Commit 30cfe3b4 authored by Daniel Borkmann's avatar Daniel Borkmann
Browse files

Merge branch 'bpf-multi-prog-improvements' 



Sandipan Das says:

====================
[1] Support for bpf-to-bpf function calls in the powerpc64 JIT compiler.

[2] Provide a way for resolving function calls because of the way JITed
    images are allocated in powerpc64.

[3] Fix to get JITed instruction dumps for multi-function programs from
    the bpf system call.

[4] Fix for bpftool to show delimited multi-function JITed image dumps.

v4:
 - Incorporate review comments from Jakub.
 - Fix JSON output for bpftool.

v3:
 - Change base tree tag to bpf-next.
 - Incorporate review comments from Alexei, Daniel and Jakub.
 - Make sure that the JITed image does not grow or shrink after
   the last pass due to the way the instruction sequence used
   to load a callee's address maybe optimized.
 - Make additional changes to the bpf system call and bpftool to
   make multi-function JITed dumps easier to correlate.

v2:
 - Incorporate review comments from Jakub.
====================

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parents a2889a4c f7f62c71

arch/powerpc/net/bpf_jit_comp64.c

+89 −21
Original line number Diff line number Diff line
@@ -167,25 +167,37 @@ static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) 


static void bpf_jit_emit_func_call(u32 *image, struct codegen_context *ctx, u64 func)

{

	unsigned int i, ctx_idx = ctx->idx;



	/* Load function address into r12 */

	PPC_LI64(12, func);



	/* For bpf-to-bpf function calls, the callee's address is unknown

	 * until the last extra pass. As seen above, we use PPC_LI64() to

	 * load the callee's address, but this may optimize the number of

	 * instructions required based on the nature of the address.

	 *

	 * Since we don't want the number of instructions emitted to change,

	 * we pad the optimized PPC_LI64() call with NOPs to guarantee that

	 * we always have a five-instruction sequence, which is the maximum

	 * that PPC_LI64() can emit.

	 */

	for (i = ctx->idx - ctx_idx; i < 5; i++)

		PPC_NOP();



#ifdef PPC64_ELF_ABI_v1

	/* func points to the function descriptor */

	PPC_LI64(b2p[TMP_REG_2], func);

	/* Load actual entry point from function descriptor */

	PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);

	/* ... and move it to LR */

	PPC_MTLR(b2p[TMP_REG_1]);

	/*

	 * Load TOC from function descriptor at offset 8.

	 * We can clobber r2 since we get called through a

	 * function pointer (so caller will save/restore r2)

	 * and since we don't use a TOC ourself.

	 */

	PPC_BPF_LL(2, b2p[TMP_REG_2], 8);

#else

	/* We can clobber r12 */

	PPC_FUNC_ADDR(12, func);

	PPC_MTLR(12);

	PPC_BPF_LL(2, 12, 8);

	/* Load actual entry point from function descriptor */

	PPC_BPF_LL(12, 12, 0);

#endif



	PPC_MTLR(12);

	PPC_BLRL();

}
@@ -256,7 +268,7 @@ static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 
/* Assemble the body code between the prologue & epilogue */

static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,

			      struct codegen_context *ctx,

			      u32 *addrs)

			      u32 *addrs, bool extra_pass)

{

	const struct bpf_insn *insn = fp->insnsi;

	int flen = fp->len;
@@ -712,10 +724,24 @@ emit_clear: 
			break;



		/*

		 * Call kernel helper

		 * Call kernel helper or bpf function

		 */

		case BPF_JMP | BPF_CALL:

			ctx->seen |= SEEN_FUNC;



			/* bpf function call */

			if (insn[i].src_reg == BPF_PSEUDO_CALL)

				if (!extra_pass)

					func = NULL;

				else if (fp->aux->func && off < fp->aux->func_cnt)

					/* use the subprog id from the off

					 * field to lookup the callee address

					 */

					func = (u8 *) fp->aux->func[off]->bpf_func;

				else

					return -EINVAL;

			/* kernel helper call */

			else

				func = (u8 *) __bpf_call_base + imm;



			bpf_jit_emit_func_call(image, ctx, (u64)func);
@@ -864,6 +890,14 @@ cond_branch: 
	return 0;

}



struct powerpc64_jit_data {

	struct bpf_binary_header *header;

	u32 *addrs;

	u8 *image;

	u32 proglen;

	struct codegen_context ctx;

};



struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)

{

	u32 proglen;
@@ -871,6 +905,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 
	u8 *image = NULL;

	u32 *code_base;

	u32 *addrs;

	struct powerpc64_jit_data *jit_data;

	struct codegen_context cgctx;

	int pass;

	int flen;
@@ -878,6 +913,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 
	struct bpf_prog *org_fp = fp;

	struct bpf_prog *tmp_fp;

	bool bpf_blinded = false;

	bool extra_pass = false;



	if (!fp->jit_requested)

		return org_fp;
@@ -891,11 +927,32 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 
		fp = tmp_fp;

	}



	jit_data = fp->aux->jit_data;

	if (!jit_data) {

		jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);

		if (!jit_data) {

			fp = org_fp;

			goto out;

		}

		fp->aux->jit_data = jit_data;

	}



	flen = fp->len;

	addrs = jit_data->addrs;

	if (addrs) {

		cgctx = jit_data->ctx;

		image = jit_data->image;

		bpf_hdr = jit_data->header;

		proglen = jit_data->proglen;

		alloclen = proglen + FUNCTION_DESCR_SIZE;

		extra_pass = true;

		goto skip_init_ctx;

	}



	addrs = kzalloc((flen+1) * sizeof(*addrs), GFP_KERNEL);

	if (addrs == NULL) {

		fp = org_fp;

		goto out;

		goto out_addrs;

	}



	memset(&cgctx, 0, sizeof(struct codegen_context));
@@ -904,10 +961,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 
	cgctx.stack_size = round_up(fp->aux->stack_depth, 16);



	/* Scouting faux-generate pass 0 */

	if (bpf_jit_build_body(fp, 0, &cgctx, addrs)) {

	if (bpf_jit_build_body(fp, 0, &cgctx, addrs, false)) {

		/* We hit something illegal or unsupported. */

		fp = org_fp;

		goto out;

		goto out_addrs;

	}



	/*
@@ -925,9 +982,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 
			bpf_jit_fill_ill_insns);

	if (!bpf_hdr) {

		fp = org_fp;

		goto out;

		goto out_addrs;

	}



skip_init_ctx:

	code_base = (u32 *)(image + FUNCTION_DESCR_SIZE);



	/* Code generation passes 1-2 */
@@ -935,7 +993,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 
		/* Now build the prologue, body code & epilogue for real. */

		cgctx.idx = 0;

		bpf_jit_build_prologue(code_base, &cgctx);

		bpf_jit_build_body(fp, code_base, &cgctx, addrs);

		bpf_jit_build_body(fp, code_base, &cgctx, addrs, extra_pass);

		bpf_jit_build_epilogue(code_base, &cgctx);



		if (bpf_jit_enable > 1)
@@ -961,10 +1019,20 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 
	fp->jited_len = alloclen;



	bpf_flush_icache(bpf_hdr, (u8 *)bpf_hdr + (bpf_hdr->pages * PAGE_SIZE));



out:

	if (!fp->is_func || extra_pass) {

out_addrs:

		kfree(addrs);

		kfree(jit_data);

		fp->aux->jit_data = NULL;

	} else {

		jit_data->addrs = addrs;

		jit_data->ctx = cgctx;

		jit_data->proglen = proglen;

		jit_data->image = image;

		jit_data->header = bpf_hdr;

	}



out:

	if (bpf_blinded)

		bpf_jit_prog_release_other(fp, fp == org_fp ? tmp_fp : org_fp);

include/uapi/linux/bpf.h

+4 −0
Original line number Diff line number Diff line
@@ -2205,6 +2205,10 @@ struct bpf_prog_info { 
	__u32 gpl_compatible:1;

	__u64 netns_dev;

	__u64 netns_ino;

	__u32 nr_jited_ksyms;

	__u32 nr_jited_func_lens;

	__aligned_u64 jited_ksyms;

	__aligned_u64 jited_func_lens;

} __attribute__((aligned(8)));



struct bpf_map_info {

kernel/bpf/syscall.c

+79 −3
Original line number Diff line number Diff line
@@ -1933,6 +1933,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, 
	if (!capable(CAP_SYS_ADMIN)) {

		info.jited_prog_len = 0;

		info.xlated_prog_len = 0;

		info.nr_jited_ksyms = 0;

		goto done;

	}
@@ -1969,18 +1970,93 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, 
	 * for offload.

	 */

	ulen = info.jited_prog_len;

	if (prog->aux->func_cnt) {

		u32 i;



		info.jited_prog_len = 0;

		for (i = 0; i < prog->aux->func_cnt; i++)

			info.jited_prog_len += prog->aux->func[i]->jited_len;

	} else {

		info.jited_prog_len = prog->jited_len;

	}



	if (info.jited_prog_len && ulen) {

		if (bpf_dump_raw_ok()) {

			uinsns = u64_to_user_ptr(info.jited_prog_insns);

			ulen = min_t(u32, info.jited_prog_len, ulen);



			/* for multi-function programs, copy the JITed

			 * instructions for all the functions

			 */

			if (prog->aux->func_cnt) {

				u32 len, free, i;

				u8 *img;



				free = ulen;

				for (i = 0; i < prog->aux->func_cnt; i++) {

					len = prog->aux->func[i]->jited_len;

					len = min_t(u32, len, free);

					img = (u8 *) prog->aux->func[i]->bpf_func;

					if (copy_to_user(uinsns, img, len))

						return -EFAULT;

					uinsns += len;

					free -= len;

					if (!free)

						break;

				}

			} else {

				if (copy_to_user(uinsns, prog->bpf_func, ulen))

					return -EFAULT;

			}

		} else {

			info.jited_prog_insns = 0;

		}

	}



	ulen = info.nr_jited_ksyms;

	info.nr_jited_ksyms = prog->aux->func_cnt;

	if (info.nr_jited_ksyms && ulen) {

		if (bpf_dump_raw_ok()) {

			u64 __user *user_ksyms;

			ulong ksym_addr;

			u32 i;



			/* copy the address of the kernel symbol

			 * corresponding to each function

			 */

			ulen = min_t(u32, info.nr_jited_ksyms, ulen);

			user_ksyms = u64_to_user_ptr(info.jited_ksyms);

			for (i = 0; i < ulen; i++) {

				ksym_addr = (ulong) prog->aux->func[i]->bpf_func;

				ksym_addr &= PAGE_MASK;

				if (put_user((u64) ksym_addr, &user_ksyms[i]))

					return -EFAULT;

			}

		} else {

			info.jited_ksyms = 0;

		}

	}



	ulen = info.nr_jited_func_lens;

	info.nr_jited_func_lens = prog->aux->func_cnt;

	if (info.nr_jited_func_lens && ulen) {

		if (bpf_dump_raw_ok()) {

			u32 __user *user_lens;

			u32 func_len, i;



			/* copy the JITed image lengths for each function */

			ulen = min_t(u32, info.nr_jited_func_lens, ulen);

			user_lens = u64_to_user_ptr(info.jited_func_lens);

			for (i = 0; i < ulen; i++) {

				func_len = prog->aux->func[i]->jited_len;

				if (put_user(func_len, &user_lens[i]))

					return -EFAULT;

			}

		} else {

			info.jited_func_lens = 0;

		}

	}



done:

	if (copy_to_user(uinfo, &info, info_len) ||

	    put_user(info_len, &uattr->info.info_len))

kernel/bpf/verifier.c

+15 −7
Original line number Diff line number Diff line
@@ -5383,11 +5383,24 @@ static int jit_subprogs(struct bpf_verifier_env *env) 
			    insn->src_reg != BPF_PSEUDO_CALL)

				continue;

			subprog = insn->off;

			insn->off = 0;

			insn->imm = (u64 (*)(u64, u64, u64, u64, u64))

				func[subprog]->bpf_func -

				__bpf_call_base;

		}



		/* we use the aux data to keep a list of the start addresses

		 * of the JITed images for each function in the program

		 *

		 * for some architectures, such as powerpc64, the imm field

		 * might not be large enough to hold the offset of the start

		 * address of the callee's JITed image from __bpf_call_base

		 *

		 * in such cases, we can lookup the start address of a callee

		 * by using its subprog id, available from the off field of

		 * the call instruction, as an index for this list

		 */

		func[i]->aux->func = func;

		func[i]->aux->func_cnt = env->subprog_cnt;

	}

	for (i = 0; i < env->subprog_cnt; i++) {

		old_bpf_func = func[i]->bpf_func;
@@ -5413,17 +5426,12 @@ static int jit_subprogs(struct bpf_verifier_env *env) 
	 * later look the same as if they were interpreted only.

	 */

	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {

		unsigned long addr;



		if (insn->code != (BPF_JMP | BPF_CALL) ||

		    insn->src_reg != BPF_PSEUDO_CALL)

			continue;

		insn->off = env->insn_aux_data[i].call_imm;

		subprog = find_subprog(env, i + insn->off + 1);

		addr  = (unsigned long)func[subprog]->bpf_func;

		addr &= PAGE_MASK;

		insn->imm = (u64 (*)(u64, u64, u64, u64, u64))

			    addr - __bpf_call_base;

		insn->imm = subprog;

	}



	prog->jited = 1;

tools/bpf/bpftool/prog.c

+96 −1
Original line number Diff line number Diff line
@@ -420,7 +420,11 @@ static int do_show(int argc, char **argv) 


static int do_dump(int argc, char **argv)

{

	unsigned long *func_ksyms = NULL;

	struct bpf_prog_info info = {};

	unsigned int *func_lens = NULL;

	unsigned int nr_func_ksyms;

	unsigned int nr_func_lens;

	struct dump_data dd = {};

	__u32 len = sizeof(info);

	unsigned int buf_size;
@@ -496,10 +500,34 @@ static int do_dump(int argc, char **argv) 
		return -1;

	}



	nr_func_ksyms = info.nr_jited_ksyms;

	if (nr_func_ksyms) {

		func_ksyms = malloc(nr_func_ksyms * sizeof(__u64));

		if (!func_ksyms) {

			p_err("mem alloc failed");

			close(fd);

			goto err_free;

		}

	}



	nr_func_lens = info.nr_jited_func_lens;

	if (nr_func_lens) {

		func_lens = malloc(nr_func_lens * sizeof(__u32));

		if (!func_lens) {

			p_err("mem alloc failed");

			close(fd);

			goto err_free;

		}

	}



	memset(&info, 0, sizeof(info));



	*member_ptr = ptr_to_u64(buf);

	*member_len = buf_size;

	info.jited_ksyms = ptr_to_u64(func_ksyms);

	info.nr_jited_ksyms = nr_func_ksyms;

	info.jited_func_lens = ptr_to_u64(func_lens);

	info.nr_jited_func_lens = nr_func_lens;



	err = bpf_obj_get_info_by_fd(fd, &info, &len);

	close(fd);
@@ -513,6 +541,16 @@ static int do_dump(int argc, char **argv) 
		goto err_free;

	}



	if (info.nr_jited_ksyms > nr_func_ksyms) {

		p_err("too many addresses returned");

		goto err_free;

	}



	if (info.nr_jited_func_lens > nr_func_lens) {

		p_err("too many values returned");

		goto err_free;

	}



	if ((member_len == &info.jited_prog_len &&

	     info.jited_prog_insns == 0) ||

	    (member_len == &info.xlated_prog_len &&
@@ -550,7 +588,57 @@ static int do_dump(int argc, char **argv) 
				goto err_free;

		}



		if (info.nr_jited_func_lens && info.jited_func_lens) {

			struct kernel_sym *sym = NULL;

			char sym_name[SYM_MAX_NAME];

			unsigned char *img = buf;

			__u64 *ksyms = NULL;

			__u32 *lens;

			__u32 i;



			if (info.nr_jited_ksyms) {

				kernel_syms_load(&dd);

				ksyms = (__u64 *) info.jited_ksyms;

			}



			if (json_output)

				jsonw_start_array(json_wtr);



			lens = (__u32 *) info.jited_func_lens;

			for (i = 0; i < info.nr_jited_func_lens; i++) {

				if (ksyms) {

					sym = kernel_syms_search(&dd, ksyms[i]);

					if (sym)

						sprintf(sym_name, "%s", sym->name);

					else

						sprintf(sym_name, "0x%016llx", ksyms[i]);

				} else {

					strcpy(sym_name, "unknown");

				}



				if (json_output) {

					jsonw_start_object(json_wtr);

					jsonw_name(json_wtr, "name");

					jsonw_string(json_wtr, sym_name);

					jsonw_name(json_wtr, "insns");

				} else {

					printf("%s:\n", sym_name);

				}



				disasm_print_insn(img, lens[i], opcodes, name);

				img += lens[i];



				if (json_output)

					jsonw_end_object(json_wtr);

				else

					printf("\n");

			}



			if (json_output)

				jsonw_end_array(json_wtr);

		} else {

			disasm_print_insn(buf, *member_len, opcodes, name);

		}

	} else if (visual) {

		if (json_output)

			jsonw_null(json_wtr);
@@ -558,6 +646,9 @@ static int do_dump(int argc, char **argv) 
			dump_xlated_cfg(buf, *member_len);

	} else {

		kernel_syms_load(&dd);

		dd.nr_jited_ksyms = info.nr_jited_ksyms;

		dd.jited_ksyms = (__u64 *) info.jited_ksyms;



		if (json_output)

			dump_xlated_json(&dd, buf, *member_len, opcodes);

		else
@@ -566,10 +657,14 @@ static int do_dump(int argc, char **argv) 
	}



	free(buf);

	free(func_ksyms);

	free(func_lens);

	return 0;



err_free:

	free(buf);

	free(func_ksyms);

	free(func_lens);

	return -1;

}

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