bpf, riscv: introduce emit_store_stack_imm64() for trampoline

Introduce a helper to store 64-bit immediate on the trampoline stack with
a help of a register.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Tested-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20260208053311.698352-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 37888abee70c3b3f71600c31c48997fa5bb7ea60..e4f45e2e7e2f0ad7c03fc86a778f803f257bf971 100644 (file)
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -926,6 +926,14 @@ static void restore_stack_args(int nr_stack_args, int args_off, int stk_arg_off,
        }
 }
 
+static void emit_store_stack_imm64(u8 reg, int stack_off, u64 imm64,
+                                  struct rv_jit_context *ctx)
+{
+       /* Load imm64 into reg and store it at [FP + stack_off]. */
+       emit_imm(reg, (s64)imm64, ctx);
+       emit_sd(RV_REG_FP, stack_off, reg, ctx);
+}
+
 static int invoke_bpf_prog(struct bpf_tramp_link *l, int args_off, int retval_off,
                           int run_ctx_off, bool save_ret, struct rv_jit_context *ctx)
 {
@@ -933,12 +941,10 @@ static int invoke_bpf_prog(struct bpf_tramp_link *l, int args_off, int retval_of
        struct bpf_prog *p = l->link.prog;
        int cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
 
-       if (l->cookie) {
-               emit_imm(RV_REG_T1, l->cookie, ctx);
-               emit_sd(RV_REG_FP, -run_ctx_off + cookie_off, RV_REG_T1, ctx);
-       } else {
+       if (l->cookie)
+               emit_store_stack_imm64(RV_REG_T1, -run_ctx_off + cookie_off, l->cookie, ctx);
+       else
                emit_sd(RV_REG_FP, -run_ctx_off + cookie_off, RV_REG_ZERO, ctx);
-       }
 
        /* arg1: prog */
        emit_imm(RV_REG_A0, (const s64)p, ctx);
@@ -1123,13 +1129,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
        emit_sd(RV_REG_FP, -sreg_off, RV_REG_S1, ctx);
 
        /* store ip address of the traced function */
-       if (flags & BPF_TRAMP_F_IP_ARG) {
-               emit_imm(RV_REG_T1, (const s64)func_addr, ctx);
-               emit_sd(RV_REG_FP, -ip_off, RV_REG_T1, ctx);
-       }
+       if (flags & BPF_TRAMP_F_IP_ARG)
+               emit_store_stack_imm64(RV_REG_T1, -ip_off, (u64)func_addr, ctx);
 
-       emit_li(RV_REG_T1, nr_arg_slots, ctx);
-       emit_sd(RV_REG_FP, -nregs_off, RV_REG_T1, ctx);
+       emit_store_stack_imm64(RV_REG_T1, -nregs_off, nr_arg_slots, ctx);
 
        store_args(nr_arg_slots, args_off, ctx);