Commit c454a46b authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

bpf: Add bpf_line_info support 



This patch adds bpf_line_info support.

It accepts an array of bpf_line_info objects during BPF_PROG_LOAD.
The "line_info", "line_info_cnt" and "line_info_rec_size" are added
to the "union bpf_attr".  The "line_info_rec_size" makes
bpf_line_info extensible in the future.

The new "check_btf_line()" ensures the userspace line_info is valid
for the kernel to use.

When the verifier is translating/patching the bpf_prog (through
"bpf_patch_insn_single()"), the line_infos' insn_off is also
adjusted by the newly added "bpf_adj_linfo()".

If the bpf_prog is jited, this patch also provides the jited addrs (in
aux->jited_linfo) for the corresponding line_info.insn_off.
"bpf_prog_fill_jited_linfo()" is added to fill the aux->jited_linfo.
It is currently called by the x86 jit.  Other jits can also use
"bpf_prog_fill_jited_linfo()" and it will be done in the followup patches.
In the future, if it deemed necessary, a particular jit could also provide
its own "bpf_prog_fill_jited_linfo()" implementation.

A few "*line_info*" fields are added to the bpf_prog_info such
that the user can get the xlated line_info back (i.e. the line_info
with its insn_off reflecting the translated prog).  The jited_line_info
is available if the prog is jited.  It is an array of __u64.
If the prog is not jited, jited_line_info_cnt is 0.

The verifier's verbose log with line_info will be done in
a follow up patch.

Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 6baefa1a

arch/x86/net/bpf_jit_comp.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -1181,6 +1181,8 @@ out_image: 
	}

	}





	if (!image || !prog->is_func || extra_pass) {

	if (!image || !prog->is_func || extra_pass) {

		if (image)

			bpf_prog_fill_jited_linfo(prog, addrs);

out_addrs:

out_addrs:

		kfree(addrs);

		kfree(addrs);

		kfree(jit_data);

		kfree(jit_data);

include/linux/bpf.h

+21 −0
Original line number Original line Diff line number Diff line
@@ -319,7 +319,28 @@ struct bpf_prog_aux { 
	struct bpf_prog_offload *offload;

	struct bpf_prog_offload *offload;

	struct btf *btf;

	struct btf *btf;

	struct bpf_func_info *func_info;

	struct bpf_func_info *func_info;

	/* bpf_line_info loaded from userspace.  linfo->insn_off

	 * has the xlated insn offset.

	 * Both the main and sub prog share the same linfo.

	 * The subprog can access its first linfo by

	 * using the linfo_idx.

	 */

	struct bpf_line_info *linfo;

	/* jited_linfo is the jited addr of the linfo.  It has a

	 * one to one mapping to linfo:

	 * jited_linfo[i] is the jited addr for the linfo[i]->insn_off.

	 * Both the main and sub prog share the same jited_linfo.

	 * The subprog can access its first jited_linfo by

	 * using the linfo_idx.

	 */

	void **jited_linfo;

	u32 func_info_cnt;

	u32 func_info_cnt;

	u32 nr_linfo;

	/* subprog can use linfo_idx to access its first linfo and

	 * jited_linfo.

	 * main prog always has linfo_idx == 0

	 */

	u32 linfo_idx;

	union {

	union {

		struct work_struct work;

		struct work_struct work;

		struct rcu_head	rcu;

		struct rcu_head	rcu;

include/linux/bpf_verifier.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -203,6 +203,7 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log) 




struct bpf_subprog_info {

struct bpf_subprog_info {

	u32 start; /* insn idx of function entry point */

	u32 start; /* insn idx of function entry point */

	u32 linfo_idx; /* The idx to the main_prog->aux->linfo */

	u16 stack_depth; /* max. stack depth used by this function */

	u16 stack_depth; /* max. stack depth used by this function */

};

};

include/linux/btf.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -46,6 +46,7 @@ void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj, 
		       struct seq_file *m);

		       struct seq_file *m);

int btf_get_fd_by_id(u32 id);

int btf_get_fd_by_id(u32 id);

u32 btf_id(const struct btf *btf);

u32 btf_id(const struct btf *btf);

bool btf_name_offset_valid(const struct btf *btf, u32 offset);





#ifdef CONFIG_BPF_SYSCALL

#ifdef CONFIG_BPF_SYSCALL

const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);

const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);

include/linux/filter.h

+7 −0
Original line number Original line Diff line number Diff line
@@ -718,6 +718,13 @@ void bpf_prog_free(struct bpf_prog *fp); 




bool bpf_opcode_in_insntable(u8 code);

bool bpf_opcode_in_insntable(u8 code);





void bpf_prog_free_linfo(struct bpf_prog *prog);

void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,

			       const u32 *insn_to_jit_off);

int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog);

void bpf_prog_free_jited_linfo(struct bpf_prog *prog);

void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog);



struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);

struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);

struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,

struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,

				  gfp_t gfp_extra_flags);

				  gfp_t gfp_extra_flags);

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