diff options
| author |  Menglong Dong <imagedong@tencent.com>
| 2023-07-13 12:07:36 +0800 |
|---|---|---|
| committer |  Alexei Starovoitov <ast@kernel.org>
| 2023-07-13 16:04:56 -0700 |
| commit | 02a6dfa8ff43efb1c989f87a4d862aedf436088a (patch) | |
| tree | 1f48fb9794d958125471c4f451f56f7688da4e69 /arch/x86/net/bpf_jit_comp.c | |
| parent | bpftool: Use "fallthrough;" keyword instead of comments (diff) | |
| download | linux-02a6dfa8ff43efb1c989f87a4d862aedf436088a.tar.gz linux-02a6dfa8ff43efb1c989f87a4d862aedf436088a.tar.bz2 linux-02a6dfa8ff43efb1c989f87a4d862aedf436088a.zip | |
bpf, x86: save/restore regs with BPF_DW size
As we already reserve 8 byte in the stack for each reg, it is ok to
store/restore the regs in BPF_DW size. This will make the code in
save_regs()/restore_regs() simpler.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230713040738.1789742-2-imagedong@tencent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'arch/x86/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 35 |
1 files changed, 6 insertions, 29 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 438adb695daa..fcbd3b7123a4 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1860,57 +1860,34 @@ emit_jmp: static void save_regs(const struct btf_func_model *m, u8 **prog, int nr_regs, int stack_size) { - int i, j, arg_size; - bool next_same_struct = false; + int i; /* Store function arguments to stack. * For a function that accepts two pointers the sequence will be: * mov QWORD PTR [rbp-0x10],rdi * mov QWORD PTR [rbp-0x8],rsi */ - for (i = 0, j = 0; i < min(nr_regs, 6); i++) { - /* The arg_size is at most 16 bytes, enforced by the verifier. */ - arg_size = m->arg_size[j]; - if (arg_size > 8) { - arg_size = 8; - next_same_struct = !next_same_struct; - } - - emit_stx(prog, bytes_to_bpf_size(arg_size), - BPF_REG_FP, + for (i = 0; i < min(nr_regs, 6); i++) + emit_stx(prog, BPF_DW, BPF_REG_FP, i == 5 ? X86_REG_R9 : BPF_REG_1 + i, -(stack_size - i * 8)); - - j = next_same_struct ? j : j + 1; - } } static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_regs, int stack_size) { - int i, j, arg_size; - bool next_same_struct = false; + int i; /* Restore function arguments from stack. * For a function that accepts two pointers the sequence will be: * EMIT4(0x48, 0x8B, 0x7D, 0xF0); mov rdi,QWORD PTR [rbp-0x10] * EMIT4(0x48, 0x8B, 0x75, 0xF8); mov rsi,QWORD PTR [rbp-0x8] */ - for (i = 0, j = 0; i < min(nr_regs, 6); i++) { - /* The arg_size is at most 16 bytes, enforced by the verifier. */ - arg_size = m->arg_size[j]; - if (arg_size > 8) { - arg_size = 8; - next_same_struct = !next_same_struct; - } - - emit_ldx(prog, bytes_to_bpf_size(arg_size), + for (i = 0; i < min(nr_regs, 6); i++) + emit_ldx(prog, BPF_DW, i == 5 ? X86_REG_R9 : BPF_REG_1 + i, BPF_REG_FP, -(stack_size - i * 8)); - - j = next_same_struct ? j : j + 1; - } } static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog, |