diff options
| author | Song Liu <song@kernel.org> | 2022-07-20 03:21:26 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2022-07-22 23:04:37 +0300 |
| commit | 00963a2e75a872e5fce4d0115ac2786ec86b57a6 (patch) | |
| tree | 91073f9e37c12cf4321a60f5c1b20c307c64e199 /include | |
| parent | 316cba62dfb7878b7353177e6a7da9cc0c979cde (diff) | |
| download | linux-00963a2e75a872e5fce4d0115ac2786ec86b57a6.tar.xz | |
bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)
When tracing a function with IPMODIFY ftrace_ops (livepatch), the bpf
trampoline must follow the instruction pointer saved on stack. This needs
extra handling for bpf trampolines with BPF_TRAMP_F_CALL_ORIG flag.
Implement bpf_tramp_ftrace_ops_func and use it for the ftrace_ops used
by BPF trampoline. This enables tracing functions with livepatch.
This also requires moving bpf trampoline to *_ftrace_direct_mult APIs.
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/all/20220602193706.2607681-2-song@kernel.org/
Link: https://lore.kernel.org/bpf/20220720002126.803253-5-song@kernel.org
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/bpf.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 1d22df8bf306..20c26aed7896 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -47,6 +47,7 @@ struct kobject; struct mem_cgroup; struct module; struct bpf_func_state; +struct ftrace_ops; extern struct idr btf_idr; extern spinlock_t btf_idr_lock; @@ -756,6 +757,11 @@ struct btf_func_model { */ #define BPF_TRAMP_F_ORIG_STACK BIT(5) +/* This trampoline is on a function with another ftrace_ops with IPMODIFY, + * e.g., a live patch. This flag is set and cleared by ftrace call backs, + */ +#define BPF_TRAMP_F_SHARE_IPMODIFY BIT(6) + /* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50 * bytes on x86. */ @@ -838,9 +844,11 @@ struct bpf_tramp_image { struct bpf_trampoline { /* hlist for trampoline_table */ struct hlist_node hlist; + struct ftrace_ops *fops; /* serializes access to fields of this trampoline */ struct mutex mutex; refcount_t refcnt; + u32 flags; u64 key; struct { struct btf_func_model model; |