITed. Therefore (just like x64) arm64 JIT needs one extra pass over the program to emit correct call offsets. Implementation detail: Avoid being too clever in 64-bit immediate moves and always use 4 instructions (instead of 3-4 depending on the address) to make sure only one extra pass is needed. If some future optimization would make it worth while to optimize 'call 64-bit imm' further, the JIT would need to do 4 passes over the program instead of 3 as in this patch. For typical bpf program address the mov needs 3 or 4 insns, so unconditional 4 insns to save extra pass is a worthy trade off at this state of JIT. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2017-12-17bpf: fix net.core.bpf_jit_enable raceAlexei Starovoitov1-1/+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>
2017-08-10bpf, arm64: implement jiting of BPF_J{LT, LE, SLT, SLE}Daniel Borkmann2-0/+24
This work implements jiting of BPF_J{LT,LE,SLT,SLE} instructions with BPF_X/BPF_K variants for the arm64 eBPF JIT. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-06Merge tag 'arm64-upstream' of ↵Linus Torvalds1-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Will Deacon: - RAS reporting via GHES/APEI (ACPI) - Indirect ftrace trampolines for modules - Improvements to kernel fault reporting - Page poisoning - Sigframe cleanups and preparation for SVE context - Core dump fixes - Sparse fixes (mainly relating to endianness) - xgene SoC PMU v3 driver - Misc cleanups and non-critical fixes * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (75 commits) arm64: fix endianness annotation for 'struct jit_ctx' and friends arm64: cpuinfo: constify attribute_group structures. arm64: ptrace: Fix incorrect get_user() use in compat_vfp_set() arm64: ptrace: Remove redundant overrun check from compat_vfp_set() arm64: ptrace: Avoid setting compat FP[SC]R to garbage if get_user fails arm64: fix endianness annotation for __apply_alternatives()/get_alt_insn() arm64: fix endianness annotation in get_kaslr_seed() arm64: add missing conversion to __wsum in ip_fast_csum() arm64: fix endianness annotation in acpi_parking_protocol.c arm64: use readq() instead of readl() to read 64bit entry_point arm64: fix endianness annotation for reloc_insn_movw() & reloc_insn_imm() arm64: fix endianness annotation for aarch64_insn_write() arm64: fix endianness annotation in aarch64_insn_read() arm64: fix endianness annotation in call_undef_hook() arm64: fix endianness annotation for debug-monitors.c ras: mark stub functions as 'inline' arm64: pass endianness info to sparse arm64: ftrace: fix !CONFIG_ARM64_MODULE_PLTS kernels arm64: signal: Allow expansion of the signal frame acpi: apei: check for pending errors when probing GHES entries ...
2017-06-30arm64: fix endianness annotation for 'struct jit_ctx' and friendsLuc Van Oostenryck1-3/+3
struct jit_ctx::image is used the store a pointer to the jitted intructions, which are always little-endian. These instructions are thus correctly converted from native order to little-endian before being stored but the pointer 'image' is declared as for native order values. Fix this by declaring the field as __le32* instead of u32*. Same for the pointer used in jit_fill_hole() to initialize the image. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-06-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-2/+5
The conflicts were two cases of overlapping changes in batman-adv and the qed driver. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-12bpf, arm64: take advantage of stack_depth trackingDaniel Borkmann1-11/+11
Make use of recently implemented stack_depth tracking for arm64 JIT, so that stack usage can be reduced heavily for programs not using tail calls at least. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-07bpf, arm64: use separate register for state in stxrDaniel Borkmann1-2/+5
Will reported that in BPF_XADD we must use a different register in stxr instruction for the status flag due to otherwise CONSTRAINED UNPREDICTABLE behavior per architecture. Reference manual says [1]: If s == t, then one of the following behaviors must occur: * The instruction is UNDEFINED. * The instruction executes as a NOP. * The instruction performs the store to the specified address, but the value stored is UNKNOWN. Thus, use a different temporary register for the status flag to fix it. Disassembly extract from test 226/STX_XADD_DW from test_bpf.ko: [...] 0000003c: c85f7d4b ldxr x11, [x10] 00000040: 8b07016b add x11, x11, x7 00000044: c80c7d4b stxr w12, x11, [x10] 00000048: 35ffffac cbnz w12, 0x0000003c [...] [1] https://static.docs.arm.com/ddi0487/b/DDI0487B_a_armv8_arm.pdf, p.6132 Fixes: 85f68fe89832 ("bpf, arm64: implement jiting of BPF_XADD") Reported-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-06bpf: Add jited_len to struct bpf_progMartin KaFai Lau1-0/+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>
2017-06-01bpf: free up BPF_JMP | BPF_CALL | BPF_X opcodeAlexei Starovoitov1-1/+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>
2017-05-11bpf, arm64: fix faulty emission of map access in tail callsDaniel Borkmann1-2/+3
Shubham was recently asking on netdev why in arm64 JIT we don't multiply the index for accessing the tail call map by 8. That led me into testing out arm64 JIT wrt tail calls and it turned out I got a NULL pointer dereference on the tail call. The buggy access is at: prog = array->ptrs[index]; if (prog == NULL) goto out; [...] 00000060: d2800e0a mov x10, #0x70 // #112 00000064: f86a682a ldr x10, [x1,x10] 00000068: f862694b ldr x11, [x10,x2] 0000006c: b40000ab cbz x11, 0x00000080 [...] The code triggering the crash is f862694b. x1 at the time contains the address of the bpf array, x10 offsetof(struct bpf_array, ptrs). Meaning, above we load the pointer to the program at map slot 0 into x10. x10 can then be NULL if the slot is not occupied, which we later on try to access with a user given offset in x2 that is the map index. Fix this by emitting the following instead: [...] 00000060: d2800e0a mov x10, #0x70 // #112 00000064: 8b0a002a add x10, x1, x10 00000068: d37df04b lsl x11, x2, #3 0000006c: f86b694b ldr x11, [x10,x11] 00000070: b40000ab cbz x11, 0x00000084 [...] This basically adds the offset to ptrs to the base address of the bpf array we got and we later on access the map with an index * 8 offset relative to that. The tail call map itself is basically one large area with meta data at the head followed by the array of prog pointers. This makes tail calls working again, tested on Cavium ThunderX ARMv8. Fixes: ddb55992b04d ("arm64: bpf: implement bpf_tail_call() helper") Reported-by: Shubham Bansal <illusionist.neo@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-09arm64: use set_memory.h headerLaura Abbott1-0/+1
The set_memory_* functions have moved to set_memory.h. Use that header explicitly. Link: http://lkml.kernel.org/r/1488920133-27229-4-git-send-email-labbott@redhat.com Signed-off-by: Laura Abbott <labbott@redhat.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-02bpf, arm64: fix jit branch offset related to ldimm64Daniel Borkmann1-4/+4
When the instruction right before the branch destination is a 64 bit load immediate, we currently calculate the wrong jump offset in the ctx->offset[] array as we only account one instruction slot for the 64 bit load immediate although it uses two BPF instructions. Fix it up by setting the offset into the right slot after we incremented the index. Before (ldimm64 test 1): [...] 00000020: 52800007 mov w7, #0x0 // #0 00000024: d2800060 mov x0, #0x3 // #3 00000028: d2800041 mov x1, #0x2 // #2 0000002c: eb01001f cmp x0, x1 00000030: 54ffff82 b.cs 0x00000020 00000034: d29fffe7 mov x7, #0xffff // #65535 00000038: f2bfffe7 movk x7, #0xffff, lsl #16 0000003c: f2dfffe7 movk x7, #0xffff, lsl #32 00000040: f2ffffe7 movk x7, #0xffff, lsl #48 00000044: d29dddc7 mov x7, #0xeeee // #61166 00000048: f2bdddc7 movk x7, #0xeeee, lsl #16 0000004c: f2ddddc7 movk x7, #0xeeee, lsl #32 00000050: f2fdddc7 movk x7, #0xeeee, lsl #48 [...] After (ldimm64 test 1): [...] 00000020: 52800007 mov w7, #0x0 // #0 00000024: d2800060 mov x0, #0x3 // #3 00000028: d2800041 mov x1, #0x2 // #2 0000002c: eb01001f cmp x0, x1 00000030: 540000a2 b.cs 0x00000044 00000034: d29fffe7 mov x7, #0xffff // #65535 00000038: f2bfffe7 movk x7, #0xffff, lsl #16 0000003c: f2dfffe7 movk x7, #0xffff, lsl #32 00000040: f2ffffe7 movk x7, #0xffff, lsl #48 00000044: d29dddc7 mov x7, #0xeeee // #61166 00000048: f2bdddc7 movk x7, #0xeeee, lsl #16 0000004c: f2ddddc7 movk x7, #0xeeee, lsl #32 00000050: f2fdddc7 movk x7, #0xeeee, lsl #48 [...] Also, add a couple of test cases to make sure JITs pass this test. Tested on Cavium ThunderX ARMv8. The added test cases all pass after the fix. Fixes: 8eee539ddea0 ("arm64: bpf: fix out-of-bounds read in bpf2a64_offset()") Reported-by: David S. Miller <davem@davemloft.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Xi Wang <xi.wang@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-02bpf, arm64: implement jiting of BPF_XADDDaniel Borkmann2-5/+30
This work adds BPF_XADD for BPF_W/BPF_DW to the arm64 JIT and therefore completes JITing of all BPF instructions, meaning we can thus also remove the 'notyet' label and do not need to fall back to the interpreter when BPF_XADD is used in a program! This now also brings arm64 JIT in line with x86_64, s390x, ppc64, sparc64, where all current eBPF features are supported. BPF_W example from test_bpf: .u.insns_int = { BPF_ALU32_IMM(BPF_MOV, R0, 0x12), BPF_ST_MEM(BPF_W, R10, -40, 0x10), BPF_STX_XADD(BPF_W, R10, R0, -40), BPF_LDX_MEM(BPF_W, R0, R10, -40), BPF_EXIT_INSN(), }, [...] 00000020: 52800247 mov w7, #0x12 // #18 00000024: 928004eb mov x11, #0xffffffffffffffd8 // #-40 00000028: d280020a mov x10, #0x10 // #16 0000002c: b82b6b2a str w10, [x25,x11] // start of xadd mapping: 00000030: 928004ea mov x10, #0xffffffffffffffd8 // #-40 00000034: 8b19014a add x10, x10, x25 00000038: f9800151 prfm pstl1strm, [x10] 0000003c: 885f7d4b ldxr w11, [x10] 00000040: 0b07016b add w11, w11, w7 00000044: 880b7d4b stxr w11, w11, [x10] 00000048: 35ffffab cbnz w11, 0x0000003c // end of xadd mapping: [...] BPF_DW example from test_bpf: .u.insns_int = { BPF_ALU32_IMM(BPF_MOV, R0, 0x12), BPF_ST_MEM(BPF_DW, R10, -40, 0x10), BPF_STX_XADD(BPF_DW, R10, R0, -40), BPF_LDX_MEM(BPF_DW, R0, R10, -40), BPF_EXIT_INSN(), }, [...] 00000020: 52800247 mov w7, #0x12 // #18 00000024: 928004eb mov x11, #0xffffffffffffffd8 // #-40 00000028: d280020a mov x10, #0x10 // #16 0000002c: f82b6b2a str x10, [x25,x11] // start of xadd mapping: 00000030: 928004ea mov x10, #0xffffffffffffffd8 // #-40 00000034: 8b19014a add x10, x10, x25 00000038: f9800151 prfm pstl1strm, [x10] 0000003c: c85f7d4b ldxr x11, [x10] 00000040: 8b07016b add x11, x11, x7 00000044: c80b7d4b stxr w11, x11, [x10] 00000048: 35ffffab cbnz w11, 0x0000003c // end of xadd mapping: [...] Tested on Cavium ThunderX ARMv8, test suite results after the patch: No JIT: [ 3751.855362] test_bpf: Summary: 311 PASSED, 0 FAILED, [0/303 JIT'ed] With JIT: [ 3573.759527] test_bpf: Summary: 311 PASSED, 0 FAILED, [303/303 JIT'ed] Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-28bpf, x86_64/arm64: remove old ldimm64 artifacts from jitsDaniel Borkmann1-9/+0
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>
2017-02-21bpf: fix unlocking of jited image when module ronx not setDaniel Borkmann1-1/+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>
2017-02-17bpf: make jited programs visible in tracesDaniel Borkmann1-15/+0
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>
2017-02-17bpf: remove stubs for cBPF from arch codeDaniel Borkmann1-5/+0
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>
2016-06-11arm64: bpf: optimize LD_ABS, LD_INDZi Shen Lim1-3/+0
Remove superfluous stack frame, saving us 3 instructions for every LD_ABS or LD_IND. Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-11arm64: bpf: optimize JMP_CALLZi Shen Lim1-3/+0
Remove superfluous stack frame, saving us 3 instructions for every JMP_CALL. Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-11arm64: bpf: implement bpf_tail_call() helperZi Shen Lim2-10/+98
Add support for JMP_CALL_X (tail call) introduced by commit 04fd61ab36ec ("bpf: allow bpf programs to tail-call other bpf programs"). bpf_tail_call() arguments: ctx - context pointer passed to next program array - pointer to map which type is BPF_MAP_TYPE_PROG_ARRAY index - index inside array that selects specific program to run In this implementation arm64 JIT jumps into callee program after prologue, so callee program reuses the same stack. For tail_call_cnt, we use the callee-saved R26 (which was already saved/restored but previously unused by JIT). With this patch a tail call generates the following code on arm64: if (index >= array->map.max_entries) goto out; 34: mov x10, #0x10 // #16 38: ldr w10, [x1,x10] 3c: cmp w2, w10 40: b.ge 0x0000000000000074 if (tail_call_cnt > MAX_TAIL_CALL_CNT) goto out; tail_call_cnt++; 44: mov x10, #0x20 // #32 48: cmp x26, x10 4c: b.gt 0x0000000000000074 50: add x26, x26, #0x1 prog = array->ptrs[index]; if (prog == NULL) goto out; 54: mov x10, #0x68 // #104 58: ldr x10, [x1,x10] 5c: ldr x11, [x10,x2] 60: cbz x11, 0x0000000000000074 goto *(prog->bpf_func + prologue_size); 64: mov x10, #0x20 // #32 68: ldr x10, [x11,x10] 6c: add x10, x10, #0x20 70: br x10 74: Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-17bpf: arm64: remove callee-save registers use for tmp registersYang Shi1-29/+5
In the current implementation of ARM64 eBPF JIT, R23 and R24 are used for tmp registers, which are callee-saved registers. This leads to variable size of JIT prologue and epilogue. The latest blinding constant change prefers to constant size of prologue and epilogue. AAPCS reserves R9 ~ R15 for temp registers which not need to be saved/restored during function call. So, replace R23 and R24 to R10 and R11, and remove tmp_used flag to save 2 instructions for some jited BPF program. CC: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: Yang Shi <yang.shi@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16bpf, arm64: add support for constant blindingDaniel Borkmann1-12/+40
This patch adds recently added constant blinding helpers into the arm64 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 is on x9. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Zi Shen Lim <zlim.lnx@gmail.com> Acked-by: Yang Shi <yang.shi@linaro.org> Tested-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16bpf: prepare bpf_int_jit_compile/bpf_prog_select_runtime apisDaniel Borkmann1-3/+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>
2016-05-16bpf, x86/arm64: remove useless checks on progDaniel Borkmann1-3/+0
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>
2016-05-14arm64: bpf: jit JMP_JSET_{X,K}Zi Shen Lim1-0/+1
Original implementation commit e54bcde3d69d ("arm64: eBPF JIT compiler") had the relevant code paths, but due to an oversight always fail jiting. As a result, we had been falling back to BPF interpreter whenever a BPF program has JMP_JSET_{X,K} instructions. With this fix, we confirm that the corresponding tests in lib/test_bpf continue to pass, and also jited. ... [ 2.784553] test_bpf: #30 JSET jited:1 188 192 197 PASS [ 2.791373] test_bpf: #31 tcpdump port 22 jited:1 325 677 625 PASS [ 2.808800] test_bpf: #32 tcpdump complex jited:1 323 731 991 PASS ... [ 3.190759] test_bpf: #237 JMP_JSET_K: if (0x3 & 0x2) return 1 jited:1 110 PASS [ 3.192524] test_bpf: #238 JMP_JSET_K: if (0x3 & 0xffffffff) return 1 jited:1 98 PASS [ 3.211014] test_bpf: #249 JMP_JSET_X: if (0x3 & 0x2) return 1 jited:1 120 PASS [ 3.212973] test_bpf: #250 JMP_JSET_X: if (0x3 & 0xffffffff) return 1 jited:1 89 PASS ... Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler") Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-01-18arm64: bpf: add extra pass to handle faulty codegenZi Shen Lim1-1/+21
Code generation functions in arch/arm64/kernel/insn.c previously BUG_ON invalid parameters. Following change of that behavior, now we need to handle the error case where AARCH64_BREAK_FAULT is returned. Instead of error-handling on every emit() in JIT, we add a new validation pass at the end of JIT compilation. There's no point in running JITed code at run-time only to trap due to AARCH64_BREAK_FAULT. Instead, we drop this failed JIT compilation and allow the system to gracefully fallback on the BPF interpreter. Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com> Suggested-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-19bpf: move clearing of A/X into classic to eBPF migration prologueDaniel Borkmann1-6/+0
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>
2015-12-03arm64: bpf: add 'store immediate' instructionYang Shi1-1/+19
aarch64 doesn't have native store immediate instruction, such operation has to be implemented by the below instruction sequence: Load immediate to register Store register Signed-off-by: Yang Shi <yang.shi@linaro.org> CC: Zi Shen Lim <zlim.lnx@gmail.com> CC: Xi Wang <xi.wang@gmail.com> Reviewed-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-19arm64: bpf: fix buffer pointerZi Shen Lim1-14/+13
During code review, I noticed we were passing a bad buffer pointer to bpf_load_pointer helper function called by jitted code. Point to the buffer allocated by JIT, so we don't silently corrupt other parts of the stack. Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com> Acked-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds1-7/+41
Pull networking fixes from David Miller: 1) Fix list tests in netfilter ingress support, from Florian Westphal. 2) Fix reversal of input and output interfaces in ingress hook invocation, from Pablo Neira Ayuso. 3) We have a use after free in r8169, caught by Dave Jones, fixed by Francois Romieu. 4) Splice use-after-free fix in AF_UNIX frmo Hannes Frederic Sowa. 5) Three ipv6 route handling bug fixes from Martin KaFai Lau: a) Don't create clone routes not managed by the fib6 tree b) Don't forget to check expiration of DST_NOCACHE routes. c) Handle rt->dst.from == NULL properly. 6) Several AF_PACKET fixes wrt transport header setting and SKB protocol setting, from Daniel Borkmann. 7) Fix thunder driver crash on shutdown, from Pavel Fedin. 8) Several Mellanox driver fixes (max MTU calculations, use of correct DMA unmap in TX path, etc.) from Saeed Mahameed, Tariq Toukan, Doron Tsur, Achiad Shochat, Eran Ben Elisha, and Noa Osherovich. 9) Several mv88e6060 DSA driver fixes (wrong bit definitions for certain registers, etc.) from Neil Armstrong. 10) Make sure to disable preemption while updating per-cpu stats of ip tunnels, from Jason A. Donenfeld. 11) Various ARM64 bpf JIT fixes, from Yang Shi. 12) Flush icache properly in ARM JITs, from Daniel Borkmann. 13) Fix masking of RX and TX interrupts in ravb driver, from Masaru Nagai. 14) Fix netdev feature propagation for devices not implementing ->ndo_set_features(). From Nikolay Aleksandrov. 15) Big endian fix in vmxnet3 driver, from Shrikrishna Khare. 16) RAW socket code increments incorrect SNMP counters, fix from Ben Cartwright-Cox. 17) IPv6 multicast SNMP counters are bumped twice, fix from Neil Horman. 18) Fix handling of VLAN headers on stacked devices when REORDER is disabled. From Vlad Yasevich. 19) Fix SKB leaks and use-after-free in ipvlan and macvlan drivers, from Sabrina Dubroca. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (83 commits) MAINTAINERS: Update Mellanox's Eth NIC driver entries net/core: revert "net: fix __netdev_update_features return.." and add comment af_unix: take receive queue lock while appending new skb rtnetlink: fix frame size warning in rtnl_fill_ifinfo net: use skb_clone to avoid alloc_pages failure. packet: Use PAGE_ALIGNED macro packet: Don't check frames_per_block against negative values net: phy: Use interrupts when available in NOLINK state phy: marvell: Add support for 88E1540 PHY arm64: bpf: make BPF prologue and epilogue align with ARM64 AAPCS macvlan: fix leak in macvlan_handle_frame ipvlan: fix use after free of skb ipvlan: fix leak in ipvlan_rcv_frame vlan: Do not put vlan headers back on bridge and macvlan ports vlan: Fix untag operations of stacked vlans with REORDER_HEADER off via-velocity: unconditionally drop frames with bad l2 length ipg: Remove ipg driver dl2k: Add support for IP1000A-based cards snmp: Remove duplicate OUTMCAST stat increment net: thunder: Check for driver data in nicvf_remove() ...
2015-11-17arm64: bpf: make BPF prologue and epilogue align with ARM64 AAPCSYang Shi1-5/+39
Save and restore FP/LR in BPF prog prologue and epilogue, save SP to FP in prologue in order to get the correct stack backtrace. However, ARM64 JIT used FP (x29) as eBPF fp register, FP is subjected to change during function call so it may cause the BPF prog stack base address change too. Use x25 to replace FP as BPF stack base register (fp). Since x25 is callee saved register, so it will keep intact during function call. It is initialized in BPF prog prologue when BPF prog is started to run everytime. Save and restore x25/x26 in BPF prologue and epilogue to keep them intact for the outside of BPF. Actually, x26 is unnecessary, but SP requires 16 bytes alignment. So, the BPF stack layout looks like: high original A64_SP => 0:+-----+ BPF prologue |FP/LR| current A64_FP => -16:+-----+ | ... | callee saved registers +-----+ | | x25/x26 BPF fp register => -80:+-----+ | | | ... | BPF prog stack | | | | current A64_SP => +-----+ | | | ... | Function call stack | | +-----+ low CC: Zi Shen Lim <zlim.lnx@gmail.com> CC: Xi Wang <xi.wang@gmail.com> Signed-off-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>
2015-11-16bpf, arm64: start flushing icache range from headerDaniel Borkmann1-1/+1
While recently going over ARM64's BPF code, I noticed that the icache range we're flushing should start at header already and not at ctx.image. Reason is that after b569c1c622c5 ("net: bpf: arm64: address randomize and write protect JIT code"), we also want to make sure to flush the random-sized trap in front of the start of the actual program (analogous to x86). No operational differences from user side. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Zi Shen Lim <zlim.lnx@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-16arm64: bpf: fix JIT frame pointer setupYang Shi1-3/+3
BPF fp should point to the top of the BPF prog stack. The original implementation made it point to the bottom incorrectly. Move A64_SP to fp before reserve BPF prog stack space. CC: Zi Shen Lim <zlim.lnx@gmail.com> CC: Xi Wang <xi.wang@gmail.com> Signed-off-by: Yang Shi <yang.shi@linaro.org> Reviewed-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-13Merge tag 'arm64-fixes' of ↵Linus Torvalds2-19/+38
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 fixes and clean-ups from Catalin Marinas: "Here's a second pull request for this merging window with some fixes/clean-ups: - __cmpxchg_double*() return type fix to avoid truncation of a long to int and subsequent logical "not" in cmpxchg_double() misinterpreting the operation success/failure - BPF fixes for mod and div by zero - Fix compilation with STRICT_MM_TYPECHECKS enabled - VDSO build fix without libgcov - Some static and __maybe_unused annotations - Kconfig clean-up (FRAME_POINTER) - defconfig update for CRYPTO_CRC32_ARM64" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: suspend: make hw_breakpoint_restore static arm64: mmu: make split_pud and fixup_executable static arm64: smp: make of_parse_and_init_cpus static arm64: use linux/types.h in kvm.h arm64: build vdso without libgcov arm64: mark cpus_have_hwcap as __maybe_unused arm64: remove redundant FRAME_POINTER kconfig option and force to select it arm64: fix R/O permissions of FDT mapping arm64: fix STRICT_MM_TYPECHECKS issue in PTE_CONT manipulation arm64: bpf: fix mod-by-zero case arm64: bpf: fix div-by-zero case arm64: Enable CRYPTO_CRC32_ARM64 in defconfig arm64: cmpxchg_dbl: fix return value type
2015-11-06arm64: bpf: fix mod-by-zero caseZi Shen Lim1-8/+13
Turns out in the case of modulo by zero in a BPF program: A = A % X; (X == 0) the expected behavior is to terminate with return value 0. The bug in JIT is exposed by a new test case [1]. [1] https://lkml.org/lkml/2015/11/4/499 Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com> Reported-by: Yang Shi <yang.shi@linaro.org> Reported-by: Xi Wang <xi.wang@gmail.com> CC: Alexei Starovoitov <ast@plumgrid.com> Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler") Cc: <stable@vger.kernel.org> # 3.18+ Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-11-06arm64: bpf: fix div-by-zero caseZi Shen Lim2-13/+27
In the case of division by zero in a BPF program: A = A / X; (X == 0) the expected behavior is to terminate with return value 0. This is confirmed by the test case introduced in commit 86bf1721b226 ("test_bpf: add tests checking that JIT/interpreter sets A and X to 0."). Reported-by: Yang Shi <yang.shi@linaro.org> Tested-by: Yang Shi <yang.shi@linaro.org> CC: Xi Wang <xi.wang@gmail.com> CC: Alexei Starovoitov <ast@plumgrid.com> CC: linux-arm-kernel@lists.infradead.org CC: linux-kernel@vger.kernel.org Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler") Cc: <stable@vger.kernel.org> # 3.18+ Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>