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bpf: Refactor trampoline update code

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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
This commit is contained in:
KP Singh
2020-03-04 20:18:47 +01:00
committed by Alexei Starovoitov
parent cc6fa77102
commit 88fd9e5352
4 changed files with 71 additions and 45 deletions
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31
arch/x86/net/bpf_jit_comp.c
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@@ -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)