bpf: Refactor trampoline update code

As we need to introduce a third type of attachment for trampolines, the
flattened signature of arch_prepare_bpf_trampoline gets even more
complicated.

Refactor the prog and count argument to arch_prepare_bpf_trampoline to
use bpf_tramp_progs to simplify the addition and accounting for new
attachment types.

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200304191853.1529-2-kpsingh@chromium.org

1 files changed, 16 insertions, 15 deletions

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 9ba08e9abc09..15c7d28bc05c 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1362,12 +1362,12 @@ static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_args,
 }
 
 static int invoke_bpf(const struct btf_func_model *m, u8 **pprog,
-		      struct bpf_prog **progs, int prog_cnt, int stack_size)
+		      struct bpf_tramp_progs *tp, int stack_size)
 {
 	u8 *prog = *pprog;
 	int cnt = 0, i;
 
-	for (i = 0; i < prog_cnt; i++) {
+	for (i = 0; i < tp->nr_progs; i++) {
 		if (emit_call(&prog, __bpf_prog_enter, prog))
 			return -EINVAL;
 		/* remember prog start time returned by __bpf_prog_enter */
@@ -1376,17 +1376,17 @@ static int invoke_bpf(const struct btf_func_model *m, u8 **pprog,
 		/* arg1: lea rdi, [rbp - stack_size] */
 		EMIT4(0x48, 0x8D, 0x7D, -stack_size);
 		/* arg2: progs[i]->insnsi for interpreter */
-		if (!progs[i]->jited)
+		if (!tp->progs[i]->jited)
 			emit_mov_imm64(&prog, BPF_REG_2,
-				       (long) progs[i]->insnsi >> 32,
-				       (u32) (long) progs[i]->insnsi);
+				       (long) tp->progs[i]->insnsi >> 32,
+				       (u32) (long) tp->progs[i]->insnsi);
 		/* call JITed bpf program or interpreter */
-		if (emit_call(&prog, progs[i]->bpf_func, prog))
+		if (emit_call(&prog, tp->progs[i]->bpf_func, prog))
 			return -EINVAL;
 
 		/* arg1: mov rdi, progs[i] */
-		emit_mov_imm64(&prog, BPF_REG_1, (long) progs[i] >> 32,
-			       (u32) (long) progs[i]);
+		emit_mov_imm64(&prog, BPF_REG_1, (long) tp->progs[i] >> 32,
+			       (u32) (long) tp->progs[i]);
 		/* arg2: mov rsi, rbx <- start time in nsec */
 		emit_mov_reg(&prog, true, BPF_REG_2, BPF_REG_6);
 		if (emit_call(&prog, __bpf_prog_exit, prog))
@@ -1458,12 +1458,13 @@ static int invoke_bpf(const struct btf_func_model *m, u8 **pprog,
  */
 int arch_prepare_bpf_trampoline(void *image, void *image_end,
 				const struct btf_func_model *m, u32 flags,
-				struct bpf_prog **fentry_progs, int fentry_cnt,
-				struct bpf_prog **fexit_progs, int fexit_cnt,
+				struct bpf_tramp_progs *tprogs,
 				void *orig_call)
 {
 	int cnt = 0, nr_args = m->nr_args;
 	int stack_size = nr_args * 8;
+	struct bpf_tramp_progs *fentry = &tprogs[BPF_TRAMP_FENTRY];
+	struct bpf_tramp_progs *fexit = &tprogs[BPF_TRAMP_FEXIT];
 	u8 *prog;
 
 	/* x86-64 supports up to 6 arguments. 7+ can be added in the future */
@@ -1492,12 +1493,12 @@ int arch_prepare_bpf_trampoline(void *image, void *image_end,
 
 	save_regs(m, &prog, nr_args, stack_size);
 
-	if (fentry_cnt)
-		if (invoke_bpf(m, &prog, fentry_progs, fentry_cnt, stack_size))
+	if (fentry->nr_progs)
+		if (invoke_bpf(m, &prog, fentry, stack_size))
 			return -EINVAL;
 
 	if (flags & BPF_TRAMP_F_CALL_ORIG) {
-		if (fentry_cnt)
+		if (fentry->nr_progs)
 			restore_regs(m, &prog, nr_args, stack_size);
 
 		/* call original function */
@@ -1507,8 +1508,8 @@ int arch_prepare_bpf_trampoline(void *image, void *image_end,
 		emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
 	}
 
-	if (fexit_cnt)
-		if (invoke_bpf(m, &prog, fexit_progs, fexit_cnt, stack_size))
+	if (fexit->nr_progs)
+		if (invoke_bpf(m, &prog, fexit, stack_size))
 			return -EINVAL;
 
 	if (flags & BPF_TRAMP_F_RESTORE_REGS)