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| author | Menglong Dong <menglong8.dong@gmail.com> | 2026-01-24 09:20:01 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-01-25 05:49:36 +0300 |
| commit | 37c7ba1b39c493229d1b3c1f6ab466a23362e21e (patch) | |
| tree | 5aaf12660dec685dba3b2c1dbe25b79ada4f008b | |
| parent | eeee4239dbb155a98f8ba737324ac081acde8417 (diff) | |
| download | linux-37c7ba1b39c493229d1b3c1f6ab466a23362e21e.tar.xz | |
bpf,x86: introduce emit_store_stack_imm64() for trampoline
Introduce the helper emit_store_stack_imm64(), which is used to store a
imm64 to the stack with the help of a register.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20260124062008.8657-7-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index e3b1c4b1d550..2f31331955b5 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1300,6 +1300,16 @@ static void emit_st_r12(u8 **pprog, u32 size, u32 dst_reg, int off, int imm) emit_st_index(pprog, size, dst_reg, X86_REG_R12, off, imm); } +static void emit_store_stack_imm64(u8 **pprog, int reg, int stack_off, u64 imm64) +{ + /* + * mov reg, imm64 + * mov QWORD PTR [rbp + stack_off], reg + */ + emit_mov_imm64(pprog, reg, imm64 >> 32, (u32) imm64); + emit_stx(pprog, BPF_DW, BPF_REG_FP, reg, stack_off); +} + static int emit_atomic_rmw(u8 **pprog, u32 atomic_op, u32 dst_reg, u32 src_reg, s16 off, u8 bpf_size) { @@ -3348,20 +3358,12 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im /* mov QWORD PTR [rbp - rbx_off], rbx */ emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_6, -rbx_off); - /* Store number of argument registers of the traced function: - * mov rax, nr_regs - * mov QWORD PTR [rbp - nregs_off], rax - */ - emit_mov_imm64(&prog, BPF_REG_0, 0, (u32) nr_regs); - emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -nregs_off); + /* Store number of argument registers of the traced function */ + emit_store_stack_imm64(&prog, BPF_REG_0, -nregs_off, nr_regs); if (flags & BPF_TRAMP_F_IP_ARG) { - /* Store IP address of the traced function: - * movabsq rax, func_addr - * mov QWORD PTR [rbp - ip_off], rax - */ - emit_mov_imm64(&prog, BPF_REG_0, (long) func_addr >> 32, (u32) (long) func_addr); - emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -ip_off); + /* Store IP address of the traced function */ + emit_store_stack_imm64(&prog, BPF_REG_0, -ip_off, (long)func_addr); } save_args(m, &prog, regs_off, false, flags); |