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| author | Tony Ambardar <tony.ambardar@gmail.com> | 2022-06-17 13:57:34 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-17 16:14:48 +0300 |
| commit | 7018bd9fac6237e706d175d0a5926de9226c664a (patch) | |
| tree | 0434b424f169fdae931b158107661d19de98e171 | |
| parent | 1cbe7a02e7028e782fe2027a38d005f0641d2a35 (diff) | |
| download | linux-7018bd9fac6237e706d175d0a5926de9226c664a.tar.xz | |
bpf, x64: Add predicate for bpf2bpf with tailcalls support in JIT
[ Upstream commit 95acd8817e66d031d2e6ee7def3f1e1874819317 ]
The BPF core/verifier is hard-coded to permit mixing bpf2bpf and tail
calls for only x86-64. Change the logic to instead rely on a new weak
function 'bool bpf_jit_supports_subprog_tailcalls(void)', which a capable
JIT backend can override.
Update the x86-64 eBPF JIT to reflect this.
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
[jakub: drop MIPS bits and tweak patch subject]
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220617105735.733938-2-jakub@cloudflare.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 6 | ||||
| -rw-r--r-- | include/linux/filter.h | 1 | ||||
| -rw-r--r-- | kernel/bpf/core.c | 6 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 3 |
4 files changed, 15 insertions, 1 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index b808c9a80d1b..eba704b9ce1e 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2506,3 +2506,9 @@ void *bpf_arch_text_copy(void *dst, void *src, size_t len) return ERR_PTR(-EINVAL); return dst; } + +/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */ +bool bpf_jit_supports_subprog_tailcalls(void) +{ + return true; +} diff --git a/include/linux/filter.h b/include/linux/filter.h index ed0c0ff42ad5..d9a0db845b50 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -948,6 +948,7 @@ u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog); void bpf_jit_compile(struct bpf_prog *prog); bool bpf_jit_needs_zext(void); +bool bpf_jit_supports_subprog_tailcalls(void); bool bpf_jit_supports_kfunc_call(void); bool bpf_helper_changes_pkt_data(void *func); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index e7961508a47d..6e3fe4b7230b 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2716,6 +2716,12 @@ bool __weak bpf_jit_needs_zext(void) return false; } +/* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ +bool __weak bpf_jit_supports_subprog_tailcalls(void) +{ + return false; +} + bool __weak bpf_jit_supports_kfunc_call(void) { return false; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 0efbac0fd126..602366bc230f 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6143,7 +6143,8 @@ static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id) static bool allow_tail_call_in_subprogs(struct bpf_verifier_env *env) { - return env->prog->jit_requested && IS_ENABLED(CONFIG_X86_64); + return env->prog->jit_requested && + bpf_jit_supports_subprog_tailcalls(); } static int check_map_func_compatibility(struct bpf_verifier_env *env, |