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| author | Eduard Zingerman <eddyz87@gmail.com> | 2024-07-22 16:38:37 -0700 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-07-29 15:05:05 -0700 |
| commit | 91b7fbf3936f5c27d1673264dc24a713290e2165 (patch) | |
| tree | ebabfbc28ab41c57b9684db2bd8e588ae4fbc4b7 /kernel/bpf/helpers.c | |
| parent | bpf: no_caller_saved_registers attribute for helper calls (diff) | |
| download | linux-91b7fbf3936f5c27d1673264dc24a713290e2165.tar.gz linux-91b7fbf3936f5c27d1673264dc24a713290e2165.zip | |
bpf, x86, riscv, arm: no_caller_saved_registers for bpf_get_smp_processor_id()
The function bpf_get_smp_processor_id() is processed in a different
way, depending on the arch:
- on x86 verifier replaces call to bpf_get_smp_processor_id() with a
sequence of instructions that modify only r0;
- on riscv64 jit replaces call to bpf_get_smp_processor_id() with a
sequence of instructions that modify only r0;
- on arm64 jit replaces call to bpf_get_smp_processor_id() with a
sequence of instructions that modify only r0 and tmp registers.
These rewrites satisfy attribute no_caller_saved_registers contract.
Allow rewrite of no_caller_saved_registers patterns for
bpf_get_smp_processor_id() in order to use this function as a canary
for no_caller_saved_registers tests.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240722233844.1406874-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Diffstat (limited to 'kernel/bpf/helpers.c')
| -rw-r--r-- | kernel/bpf/helpers.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index b5f0adae8293..d02ae323996b 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -158,6 +158,7 @@ const struct bpf_func_proto bpf_get_smp_processor_id_proto = { .func = bpf_get_smp_processor_id, .gpl_only = false, .ret_type = RET_INTEGER, + .allow_nocsr = true, }; BPF_CALL_0(bpf_get_numa_node_id) |