The current code for BPF_{AND,OR,XOR,JSET} BPF_K loads the immediate to
a temporary register before use.
This patch changes the code to avoid using a temporary register
when the BPF immediate is encodable using an arm64 logical immediate
instruction. If the encoding fails (due to the immediate not being
encodable), it falls back to using a temporary register.
Example of generated code for BPF_ALU32_IMM(BPF_AND, R0, 0x80000001):
without optimization:
24: mov w10, #0x8000ffff
28: movk w10, #0x1
2c: and w7, w7, w10
with optimization:
24: and w7, w7, #0x80000001
Since the encoding process is quite complex, the JIT reuses existing
functionality in arch/arm64/kernel/insn.c for encoding logical immediates
rather than duplicate it in the JIT.
Co-developed-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20200508181547.24783-3-luke.r.nels@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>
In order to extend the protection offered by BTI to all code executing in
kernel mode we need to annotate JITed BPF code appropriately for BTI. To
do this we need to add a landing pad to the start of each BPF function and
also immediately after the function prologue if we are emitting a function
which can be tail called. Jumps within BPF functions are all to immediate
offsets and therefore do not require landing pads.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200506195138.22086-6-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Optimize modulo operation instruction generation by
using single MSUB instruction vs MUL followed by SUB
instruction scheme.
Signed-off-by: Jerin Jacob <jerinj@marvell.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
- arm64 support for syscall emulation via PTRACE_SYSEMU{,_SINGLESTEP}
- Wire up VM_FLUSH_RESET_PERMS for arm64, allowing the core code to
manage the permissions of executable vmalloc regions more strictly
- Slight performance improvement by keeping softirqs enabled while
touching the FPSIMD/SVE state (kernel_neon_begin/end)
- Expose a couple of ARMv8.5 features to user (HWCAP): CondM (new XAFLAG
and AXFLAG instructions for floating point comparison flags
manipulation) and FRINT (rounding floating point numbers to integers)
- Re-instate ARM64_PSEUDO_NMI support which was previously marked as
BROKEN due to some bugs (now fixed)
- Improve parking of stopped CPUs and implement an arm64-specific
panic_smp_self_stop() to avoid warning on not being able to stop
secondary CPUs during panic
- perf: enable the ARM Statistical Profiling Extensions (SPE) on ACPI
platforms
- perf: DDR performance monitor support for iMX8QXP
- cache_line_size() can now be set from DT or ACPI/PPTT if provided to
cope with a system cache info not exposed via the CPUID registers
- Avoid warning on hardware cache line size greater than
ARCH_DMA_MINALIGN if the system is fully coherent
- arm64 do_page_fault() and hugetlb cleanups
- Refactor set_pte_at() to avoid redundant READ_ONCE(*ptep)
- Ignore ACPI 5.1 FADTs reported as 5.0 (infer from the 'arm_boot_flags'
introduced in 5.1)
- CONFIG_RANDOMIZE_BASE now enabled in defconfig
- Allow the selection of ARM64_MODULE_PLTS, currently only done via
RANDOMIZE_BASE (and an erratum workaround), allowing modules to spill
over into the vmalloc area
- Make ZONE_DMA32 configurable
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- arm64 support for syscall emulation via PTRACE_SYSEMU{,_SINGLESTEP}
- Wire up VM_FLUSH_RESET_PERMS for arm64, allowing the core code to
manage the permissions of executable vmalloc regions more strictly
- Slight performance improvement by keeping softirqs enabled while
touching the FPSIMD/SVE state (kernel_neon_begin/end)
- Expose a couple of ARMv8.5 features to user (HWCAP): CondM (new
XAFLAG and AXFLAG instructions for floating point comparison flags
manipulation) and FRINT (rounding floating point numbers to integers)
- Re-instate ARM64_PSEUDO_NMI support which was previously marked as
BROKEN due to some bugs (now fixed)
- Improve parking of stopped CPUs and implement an arm64-specific
panic_smp_self_stop() to avoid warning on not being able to stop
secondary CPUs during panic
- perf: enable the ARM Statistical Profiling Extensions (SPE) on ACPI
platforms
- perf: DDR performance monitor support for iMX8QXP
- cache_line_size() can now be set from DT or ACPI/PPTT if provided to
cope with a system cache info not exposed via the CPUID registers
- Avoid warning on hardware cache line size greater than
ARCH_DMA_MINALIGN if the system is fully coherent
- arm64 do_page_fault() and hugetlb cleanups
- Refactor set_pte_at() to avoid redundant READ_ONCE(*ptep)
- Ignore ACPI 5.1 FADTs reported as 5.0 (infer from the
'arm_boot_flags' introduced in 5.1)
- CONFIG_RANDOMIZE_BASE now enabled in defconfig
- Allow the selection of ARM64_MODULE_PLTS, currently only done via
RANDOMIZE_BASE (and an erratum workaround), allowing modules to spill
over into the vmalloc area
- Make ZONE_DMA32 configurable
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (54 commits)
perf: arm_spe: Enable ACPI/Platform automatic module loading
arm_pmu: acpi: spe: Add initial MADT/SPE probing
ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens
ACPI/PPTT: Modify node flag detection to find last IDENTICAL
x86/entry: Simplify _TIF_SYSCALL_EMU handling
arm64: rename dump_instr as dump_kernel_instr
arm64/mm: Drop [PTE|PMD]_TYPE_FAULT
arm64: Implement panic_smp_self_stop()
arm64: Improve parking of stopped CPUs
arm64: Expose FRINT capabilities to userspace
arm64: Expose ARMv8.5 CondM capability to userspace
arm64: defconfig: enable CONFIG_RANDOMIZE_BASE
arm64: ARM64_MODULES_PLTS must depend on MODULES
arm64: bpf: do not allocate executable memory
arm64/kprobes: set VM_FLUSH_RESET_PERMS on kprobe instruction pages
arm64/mm: wire up CONFIG_ARCH_HAS_SET_DIRECT_MAP
arm64: module: create module allocations without exec permissions
arm64: Allow user selection of ARM64_MODULE_PLTS
acpi/arm64: ignore 5.1 FADTs that are reported as 5.0
arm64: Allow selecting Pseudo-NMI again
...
The BPF code now takes care of mapping the code pages executable
after mapping them read-only, to ensure that no RWX mapped regions
are needed, even transiently. This means we can drop the executable
permissions from the mapping at allocation time.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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 version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 503 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
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: 85f68fe898 ("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>
This patch implements code-gen for new JMP32 instructions on arm64.
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch enables arm64's bpf_int_jit_compile() to provide
bpf_line_info by calling bpf_prog_fill_jited_linfo().
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The arm64 module region is a 128 MB region that is kept close to
the core kernel, in order to ensure that relative branches are
always in range. So using the same region for programs that do
not have this restriction is wasteful, and preferably avoided.
Now that the core BPF JIT code permits the alloc/free routines to
be overridden, implement them by vmalloc()/vfree() calls from a
dedicated 128 MB region set aside for BPF programs. This ensures
that BPF programs are still in branching range of each other, which
is something the JIT currently depends upon (and is not guaranteed
when using module_alloc() on KASLR kernels like we do currently).
It also ensures that placement of BPF programs does not correlate
with the placement of the core kernel or modules, making it less
likely that leaking the former will reveal the latter.
This also solves an issue under KASAN, where shadow memory is
needlessly allocated for all BPF programs (which don't require KASAN
shadow pages since they are not KASAN instrumented)
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
On arm64, all executable code is guaranteed to reside in the vmalloc
space (or the module space), and so jump targets will only use 48
bits at most, and the remaining bits are guaranteed to be 0x1.
This means we can generate an immediate jump address using a sequence
of one MOVN (move wide negated) and two MOVK instructions, where the
first one sets the lower 16 bits but also sets all top bits to 0x1.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The arm64 JIT has the same issue as ppc64 JIT in that the relative BPF
to BPF call offset can be too far away from core kernel in that relative
encoding into imm is not sufficient and could potentially be truncated,
see also fd045f6cd9 ("arm64: add support for module PLTs") which adds
spill-over space for module_alloc() and therefore bpf_jit_binary_alloc().
Therefore, use the recently added bpf_jit_get_func_addr() helper for
properly fetching the address through prog->aux->func[off]->bpf_func
instead. This also has the benefit to optimize normal helper calls since
their address can use the optimized emission. Tested on Cavium ThunderX
CN8890.
Fixes: db496944fd ("bpf: arm64: add JIT support for multi-function programs")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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>
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 6fe8b9c1f4 ("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>
Follow-up to 816d9ef32a ("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>
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>
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 ddb55992b0 ("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 90caccdd8c
("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: ddb55992b0 ("arm64: bpf: implement bpf_tail_call() helper")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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>
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>
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>
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>
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: f1c9eed7f4 ("bpf, arm64: take advantage of stack_depth tracking")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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: db496944fd ("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>
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>
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>
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>
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>
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>
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: 85f68fe898 ("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>
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>
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>
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: ddb55992b0 ("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>
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>
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>
Eric and Willem reported that they recently saw random crashes when
JIT was in use and bisected this to 74451e66d5 ("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: 74451e66d5 ("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>
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>
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>
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>
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>
Add support for JMP_CALL_X (tail call) introduced by commit 04fd61ab36
("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>
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>
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>
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>
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>
Original implementation commit e54bcde3d6 ("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: e54bcde3d6 ("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>
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>
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 83d5b7ef99
("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
f75298f5c3 ("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. cde66c2d88
("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>
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>
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>
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()
...
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>
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 b569c1c622 ("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>
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>
- __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
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Merge tag 'arm64-fixes' of 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
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: e54bcde3d6 ("arm64: eBPF JIT compiler")
Cc: <stable@vger.kernel.org> # 3.18+
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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 86bf1721b2
("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: e54bcde3d6 ("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>
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>
Upper bits should be zeroed in endianness conversion:
- even when there's no need to change endianness (i.e., BPF_FROM_BE
on big endian or BPF_FROM_LE on little endian);
- after rev16.
This patch fixes such bugs by emitting extra instructions to clear
upper bits.
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Fixes: e54bcde3d6 ("arm64: eBPF JIT compiler")
Cc: <stable@vger.kernel.org> # 3.18+
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Problems occur when bpf_to or bpf_from has value prog->len - 1 (e.g.,
"Very long jump backwards" in test_bpf where the last instruction is a
jump): since ctx->offset has length prog->len, ctx->offset[bpf_to + 1]
or ctx->offset[bpf_from + 1] will cause an out-of-bounds read, leading
to a bogus jump offset and kernel panic.
This patch moves updating ctx->offset to after calling build_insn(),
and changes indexing to use bpf_to and bpf_from without + 1.
Fixes: e54bcde3d6 ("arm64: eBPF JIT compiler")
Cc: <stable@vger.kernel.org> # 3.18+
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Consider "(u64)insn1.imm << 32 | imm" in the arm64 JIT. Since imm is
signed 32-bit, it is sign-extended to 64-bit, losing the high 32 bits.
The fix is to convert imm to u32 first, which will be zero-extended to
u64 implicitly.
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: 30d3d94cc3 ("arm64: bpf: add 'load 64-bit immediate' instruction")
Signed-off-by: Xi Wang <xi.wang@gmail.com>
[will: removed non-arm64 bits and redundant casting]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Earlier implementation assumed last instruction is BPF_EXIT.
Since this is no longer a restriction in eBPF, we remove this
limitation.
Per Alexei Starovoitov [1]:
> classic BPF has a restriction that last insn is always BPF_RET.
> eBPF doesn't have BPF_RET instruction and this restriction.
> It has BPF_EXIT insn which can appear anywhere in the program
> one or more times and it doesn't have to be last insn.
[1] https://lkml.org/lkml/2014/11/27/2
Fixes: e54bcde3d6 ("arm64: eBPF JIT compiler")
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Commit 286aad3c40 ("net: bpf: be friendly to kmemcheck") changed the
type of jited from a bitfield into a bool. As this commmit wasn't available
at the time when arm64 eBPF JIT was merged, fix it up now as net is merged
into mainline.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit 02ab695bb3 (net: filter: add "load 64-bit immediate" eBPF
instruction) introduced a new eBPF instruction. Let's add support
for this for arm64 as well.
Our arm64 eBPF JIT compiler now passes the new "load 64-bit
immediate" test case introduced in the same commit 02ab695bb3.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit 72b603ee8c ("bpf: x86: add missing 'shift by register'
instructions to x64 eBPF JIT") noted support for 'shift by register'
in eBPF and added support for it for x64. Let's enable this for arm64
as well.
The arm64 eBPF JIT compiler now passes the new 'shift by register'
test case introduced in the same commit 72b603ee8c.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This is the ARM64 variant for 314beb9bca ("x86: bpf_jit_comp: secure bpf
jit against spraying attacks").
Thanks to commit 11d91a770f ("arm64: Add CONFIG_DEBUG_SET_MODULE_RONX
support") which added necessary infrastructure, we can now implement
RO marking of eBPF generated JIT image pages and randomize start offset
for the JIT code, so that it does not reside directly on a page boundary
anymore. Likewise, the holes are filled with illegal instructions: here
we use BRK #0x100 (opcode 0xd4202000) to trigger a fault in the kernel
(unallocated BRKs would trigger a fault through do_debug_exception). This
seems more reliable as we don't have a guaranteed undefined instruction
space on ARM64.
This is basically the ARM64 variant of what we already have in ARM via
commit 55309dd3d4 ("net: bpf: arm: address randomize and write protect
JIT code"). Moreover, this commit also presents a merge resolution due to
conflicts with commit 60a3b2253c ("net: bpf: make eBPF interpreter images
read-only") as we don't use kfree() in bpf_jit_free() anymore to release
the locked bpf_prog structure, but instead bpf_prog_unlock_free() through
a different allocator.
JIT tested on aarch64 with BPF test suite.
Reference: http://mainisusuallyafunction.blogspot.com/2012/11/attacking-hardened-linux-systems-with.html
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Reviewed-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On ARM64, when the BPF JIT compiler fills the JIT image body with
opcodes during translation of eBPF into ARM64 opcodes, we may fail
for several reasons during that phase: one being that we jump to
the notyet label for not yet supported eBPF instructions such as
BPF_ST. In that case we only free offsets, but not the actual
allocated target image where opcodes are being stored. Fix it by
calling module_free() on dismantle time in case of errors.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The JIT compiler emits A64 instructions. It supports eBPF only.
Legacy BPF is supported thanks to conversion by BPF core.
JIT is enabled in the same way as for other architectures:
echo 1 > /proc/sys/net/core/bpf_jit_enable
Or for additional compiler output:
echo 2 > /proc/sys/net/core/bpf_jit_enable
See Documentation/networking/filter.txt for more information.
The implementation passes all 57 tests in lib/test_bpf.c
on ARMv8 Foundation Model :) Also tested by Will on Juno platform.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
