Commit Graph

153 Commits

Author SHA1 Message Date
Florent Revest (Anthropic)
17637e1a58
bpf: Skip detached progs in trampoline images that are still in use
bpf_tramp_image_put() makes sure a trampoline image is not freed while
a task may still be running in it, but nothing similar is done for the
progs called by that image. Detach drops the last prog reference right
away and the prog is freed after grace periods, on the basis that a
task still in the traced function skips the fexit progs once the nop at
ip_after_call is patched to a jump.

That leaves out a task sleeping in a sleepable prog that runs before
the detached one, which no grace period waits for:

  CPU 0                               CPU 1
  in image I, sleeping in prog S
                                      detach P from I's trampoline
                                       -> new image, bpf_tramp_image_put(I)
                                      bpf_prog_put(P), last ref
                                      grace periods, P freed
  back from S
  __bpf_prog_enter(P)
  call P->bpf_func

If S and P are fexit progs the task is already past the patched jump,
and fentry only images don't have one. On x86 this is an int3 in
poisoned bpf_prog_pack memory:

  Oops: int3: 0000 [#1] SMP NOPTI
  CPU: 18 UID: 0 PID: 94573 Comm: x169 Not tainted 6.18.44 #1 PREEMPT(lazy)
  RIP: 0010:0xffffffffc0601d8d
  Call Trace:
   <TASK>
   ? bpf_trampoline_6442515411+0x1a4/0x21b
   bpf_lsm_bprm_committed_creds+0x5/0x10
   security_bprm_committed_creds+0x5f/0x70
   begin_new_exec+0x2d6/0x410
   ...

We hit this in production when progs attached through trampolines got
detached while their hooks were busy, and it was independently found
with a fuzzer and KASAN.

Have the JITs emit a patchable nop in front of each prog call sequence
and record it in the image. When a prog is detached, patch its nop to a
jump over the call sequence. Progs that stay attached keep running for
the tasks that are in the image, and ip_after_call isn't needed anymore.

The task can be in any image that isn't freed yet, not only in the
current one. It sleeps in image I1 that calls S, P and Q, then P is
detached and the trampoline moves to image I2, then Q is detached and
its call is still in I1. So the trampoline keeps a list of its images
until they are freed, and detaching a prog patches its nop in all of
them. Images hold a reference on the trampoline for that long.

On riscv and loongarch a jump of any range takes several instructions,
and a task preempted in the middle of them could resume into half of the
new sequence. The nop is a single instruction there, patched to a near
branch through arch_bpf_trampoline_skip().

With the extra nops, BPF_MAX_TRAMP_LINKS progs no longer fit in a page
on x86 and arm64 (and already didn't on powerpc), so lower the limit
there like s390 does.

Fixes: e21aa34178 ("bpf: Fix fexit trampoline.")
Reported-by: Sechang Lim <rhkrqnwk98@gmail.com>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Florent Revest (Anthropic) <florent.revest@linux.dev>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://patch.msgid.link/20260926135605.1217928-3-florent.revest@linux.dev
Closes: https://lore.kernel.org/bpf/20260815071927.147049-1-zirajs7@gmail.com/
2026-09-29 05:54:16 +00:00
Chen Pei
536b523b40
bpf, riscv: Make arena support depend on ZACAS
The arena range tree allocates its nodes with kmalloc_nolock() since
commit f8c67d8550 ("bpf: Use kmalloc_nolock() in range tree").
kmalloc_nolock() requires slab caches with cmpxchg128 support
(__CMPXCHG_DOUBLE); on riscv cmpxchg128 is provided by the ZACAS
extension. On systems without ZACAS every arena map creation fails
with a misleading -ENOMEM.

Report the missing support instead: make bpf_jit_supports_arena()
return system_has_cmpxchg128() where it is defined, so arena map
creation fails with -EOPNOTSUPP on systems without ZACAS. The macro
is only defined when both CONFIG_RISCV_ISA_ZACAS and
CONFIG_TOOLCHAIN_HAS_ZACAS are enabled, so guard it with #ifdef the
same way mm/slab.h consumes it, and reject arena otherwise. This
matches how arena BPF_CMPXCHG instructions are already gated on ZACAS
in bpf_jit_supports_insn().

Fixes: f8c67d8550 ("bpf: Use kmalloc_nolock() in range tree")
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
Acked-by: Pu Lehui <pulehui@huawei.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20260902061451.1416-1-cp0613@linux.alibaba.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-09-06 16:23:12 +02:00
Pu Lehui
f2aaa62159 riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args
On RV64, the ABI requires sign-extension for signed 1-byte and 2-byte kfunc
args. However, the RV64 JIT currently does not perform sign-extension for
such kfunc args.

Before commit 7ce090afbf ("bpf: Infer zext_dst based on static register
liveness analysis"), state pruning could potentially omit zero-extension
of 32-bit subregisters, which inadvertently masked the above issue by making
the args appear as if they had been properly sign-extended. After that
commit, the problem is exposed, causing the kfunc_call/kfunc_call_test4
selftest to fail.

Fix this by extending the existing sign-extension logic to handle signed
1-byte and 2-byte kfunc args as well.

Fixes: 443574b033 ("riscv, bpf: Fix kfunc parameters incompatibility between bpf and riscv abi")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260814064726.3607615-1-pulehui@huaweicloud.com
2026-08-14 18:31:58 +02:00
Daniel Borkmann
1519f488e8 bpf, riscv: Clear fetch destination on faulting arena atomic
A RMW atomic on an arena pointer is converted to BPF_PROBE_ATOMIC and
gets an exception table entry, but that entry records no destination
register to clear unless the instruction is a load-acquire today. That
is right for a plain BPF_{ADD,AND,OR,XOR}, which only writes memory,
but an RMW carrying BPF_FETCH also reads the old value into a register:
src_reg for BPF_{ADD,AND,OR,XOR} | BPF_FETCH and BPF_XCHG, and r0 for
BPF_CMPXCHG. emit_atomic_rmw() emits it that way, e.g.:

  [...]
  case BPF_XCHG:
          ctx->ex_insn_off = ctx->ninsns;
          emit(is64 ? rv_amoswap_d(rs, rs, rd, 1, 1) :
               rv_amoswap_w(rs, rs, rd, 1, 1), ctx);
  [...]

Thus, a fault over an unmapped arena page ex_handler_bpf() jumps over
the access but leaves rs untouched, and the program resumes with
whatever it held before the atomic instead of the 0 that every other
BPF_PROBE_* access delivers. Fill the exception table entry in from
bpf_atomic_load_reg(), which returns the BPF register an atomic reads
the memory operand into or -1 when it has none. A load-acquire ends up
with the same register it gets today, it just goes through the helper.
Unlike x86-64 and arm64, riscv64 does not report arena violations from
its exception handler, so there is no access direction to correct here,
only the missing register clear.

Fixes: fb7cefabae ("riscv, bpf: Add support arena atomics for RV64")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://patch.msgid.link/20260811131600.506721-2-daniel@iogearbox.net
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
2026-08-12 10:33:53 -07:00
Daniel Borkmann
e2577cd620
bpf, riscv: Add and use bpf_atomic_is_load_acq() helper
A load-acquire is the only BPF_STX class instruction that reads from
src_reg into dst_reg, that is, it has the operand roles of a BPF_LDX.
JIT code which tells loads from stores apart by instruction class alone
has to special case it, for example when deciding which register holds
the faulting address and which one to clear from an exception handler.

riscv64 already does so, open coded as a bare insn->imm test. Add a
bpf_atomic_is_load_acq() helper and convert riscv64 over to it, so that
the x86-64 and arm64 JITs can use the same helper in subsequent patches.

Unlike bpf_atomic_is_load_store(), which presumes that its argument is
already known to be a BPF_ATOMIC instruction, the new helper is called
from code which still sees all instruction classes, so it checks class
and mode itself.

Also, move bpf_atomic_is_load_store() to filter.h next to BPF_ATOMIC_OP,
so that both helpers stay together. No functional change intended.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260806201047.333389-2-daniel@iogearbox.net
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-08-07 14:57:13 +02:00
Feng Jiang
6ef8ff20c3
bpf, riscv: Add support for timed may_goto
Implement arch_bpf_timed_may_goto() for the RV64 JIT. The argument and
return value are carried in BPF_REG_AX, and BPF R0-R5 are preserved
across the call to the generic bpf_check_timed_may_goto().

Enable bpf_jit_supports_timed_may_goto() so the verifier uses the timed
expansion path.

Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20260723-riscv-bpf-timed-may-goto-v5-1-86acb54e5642@kylinos.cn
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-24 22:20:48 +02:00
Kuan-Wei Chiu
a1b37972ef
riscv, bpf: Add 32 bit atomic operations to RV32 JIT
The RV32 BPF JIT compiler currently only supports the BPF_ADD atomic
operation. Other 32 bit atomic operations (and, or, xor, xchg) and
their BPF_FETCH variants are not supported and gracefully fall back to
the interpreter.

Since the RISC-V A extension is required for Linux on RV32, we can
natively support these 32-bit BPF atomic operations by mapping them
directly to the corresponding RISC-V amo*.w instructions.

Implement BPF_ADD, BPF_AND, BPF_OR, BPF_XOR, and BPF_XCHG with and
without BPF_FETCH. BPF_CMPXCHG requires a more complex lr.w/sc.w
loop and is left to fall back to the interpreter.

Before this patch:
[  138.862161] test_bpf: Summary: 1054 PASSED, 0 FAILED, [843/1042 JIT'ed]

After this patch:
[  157.024124] test_bpf: Summary: 1054 PASSED, 0 FAILED, [902/1042 JIT'ed]

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/bpf/20260714002451.4091139-4-visitorckw@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 21:20:05 +02:00
Kuan-Wei Chiu
c6a08afdfe
riscv, bpf: Add support for BPF_MOVSX in RV32 JIT
The current rv32 bpf jit compiler incorrectly treats BPF_MOVSX as a
standard zero-extended move operation. The bpf instruction set allows
sign-extension moves by reusing the BPF_MOV opcode with the instruction
offset set to 8, 16, or 32.

Update the bpf_jit_emit_insn() function to check the offset field for
both ALU and ALU64 MOV operations. If the offset is non-zero, emit the
correct slli and srai instructions to perform the sign extension.

Before this patch:
[   19.549705] test_bpf: #82 ALU_MOVSX | BPF_B jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)
[   19.551354] test_bpf: #83 ALU_MOVSX | BPF_H jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)
[   19.552576] test_bpf: #84 ALU64_MOVSX | BPF_B jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)
[   19.553542] test_bpf: #85 ALU64_MOVSX | BPF_H jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)
[   19.554807] test_bpf: #86 ALU64_MOVSX | BPF_W jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)

After this patch:
[   17.931172] test_bpf: #82 ALU_MOVSX | BPF_B jited:1 125 PASS
[   17.932198] test_bpf: #83 ALU_MOVSX | BPF_H jited:1 124 PASS
[   17.933039] test_bpf: #84 ALU64_MOVSX | BPF_B jited:1 124 PASS
[   17.933918] test_bpf: #85 ALU64_MOVSX | BPF_H jited:1 124 PASS
[   17.934751] test_bpf: #86 ALU64_MOVSX | BPF_W jited:1 122 PASS

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/bpf/20260714002451.4091139-3-visitorckw@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 21:20:05 +02:00
Kuan-Wei Chiu
2e0fa2389c
riscv, bpf: Add support for BPF_SDIV and BPF_SMOD in RV32 JIT
The current rv32 bpf jit compiler incorrectly treats BPF_SDIV and
BPF_SMOD as unsigned operations. The BPF instruction set allows
signed division and modulo by reusing the BPF_DIV and BPF_MOD opcodes
with the instruction offset set to 1.

Update the emit_alu_r32() function to accept an 'is_sdiv' variable and
emit the correct div and rem instructions when the offset is 1.

Before this patch:
[   44.161771] test_bpf: #165 ALU_SDIV_X: -6 / 2 = -3 jited:1 ret 2147483645 != -3 (0x7ffffffd != 0xfffffffd)FAIL (1 times)
[   44.167385] test_bpf: #166 ALU_SDIV_K: -6 / 2 = -3 jited:1 ret 2147483645 != -3 (0x7ffffffd != 0xfffffffd)FAIL (1 times)
[   44.171053] test_bpf: #169 ALU_SMOD_X: -7 % 2 = -1 jited:1 ret 1 != -1 (0x1 != 0xffffffff)FAIL (1 times)
[   44.172081] test_bpf: #170 ALU_SMOD_K: -7 % 2 = -1 jited:1 ret 1 != -1 (0x1 != 0xffffffff)FAIL (1 times)

After this patch:
[   16.002192] test_bpf: #165 ALU_SDIV_X: -6 / 2 = -3 jited:1 95 PASS
[   16.002983] test_bpf: #166 ALU_SDIV_K: -6 / 2 = -3 jited:1 1059 PASS
[   16.017167] test_bpf: #169 ALU_SMOD_X: -7 % 2 = -1 jited:1 136 PASS
[   16.023002] test_bpf: #170 ALU_SMOD_K: -7 % 2 = -1 jited:1 109 PASS

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/bpf/20260714002451.4091139-2-visitorckw@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 21:20:04 +02:00
Feng Jiang
5eb8921371
bpf, riscv: Fix extable handling for arena load_acquire
emit_atomic_ld_st() returns 1 to have build_body() skip the zext after
a sub-word load_acquire. The caller does "ret = ret ?:
add_exception_handler(...)", which skips add_exception_handler() on any
non-zero ret, so the extable entry is missing and a faulting
PROBE_ATOMIC load_acquire oopses.

REG_DONT_CLEAR_MARKER leaves rd stale on fault, and the verifier still
thinks the load overwrote it, so a program can leak it through a map.

Check ret >= 0 before calling add_exception_handler(), and pass rd for
LOAD_ACQ so the fault zeroes rd like a PROBE_MEM load. Return ret
unchanged for the zext skip.

Fixes: fb7cefabae ("riscv, bpf: Add support arena atomics for RV64")
Suggested-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20260720-bpf-riscv-fix-extable-v4-1-165c0b3b07d5@kylinos.cn
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 20:23:54 +02:00
Pu Lehui
ec72848ca0
riscv, bpf: Mixing bpf2bpf and tailcalls
In the current RV64 JIT, if we just don't initialize the TCC in subprog,
the TCC can be propagated from the parent process to the subprocess, but
the updated TCC of the parent process cannot be restored when the
subprocess exits. Since the RV64 TCC is initialized before saving the
callee saved registers into the stack, we cannot use the callee saved
register to pass the TCC, otherwise the original value of the callee
saved register will be destroyed. So we implemented mixing bpf2bpf and
tailcalls similar to x86_64, i.e. using a non-callee saved register to
transfer the TCC between functions, and saving that register to the
stack to protect the TCC value. As for the tailcall hierarchy issue,
inspired by the s390's low-overhead approach, we store TCC from
RV_REG_TCC back to stack after calling bpf2bpf call or calling orig bpf
func in bpf trampoline.

Tests test_bpf.ko and test_verifier have passed, as well as the relative
testcases of test_progs*.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20260708064436.2971933-7-pulehui@huaweicloud.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 20:19:07 +02:00
Pu Lehui
a21731f54c
riscv, bpf: Add RV_TAILCALL_OFFSET macro to format tailcall offset
Add RV_TAILCALL_OFFSET macro to format tailcall offset, and correct the
relevant comments.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20260708064436.2971933-6-pulehui@huaweicloud.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 20:19:03 +02:00
Pu Lehui
52fb1756ea
riscv, bpf: Fix kernel stack corruption in tailcall with CFI
When CONFIG_CFI_CLANG is enabled, prog->bpf_func already skips the kcfi
instruction during setup. Including it again in the tailcall jump offset
causes it to jump over an extra 4 bytes, skipping the stack pointer
adjustment, which will result in kernel stack corruption.

Fixes: 30a59cc797 ("riscv, bpf: Fix possible infinite tailcall when CONFIG_CFI_CLANG is enabled")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20260708064436.2971933-5-pulehui@huaweicloud.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 20:18:56 +02:00
Pu Lehui
f3ab878594
riscv, bpf: Using kvzalloc_objs to allocate cache buffer
It is unnecessary to allocate continuous physical memory for cache
buffer, and when ebpf program is too large, it may cause memory
allocation failure.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20260708064436.2971933-4-pulehui@huaweicloud.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 20:18:48 +02:00
Pu Lehui
369e4635d0
riscv, bpf: Fix memory leak in bpf_jit_free
When bpf_int_jit_compile() is called for subprograms, it returns early
during the first pass (!prog->is_func || extra_pass is false), keeping
ctx->offset alive for the subsequent extra pass.

If JIT compilation fails for a later subprogram, the BPF core aborts
and calls bpf_jit_free() to clean up the first subprogram. However,
bpf_jit_free() fails to free jit_data->ctx.offset, which causes a
memory leak of the JIT context offsets array.

Fix this by adding the missing kfree(jit_data->ctx.offset) in
bpf_jit_free().

Fixes: 48a8f78c50 ("bpf, riscv: use prog pack allocator in the BPF JIT")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20260708064436.2971933-3-pulehui@huaweicloud.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 20:18:42 +02:00
Pu Lehui
6bcecae4b6
bpf: Extract the is_struct_ops_tramp helper
Extract the is_struct_ops_tramp helper, and use it in riscv
as the current checks are somewhat hacky.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20260708064436.2971933-2-pulehui@huaweicloud.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-07-21 20:17:45 +02:00
Pawan Gupta
0bb99f2cfa bpf: Restrict JIT predictor flush to cBPF
Currently predictor flush on memory reuse is done for all BPF JIT
allocations, but only cBPF programs can be loaded by an unprivileged user.
eBPF is privileged by default, and flushing predictors for all CPUs on
every eBPF reuse penalizes the common case for no security benefit.

eBPF allocations can be frequent on busy systems, only flush predictors
for cBPF programs. Trampoline and dispatcher allocations also skip the
flush as they are eBPF-only.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2026-07-01 10:33:38 +02:00
Jiri Olsa
65499074ef bpf: Add struct bpf_tramp_node object
Adding struct bpf_tramp_node to decouple the link out of the trampoline
attachment info.

At the moment the object for attaching bpf program to the trampoline is
'struct bpf_tramp_link':

  struct bpf_tramp_link {
       struct bpf_link link;
       struct hlist_node tramp_hlist;
       u64 cookie;
  }

The link holds the bpf_prog pointer and forces one link - one program
binding logic. In following changes we want to attach program to multiple
trampolines but we want to keep just one bpf_link object.

Splitting struct bpf_tramp_link into:

  struct bpf_tramp_link {
       struct bpf_link link;
       struct bpf_tramp_node node;
  };

  struct bpf_tramp_node {
       struct bpf_link *link;
       struct hlist_node tramp_hlist;
       u64 cookie;
  };

The 'struct bpf_tramp_link' defines standard single trampoline link
and 'struct bpf_tramp_node' is the attachment trampoline object with
pointer to the bpf_link object.

This will allow us to define link for multiple trampolines, like:

  struct bpf_tracing_multi_link {
       struct bpf_link link;
       ...
       int nodes_cnt;
       struct bpf_tracing_multi_node nodes[] __counted_by(nodes_cnt);
  };

Cc: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-9-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-07 10:03:01 -07:00
Varun R Mallya
6d13ddb1d4 bpf, riscv: inline bpf_get_current_task() and bpf_get_current_task_btf()
On RISC-V, the current task pointer is stored in the thread pointer
register (tp). Emit a single `mv a5, tp` instead of a full helper
call for BPF_FUNC_get_current_task and BPF_FUNC_get_current_task_btf.

Register bpf_jit_inlines_helper_call() entries for both helpers so the
verifier treats them as inlined, and add the expected `mv a5, tp`
annotation to the riscv64 selftests.

The following show changes before and after this patch.

Before patch:

      auipc  t1,0x817a    # load upper PC-relative address
      jalr   -2004(t1)    # call bpf_get_current_task helper
      mv     a5,a0        # move return value to BPF_REG_0

After patch:

      mv     a5,tp        # directly: a5 = current (tp = thread pointer)

Benchmark (bpf_prog_test_run wrapping bpf_get_current_task in loop,
batch=100, 10s, QEMU RISC-V):

              | runs/sec  | helper-calls/sec | ns/call
 -------------+-----------+------------------+---------
 Before patch |   173,490 |       17,349,090 |      57
 After patch  |   320,497 |       32,049,780 |      31
 -------------+-----------+------------------+---------
 Improvement  |   +84.7%  |          +84.7%  |  -45.6%

Signed-off-by: Varun R Mallya <varunrmallya@gmail.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20260602205847.102825-3-varunrmallya@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05 15:26:18 -07:00
Xu Kuohai
d9ef13f727 bpf: Pass bpf_verifier_env to JIT
Pass bpf_verifier_env to bpf_int_jit_compile(). The follow-up patch will
use env->insn_aux_data in the JIT stage to detect indirect jump targets.

Since bpf_prog_select_runtime() can be called by cbpf and lib/test_bpf.c
code without verifier, introduce helper __bpf_prog_select_runtime()
to accept the env parameter.

Remove the call to bpf_prog_select_runtime() in bpf_prog_load(), and
switch to call __bpf_prog_select_runtime() in the verifier, with env
variable passed. The original bpf_prog_select_runtime() is preserved for
cbpf and lib/test_bpf.c, where env is NULL.

Now all constants blinding calls are moved into the verifier, except
the cbpf and lib/test_bpf.c cases. The instructions arrays are adjusted
by bpf_patch_insn_data() function for normal cases, so there is no need
to call adjust_insn_arrays() in bpf_jit_blind_constants(). Remove it.

Reviewed-by: Anton Protopopov <a.s.protopopov@gmail.com> # v8
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> # v12
Acked-by: Hengqi Chen <hengqi.chen@gmail.com> # v14
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20260416064341.151802-3-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-04-16 07:03:40 -07:00
Xu Kuohai
d3e945223e bpf: Move constants blinding out of arch-specific JITs
During the JIT stage, constants blinding rewrites instructions but only
rewrites the private instruction copy of the JITed subprog, leaving the
global env->prog->insnsi and env->insn_aux_data untouched. This causes a
mismatch between subprog instructions and the global state, making it
difficult to use the global data in the JIT.

To avoid this mismatch, and given that all arch-specific JITs already
support constants blinding, move it to the generic verifier code, and
switch to rewrite the global env->prog->insnsi with the global states
adjusted, as other rewrites in the verifier do.

This removes the constants blinding calls in each JIT, which are largely
duplicated code across architectures.

Since constants blinding is only required for JIT, and there are two
JIT entry functions, jit_subprogs() for BPF programs with multiple
subprogs and bpf_prog_select_runtime() for programs with no subprogs,
move the constants blinding invocation into these two functions.

In the verifier path, bpf_patch_insn_data() is used to keep global
verifier auxiliary data in sync with patched instructions. A key
question is whether this global auxiliary data should be restored
on the failure path.

Besides instructions, bpf_patch_insn_data() adjusts:
  - prog->aux->poke_tab
  - env->insn_array_maps
  - env->subprog_info
  - env->insn_aux_data

For prog->aux->poke_tab, it is only used by JIT or only meaningful after
JIT succeeds, so it does not need to be restored on the failure path.

For env->insn_array_maps, when JIT fails, programs using insn arrays
are rejected by bpf_insn_array_ready() due to missing JIT addresses.
Hence, env->insn_array_maps is only meaningful for JIT and does not need
to be restored.

For subprog_info, if jit_subprogs fails and CONFIG_BPF_JIT_ALWAYS_ON
is not enabled, kernel falls back to interpreter. In this case,
env->subprog_info is used to determine subprogram stack depth. So it
must be restored on failure.

For env->insn_aux_data, it is freed by clear_insn_aux_data() at the
end of bpf_check(). Before freeing, clear_insn_aux_data() loops over
env->insn_aux_data to release jump targets recorded in it. The loop
uses env->prog->len as the array length, but this length no longer
matches the actual size of the adjusted env->insn_aux_data array after
constants blinding.

To address it, a simple approach is to keep insn_aux_data as adjusted
after failure, since it will be freed shortly, and record its actual size
for the loop in clear_insn_aux_data(). But since clear_insn_aux_data()
uses the same index to loop over both env->prog->insnsi and env->insn_aux_data,
this approach results in incorrect index for the insnsi array. So an
alternative approach is adopted: clone the original env->insn_aux_data
before blinding and restore it after failure, similar to env->prog.

For classic BPF programs, constants blinding works as before since it
is still invoked from bpf_prog_select_runtime().

Reviewed-by: Anton Protopopov <a.s.protopopov@gmail.com> # v8
Reviewed-by: Hari Bathini <hbathini@linux.ibm.com> # powerpc jit
Reviewed-by: Pu Lehui <pulehui@huawei.com> # riscv jit
Acked-by: Hengqi Chen <hengqi.chen@gmail.com> # loongarch jit
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20260416064341.151802-2-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-04-16 07:03:40 -07:00
Puranjay Mohan
46ee1342b8 bpf, riscv: Remove redundant bpf_flush_icache() after pack allocator finalize
bpf_flush_icache() calls flush_icache_range() to clean the data cache
and invalidate the instruction cache for the JITed code region. However,
since commit 48a8f78c50 ("bpf, riscv: use prog pack allocator in the
BPF JIT"), this flush is redundant.

bpf_jit_binary_pack_finalize() copies the JITed instructions to the ROX
region via bpf_arch_text_copy() -> patch_text_nosync(), and
patch_text_nosync() already calls flush_icache_range() on the written
range. The subsequent bpf_flush_icache() repeats the same cache
maintenance on an overlapping range.

Remove the redundant bpf_flush_icache() call and its now-unused
definition.

Fixes: 48a8f78c50 ("bpf, riscv: use prog pack allocator in the BPF JIT")
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Tested-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/20260413191111.3426023-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-04-15 12:09:46 -07:00
Linus Torvalds
bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Kees Cook
69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Menglong Dong
35b3515be0 bpf, riscv: add fsession support for trampolines
Implement BPF_TRACE_FSESSION support in the RISC-V trampoline JIT. The
logic here is similar to what we did in x86_64.

In order to simply the logic, we factor out the function invoke_bpf() for
fentry and fexit.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Tested-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20260208053311.698352-3-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-02-13 14:14:27 -08:00
Menglong Dong
93fd420d71 bpf, riscv: introduce emit_store_stack_imm64() for trampoline
Introduce a helper to store 64-bit immediate on the trampoline stack with
a help of a register.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Tested-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20260208053311.698352-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-02-13 14:14:27 -08:00
Menglong Dong
8f3e00af8e riscv, bpf: Fix incorrect usage of BPF_TRAMP_F_ORIG_STACK
The usage of BPF_TRAMP_F_ORIG_STACK in __arch_prepare_bpf_trampoline() is
wrong, and it should be BPF_TRAMP_F_CALL_ORIG, which caused crash as
Andreas reported:

  Insufficient stack space to handle exception!
  Task stack:     [0xff20000000010000..0xff20000000014000]
  Overflow stack: [0xff600000ffdad070..0xff600000ffdae070]
  CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary)
  Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025
  epc : copy_from_kernel_nofault+0xa/0x198
   ra : bpf_probe_read_kernel+0x20/0x60
  epc : ffffffff802b732a ra : ffffffff801e6070 sp : ff2000000000ffe0
   gp : ffffffff82262ed0 tp : 0000000000000000 t0 : ffffffff80022320
   t1 : ffffffff801e6056 t2 : 0000000000000000 s0 : ff20000000010040
   s1 : 0000000000000008 a0 : ff20000000010050 a1 : ff60000083b3d320
   a2 : 0000000000000008 a3 : 0000000000000097 a4 : 0000000000000000
   a5 : 0000000000000000 a6 : 0000000000000021 a7 : 0000000000000003
   s2 : ff20000000010050 s3 : ff6000008459fc18 s4 : ff60000083b3d340
   s5 : ff20000000010060 s6 : 0000000000000000 s7 : ff20000000013aa8
   s8 : 0000000000000000 s9 : 0000000000008000 s10: 000000000058dcb0
   s11: 000000000058dca7 t3 : 000000006925116d t4 : ff6000008090f026
   t5 : 00007fff9b0cbaa8 t6 : 0000000000000016
  status: 0000000200000120 badaddr: 0000000000000000 cause: 8000000000000005
  Kernel panic - not syncing: Kernel stack overflow
  CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary)
  Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025
  Call Trace:
  [<ffffffff8001a1f8>] dump_backtrace+0x28/0x38
  [<ffffffff80002502>] show_stack+0x3a/0x50
  [<ffffffff800122be>] dump_stack_lvl+0x56/0x80
  [<ffffffff80012300>] dump_stack+0x18/0x22
  [<ffffffff80002abe>] vpanic+0xf6/0x328
  [<ffffffff80002d2e>] panic+0x3e/0x40
  [<ffffffff80019ef0>] handle_bad_stack+0x98/0xa0
  [<ffffffff801e6070>] bpf_probe_read_kernel+0x20/0x60

Just fix it.

Fixes: 47c9214dcb ("bpf: fix the usage of BPF_TRAMP_F_SKIP_FRAME")
Link: https://lore.kernel.org/bpf/20251219142948.204312-1-dongml2@chinatelecom.cn
Closes: https://lore.kernel.org/bpf/874ipnkfvt.fsf@igel.home/
Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-06 11:40:48 -08:00
Menglong Dong
ae4a3160d1 bpf: specify the old and new poke_type for bpf_arch_text_poke
In the origin logic, the bpf_arch_text_poke() assume that the old and new
instructions have the same opcode. However, they can have different opcode
if we want to replace a "call" insn with a "jmp" insn.

Therefore, add the new function parameter "old_t" along with the "new_t",
which are used to indicate the old and new poke type. Meanwhile, adjust
the implement of bpf_arch_text_poke() for all the archs.

"BPF_MOD_NOP" is added to make the code more readable. In
bpf_arch_text_poke(), we still check if the new and old address is NULL to
determine if nop insn should be used, which I think is more safe.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20251118123639.688444-6-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-11-24 09:47:03 -08:00
Menglong Dong
47c9214dcb bpf: fix the usage of BPF_TRAMP_F_SKIP_FRAME
Some places calculate the origin_call by checking if
BPF_TRAMP_F_SKIP_FRAME is set. However, it should use
BPF_TRAMP_F_ORIG_STACK for this propose. Just fix them.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20251118123639.688444-4-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-11-24 09:47:03 -08:00
Linus Torvalds
ae28ed4578 bpf-next-6.18
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Merge tag 'bpf-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Pull bpf updates from Alexei Starovoitov:

 - Support pulling non-linear xdp data with bpf_xdp_pull_data() kfunc
   (Amery Hung)

   Applied as a stable branch in bpf-next and net-next trees.

 - Support reading skb metadata via bpf_dynptr (Jakub Sitnicki)

   Also a stable branch in bpf-next and net-next trees.

 - Enforce expected_attach_type for tailcall compatibility (Daniel
   Borkmann)

 - Replace path-sensitive with path-insensitive live stack analysis in
   the verifier (Eduard Zingerman)

   This is a significant change in the verification logic. More details,
   motivation, long term plans are in the cover letter/merge commit.

 - Support signed BPF programs (KP Singh)

   This is another major feature that took years to materialize.

   Algorithm details are in the cover letter/marge commit

 - Add support for may_goto instruction to s390 JIT (Ilya Leoshkevich)

 - Add support for may_goto instruction to arm64 JIT (Puranjay Mohan)

 - Fix USDT SIB argument handling in libbpf (Jiawei Zhao)

 - Allow uprobe-bpf program to change context registers (Jiri Olsa)

 - Support signed loads from BPF arena (Kumar Kartikeya Dwivedi and
   Puranjay Mohan)

 - Allow access to union arguments in tracing programs (Leon Hwang)

 - Optimize rcu_read_lock() + migrate_disable() combination where it's
   used in BPF subsystem (Menglong Dong)

 - Introduce bpf_task_work_schedule*() kfuncs to schedule deferred
   execution of BPF callback in the context of a specific task using the
   kernel’s task_work infrastructure (Mykyta Yatsenko)

 - Enforce RCU protection for KF_RCU_PROTECTED kfuncs (Kumar Kartikeya
   Dwivedi)

 - Add stress test for rqspinlock in NMI (Kumar Kartikeya Dwivedi)

 - Improve the precision of tnum multiplier verifier operation
   (Nandakumar Edamana)

 - Use tnums to improve is_branch_taken() logic (Paul Chaignon)

 - Add support for atomic operations in arena in riscv JIT (Pu Lehui)

 - Report arena faults to BPF error stream (Puranjay Mohan)

 - Search for tracefs at /sys/kernel/tracing first in bpftool (Quentin
   Monnet)

 - Add bpf_strcasecmp() kfunc (Rong Tao)

 - Support lookup_and_delete_elem command in BPF_MAP_STACK_TRACE (Tao
   Chen)

* tag 'bpf-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (197 commits)
  libbpf: Replace AF_ALG with open coded SHA-256
  selftests/bpf: Add stress test for rqspinlock in NMI
  selftests/bpf: Add test case for different expected_attach_type
  bpf: Enforce expected_attach_type for tailcall compatibility
  bpftool: Remove duplicate string.h header
  bpf: Remove duplicate crypto/sha2.h header
  libbpf: Fix error when st-prefix_ops and ops from differ btf
  selftests/bpf: Test changing packet data from kfunc
  selftests/bpf: Add stacktrace map lookup_and_delete_elem test case
  selftests/bpf: Refactor stacktrace_map case with skeleton
  bpf: Add lookup_and_delete_elem for BPF_MAP_STACK_TRACE
  selftests/bpf: Fix flaky bpf_cookie selftest
  selftests/bpf: Test changing packet data from global functions with a kfunc
  bpf: Emit struct bpf_xdp_sock type in vmlinux BTF
  selftests/bpf: Task_work selftest cleanup fixes
  MAINTAINERS: Delete inactive maintainers from AF_XDP
  bpf: Mark kfuncs as __noclone
  selftests/bpf: Add kprobe multi write ctx attach test
  selftests/bpf: Add kprobe write ctx attach test
  selftests/bpf: Add uprobe context ip register change test
  ...
2025-09-30 17:58:11 -07:00
Linus Torvalds
a5ba183bde hardening updates for v6.18-rc1
- Clean up usage of TRAILING_OVERLAP() (Gustavo A. R. Silva)
 
 - lkdtm: fortify: Fix potential NULL dereference on kmalloc failure
   (Junjie Cao)
 
 - Add str_assert_deassert() helper (Lad Prabhakar)
 
 - gcc-plugins: Remove TODO_verify_il for GCC >= 16
 
 - kconfig: Fix BrokenPipeError warnings in selftests
 
 - kconfig: Add transitional symbol attribute for migration support
 
 - kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI
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Merge tag 'hardening-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:
 "One notable addition is the creation of the 'transitional' keyword for
  kconfig so CONFIG renaming can go more smoothly.

  This has been a long-standing deficiency, and with the renaming of
  CONFIG_CFI_CLANG to CONFIG_CFI (since GCC will soon have KCFI
  support), this came up again.

  The breadth of the diffstat is mainly this renaming.

   - Clean up usage of TRAILING_OVERLAP() (Gustavo A. R. Silva)

   - lkdtm: fortify: Fix potential NULL dereference on kmalloc failure
     (Junjie Cao)

   - Add str_assert_deassert() helper (Lad Prabhakar)

   - gcc-plugins: Remove TODO_verify_il for GCC >= 16

   - kconfig: Fix BrokenPipeError warnings in selftests

   - kconfig: Add transitional symbol attribute for migration support

   - kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI"

* tag 'hardening-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lib/string_choices: Add str_assert_deassert() helper
  kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI
  kconfig: Add transitional symbol attribute for migration support
  kconfig: Fix BrokenPipeError warnings in selftests
  gcc-plugins: Remove TODO_verify_il for GCC >= 16
  stddef: Introduce __TRAILING_OVERLAP()
  stddef: Remove token-pasting in TRAILING_OVERLAP()
  lkdtm: fortify: Fix potential NULL dereference on kmalloc failure
2025-09-29 17:48:27 -07:00
Kees Cook
23ef9d4397 kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI
The kernel's CFI implementation uses the KCFI ABI specifically, and is
not strictly tied to a particular compiler. In preparation for GCC
supporting KCFI, rename CONFIG_CFI_CLANG to CONFIG_CFI (along with
associated options).

Use new "transitional" Kconfig option for old CONFIG_CFI_CLANG that will
enable CONFIG_CFI during olddefconfig.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250923213422.1105654-3-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
2025-09-24 14:29:14 -07:00
Chenghao Duan
d0bf7cd5df riscv: bpf: Fix uninitialized symbol 'retval_off'
In the __arch_prepare_bpf_trampoline() function, retval_off is only
meaningful when save_ret is true, so the current logic is correct.
However, in the original logic, retval_off is only initialized under
certain conditions; for example, in the fmod_ret logic, the compiler is
not aware that the flags of the fmod_ret program (prog) have set
BPF_TRAMP_F_CALL_ORIG, which results in an uninitialized symbol
compilation warning.

So initialize retval_off unconditionally to fix it.

Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20250922062244.822937-2-duanchenghao@kylinos.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-23 12:29:03 -07:00
Kumar Kartikeya Dwivedi
a91ae3c893 bpf, x86: Add support for signed arena loads
Currently, signed load instructions into arena memory are unsupported.
The compiler is free to generate these, and on GCC-14 we see a
corresponding error when it happens. The hurdle in supporting them is
deciding which unused opcode to use to mark them for the JIT's own
consumption. After much thinking, it appears 0xc0 / BPF_NOSPEC can be
combined with load instructions to identify signed arena loads. Use
this to recognize and JIT them appropriately, and remove the verifier
side limitation on the program if the JIT supports them.

Co-developed-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20250923110157.18326-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-23 12:00:22 -07:00
Hengqi Chen
fd2e081289 riscv, bpf: Sign extend struct ops return values properly
The ns_bpf_qdisc selftest triggers a kernel panic:

    Unable to handle kernel paging request at virtual address ffffffffa38dbf58
    Current test_progs pgtable: 4K pagesize, 57-bit VAs, pgdp=0x00000001109cc000
    [ffffffffa38dbf58] pgd=000000011fffd801, p4d=000000011fffd401, pud=000000011fffd001, pmd=0000000000000000
    Oops [#1]
    Modules linked in: bpf_testmod(OE) xt_conntrack nls_iso8859_1 [...] [last unloaded: bpf_testmod(OE)]
    CPU: 1 UID: 0 PID: 23584 Comm: test_progs Tainted: G        W  OE       6.17.0-rc1-g2465bb83e0b4 #1 NONE
    Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
    Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2024.01+dfsg-1ubuntu5.1 01/01/2024
    epc : __qdisc_run+0x82/0x6f0
     ra : __qdisc_run+0x6e/0x6f0
    epc : ffffffff80bd5c7a ra : ffffffff80bd5c66 sp : ff2000000eecb550
     gp : ffffffff82472098 tp : ff60000096895940 t0 : ffffffff8001f180
     t1 : ffffffff801e1664 t2 : 0000000000000000 s0 : ff2000000eecb5d0
     s1 : ff60000093a6a600 a0 : ffffffffa38dbee8 a1 : 0000000000000001
     a2 : ff2000000eecb510 a3 : 0000000000000001 a4 : 0000000000000000
     a5 : 0000000000000010 a6 : 0000000000000000 a7 : 0000000000735049
     s2 : ffffffffa38dbee8 s3 : 0000000000000040 s4 : ff6000008bcda000
     s5 : 0000000000000008 s6 : ff60000093a6a680 s7 : ff60000093a6a6f0
     s8 : ff60000093a6a6ac s9 : ff60000093140000 s10: 0000000000000000
     s11: ff2000000eecb9d0 t3 : 0000000000000000 t4 : 0000000000ff0000
     t5 : 0000000000000000 t6 : ff60000093a6a8b6
    status: 0000000200000120 badaddr: ffffffffa38dbf58 cause: 000000000000000d
    [<ffffffff80bd5c7a>] __qdisc_run+0x82/0x6f0
    [<ffffffff80b6fe58>] __dev_queue_xmit+0x4c0/0x1128
    [<ffffffff80b80ae0>] neigh_resolve_output+0xd0/0x170
    [<ffffffff80d2daf6>] ip6_finish_output2+0x226/0x6c8
    [<ffffffff80d31254>] ip6_finish_output+0x10c/0x2a0
    [<ffffffff80d31446>] ip6_output+0x5e/0x178
    [<ffffffff80d2e232>] ip6_xmit+0x29a/0x608
    [<ffffffff80d6f4c6>] inet6_csk_xmit+0xe6/0x140
    [<ffffffff80c985e4>] __tcp_transmit_skb+0x45c/0xaa8
    [<ffffffff80c995fe>] tcp_connect+0x9ce/0xd10
    [<ffffffff80d66524>] tcp_v6_connect+0x4ac/0x5e8
    [<ffffffff80cc19b8>] __inet_stream_connect+0xd8/0x318
    [<ffffffff80cc1c36>] inet_stream_connect+0x3e/0x68
    [<ffffffff80b42b20>] __sys_connect_file+0x50/0x88
    [<ffffffff80b42bee>] __sys_connect+0x96/0xc8
    [<ffffffff80b42c40>] __riscv_sys_connect+0x20/0x30
    [<ffffffff80e5bcae>] do_trap_ecall_u+0x256/0x378
    [<ffffffff80e69af2>] handle_exception+0x14a/0x156
    Code: 892a 0363 1205 489c 8bc1 c7e5 2d03 084a 2703 080a (2783) 0709
    ---[ end trace 0000000000000000 ]---

The bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer
is treated as a 32bit value and sign extend to 64bit in epilogue. This
behavior is right for most bpf prog types but wrong for struct ops which
requires RISC-V ABI.

So let's sign extend struct ops return values according to the function
model and RISC-V ABI([0]).

  [0]: https://riscv.org/wp-content/uploads/2024/12/riscv-calling.pdf

Fixes: 25ad10658d ("riscv, bpf: Adapt bpf trampoline to optimized riscv ftrace framework")
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/bpf/20250908012448.1695-1-hengqi.chen@gmail.com
2025-09-15 13:21:32 +02:00
Hengqi Chen
6798668ab1 riscv, bpf: Remove duplicated bpf_flush_icache()
The bpf_flush_icache() is done by bpf_arch_text_copy() already.
Remove the duplicated one in arch_prepare_bpf_trampoline().

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/bpf/20250904105119.21861-1-hengqi.chen@gmail.com
2025-09-15 13:16:55 +02:00
Alexei Starovoitov
5d87e96a49 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf after rc5
Cross-merge BPF and other fixes after downstream PR.

No conflicts.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-11 09:34:37 -07:00
Radim Krčmář
8a16586fa7 riscv, bpf: use lw when reading int cpu in bpf_get_smp_processor_id
emit_ld is wrong, because thread_info.cpu is 32-bit, not xlen-bit wide.
The struct currently has a hole after cpu, so little endian accesses
seemed fine.

Fixes: 2ddec2c80b ("riscv, bpf: inline bpf_get_smp_processor_id()")
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@ventanamicro.com>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20250812090256.757273-4-rkrcmar@ventanamicro.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
2025-09-05 15:31:20 -06:00
Radim Krčmář
ad5348c765 riscv, bpf: use lw when reading int cpu in BPF_MOV64_PERCPU_REG
emit_ld is wrong, because thread_info.cpu is 32-bit, not xlen-bit wide.
The struct currently has a hole after cpu, so little endian accesses
seemed fine.

Fixes: 19c56d4e5b ("riscv, bpf: add internal-only MOV instruction to resolve per-CPU addrs")
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@ventanamicro.com>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Tested-by: Björn Töpel <bjorn@rivosinc.com> # QEMU
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250812090256.757273-3-rkrcmar@ventanamicro.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
2025-09-05 15:31:17 -06:00
Pu Lehui
fb7cefabae riscv, bpf: Add support arena atomics for RV64
Add arena atomics support for RMW atomics and load-acquire and
store-release instructions. Non-Zacas cmpxchg is implemented via loop,
which is not currently supported because it requires more complex
extable and loop logic.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20250719091730.2660197-10-pulehui@huaweicloud.com
2025-08-15 10:46:51 +02:00
Pu Lehui
b18f4aae6a riscv, bpf: Add ex_insn_off and ex_jmp_off for exception table handling
Add ex_insn_off and ex_jmp_off fields to struct rv_jit_context so that
add_exception_handler() does not need to be immediately followed by the
instruction to add the exception table. ex_insn_off indicates the offset
of the instruction to add the exception table, and ex_jmp_off indicates
the offset to jump over the faulting instruction. This is to prepare for
adding the exception table to atomic instructions later, because some
atomic instructions need to perform zext or other operations.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20250719091730.2660197-9-pulehui@huaweicloud.com
2025-08-15 10:46:51 +02:00
Pu Lehui
1c0196b878 riscv, bpf: Optimize cmpxchg insn with Zacas support
Optimize cmpxchg instruction with amocas.w and amocas.d
Zacas instructions.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20250719091730.2660197-8-pulehui@huaweicloud.com
2025-08-15 10:46:51 +02:00
Pu Lehui
de39d2c4cd riscv, bpf: Add Zacas instructions
Add Zacas instructions introduced by [0] to reduce code size and
improve performance of RV64 JIT.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://github.com/riscvarchive/riscv-zacas/releases/download/v1.0/riscv-zacas.pdf [0]
Link: https://lore.kernel.org/bpf/20250719091730.2660197-7-pulehui@huaweicloud.com
2025-08-15 10:46:51 +02:00
Pu Lehui
5090b339ee riscv, bpf: Add rv_ext_enabled macro for runtime detection extentsion
Add rv_ext_enabled macro to check whether the runtime detection
extension is enabled.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20250719091730.2660197-6-pulehui@huaweicloud.com
2025-08-15 10:46:51 +02:00
Pu Lehui
01422a4f2c riscv, bpf: Extract emit_ldx() helper
There's a lot of redundant code related to load into register
operations, let's extract emit_ldx() to make code more compact.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20250719091730.2660197-4-pulehui@huaweicloud.com
2025-08-15 10:46:51 +02:00
Pu Lehui
d92c11a6b5 riscv, bpf: Extract emit_st() helper
There's a lot of redundant code related to store from immediate
operations, let's extract emit_st() to make code more compact.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20250719091730.2660197-3-pulehui@huaweicloud.com
2025-08-15 10:46:51 +02:00
Pu Lehui
02fc01adec riscv, bpf: Extract emit_stx() helper
There's a lot of redundant code related to store from register
operations, let's extract emit_stx() to make code more compact.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20250719091730.2660197-2-pulehui@huaweicloud.com
2025-08-15 10:46:51 +02:00
Peilin Ye
db7a3822b5 bpf, riscv64: Skip redundant zext instruction after load-acquire
Currently, the verifier inserts a zext instruction right after every 8-,
16- or 32-bit load-acquire, which is already zero-extending.  Skip such
redundant zext instructions.

While we are here, update that already-obsolete comment about "skip the
next instruction" in build_body().  Also change emit_atomic_rmw()'s
parameters to keep it consistent with emit_atomic_ld_st().

Note that checking 'insn[1]' relies on 'insn' not being the last
instruction, which should have been guaranteed by the verifier; we
already use 'insn[1]' elsewhere in the file for similar purposes.
Additionally, we don't check if 'insn[1]' is actually a zext for our
load-acquire's dst_reg, or some other registers - in other words, here
we are relying on the verifier to always insert a redundant zext right
after a 8/16/32-bit load-acquire, for its dst_reg.

Acked-by: Björn Töpel <bjorn@kernel.org>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com> # QEMU/RVA23
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/10e90e0eab042f924d35ad0d1c1f7ca29f673152.1746588351.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-05-09 10:05:27 -07:00
Andrea Parri
8afd3170d5 bpf, riscv64: Support load-acquire and store-release instructions
Support BPF load-acquire (BPF_LOAD_ACQ) and store-release
(BPF_STORE_REL) instructions in the riscv64 JIT compiler.  For example,
consider the following 64-bit load-acquire (assuming little-endian):

  db 10 00 00 00 01 00 00  r1 = load_acquire((u64 *)(r1 + 0x0))
  95 00 00 00 00 00 00 00  exit

  opcode (0xdb): BPF_ATOMIC | BPF_DW | BPF_STX
  imm (0x00000100): BPF_LOAD_ACQ

The JIT compiler will emit an LD instruction followed by a FENCE R,RW
instruction for the above, e.g.:

  ld x7,0(x6)
  fence r,rw

Similarly, consider the following 16-bit store-release:

  cb 21 00 00 10 01 00 00  store_release((u16 *)(r1 + 0x0), w2)
  95 00 00 00 00 00 00 00  exit

  opcode (0xcb): BPF_ATOMIC | BPF_H | BPF_STX
  imm (0x00000110): BPF_STORE_REL

A FENCE RW,W instruction followed by an SH instruction will be emitted,
e.g.:

  fence rw,w
  sh x2,0(x4)

8-bit and 16-bit load-acquires are zero-extending (cf., LBU, LHU).  The
verifier always rejects misaligned load-acquires/store-releases (even if
BPF_F_ANY_ALIGNMENT is set), so the emitted load and store instructions
are guaranteed to be single-copy atomic.

Introduce primitives to emit the relevant (and the most common/used in
the kernel) fences, i.e. fences with R -> RW, RW -> W and RW -> RW.

Rename emit_atomic() to emit_atomic_rmw() to make it clear that it only
handles RMW atomics, and replace its is64 parameter to allow to perform
the required checks on the opsize (BPF_SIZE(code)).

Acked-by: Björn Töpel <bjorn@kernel.org>
Tested-by: Björn Töpel <bjorn@rivosinc.com> # QEMU/RVA23
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Co-developed-by: Peilin Ye <yepeilin@google.com>
Signed-off-by: Peilin Ye <yepeilin@google.com>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/3059c560e537ad43ed19055d2ebbd970c698095a.1746588351.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-05-09 10:05:27 -07:00
Andrea Parri
118ae46b79 bpf, riscv64: Introduce emit_load_*() and emit_store_*()
We're planning to add support for the load-acquire and store-release
BPF instructions.  Define emit_load_<size>() and emit_store_<size>()
to enable/facilitate the (re)use of their code.

Acked-by: Björn Töpel <bjorn@kernel.org>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com> # QEMU/RVA23
Tested-by: Peilin Ye <yepeilin@google.com>
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
[yepeilin@google.com: cosmetic change to commit title]
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/fce89473a5748e1631d18a5917d953460d1ae0d0.1746588351.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-05-09 10:05:27 -07:00