From: Menglong Dong <imagedong@xxxxxxxxxxx>
There are garbage values in upper bytes when we store the arguments
into stack in save_regs() if the size of the argument less then 8.
As we already reserve 8 byte for the arguments in regs and stack,
it is ok to store/restore the regs in BPF_DW size. Then, the garbage
values in upper bytes will be cleaned.
Reviewed-by: Jiang Biao <benbjiang@xxxxxxxxxxx>
Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
---
arch/x86/net/bpf_jit_comp.c | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 413b986b5afd..e9bc0b50656b 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1878,20 +1878,16 @@ static void save_regs(const struct btf_func_model *m, u8 **prog, int nr_regs,
if (i <= 5) {
/* copy function arguments from regs into stack */
- emit_stx(prog, bytes_to_bpf_size(arg_size),
- BPF_REG_FP,
+ emit_stx(prog, BPF_DW, BPF_REG_FP,
i == 5 ? X86_REG_R9 : BPF_REG_1 + i,
-(stack_size - i * 8));
} else {
/* copy function arguments from origin stack frame
* into current stack frame.
*/
- emit_ldx(prog, bytes_to_bpf_size(arg_size),
- BPF_REG_0, BPF_REG_FP,
+ emit_ldx(prog, BPF_DW, BPF_REG_0, BPF_REG_FP,
(i - 6) * 8 + 0x18);
- emit_stx(prog, bytes_to_bpf_size(arg_size),
- BPF_REG_FP,
- BPF_REG_0,
+ emit_stx(prog, BPF_DW, BPF_REG_FP, BPF_REG_0,
-(stack_size - i * 8));
}
@@ -1918,7 +1914,7 @@ static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_regs,
next_same_struct = !next_same_struct;
}
- emit_ldx(prog, bytes_to_bpf_size(arg_size),
+ emit_ldx(prog, BPF_DW,
i == 5 ? X86_REG_R9 : BPF_REG_1 + i,
BPF_REG_FP,
-(stack_size - i * 8));
@@ -1949,12 +1945,9 @@ static void prepare_origin_stack(const struct btf_func_model *m, u8 **prog,
}
if (i > 5) {
- emit_ldx(prog, bytes_to_bpf_size(arg_size),
- BPF_REG_0, BPF_REG_FP,
+ emit_ldx(prog, BPF_DW, BPF_REG_0, BPF_REG_FP,
(i - 6) * 8 + 0x18);
- emit_stx(prog, bytes_to_bpf_size(arg_size),
- BPF_REG_FP,
- BPF_REG_0,
+ emit_stx(prog, BPF_DW, BPF_REG_FP, BPF_REG_0,
-(stack_size - (i - 6) * 8));
}
--
2.40.1
