* [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program.
@ 2022-04-07 19:25 Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 1/5] bpf, x86: Generate trampolines from bpf_tramp_links Kui-Feng Lee
` (5 more replies)
0 siblings, 6 replies; 9+ messages in thread
From: Kui-Feng Lee @ 2022-04-07 19:25 UTC (permalink / raw)
To: bpf, ast, daniel, andrii, kernel-team; +Cc: Kui-Feng Lee
Allow users to attach a 64-bits cookie to a bpf_link of fentry, fexit,
or fmod_ret.
This patchset includes several major changes.
- Define struct bpf_tramp_links to replace bpf_tramp_prog.
struct bpf_tramp_links collects bpf_links of a trampoline
- Generate a trampoline to call bpf_progs of given bpf_links.
- Trampolines always set/reset bpf_run_ctx before/after
calling/leaving a tracing program.
- Attach a cookie to a bpf_link of fentry/fexit/fmod_ret. The value
will be available when running the associated bpf_prog.
The major differences from v2:
- Move the allocations of run_ctx (struct bpf_tramp_run_ctx) out of
invoke_bpf_prog().
- Move hlist_node out of bpf_link and introduce struct bpf_tramp_link
to own hlist_node.
- Store cookies at struct bpf_tracing_link.
- Use SIB byte to reduce the number of instructions to set cookie
values. (Use RSP directly)
v1: https://lore.kernel.org/all/20220126214809.3868787-1-kuifeng@fb.com/
v2: https://lore.kernel.org/bpf/20220316004231.1103318-1-kuifeng@fb.com/
Kui-Feng Lee (5):
bpf, x86: Generate trampolines from bpf_tramp_links
bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack
bpf, x86: Attach a cookie to fentry/fexit/fmod_ret.
lib/bpf: Assign cookies to links in libbpf.
selftest/bpf: The test cses of BPF cookie for fentry/fexit/fmod_ret.
arch/x86/net/bpf_jit_comp.c | 98 +++++++++++++++----
include/linux/bpf.h | 56 ++++++++---
include/linux/bpf_types.h | 1 +
include/uapi/linux/bpf.h | 9 ++
kernel/bpf/bpf_struct_ops.c | 69 ++++++++-----
kernel/bpf/syscall.c | 54 ++++++----
kernel/bpf/trampoline.c | 96 +++++++++++-------
kernel/trace/bpf_trace.c | 17 ++++
net/bpf/bpf_dummy_struct_ops.c | 35 ++++++-
tools/bpf/bpftool/link.c | 1 +
tools/include/uapi/linux/bpf.h | 8 ++
tools/lib/bpf/bpf.c | 7 ++
tools/lib/bpf/bpf.h | 3 +
tools/lib/bpf/libbpf.c | 33 +++++++
tools/lib/bpf/libbpf.h | 12 +++
tools/lib/bpf/libbpf.map | 1 +
.../selftests/bpf/prog_tests/bpf_cookie.c | 52 ++++++++++
.../selftests/bpf/progs/test_bpf_cookie.c | 24 +++++
18 files changed, 459 insertions(+), 117 deletions(-)
--
2.30.2
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH bpf-next v3 1/5] bpf, x86: Generate trampolines from bpf_tramp_links
2022-04-07 19:25 [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Kui-Feng Lee
@ 2022-04-07 19:25 ` Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack Kui-Feng Lee
` (4 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Kui-Feng Lee @ 2022-04-07 19:25 UTC (permalink / raw)
To: bpf, ast, daniel, andrii, kernel-team; +Cc: Kui-Feng Lee
Replace struct bpf_tramp_progs with struct bpf_tramp_links to collect
struct bpf_tramp_link(s) for a trampoline. struct bpf_tramp_link
extends bpf_link to act as a linked list node.
arch_prepare_bpf_trampoline() accepts a struct bpf_tramp_links to
collects all bpf_tramp_link(s) that a trampoline should call.
Change BPF trampoline and bpf_struct_ops to pass bpf_tramp_links
instead of bpf_tramp_progs.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
arch/x86/net/bpf_jit_comp.c | 36 +++++++++--------
include/linux/bpf.h | 38 ++++++++++++------
include/linux/bpf_types.h | 1 +
include/uapi/linux/bpf.h | 1 +
kernel/bpf/bpf_struct_ops.c | 69 ++++++++++++++++++++++----------
kernel/bpf/syscall.c | 23 ++++-------
kernel/bpf/trampoline.c | 73 +++++++++++++++++++---------------
net/bpf/bpf_dummy_struct_ops.c | 35 +++++++++++++---
tools/bpf/bpftool/link.c | 1 +
tools/include/uapi/linux/bpf.h | 1 +
10 files changed, 175 insertions(+), 103 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index e6ff8f4f9ea4..8a1720988996 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1743,10 +1743,12 @@ static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_args,
}
static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
- struct bpf_prog *p, int stack_size, bool save_ret)
+ struct bpf_tramp_link *l, int stack_size,
+ bool save_ret)
{
u8 *prog = *pprog;
u8 *jmp_insn;
+ struct bpf_prog *p = l->link.prog;
/* arg1: mov rdi, progs[i] */
emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
@@ -1831,14 +1833,14 @@ static int emit_cond_near_jump(u8 **pprog, void *func, void *ip, u8 jmp_cond)
}
static int invoke_bpf(const struct btf_func_model *m, u8 **pprog,
- struct bpf_tramp_progs *tp, int stack_size,
+ struct bpf_tramp_links *tl, int stack_size,
bool save_ret)
{
int i;
u8 *prog = *pprog;
- for (i = 0; i < tp->nr_progs; i++) {
- if (invoke_bpf_prog(m, &prog, tp->progs[i], stack_size,
+ for (i = 0; i < tl->nr_links; i++) {
+ if (invoke_bpf_prog(m, &prog, tl->links[i], stack_size,
save_ret))
return -EINVAL;
}
@@ -1847,7 +1849,7 @@ static int invoke_bpf(const struct btf_func_model *m, u8 **pprog,
}
static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog,
- struct bpf_tramp_progs *tp, int stack_size,
+ struct bpf_tramp_links *tl, int stack_size,
u8 **branches)
{
u8 *prog = *pprog;
@@ -1858,8 +1860,8 @@ static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog,
*/
emit_mov_imm32(&prog, false, BPF_REG_0, 0);
emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
- for (i = 0; i < tp->nr_progs; i++) {
- if (invoke_bpf_prog(m, &prog, tp->progs[i], stack_size, true))
+ for (i = 0; i < tl->nr_links; i++) {
+ if (invoke_bpf_prog(m, &prog, tl->links[i], stack_size, true))
return -EINVAL;
/* mod_ret prog stored return value into [rbp - 8]. Emit:
@@ -1961,14 +1963,14 @@ static bool is_valid_bpf_tramp_flags(unsigned int flags)
*/
int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end,
const struct btf_func_model *m, u32 flags,
- struct bpf_tramp_progs *tprogs,
+ struct bpf_tramp_links *tlinks,
void *orig_call)
{
int ret, i, nr_args = m->nr_args;
int regs_off, ip_off, args_off, stack_size = nr_args * 8;
- struct bpf_tramp_progs *fentry = &tprogs[BPF_TRAMP_FENTRY];
- struct bpf_tramp_progs *fexit = &tprogs[BPF_TRAMP_FEXIT];
- struct bpf_tramp_progs *fmod_ret = &tprogs[BPF_TRAMP_MODIFY_RETURN];
+ struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
+ struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
+ struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN];
u8 **branches = NULL;
u8 *prog;
bool save_ret;
@@ -2055,13 +2057,13 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
}
}
- if (fentry->nr_progs)
+ if (fentry->nr_links)
if (invoke_bpf(m, &prog, fentry, regs_off,
flags & BPF_TRAMP_F_RET_FENTRY_RET))
return -EINVAL;
- if (fmod_ret->nr_progs) {
- branches = kcalloc(fmod_ret->nr_progs, sizeof(u8 *),
+ if (fmod_ret->nr_links) {
+ branches = kcalloc(fmod_ret->nr_links, sizeof(u8 *),
GFP_KERNEL);
if (!branches)
return -ENOMEM;
@@ -2088,7 +2090,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
prog += X86_PATCH_SIZE;
}
- if (fmod_ret->nr_progs) {
+ if (fmod_ret->nr_links) {
/* From Intel 64 and IA-32 Architectures Optimization
* Reference Manual, 3.4.1.4 Code Alignment, Assembly/Compiler
* Coding Rule 11: All branch targets should be 16-byte
@@ -2098,12 +2100,12 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
/* Update the branches saved in invoke_bpf_mod_ret with the
* aligned address of do_fexit.
*/
- for (i = 0; i < fmod_ret->nr_progs; i++)
+ for (i = 0; i < fmod_ret->nr_links; i++)
emit_cond_near_jump(&branches[i], prog, branches[i],
X86_JNE);
}
- if (fexit->nr_progs)
+ if (fexit->nr_links)
if (invoke_bpf(m, &prog, fexit, regs_off, false)) {
ret = -EINVAL;
goto cleanup;
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 88449fbbe063..c4b8ca17024b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -674,11 +674,11 @@ struct btf_func_model {
/* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50
* bytes on x86. Pick a number to fit into BPF_IMAGE_SIZE / 2
*/
-#define BPF_MAX_TRAMP_PROGS 38
+#define BPF_MAX_TRAMP_LINKS 38
-struct bpf_tramp_progs {
- struct bpf_prog *progs[BPF_MAX_TRAMP_PROGS];
- int nr_progs;
+struct bpf_tramp_links {
+ struct bpf_tramp_link *links[BPF_MAX_TRAMP_LINKS];
+ int nr_links;
};
/* Different use cases for BPF trampoline:
@@ -704,7 +704,7 @@ struct bpf_tramp_progs {
struct bpf_tramp_image;
int arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *image_end,
const struct btf_func_model *m, u32 flags,
- struct bpf_tramp_progs *tprogs,
+ struct bpf_tramp_links *tlinks,
void *orig_call);
/* these two functions are called from generated trampoline */
u64 notrace __bpf_prog_enter(struct bpf_prog *prog);
@@ -803,9 +803,12 @@ static __always_inline __nocfi unsigned int bpf_dispatcher_nop_func(
{
return bpf_func(ctx, insnsi);
}
+
+struct bpf_link;
+
#ifdef CONFIG_BPF_JIT
-int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr);
-int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr);
+int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr);
+int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr);
struct bpf_trampoline *bpf_trampoline_get(u64 key,
struct bpf_attach_target_info *tgt_info);
void bpf_trampoline_put(struct bpf_trampoline *tr);
@@ -856,12 +859,12 @@ int bpf_jit_charge_modmem(u32 size);
void bpf_jit_uncharge_modmem(u32 size);
bool bpf_prog_has_trampoline(const struct bpf_prog *prog);
#else
-static inline int bpf_trampoline_link_prog(struct bpf_prog *prog,
+static inline int bpf_trampoline_link_prog(struct bpf_link *link,
struct bpf_trampoline *tr)
{
return -ENOTSUPP;
}
-static inline int bpf_trampoline_unlink_prog(struct bpf_prog *prog,
+static inline int bpf_trampoline_unlink_prog(struct bpf_link *link,
struct bpf_trampoline *tr)
{
return -ENOTSUPP;
@@ -960,7 +963,6 @@ struct bpf_prog_aux {
bool tail_call_reachable;
bool xdp_has_frags;
bool use_bpf_prog_pack;
- struct hlist_node tramp_hlist;
/* BTF_KIND_FUNC_PROTO for valid attach_btf_id */
const struct btf_type *attach_func_proto;
/* function name for valid attach_btf_id */
@@ -1047,6 +1049,18 @@ struct bpf_link_ops {
struct bpf_link_info *info);
};
+struct bpf_tramp_link {
+ struct bpf_link link;
+ struct hlist_node tramp_hlist;
+};
+
+struct bpf_tracing_link {
+ struct bpf_tramp_link link;
+ enum bpf_attach_type attach_type;
+ struct bpf_trampoline *trampoline;
+ struct bpf_prog *tgt_prog;
+};
+
struct bpf_link_primer {
struct bpf_link *link;
struct file *file;
@@ -1084,8 +1098,8 @@ bool bpf_struct_ops_get(const void *kdata);
void bpf_struct_ops_put(const void *kdata);
int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
void *value);
-int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_progs *tprogs,
- struct bpf_prog *prog,
+int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks,
+ struct bpf_tramp_link *link,
const struct btf_func_model *model,
void *image, void *image_end);
static inline bool bpf_try_module_get(const void *data, struct module *owner)
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index 48a91c51c015..8228c86eb92b 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -140,3 +140,4 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_XDP, xdp)
#ifdef CONFIG_PERF_EVENTS
BPF_LINK_TYPE(BPF_LINK_TYPE_PERF_EVENT, perf)
#endif
+BPF_LINK_TYPE(BPF_LINK_TYPE_STRUCT_OPS, struct_ops)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 99fab54ae9c0..9e34da50440c 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1011,6 +1011,7 @@ enum bpf_link_type {
BPF_LINK_TYPE_NETNS = 5,
BPF_LINK_TYPE_XDP = 6,
BPF_LINK_TYPE_PERF_EVENT = 7,
+ BPF_LINK_TYPE_STRUCT_OPS = 8,
MAX_BPF_LINK_TYPE,
};
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 21069dbe9138..6aaaec69ec54 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -32,15 +32,15 @@ struct bpf_struct_ops_map {
const struct bpf_struct_ops *st_ops;
/* protect map_update */
struct mutex lock;
- /* progs has all the bpf_prog that is populated
+ /* link has all the bpf_links that is populated
* to the func ptr of the kernel's struct
* (in kvalue.data).
*/
- struct bpf_prog **progs;
+ struct bpf_link **links;
/* image is a page that has all the trampolines
* that stores the func args before calling the bpf_prog.
* A PAGE_SIZE "image" is enough to store all trampoline for
- * "progs[]".
+ * "links[]".
*/
void *image;
/* uvalue->data stores the kernel struct
@@ -282,9 +282,9 @@ static void bpf_struct_ops_map_put_progs(struct bpf_struct_ops_map *st_map)
u32 i;
for (i = 0; i < btf_type_vlen(t); i++) {
- if (st_map->progs[i]) {
- bpf_prog_put(st_map->progs[i]);
- st_map->progs[i] = NULL;
+ if (st_map->links[i]) {
+ bpf_link_put(st_map->links[i]);
+ st_map->links[i] = NULL;
}
}
}
@@ -315,18 +315,32 @@ static int check_zero_holes(const struct btf_type *t, void *data)
return 0;
}
-int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_progs *tprogs,
- struct bpf_prog *prog,
+static void bpf_struct_ops_link_release(struct bpf_link *link)
+{
+}
+
+static void bpf_struct_ops_link_dealloc(struct bpf_link *link)
+{
+ kfree(link);
+}
+
+static const struct bpf_link_ops bpf_struct_ops_link_lops = {
+ .release = bpf_struct_ops_link_release,
+ .dealloc = bpf_struct_ops_link_dealloc,
+};
+
+int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks,
+ struct bpf_tramp_link *link,
const struct btf_func_model *model,
void *image, void *image_end)
{
u32 flags;
- tprogs[BPF_TRAMP_FENTRY].progs[0] = prog;
- tprogs[BPF_TRAMP_FENTRY].nr_progs = 1;
+ tlinks[BPF_TRAMP_FENTRY].links[0] = link;
+ tlinks[BPF_TRAMP_FENTRY].nr_links = 1;
flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0;
return arch_prepare_bpf_trampoline(NULL, image, image_end,
- model, flags, tprogs, NULL);
+ model, flags, tlinks, NULL);
}
static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
@@ -337,7 +351,7 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
struct bpf_struct_ops_value *uvalue, *kvalue;
const struct btf_member *member;
const struct btf_type *t = st_ops->type;
- struct bpf_tramp_progs *tprogs = NULL;
+ struct bpf_tramp_links *tlinks = NULL;
void *udata, *kdata;
int prog_fd, err = 0;
void *image, *image_end;
@@ -361,8 +375,8 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
if (uvalue->state || refcount_read(&uvalue->refcnt))
return -EINVAL;
- tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL);
- if (!tprogs)
+ tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL);
+ if (!tlinks)
return -ENOMEM;
uvalue = (struct bpf_struct_ops_value *)st_map->uvalue;
@@ -385,6 +399,7 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
for_each_member(i, t, member) {
const struct btf_type *mtype, *ptype;
struct bpf_prog *prog;
+ struct bpf_tramp_link *link;
u32 moff;
moff = __btf_member_bit_offset(t, member) / 8;
@@ -438,16 +453,26 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
err = PTR_ERR(prog);
goto reset_unlock;
}
- st_map->progs[i] = prog;
if (prog->type != BPF_PROG_TYPE_STRUCT_OPS ||
prog->aux->attach_btf_id != st_ops->type_id ||
prog->expected_attach_type != i) {
+ bpf_prog_put(prog);
err = -EINVAL;
goto reset_unlock;
}
- err = bpf_struct_ops_prepare_trampoline(tprogs, prog,
+ link = kzalloc(sizeof(*link), GFP_USER);
+ if (!link) {
+ bpf_prog_put(prog);
+ err = -ENOMEM;
+ goto reset_unlock;
+ }
+ bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS,
+ &bpf_struct_ops_link_lops, prog);
+ st_map->links[i] = &link->link;
+
+ err = bpf_struct_ops_prepare_trampoline(tlinks, link,
&st_ops->func_models[i],
image, image_end);
if (err < 0)
@@ -490,7 +515,7 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
memset(uvalue, 0, map->value_size);
memset(kvalue, 0, map->value_size);
unlock:
- kfree(tprogs);
+ kfree(tlinks);
mutex_unlock(&st_map->lock);
return err;
}
@@ -545,9 +570,9 @@ static void bpf_struct_ops_map_free(struct bpf_map *map)
{
struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
- if (st_map->progs)
+ if (st_map->links)
bpf_struct_ops_map_put_progs(st_map);
- bpf_map_area_free(st_map->progs);
+ bpf_map_area_free(st_map->links);
bpf_jit_free_exec(st_map->image);
bpf_map_area_free(st_map->uvalue);
bpf_map_area_free(st_map);
@@ -596,11 +621,11 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
map = &st_map->map;
st_map->uvalue = bpf_map_area_alloc(vt->size, NUMA_NO_NODE);
- st_map->progs =
- bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_prog *),
+ st_map->links =
+ bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_links *),
NUMA_NO_NODE);
st_map->image = bpf_jit_alloc_exec(PAGE_SIZE);
- if (!st_map->uvalue || !st_map->progs || !st_map->image) {
+ if (!st_map->uvalue || !st_map->links || !st_map->image) {
bpf_struct_ops_map_free(map);
return ERR_PTR(-ENOMEM);
}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 9beb585be5a6..dcd285929cf3 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2639,19 +2639,12 @@ struct bpf_link *bpf_link_get_from_fd(u32 ufd)
}
EXPORT_SYMBOL(bpf_link_get_from_fd);
-struct bpf_tracing_link {
- struct bpf_link link;
- enum bpf_attach_type attach_type;
- struct bpf_trampoline *trampoline;
- struct bpf_prog *tgt_prog;
-};
-
static void bpf_tracing_link_release(struct bpf_link *link)
{
struct bpf_tracing_link *tr_link =
- container_of(link, struct bpf_tracing_link, link);
+ container_of(link, struct bpf_tracing_link, link.link);
- WARN_ON_ONCE(bpf_trampoline_unlink_prog(link->prog,
+ WARN_ON_ONCE(bpf_trampoline_unlink_prog(&tr_link->link,
tr_link->trampoline));
bpf_trampoline_put(tr_link->trampoline);
@@ -2664,7 +2657,7 @@ static void bpf_tracing_link_release(struct bpf_link *link)
static void bpf_tracing_link_dealloc(struct bpf_link *link)
{
struct bpf_tracing_link *tr_link =
- container_of(link, struct bpf_tracing_link, link);
+ container_of(link, struct bpf_tracing_link, link.link);
kfree(tr_link);
}
@@ -2673,7 +2666,7 @@ static void bpf_tracing_link_show_fdinfo(const struct bpf_link *link,
struct seq_file *seq)
{
struct bpf_tracing_link *tr_link =
- container_of(link, struct bpf_tracing_link, link);
+ container_of(link, struct bpf_tracing_link, link.link);
seq_printf(seq,
"attach_type:\t%d\n",
@@ -2684,7 +2677,7 @@ static int bpf_tracing_link_fill_link_info(const struct bpf_link *link,
struct bpf_link_info *info)
{
struct bpf_tracing_link *tr_link =
- container_of(link, struct bpf_tracing_link, link);
+ container_of(link, struct bpf_tracing_link, link.link);
info->tracing.attach_type = tr_link->attach_type;
bpf_trampoline_unpack_key(tr_link->trampoline->key,
@@ -2765,7 +2758,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
err = -ENOMEM;
goto out_put_prog;
}
- bpf_link_init(&link->link, BPF_LINK_TYPE_TRACING,
+ bpf_link_init(&link->link.link, BPF_LINK_TYPE_TRACING,
&bpf_tracing_link_lops, prog);
link->attach_type = prog->expected_attach_type;
@@ -2835,11 +2828,11 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
tgt_prog = prog->aux->dst_prog;
}
- err = bpf_link_prime(&link->link, &link_primer);
+ err = bpf_link_prime(&link->link.link, &link_primer);
if (err)
goto out_unlock;
- err = bpf_trampoline_link_prog(prog, tr);
+ err = bpf_trampoline_link_prog(&link->link, tr);
if (err) {
bpf_link_cleanup(&link_primer);
link = NULL;
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 0b41fa993825..5916f1da059d 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -180,30 +180,30 @@ static int register_fentry(struct bpf_trampoline *tr, void *new_addr)
return ret;
}
-static struct bpf_tramp_progs *
+static struct bpf_tramp_links *
bpf_trampoline_get_progs(const struct bpf_trampoline *tr, int *total, bool *ip_arg)
{
- const struct bpf_prog_aux *aux;
- struct bpf_tramp_progs *tprogs;
- struct bpf_prog **progs;
+ struct bpf_tramp_link *link;
+ struct bpf_tramp_links *tlinks;
+ struct bpf_tramp_link **links;
int kind;
*total = 0;
- tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL);
- if (!tprogs)
+ tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL);
+ if (!tlinks)
return ERR_PTR(-ENOMEM);
for (kind = 0; kind < BPF_TRAMP_MAX; kind++) {
- tprogs[kind].nr_progs = tr->progs_cnt[kind];
+ tlinks[kind].nr_links = tr->progs_cnt[kind];
*total += tr->progs_cnt[kind];
- progs = tprogs[kind].progs;
+ links = tlinks[kind].links;
- hlist_for_each_entry(aux, &tr->progs_hlist[kind], tramp_hlist) {
- *ip_arg |= aux->prog->call_get_func_ip;
- *progs++ = aux->prog;
+ hlist_for_each_entry(link, &tr->progs_hlist[kind], tramp_hlist) {
+ *ip_arg |= link->link.prog->call_get_func_ip;
+ *links++ = link;
}
}
- return tprogs;
+ return tlinks;
}
static void __bpf_tramp_image_put_deferred(struct work_struct *work)
@@ -342,14 +342,14 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
static int bpf_trampoline_update(struct bpf_trampoline *tr)
{
struct bpf_tramp_image *im;
- struct bpf_tramp_progs *tprogs;
+ struct bpf_tramp_links *tlinks;
u32 flags = BPF_TRAMP_F_RESTORE_REGS;
bool ip_arg = false;
int err, total;
- tprogs = bpf_trampoline_get_progs(tr, &total, &ip_arg);
- if (IS_ERR(tprogs))
- return PTR_ERR(tprogs);
+ tlinks = bpf_trampoline_get_progs(tr, &total, &ip_arg);
+ if (IS_ERR(tlinks))
+ return PTR_ERR(tlinks);
if (total == 0) {
err = unregister_fentry(tr, tr->cur_image->image);
@@ -365,15 +365,15 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr)
goto out;
}
- if (tprogs[BPF_TRAMP_FEXIT].nr_progs ||
- tprogs[BPF_TRAMP_MODIFY_RETURN].nr_progs)
+ if (tlinks[BPF_TRAMP_FEXIT].nr_links ||
+ tlinks[BPF_TRAMP_MODIFY_RETURN].nr_links)
flags = BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME;
if (ip_arg)
flags |= BPF_TRAMP_F_IP_ARG;
err = arch_prepare_bpf_trampoline(im, im->image, im->image + PAGE_SIZE,
- &tr->func.model, flags, tprogs,
+ &tr->func.model, flags, tlinks,
tr->func.addr);
if (err < 0)
goto out;
@@ -393,7 +393,7 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr)
tr->cur_image = im;
tr->selector++;
out:
- kfree(tprogs);
+ kfree(tlinks);
return err;
}
@@ -419,13 +419,14 @@ static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(struct bpf_prog *prog)
}
}
-int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
+int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
{
enum bpf_tramp_prog_type kind;
+ struct bpf_tramp_link *link_exiting;
int err = 0;
int cnt;
- kind = bpf_attach_type_to_tramp(prog);
+ kind = bpf_attach_type_to_tramp(link->link.prog);
mutex_lock(&tr->mutex);
if (tr->extension_prog) {
/* cannot attach fentry/fexit if extension prog is attached.
@@ -441,25 +442,33 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
err = -EBUSY;
goto out;
}
- tr->extension_prog = prog;
+ tr->extension_prog = link->link.prog;
err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL,
- prog->bpf_func);
+ link->link.prog->bpf_func);
goto out;
}
- if (cnt >= BPF_MAX_TRAMP_PROGS) {
+ if (cnt >= BPF_MAX_TRAMP_LINKS) {
err = -E2BIG;
goto out;
}
- if (!hlist_unhashed(&prog->aux->tramp_hlist)) {
+ if (!hlist_unhashed(&link->tramp_hlist)) {
/* prog already linked */
err = -EBUSY;
goto out;
}
- hlist_add_head(&prog->aux->tramp_hlist, &tr->progs_hlist[kind]);
+ hlist_for_each_entry(link_exiting, &tr->progs_hlist[kind], tramp_hlist) {
+ if (link_exiting->link.prog != link->link.prog)
+ continue;
+ /* prog already linked */
+ err = -EBUSY;
+ goto out;
+ }
+
+ hlist_add_head(&link->tramp_hlist, &tr->progs_hlist[kind]);
tr->progs_cnt[kind]++;
err = bpf_trampoline_update(tr);
if (err) {
- hlist_del_init(&prog->aux->tramp_hlist);
+ hlist_del_init(&link->tramp_hlist);
tr->progs_cnt[kind]--;
}
out:
@@ -468,12 +477,12 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
}
/* bpf_trampoline_unlink_prog() should never fail. */
-int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
+int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
{
enum bpf_tramp_prog_type kind;
int err;
- kind = bpf_attach_type_to_tramp(prog);
+ kind = bpf_attach_type_to_tramp(link->link.prog);
mutex_lock(&tr->mutex);
if (kind == BPF_TRAMP_REPLACE) {
WARN_ON_ONCE(!tr->extension_prog);
@@ -482,7 +491,7 @@ int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
tr->extension_prog = NULL;
goto out;
}
- hlist_del_init(&prog->aux->tramp_hlist);
+ hlist_del_init(&link->tramp_hlist);
tr->progs_cnt[kind]--;
err = bpf_trampoline_update(tr);
out:
@@ -647,7 +656,7 @@ void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr)
int __weak
arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *image_end,
const struct btf_func_model *m, u32 flags,
- struct bpf_tramp_progs *tprogs,
+ struct bpf_tramp_links *tlinks,
void *orig_call)
{
return -ENOTSUPP;
diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c
index d0e54e30658a..b3717f3ab44b 100644
--- a/net/bpf/bpf_dummy_struct_ops.c
+++ b/net/bpf/bpf_dummy_struct_ops.c
@@ -72,13 +72,28 @@ static int dummy_ops_call_op(void *image, struct bpf_dummy_ops_test_args *args)
args->args[3], args->args[4]);
}
+static void bpf_struct_ops_link_release(struct bpf_link *link)
+{
+}
+
+static void bpf_struct_ops_link_dealloc(struct bpf_link *link)
+{
+ kfree(link);
+}
+
+static const struct bpf_link_ops bpf_struct_ops_link_lops = {
+ .release = bpf_struct_ops_link_release,
+ .dealloc = bpf_struct_ops_link_dealloc,
+};
+
int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
const struct bpf_struct_ops *st_ops = &bpf_bpf_dummy_ops;
const struct btf_type *func_proto;
struct bpf_dummy_ops_test_args *args;
- struct bpf_tramp_progs *tprogs;
+ struct bpf_tramp_links *tlinks;
+ struct bpf_tramp_link *link = NULL;
void *image = NULL;
unsigned int op_idx;
int prog_ret;
@@ -92,8 +107,8 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
if (IS_ERR(args))
return PTR_ERR(args);
- tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL);
- if (!tprogs) {
+ tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL);
+ if (!tlinks) {
err = -ENOMEM;
goto out;
}
@@ -105,10 +120,18 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
}
set_vm_flush_reset_perms(image);
+ link = kzalloc(sizeof(*link), GFP_USER);
+ if (!link) {
+ err = -ENOMEM;
+ goto out;
+ }
+ bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_link_lops, prog);
+
op_idx = prog->expected_attach_type;
- err = bpf_struct_ops_prepare_trampoline(tprogs, prog,
+ err = bpf_struct_ops_prepare_trampoline(tlinks, link,
&st_ops->func_models[op_idx],
image, image + PAGE_SIZE);
+
if (err < 0)
goto out;
@@ -124,7 +147,9 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
out:
kfree(args);
bpf_jit_free_exec(image);
- kfree(tprogs);
+ if (link)
+ bpf_link_put(&link->link);
+ kfree(tlinks);
return err;
}
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index 97dec81950e5..d49a2bdc983f 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -20,6 +20,7 @@ static const char * const link_type_name[] = {
[BPF_LINK_TYPE_CGROUP] = "cgroup",
[BPF_LINK_TYPE_ITER] = "iter",
[BPF_LINK_TYPE_NETNS] = "netns",
+ [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops",
};
static struct hashmap *link_table;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 99fab54ae9c0..9e34da50440c 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1011,6 +1011,7 @@ enum bpf_link_type {
BPF_LINK_TYPE_NETNS = 5,
BPF_LINK_TYPE_XDP = 6,
BPF_LINK_TYPE_PERF_EVENT = 7,
+ BPF_LINK_TYPE_STRUCT_OPS = 8,
MAX_BPF_LINK_TYPE,
};
--
2.30.2
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH bpf-next v3 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack
2022-04-07 19:25 [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 1/5] bpf, x86: Generate trampolines from bpf_tramp_links Kui-Feng Lee
@ 2022-04-07 19:25 ` Kui-Feng Lee
2022-04-09 0:01 ` Alexei Starovoitov
2022-04-07 19:25 ` [PATCH bpf-next v3 3/5] bpf, x86: Attach a cookie to fentry/fexit/fmod_ret Kui-Feng Lee
` (3 subsequent siblings)
5 siblings, 1 reply; 9+ messages in thread
From: Kui-Feng Lee @ 2022-04-07 19:25 UTC (permalink / raw)
To: bpf, ast, daniel, andrii, kernel-team; +Cc: Kui-Feng Lee
BPF trampolines will create a bpf_tramp_run_ctx, a bpf_run_ctx, on
stacks and set/reset the current bpf_run_ctx before/after calling a
bpf_prog.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
arch/x86/net/bpf_jit_comp.c | 55 +++++++++++++++++++++++++++++++++++++
include/linux/bpf.h | 17 +++++++++---
kernel/bpf/syscall.c | 4 +--
kernel/bpf/trampoline.c | 23 +++++++++++++---
4 files changed, 89 insertions(+), 10 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 8a1720988996..61b72d537f5b 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1748,10 +1748,26 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
{
u8 *prog = *pprog;
u8 *jmp_insn;
+ int ctx_cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
struct bpf_prog *p = l->link.prog;
+ /* mov rdi, 0 */
+ emit_mov_imm64(&prog, BPF_REG_1, 0, 0);
+
+ /* Prepare struct bpf_tramp_run_ctx.
+ *
+ * bpf_tramp_run_ctx is already preserved by
+ * arch_prepare_bpf_trampoline().
+ *
+ * mov QWORD PTR [rsp + ctx_cookie_off], rdi
+ */
+ EMIT4(0x48, 0x89, 0x7C, 0x24); EMIT1(ctx_cookie_off);
+
/* arg1: mov rdi, progs[i] */
emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
+ /* arg2: mov rsi, rsp (struct bpf_run_ctx *) */
+ EMIT3(0x48, 0x89, 0xE6);
+
if (emit_call(&prog,
p->aux->sleepable ? __bpf_prog_enter_sleepable :
__bpf_prog_enter, prog))
@@ -1797,6 +1813,8 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
/* arg2: mov rsi, rbx <- start time in nsec */
emit_mov_reg(&prog, true, BPF_REG_2, BPF_REG_6);
+ /* arg3: mov rdx, rsp (struct bpf_run_ctx *) */
+ EMIT3(0x48, 0x89, 0xE2);
if (emit_call(&prog,
p->aux->sleepable ? __bpf_prog_exit_sleepable :
__bpf_prog_exit, prog))
@@ -2057,6 +2075,16 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
}
}
+ if (nr_args < 3 && (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links))
+ EMIT1(0x52); /* push rdx */
+
+ if (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links) {
+ /* Prepare struct bpf_tramp_run_ctx.
+ * sub rsp, sizeof(struct bpf_tramp_run_ctx)
+ */
+ EMIT4(0x48, 0x83, 0xEC, sizeof(struct bpf_tramp_run_ctx));
+ }
+
if (fentry->nr_links)
if (invoke_bpf(m, &prog, fentry, regs_off,
flags & BPF_TRAMP_F_RET_FENTRY_RET))
@@ -2076,6 +2104,15 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
}
if (flags & BPF_TRAMP_F_CALL_ORIG) {
+ /* pop struct bpf_tramp_run_ctx
+ * add rsp, sizeof(struct bpf_tramp_run_ctx)
+ */
+ if (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links)
+ EMIT4(0x48, 0x83, 0xC4, sizeof(struct bpf_tramp_run_ctx));
+
+ if (nr_args < 3 && (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links))
+ EMIT1(0x5A); /* pop rdx */
+
restore_regs(m, &prog, nr_args, regs_off);
/* call original function */
@@ -2088,6 +2125,15 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
im->ip_after_call = prog;
memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
prog += X86_PATCH_SIZE;
+
+ if (nr_args < 3 && (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links))
+ EMIT1(0x52); /* push rdx */
+
+ /* Prepare struct bpf_tramp_run_ctx.
+ * sub rsp, sizeof(struct bpf_tramp_run_ctx)
+ */
+ if (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links)
+ EMIT4(0x48, 0x83, 0xEC, sizeof(struct bpf_tramp_run_ctx));
}
if (fmod_ret->nr_links) {
@@ -2111,6 +2157,15 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
goto cleanup;
}
+ /* pop struct bpf_tramp_run_ctx
+ * add rsp, sizeof(struct bpf_tramp_run_ctx)
+ */
+ if (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links)
+ EMIT4(0x48, 0x83, 0xC4, sizeof(struct bpf_tramp_run_ctx));
+
+ if (nr_args < 3 && (fentry->nr_links || fexit->nr_links || fmod_ret->nr_links))
+ EMIT1(0x5A); /* pop rdx */
+
if (flags & BPF_TRAMP_F_RESTORE_REGS)
restore_regs(m, &prog, nr_args, regs_off);
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index c4b8ca17024b..7b4896c86dcc 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -681,6 +681,8 @@ struct bpf_tramp_links {
int nr_links;
};
+struct bpf_tramp_run_ctx;
+
/* Different use cases for BPF trampoline:
* 1. replace nop at the function entry (kprobe equivalent)
* flags = BPF_TRAMP_F_RESTORE_REGS
@@ -707,10 +709,11 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *i
struct bpf_tramp_links *tlinks,
void *orig_call);
/* these two functions are called from generated trampoline */
-u64 notrace __bpf_prog_enter(struct bpf_prog *prog);
-void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start);
-u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog);
-void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start);
+u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx);
+void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start, struct bpf_tramp_run_ctx *run_ctx);
+u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx);
+void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start,
+ struct bpf_tramp_run_ctx *run_ctx);
void notrace __bpf_tramp_enter(struct bpf_tramp_image *tr);
void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr);
@@ -1304,6 +1307,12 @@ struct bpf_trace_run_ctx {
u64 bpf_cookie;
};
+struct bpf_tramp_run_ctx {
+ struct bpf_run_ctx run_ctx;
+ u64 bpf_cookie;
+ struct bpf_run_ctx *saved_run_ctx;
+};
+
static inline struct bpf_run_ctx *bpf_set_run_ctx(struct bpf_run_ctx *new_ctx)
{
struct bpf_run_ctx *old_ctx = NULL;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index dcd285929cf3..12a1c0ff6646 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4786,13 +4786,13 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
return -EINVAL;
}
- if (!__bpf_prog_enter_sleepable(prog)) {
+ if (!__bpf_prog_enter_sleepable(prog, NULL)) {
/* recursion detected */
bpf_prog_put(prog);
return -EBUSY;
}
attr->test.retval = bpf_prog_run(prog, (void *) (long) attr->test.ctx_in);
- __bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */);
+ __bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */, NULL);
bpf_prog_put(prog);
return 0;
#endif
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 5916f1da059d..a2971119ca10 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -580,11 +580,15 @@ static void notrace inc_misses_counter(struct bpf_prog *prog)
* [2..MAX_U64] - execute bpf prog and record execution time.
* This is start time.
*/
-u64 notrace __bpf_prog_enter(struct bpf_prog *prog)
+u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
__acquires(RCU)
{
rcu_read_lock();
migrate_disable();
+
+ if (run_ctx)
+ run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) {
inc_misses_counter(prog);
return 0;
@@ -614,20 +618,27 @@ static void notrace update_prog_stats(struct bpf_prog *prog,
}
}
-void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start)
+void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start, struct bpf_tramp_run_ctx *run_ctx)
__releases(RCU)
{
+ if (run_ctx)
+ bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
update_prog_stats(prog, start);
__this_cpu_dec(*(prog->active));
migrate_enable();
rcu_read_unlock();
}
-u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog)
+u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
{
rcu_read_lock_trace();
migrate_disable();
might_fault();
+
+ if (run_ctx)
+ run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) {
inc_misses_counter(prog);
return 0;
@@ -635,8 +646,12 @@ u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog)
return bpf_prog_start_time();
}
-void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start)
+void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start,
+ struct bpf_tramp_run_ctx *run_ctx)
{
+ if (run_ctx)
+ bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
update_prog_stats(prog, start);
__this_cpu_dec(*(prog->active));
migrate_enable();
--
2.30.2
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH bpf-next v3 3/5] bpf, x86: Attach a cookie to fentry/fexit/fmod_ret.
2022-04-07 19:25 [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 1/5] bpf, x86: Generate trampolines from bpf_tramp_links Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack Kui-Feng Lee
@ 2022-04-07 19:25 ` Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 4/5] lib/bpf: Assign cookies to links in libbpf Kui-Feng Lee
` (2 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Kui-Feng Lee @ 2022-04-07 19:25 UTC (permalink / raw)
To: bpf, ast, daniel, andrii, kernel-team; +Cc: Kui-Feng Lee
Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie
to a link of a trace hook. A cookie of a bpf_tracing_link is
available by calling bpf_get_attach_cookie when running the BPF
program of the attached link.
The value of a cookie will be set at bpf_tramp_run_ctx by the
trampoline of the link.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
arch/x86/net/bpf_jit_comp.c | 11 +++++++++--
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 8 ++++++++
kernel/bpf/syscall.c | 27 +++++++++++++++++++++++----
kernel/trace/bpf_trace.c | 17 +++++++++++++++++
tools/include/uapi/linux/bpf.h | 7 +++++++
6 files changed, 65 insertions(+), 6 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 61b72d537f5b..8d834f44efea 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1746,13 +1746,20 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
struct bpf_tramp_link *l, int stack_size,
bool save_ret)
{
+ u64 cookie = 0;
u8 *prog = *pprog;
u8 *jmp_insn;
int ctx_cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
struct bpf_prog *p = l->link.prog;
- /* mov rdi, 0 */
- emit_mov_imm64(&prog, BPF_REG_1, 0, 0);
+ if (l->link.type == BPF_LINK_TYPE_TRACING) {
+ struct bpf_tracing_link *tr_link =
+ container_of(l, struct bpf_tracing_link, link);
+ cookie = tr_link->cookie;
+ }
+
+ /* mov rdi, cookie */
+ emit_mov_imm64(&prog, BPF_REG_1, (long) cookie >> 32, (u32) (long) cookie);
/* Prepare struct bpf_tramp_run_ctx.
*
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 7b4896c86dcc..65a9b9c12a6c 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1062,6 +1062,7 @@ struct bpf_tracing_link {
enum bpf_attach_type attach_type;
struct bpf_trampoline *trampoline;
struct bpf_prog *tgt_prog;
+ u64 cookie;
};
struct bpf_link_primer {
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 9e34da50440c..9ccc77d93e97 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1429,6 +1429,7 @@ union bpf_attr {
struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
__u64 name;
__u32 prog_fd;
+ __u64 bpf_cookie;
} raw_tracepoint;
struct { /* anonymous struct for BPF_BTF_LOAD */
@@ -1476,6 +1477,13 @@ union bpf_attr {
*/
__u64 bpf_cookie;
} perf_event;
+ struct {
+ /* black box user-provided value passed through
+ * to BPF program at the execution time and
+ * accessible through bpf_get_attach_cookie() BPF helper
+ */
+ __u64 bpf_cookie;
+ } tracing;
};
} link_create;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 12a1c0ff6646..84b3fe2d65d3 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2694,9 +2694,10 @@ static const struct bpf_link_ops bpf_tracing_link_lops = {
.fill_link_info = bpf_tracing_link_fill_link_info,
};
-static int bpf_tracing_prog_attach(struct bpf_prog *prog,
- int tgt_prog_fd,
- u32 btf_id)
+static int bpf_tracing_prog_attach_cookie(struct bpf_prog *prog,
+ int tgt_prog_fd,
+ u32 btf_id,
+ u64 bpf_cookie)
{
struct bpf_link_primer link_primer;
struct bpf_prog *tgt_prog = NULL;
@@ -2761,6 +2762,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
bpf_link_init(&link->link.link, BPF_LINK_TYPE_TRACING,
&bpf_tracing_link_lops, prog);
link->attach_type = prog->expected_attach_type;
+ link->cookie = bpf_cookie;
mutex_lock(&prog->aux->dst_mutex);
@@ -2870,6 +2872,13 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
return err;
}
+static int bpf_tracing_prog_attach(struct bpf_prog *prog,
+ int tgt_prog_fd,
+ u32 btf_id)
+{
+ return bpf_tracing_prog_attach_cookie(prog, tgt_prog_fd, btf_id, 0);
+}
+
struct bpf_raw_tp_link {
struct bpf_link link;
struct bpf_raw_event_map *btp;
@@ -3017,7 +3026,7 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro
}
#endif /* CONFIG_PERF_EVENTS */
-#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
+#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.bpf_cookie
static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
{
@@ -3181,6 +3190,10 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type)
return BPF_PROG_TYPE_SK_LOOKUP;
case BPF_XDP:
return BPF_PROG_TYPE_XDP;
+ case BPF_TRACE_FENTRY:
+ case BPF_TRACE_FEXIT:
+ case BPF_MODIFY_RETURN:
+ return BPF_PROG_TYPE_TRACING;
default:
return BPF_PROG_TYPE_UNSPEC;
}
@@ -4245,6 +4258,12 @@ static int tracing_bpf_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
return bpf_tracing_prog_attach(prog,
attr->link_create.target_fd,
attr->link_create.target_btf_id);
+ else if (prog->type == BPF_PROG_TYPE_TRACING)
+ return bpf_tracing_prog_attach_cookie(prog,
+ 0,
+ 0,
+ attr->link_create.tracing.bpf_cookie);
+
return -EINVAL;
}
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index a2024ba32a20..1558b0476b3a 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1063,6 +1063,21 @@ static const struct bpf_func_proto bpf_get_attach_cookie_proto_pe = {
.arg1_type = ARG_PTR_TO_CTX,
};
+BPF_CALL_1(bpf_get_attach_cookie_tracing, void *, ctx)
+{
+ struct bpf_trace_run_ctx *run_ctx;
+
+ run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
+ return run_ctx->bpf_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_attach_cookie_proto_tracing = {
+ .func = bpf_get_attach_cookie_tracing,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+};
+
BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags)
{
#ifndef CONFIG_X86
@@ -1687,6 +1702,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return bpf_prog_has_trampoline(prog) ? &bpf_get_func_ret_proto : NULL;
case BPF_FUNC_get_func_arg_cnt:
return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_cnt_proto : NULL;
+ case BPF_FUNC_get_attach_cookie:
+ return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto_tracing : NULL;
default:
fn = raw_tp_prog_func_proto(func_id, prog);
if (!fn && prog->expected_attach_type == BPF_TRACE_ITER)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 9e34da50440c..6c3e2f5a3474 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1476,6 +1476,13 @@ union bpf_attr {
*/
__u64 bpf_cookie;
} perf_event;
+ struct {
+ /* black box user-provided value passed through
+ * to BPF program at the execution time and
+ * accessible through bpf_get_attach_cookie() BPF helper
+ */
+ __u64 bpf_cookie;
+ } tracing;
};
} link_create;
--
2.30.2
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH bpf-next v3 4/5] lib/bpf: Assign cookies to links in libbpf.
2022-04-07 19:25 [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Kui-Feng Lee
` (2 preceding siblings ...)
2022-04-07 19:25 ` [PATCH bpf-next v3 3/5] bpf, x86: Attach a cookie to fentry/fexit/fmod_ret Kui-Feng Lee
@ 2022-04-07 19:25 ` Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 5/5] selftest/bpf: The test cses of BPF cookie for fentry/fexit/fmod_ret Kui-Feng Lee
2022-04-08 21:33 ` [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Daniel Borkmann
5 siblings, 0 replies; 9+ messages in thread
From: Kui-Feng Lee @ 2022-04-07 19:25 UTC (permalink / raw)
To: bpf, ast, daniel, andrii, kernel-team; +Cc: Kui-Feng Lee
Add a cookie field to the attributes of bpf_link_create().
Add bpf_program__attach_trace_opts() to attach a cookie to a link.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
tools/lib/bpf/bpf.c | 7 +++++++
tools/lib/bpf/bpf.h | 3 +++
tools/lib/bpf/libbpf.c | 33 +++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 12 ++++++++++++
tools/lib/bpf/libbpf.map | 1 +
5 files changed, 56 insertions(+)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index f69ce3a01385..1586f2e87964 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -854,6 +854,13 @@ int bpf_link_create(int prog_fd, int target_fd,
if (!OPTS_ZEROED(opts, perf_event))
return libbpf_err(-EINVAL);
break;
+ case BPF_TRACE_FENTRY:
+ case BPF_TRACE_FEXIT:
+ case BPF_MODIFY_RETURN:
+ attr.link_create.tracing.bpf_cookie = OPTS_GET(opts, tracing.bpf_cookie, 0);
+ if (!OPTS_ZEROED(opts, tracing))
+ return libbpf_err(-EINVAL);
+ break;
default:
if (!OPTS_ZEROED(opts, flags))
return libbpf_err(-EINVAL);
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 5253cb4a4c0a..e7df17277c8d 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -410,6 +410,9 @@ struct bpf_link_create_opts {
__u32 iter_info_len;
__u32 target_btf_id;
union {
+ struct {
+ __u64 bpf_cookie;
+ } tracing;
struct {
__u64 bpf_cookie;
} perf_event;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 43161fdd44bb..ab8cfb59073a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10611,6 +10611,39 @@ struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog)
return bpf_program__attach_btf_id(prog);
}
+struct bpf_link *bpf_program__attach_trace_opts(const struct bpf_program *prog,
+ const struct bpf_trace_opts *opts)
+{
+ char errmsg[STRERR_BUFSIZE];
+ struct bpf_link *link;
+ int prog_fd, pfd;
+
+ LIBBPF_OPTS(bpf_link_create_opts, link_opts);
+
+ prog_fd = bpf_program__fd(prog);
+ if (prog_fd < 0) {
+ pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+ return libbpf_err_ptr(-EINVAL);
+ }
+
+ link = calloc(1, sizeof(*link));
+ if (!link)
+ return libbpf_err_ptr(-ENOMEM);
+ link->detach = &bpf_link__detach_fd;
+
+ link_opts.tracing.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
+ pfd = bpf_link_create(prog_fd, 0, prog->expected_attach_type, &link_opts);
+ if (pfd < 0) {
+ pfd = -errno;
+ free(link);
+ pr_warn("prog '%s': failed to attach: %s\n",
+ prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
+ return libbpf_err_ptr(pfd);
+ }
+ link->fd = pfd;
+ return (struct bpf_link *)link;
+}
+
struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog)
{
return bpf_program__attach_btf_id(prog);
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index c1b0c2ef14d8..42aff476bcb0 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -501,8 +501,20 @@ bpf_program__attach_tracepoint_opts(const struct bpf_program *prog,
LIBBPF_API struct bpf_link *
bpf_program__attach_raw_tracepoint(const struct bpf_program *prog,
const char *tp_name);
+
+struct bpf_trace_opts {
+ /* size of this struct, for forward/backward compatibility */
+ size_t sz;
+ /* custom user-provided value fetchable through bpf_get_attach_cookie() */
+ __u64 bpf_cookie;
+};
+#define bpf_trace_opts__last_field bpf_cookie
+
LIBBPF_API struct bpf_link *
bpf_program__attach_trace(const struct bpf_program *prog);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_trace_opts(const struct bpf_program *prog, const struct bpf_trace_opts *opts);
+
LIBBPF_API struct bpf_link *
bpf_program__attach_lsm(const struct bpf_program *prog);
LIBBPF_API struct bpf_link *
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index df1b947792c8..e2f592b2f6a9 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -424,6 +424,7 @@ LIBBPF_0.6.0 {
LIBBPF_0.7.0 {
global:
bpf_btf_load;
+ bpf_program__attach_trace_opts;
bpf_program__expected_attach_type;
bpf_program__log_buf;
bpf_program__log_level;
--
2.30.2
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH bpf-next v3 5/5] selftest/bpf: The test cses of BPF cookie for fentry/fexit/fmod_ret.
2022-04-07 19:25 [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Kui-Feng Lee
` (3 preceding siblings ...)
2022-04-07 19:25 ` [PATCH bpf-next v3 4/5] lib/bpf: Assign cookies to links in libbpf Kui-Feng Lee
@ 2022-04-07 19:25 ` Kui-Feng Lee
2022-04-08 21:33 ` [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Daniel Borkmann
5 siblings, 0 replies; 9+ messages in thread
From: Kui-Feng Lee @ 2022-04-07 19:25 UTC (permalink / raw)
To: bpf, ast, daniel, andrii, kernel-team; +Cc: Kui-Feng Lee
Make sure BPF cookies are correct for fentry/fexit/fmod_ret.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
.../selftests/bpf/prog_tests/bpf_cookie.c | 52 +++++++++++++++++++
.../selftests/bpf/progs/test_bpf_cookie.c | 24 +++++++++
2 files changed, 76 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
index 0612e79a9281..16385f0c4031 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
@@ -237,6 +237,56 @@ static void pe_subtest(struct test_bpf_cookie *skel)
bpf_link__destroy(link);
}
+static void tracing_subtest(struct test_bpf_cookie *skel)
+{
+ __u64 cookie;
+ int prog_fd;
+ int fentry_fd = -1, fexit_fd = -1, fmod_ret_fd = -1;
+
+ LIBBPF_OPTS(bpf_test_run_opts, opts, .repeat = 1);
+ LIBBPF_OPTS(bpf_link_create_opts, link_opts);
+
+ skel->bss->fentry_res = 0;
+ skel->bss->fexit_res = 0;
+
+ cookie = 0x100000;
+ prog_fd = bpf_program__fd(skel->progs.fentry_test1);
+ link_opts.tracing.bpf_cookie = cookie;
+ fentry_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_FENTRY, &link_opts);
+
+ cookie = 0x200000;
+ prog_fd = bpf_program__fd(skel->progs.fexit_test1);
+ link_opts.tracing.bpf_cookie = cookie;
+ fexit_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_FEXIT, &link_opts);
+ if (!ASSERT_GE(fexit_fd, 0, "fexit.open"))
+ goto cleanup;
+
+ cookie = 0x300000;
+ prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
+ link_opts.tracing.bpf_cookie = cookie;
+ fmod_ret_fd = bpf_link_create(prog_fd, 0, BPF_MODIFY_RETURN, &link_opts);
+ if (!ASSERT_GE(fmod_ret_fd, 0, "fmod_ret.opoen"))
+ goto cleanup;
+
+ prog_fd = bpf_program__fd(skel->progs.fentry_test1);
+ bpf_prog_test_run_opts(prog_fd, &opts);
+
+ prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
+ bpf_prog_test_run_opts(prog_fd, &opts);
+
+ ASSERT_EQ(skel->bss->fentry_res, 0x100000, "fentry_res");
+ ASSERT_EQ(skel->bss->fexit_res, 0x200000, "fexit_res");
+ ASSERT_EQ(skel->bss->fmod_ret_res, 0x300000, "fmod_ret_res");
+
+cleanup:
+ if (fentry_fd >= 0)
+ close(fentry_fd);
+ if (fexit_fd >= 0)
+ close(fexit_fd);
+ if (fmod_ret_fd >= 0)
+ close(fmod_ret_fd);
+}
+
void test_bpf_cookie(void)
{
struct test_bpf_cookie *skel;
@@ -255,6 +305,8 @@ void test_bpf_cookie(void)
tp_subtest(skel);
if (test__start_subtest("perf_event"))
pe_subtest(skel);
+ if (test__start_subtest("trampoline"))
+ tracing_subtest(skel);
test_bpf_cookie__destroy(skel);
}
diff --git a/tools/testing/selftests/bpf/progs/test_bpf_cookie.c b/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
index 2d3a7710e2ce..a9f83f46e7b7 100644
--- a/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
+++ b/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
@@ -14,6 +14,9 @@ int uprobe_res;
int uretprobe_res;
int tp_res;
int pe_res;
+int fentry_res;
+int fexit_res;
+int fmod_ret_res;
static void update(void *ctx, int *res)
{
@@ -82,4 +85,25 @@ int handle_pe(struct pt_regs *ctx)
return 0;
}
+SEC("fentry/bpf_fentry_test1")
+int BPF_PROG(fentry_test1, int a)
+{
+ update(ctx, &fentry_res);
+ return 0;
+}
+
+SEC("fexit/bpf_fentry_test1")
+int BPF_PROG(fexit_test1, int a, int ret)
+{
+ update(ctx, &fexit_res);
+ return 0;
+}
+
+SEC("fmod_ret/bpf_modify_return_test")
+int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
+{
+ update(ctx, &fmod_ret_res);
+ return 1234;
+}
+
char _license[] SEC("license") = "GPL";
--
2.30.2
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program.
2022-04-07 19:25 [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Kui-Feng Lee
` (4 preceding siblings ...)
2022-04-07 19:25 ` [PATCH bpf-next v3 5/5] selftest/bpf: The test cses of BPF cookie for fentry/fexit/fmod_ret Kui-Feng Lee
@ 2022-04-08 21:33 ` Daniel Borkmann
2022-04-11 17:36 ` Kui-Feng Lee
5 siblings, 1 reply; 9+ messages in thread
From: Daniel Borkmann @ 2022-04-08 21:33 UTC (permalink / raw)
To: Kui-Feng Lee, bpf, ast, andrii, kernel-team
On 4/7/22 9:25 PM, Kui-Feng Lee wrote:
> Allow users to attach a 64-bits cookie to a bpf_link of fentry, fexit,
> or fmod_ret.
>
> This patchset includes several major changes.
>
> - Define struct bpf_tramp_links to replace bpf_tramp_prog.
> struct bpf_tramp_links collects bpf_links of a trampoline
>
> - Generate a trampoline to call bpf_progs of given bpf_links.
>
> - Trampolines always set/reset bpf_run_ctx before/after
> calling/leaving a tracing program.
>
> - Attach a cookie to a bpf_link of fentry/fexit/fmod_ret. The value
> will be available when running the associated bpf_prog.
>
> The major differences from v2:
>
> - Move the allocations of run_ctx (struct bpf_tramp_run_ctx) out of
> invoke_bpf_prog().
>
> - Move hlist_node out of bpf_link and introduce struct bpf_tramp_link
> to own hlist_node.
>
> - Store cookies at struct bpf_tracing_link.
>
> - Use SIB byte to reduce the number of instructions to set cookie
> values. (Use RSP directly)
>
> v1: https://lore.kernel.org/all/20220126214809.3868787-1-kuifeng@fb.com/
> v2: https://lore.kernel.org/bpf/20220316004231.1103318-1-kuifeng@fb.com/
Kui-Feng, would be great if you have a chance to rebase, so that the set can
also go through BPF CI.
Thanks a lot,
Daniel
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH bpf-next v3 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack
2022-04-07 19:25 ` [PATCH bpf-next v3 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack Kui-Feng Lee
@ 2022-04-09 0:01 ` Alexei Starovoitov
0 siblings, 0 replies; 9+ messages in thread
From: Alexei Starovoitov @ 2022-04-09 0:01 UTC (permalink / raw)
To: Kui-Feng Lee; +Cc: bpf, ast, daniel, andrii, kernel-team
On Thu, Apr 07, 2022 at 12:25:49PM -0700, Kui-Feng Lee wrote:
> - if (!__bpf_prog_enter_sleepable(prog)) {
> + if (!__bpf_prog_enter_sleepable(prog, NULL)) {
> /* recursion detected */
> bpf_prog_put(prog);
> return -EBUSY;
> }
> attr->test.retval = bpf_prog_run(prog, (void *) (long) attr->test.ctx_in);
> - __bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */);
> + __bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */, NULL);
Did you miss my comment from the previous review?
Please replace NULL with actual ctx and remove below checks:
> +
> + if (run_ctx)
> + run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
...
> -void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start)
> +void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start, struct bpf_tramp_run_ctx *run_ctx)
> __releases(RCU)
> {
> + if (run_ctx)
> + bpf_reset_run_ctx(run_ctx->saved_run_ctx);
> +
...
> -u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog)
> +u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
> {
> rcu_read_lock_trace();
> migrate_disable();
> might_fault();
> +
> + if (run_ctx)
> + run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
Such 'if' in critical path should be avoided.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program.
2022-04-08 21:33 ` [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Daniel Borkmann
@ 2022-04-11 17:36 ` Kui-Feng Lee
0 siblings, 0 replies; 9+ messages in thread
From: Kui-Feng Lee @ 2022-04-11 17:36 UTC (permalink / raw)
To: daniel, Kernel Team, ast, andrii, bpf
On Fri, 2022-04-08 at 23:33 +0200, Daniel Borkmann wrote:
> On 4/7/22 9:25 PM, Kui-Feng Lee wrote:
> > Allow users to attach a 64-bits cookie to a bpf_link of fentry,
> > fexit,
> > or fmod_ret.
> >
> > This patchset includes several major changes.
> >
> > - Define struct bpf_tramp_links to replace bpf_tramp_prog.
> > struct bpf_tramp_links collects bpf_links of a trampoline
> >
> > - Generate a trampoline to call bpf_progs of given bpf_links.
> >
> > - Trampolines always set/reset bpf_run_ctx before/after
> > calling/leaving a tracing program.
> >
> > - Attach a cookie to a bpf_link of fentry/fexit/fmod_ret. The
> > value
> > will be available when running the associated bpf_prog.
> >
> > The major differences from v2:
> >
> > - Move the allocations of run_ctx (struct bpf_tramp_run_ctx) out
> > of
> > invoke_bpf_prog().
> >
> > - Move hlist_node out of bpf_link and introduce struct
> > bpf_tramp_link
> > to own hlist_node.
> >
> > - Store cookies at struct bpf_tracing_link.
> >
> > - Use SIB byte to reduce the number of instructions to set cookie
> > values. (Use RSP directly)
> >
> > v1:
> > https://lore.kernel.org/all/20220126214809.3868787-1-kuifeng@fb.com/
> > v2:
> > https://lore.kernel.org/bpf/20220316004231.1103318-1-kuifeng@fb.com/
>
> Kui-Feng, would be great if you have a chance to rebase, so that the
> set can
> also go through BPF CI.
>
> Thanks a lot,
> Daniel
Yes, just sent new patches out.
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2022-04-11 17:36 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-04-07 19:25 [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 1/5] bpf, x86: Generate trampolines from bpf_tramp_links Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 2/5] bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack Kui-Feng Lee
2022-04-09 0:01 ` Alexei Starovoitov
2022-04-07 19:25 ` [PATCH bpf-next v3 3/5] bpf, x86: Attach a cookie to fentry/fexit/fmod_ret Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 4/5] lib/bpf: Assign cookies to links in libbpf Kui-Feng Lee
2022-04-07 19:25 ` [PATCH bpf-next v3 5/5] selftest/bpf: The test cses of BPF cookie for fentry/fexit/fmod_ret Kui-Feng Lee
2022-04-08 21:33 ` [PATCH bpf-next v3 0/5] Attach a cookie to a tracing program Daniel Borkmann
2022-04-11 17:36 ` Kui-Feng Lee
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