Commit 148709bc authored by David S. Miller's avatar David S. Miller
Browse files

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 



Alexei Starovoitov says:

====================
pull-request: bpf 2019-12-11

The following pull-request contains BPF updates for your *net* tree.

We've added 8 non-merge commits during the last 1 day(s) which contain
a total of 10 files changed, 126 insertions(+), 18 deletions(-).

The main changes are:

1) Make BPF trampoline co-exist with ftrace-based tracers, from Alexei.

2) Fix build in minimal configurations, from Arnd.

3) Fix mips, riscv bpf_tail_call limit, from Paul.

4) Fix bpftool segfault, from Toke.

5) Fix samples/bpf, from Daniel.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 24dee0c7 fe330089

arch/mips/net/ebpf_jit.c

+5 −4
Original line number Diff line number Diff line
@@ -604,6 +604,7 @@ static void emit_const_to_reg(struct jit_ctx *ctx, int dst, u64 value) 
static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx)

{

	int off, b_off;

	int tcc_reg;



	ctx->flags |= EBPF_SEEN_TC;

	/*
@@ -616,14 +617,14 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx) 
	b_off = b_imm(this_idx + 1, ctx);

	emit_instr(ctx, bne, MIPS_R_AT, MIPS_R_ZERO, b_off);

	/*

	 * if (--TCC < 0)

	 * if (TCC-- < 0)

	 *     goto out;

	 */

	/* Delay slot */

	emit_instr(ctx, daddiu, MIPS_R_T5,

		   (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4, -1);

	tcc_reg = (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4;

	emit_instr(ctx, daddiu, MIPS_R_T5, tcc_reg, -1);

	b_off = b_imm(this_idx + 1, ctx);

	emit_instr(ctx, bltz, MIPS_R_T5, b_off);

	emit_instr(ctx, bltz, tcc_reg, b_off);

	/*

	 * prog = array->ptrs[index];

	 * if (prog == NULL)

arch/riscv/net/bpf_jit_comp.c

+2 −2
Original line number Diff line number Diff line
@@ -631,14 +631,14 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx) 
		return -1;

	emit(rv_bgeu(RV_REG_A2, RV_REG_T1, off >> 1), ctx);



	/* if (--TCC < 0)

	/* if (TCC-- < 0)

	 *     goto out;

	 */

	emit(rv_addi(RV_REG_T1, tcc, -1), ctx);

	off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2;

	if (is_13b_check(off, insn))

		return -1;

	emit(rv_blt(RV_REG_T1, RV_REG_ZERO, off >> 1), ctx);

	emit(rv_blt(tcc, RV_REG_ZERO, off >> 1), ctx);



	/* prog = array->ptrs[index];

	 * if (!prog)

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -461,6 +461,7 @@ struct bpf_trampoline { 
	struct {

		struct btf_func_model model;

		void *addr;

		bool ftrace_managed;

	} func;

	/* list of BPF programs using this trampoline */

	struct hlist_head progs_hlist[BPF_TRAMP_MAX];

kernel/bpf/btf.c

+1 −0
Original line number Diff line number Diff line
@@ -3470,6 +3470,7 @@ static u8 bpf_ctx_convert_map[] = { 
	[_id] = __ctx_convert##_id,

#include <linux/bpf_types.h>

#undef BPF_PROG_TYPE

	0, /* avoid empty array */

};

#undef BPF_MAP_TYPE

kernel/bpf/trampoline.c

+58 −6
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#include <linux/hash.h>

#include <linux/bpf.h>

#include <linux/filter.h>

#include <linux/ftrace.h>



/* btf_vmlinux has ~22k attachable functions. 1k htab is enough. */

#define TRAMPOLINE_HASH_BITS 10
@@ -59,6 +60,60 @@ out: 
	return tr;

}



static int is_ftrace_location(void *ip)

{

	long addr;



	addr = ftrace_location((long)ip);

	if (!addr)

		return 0;

	if (WARN_ON_ONCE(addr != (long)ip))

		return -EFAULT;

	return 1;

}



static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr)

{

	void *ip = tr->func.addr;

	int ret;



	if (tr->func.ftrace_managed)

		ret = unregister_ftrace_direct((long)ip, (long)old_addr);

	else

		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, NULL);

	return ret;

}



static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_addr)

{

	void *ip = tr->func.addr;

	int ret;



	if (tr->func.ftrace_managed)

		ret = modify_ftrace_direct((long)ip, (long)old_addr, (long)new_addr);

	else

		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, new_addr);

	return ret;

}



/* first time registering */

static int register_fentry(struct bpf_trampoline *tr, void *new_addr)

{

	void *ip = tr->func.addr;

	int ret;



	ret = is_ftrace_location(ip);

	if (ret < 0)

		return ret;

	tr->func.ftrace_managed = ret;



	if (tr->func.ftrace_managed)

		ret = register_ftrace_direct((long)ip, (long)new_addr);

	else

		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, NULL, new_addr);

	return ret;

}



/* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50

 * bytes on x86.  Pick a number to fit into PAGE_SIZE / 2

 */
@@ -77,8 +132,7 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr) 
	int err;



	if (fentry_cnt + fexit_cnt == 0) {

		err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_CALL,

					 old_image, NULL);

		err = unregister_fentry(tr, old_image);

		tr->selector = 0;

		goto out;

	}
@@ -105,12 +159,10 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr) 


	if (tr->selector)

		/* progs already running at this address */

		err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_CALL,

					 old_image, new_image);

		err = modify_fentry(tr, old_image, new_image);

	else

		/* first time registering */

		err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_CALL, NULL,

					 new_image);

		err = register_fentry(tr, new_image);

	if (err)

		goto out;

	tr->selector++;

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