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bpf: Add cookies support for uprobe_multi link

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Adding support to specify cookies array for uprobe_multi link.

The cookies array share indexes and length with other uprobe_multi
arrays (offsets/ref_ctr_offsets).

The cookies[i] value defines cookie for i-the uprobe and will be
returned by bpf_get_attach_cookie helper when called from ebpf
program hooked to that specific uprobe.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jiri Olsa 2023-08-09 10:34:16 +02:00 committed by Alexei Starovoitov
parent 89ae89f53d
commit 0b779b61f6
4 changed files with 44 additions and 5 deletions
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1
include/uapi/linux/bpf.h
View File

@ -1639,6 +1639,7 @@ union bpf_attr {
__aligned_u64 path;
__aligned_u64 offsets;
__aligned_u64 ref_ctr_offsets;
__aligned_u64 cookies;
__u32 cnt;
__u32 flags;
} uprobe_multi;

2
kernel/bpf/syscall.c
View File

@ -4882,7 +4882,7 @@ err_put:
return err;
}
#define BPF_LINK_CREATE_LAST_FIELD link_create.kprobe_multi.cookies
#define BPF_LINK_CREATE_LAST_FIELD link_create.uprobe_multi.flags
static int link_create(union bpf_attr *attr, bpfptr_t uattr)
{
struct bpf_prog *prog;

45
kernel/trace/bpf_trace.c
View File

@ -87,6 +87,8 @@ static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size,
static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx);
static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx);
static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx);
/**
* trace_call_bpf - invoke BPF program
* @call: tracepoint event
@ -1104,6 +1106,18 @@ static const struct bpf_func_proto bpf_get_attach_cookie_proto_kmulti = {
.arg1_type = ARG_PTR_TO_CTX,
};
BPF_CALL_1(bpf_get_attach_cookie_uprobe_multi, struct pt_regs *, regs)
{
return bpf_uprobe_multi_cookie(current->bpf_ctx);
}
static const struct bpf_func_proto bpf_get_attach_cookie_proto_umulti = {
.func = bpf_get_attach_cookie_uprobe_multi,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
};
BPF_CALL_1(bpf_get_attach_cookie_trace, void *, ctx)
{
struct bpf_trace_run_ctx *run_ctx;
@ -1550,9 +1564,11 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
&bpf_get_func_ip_proto_kprobe_multi :
&bpf_get_func_ip_proto_kprobe;
case BPF_FUNC_get_attach_cookie:
return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI ?
&bpf_get_attach_cookie_proto_kmulti :
&bpf_get_attach_cookie_proto_trace;
if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI)
return &bpf_get_attach_cookie_proto_kmulti;
if (prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI)
return &bpf_get_attach_cookie_proto_umulti;
return &bpf_get_attach_cookie_proto_trace;
default:
return bpf_tracing_func_proto(func_id, prog);
}
@ -2978,6 +2994,7 @@ struct bpf_uprobe_multi_link;
struct bpf_uprobe {
struct bpf_uprobe_multi_link *link;
loff_t offset;
u64 cookie;
struct uprobe_consumer consumer;
};
@ -2991,6 +3008,7 @@ struct bpf_uprobe_multi_link {
struct bpf_uprobe_multi_run_ctx {
struct bpf_run_ctx run_ctx;
unsigned long entry_ip;
struct bpf_uprobe *uprobe;
};
static void bpf_uprobe_unregister(struct path *path, struct bpf_uprobe *uprobes,
@ -3034,6 +3052,7 @@ static int uprobe_prog_run(struct bpf_uprobe *uprobe,
struct bpf_uprobe_multi_link *link = uprobe->link;
struct bpf_uprobe_multi_run_ctx run_ctx = {
.entry_ip = entry_ip,
.uprobe = uprobe,
};
struct bpf_prog *prog = link->link.prog;
bool sleepable = prog->aux->sleepable;
@ -3078,6 +3097,14 @@ uprobe_multi_link_ret_handler(struct uprobe_consumer *con, unsigned long func, s
return uprobe_prog_run(uprobe, func, regs);
}
static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx)
{
struct bpf_uprobe_multi_run_ctx *run_ctx;
run_ctx = container_of(current->bpf_ctx, struct bpf_uprobe_multi_run_ctx, run_ctx);
return run_ctx->uprobe->cookie;
}
int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
{
struct bpf_uprobe_multi_link *link = NULL;
@ -3086,6 +3113,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
struct bpf_link_primer link_primer;
struct bpf_uprobe *uprobes = NULL;
unsigned long __user *uoffsets;
u64 __user *ucookies;
void __user *upath;
u32 flags, cnt, i;
struct path path;
@ -3105,7 +3133,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
/*
* path, offsets and cnt are mandatory,
* ref_ctr_offsets is optional
* ref_ctr_offsets and cookies are optional
*/
upath = u64_to_user_ptr(attr->link_create.uprobe_multi.path);
uoffsets = u64_to_user_ptr(attr->link_create.uprobe_multi.offsets);
@ -3115,6 +3143,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
return -EINVAL;
uref_ctr_offsets = u64_to_user_ptr(attr->link_create.uprobe_multi.ref_ctr_offsets);
ucookies = u64_to_user_ptr(attr->link_create.uprobe_multi.cookies);
name = strndup_user(upath, PATH_MAX);
if (IS_ERR(name)) {
@ -3147,6 +3176,10 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
}
for (i = 0; i < cnt; i++) {
if (ucookies && __get_user(uprobes[i].cookie, ucookies + i)) {
err = -EFAULT;
goto error_free;
}
if (uref_ctr_offsets && __get_user(ref_ctr_offsets[i], uref_ctr_offsets + i)) {
err = -EFAULT;
goto error_free;
@ -3202,4 +3235,8 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
{
return -EOPNOTSUPP;
}
static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx)
{
return 0;
}
#endif /* CONFIG_UPROBES */

1
tools/include/uapi/linux/bpf.h
View File

@ -1639,6 +1639,7 @@ union bpf_attr {
__aligned_u64 path;
__aligned_u64 offsets;
__aligned_u64 ref_ctr_offsets;
__aligned_u64 cookies;
__u32 cnt;
__u32 flags;
} uprobe_multi;