Re: [PATCH bpf-next v8 06/11] bpf,x86: introduce emit_st_r0_imm64() for trampoline
From: Alexei Starovoitov <hidden>
Date: 2026-01-10 02:45:58
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bpf, lkml
On Wed, Jan 7, 2026 at 6:26 PM Menglong Dong [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Introduce the helper emit_st_r0_imm64(), which is used to store a imm64 to the stack with the help of r0. Signed-off-by: Menglong Dong <redacted> --- arch/x86/net/bpf_jit_comp.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index e3b1c4b1d550..a87304161d45 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c@@ -1300,6 +1300,15 @@ 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_st_r0_imm64(u8 **pprog, u64 value, int off) +{ + /* mov rax, value + * mov QWORD PTR [rbp - off], rax + */ + emit_mov_imm64(pprog, BPF_REG_0, value >> 32, (u32) value); + emit_stx(pprog, BPF_DW, BPF_REG_FP, BPF_REG_0, -off); +}
The name is cryptic. How about emit_store_stack_imm64(pprog, stack_off, imm64) ? or emit_mov_stack_imm64.