From: Leon Hwang <hffilwlqm@gmail.com>
To: bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
maciej.fijalkowski@intel.com, jakub@cloudflare.com,
iii@linux.ibm.com, hengqi.chen@gmail.com, hffilwlqm@gmail.com
Subject: [RFC PATCH bpf-next 2/3] bpf, x64: Load tail_call_cnt pointer
Date: Thu, 5 Oct 2023 22:58:13 +0800 [thread overview]
Message-ID: <20231005145814.83122-3-hffilwlqm@gmail.com> (raw)
In-Reply-To: <20231005145814.83122-1-hffilwlqm@gmail.com>
Rename RESTORE_TAIL_CALL_CNT() to LOAD_TAIL_CALL_CNT_PTR().
With previous commit, rax is used to propagate tail_call_cnt pointer
instead of tail_call_cnt. So, RESTORE_TAIL_CALL_CNT() is misleading.
Signed-off-by: Leon Hwang <hffilwlqm@gmail.com>
---
arch/x86/net/bpf_jit_comp.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 8ad6368353c2b..7a8397a60ea1e 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1102,7 +1102,7 @@ static void emit_shiftx(u8 **pprog, u32 dst_reg, u8 src_reg, bool is64, u8 op)
#define INSN_SZ_DIFF (((addrs[i] - addrs[i - 1]) - (prog - temp)))
/* mov rax, qword ptr [rbp - rounded_stack_depth - 8] */
-#define RESTORE_TAIL_CALL_CNT(stack) \
+#define LOAD_TAIL_CALL_CNT_PTR(stack) \
EMIT3_off32(0x48, 0x8B, 0x85, -round_up(stack, 8) - 8)
static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image,
@@ -1722,7 +1722,7 @@ st: if (is_imm8(insn->off))
func = (u8 *) __bpf_call_base + imm32;
if (tail_call_reachable) {
- RESTORE_TAIL_CALL_CNT(bpf_prog->aux->stack_depth);
+ LOAD_TAIL_CALL_CNT_PTR(bpf_prog->aux->stack_depth);
if (!imm32)
return -EINVAL;
offs = 7 + x86_call_depth_emit_accounting(&prog, func);
@@ -2624,10 +2624,10 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
save_args(m, &prog, arg_stack_off, true);
if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
- /* Before calling the original function, restore the
- * tail_call_cnt from stack to rax.
+ /* Before calling the original function, load the
+ * tail_call_cnt_ptr to rax.
*/
- RESTORE_TAIL_CALL_CNT(stack_size);
+ LOAD_TAIL_CALL_CNT_PTR(stack_size);
if (flags & BPF_TRAMP_F_ORIG_STACK) {
emit_ldx(&prog, BPF_DW, BPF_REG_6, BPF_REG_FP, 8);
@@ -2683,10 +2683,10 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
goto cleanup;
}
} else if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
- /* Before running the original function, restore the
- * tail_call_cnt from stack to rax.
+ /* Before running the original function, load the
+ * tail_call_cnt_ptr to rax.
*/
- RESTORE_TAIL_CALL_CNT(stack_size);
+ LOAD_TAIL_CALL_CNT_PTR(stack_size);
/* restore return value of orig_call or fentry prog back into RAX */
if (save_ret)
--
2.41.0
next prev parent reply other threads:[~2023-10-05 14:58 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-05 14:58 [RFC PATCH bpf-next 0/3] bpf, x64: Fix tailcall hierarchy Leon Hwang
2023-10-05 14:58 ` [RFC PATCH bpf-next 1/3] " Leon Hwang
2023-10-05 18:05 ` Stanislav Fomichev
2023-10-06 1:43 ` Leon Hwang
2023-10-06 16:44 ` Stanislav Fomichev
2023-10-07 5:50 ` Leon Hwang
2023-10-05 14:58 ` Leon Hwang [this message]
2023-10-05 14:58 ` [RFC PATCH bpf-next 3/3] selftests/bpf: Add testcases for tailcall hierarchy fixing Leon Hwang
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