@@ -695,6 +695,325 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type,
return ret;
}
+static void store_args(int nregs, int args_off, struct rv_jit_context *ctx)
+{
+ int i;
+
+ for (i = 0; i < nregs; i++) {
+ emit_sd(RV_REG_FP, -args_off, RV_REG_A0 + i, ctx);
+ args_off -= 8;
+ }
+}
+
+static void restore_args(int nregs, int args_off, struct rv_jit_context *ctx)
+{
+ int i;
+
+ for (i = 0; i < nregs; i++) {
+ emit_ld(RV_REG_A0 + i, -args_off, RV_REG_FP, ctx);
+ args_off -= 8;
+ }
+}
+
+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)
+{
+ int ret, branch_off;
+ 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 {
+ 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);
+ /* arg2: &run_ctx */
+ emit_addi(RV_REG_A1, RV_REG_FP, -run_ctx_off, ctx);
+ ret = emit_call((const u64)bpf_trampoline_enter(p), true, ctx);
+ if (ret)
+ return ret;
+
+ /* if (__bpf_prog_enter(prog) == 0)
+ * goto skip_exec_of_prog;
+ */
+ branch_off = ctx->ninsns;
+ /* nop reserved for conditional jump */
+ emit(rv_nop(), ctx);
+
+ /* store prog start time */
+ emit_mv(RV_REG_S1, RV_REG_A0, ctx);
+
+ /* arg1: &args_off */
+ emit_addi(RV_REG_A0, RV_REG_FP, -args_off, ctx);
+ if (!p->jited)
+ /* arg2: progs[i]->insnsi for interpreter */
+ emit_imm(RV_REG_A1, (const s64)p->insnsi, ctx);
+ ret = emit_call((const u64)p->bpf_func, true, ctx);
+ if (ret)
+ return ret;
+
+ if (save_ret)
+ emit_sd(RV_REG_FP, -retval_off, regmap[BPF_REG_0], ctx);
+
+ /* update branch with beqz */
+ if (ctx->insns) {
+ int offset = ninsns_rvoff(ctx->ninsns - branch_off);
+ u32 insn = rv_beq(RV_REG_A0, RV_REG_ZERO, offset >> 1);
+ *(u32 *)(ctx->insns + branch_off) = insn;
+ }
+
+ /* arg1: prog */
+ emit_imm(RV_REG_A0, (const s64)p, ctx);
+ /* arg2: prog start time */
+ emit_mv(RV_REG_A1, RV_REG_S1, ctx);
+ /* arg3: &run_ctx */
+ emit_addi(RV_REG_A2, RV_REG_FP, -run_ctx_off, ctx);
+ ret = emit_call((const u64)bpf_trampoline_exit(p), true, ctx);
+
+ return ret;
+}
+
+static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
+ const struct btf_func_model *m,
+ struct bpf_tramp_links *tlinks,
+ void *func_addr, u32 flags,
+ struct rv_jit_context *ctx)
+{
+ int i, ret, offset;
+ int *branches_off = NULL;
+ int stack_size = 0, nregs = m->nr_args;
+ int retaddr_off, fp_off, retval_off, args_off;
+ int nregs_off, ip_off, run_ctx_off, sreg_off;
+ struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
+ struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
+ struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN];
+ void *orig_call = func_addr;
+ bool save_ret;
+ u32 insn;
+
+ /* Generated trampoline stack layout:
+ *
+ * FP - 8 [ RA of parent func ] return address of parent
+ * function
+ * FP - retaddr_off [ RA of traced func ] return address of traced
+ * function
+ * FP - fp_off [ FP of parent func ]
+ *
+ * FP - retval_off [ return value ] BPF_TRAMP_F_CALL_ORIG or
+ * BPF_TRAMP_F_RET_FENTRY_RET
+ * [ argN ]
+ * [ ... ]
+ * FP - args_off [ arg1 ]
+ *
+ * FP - nregs_off [ regs count ]
+ *
+ * FP - ip_off [ traced func ] BPF_TRAMP_F_IP_ARG
+ *
+ * FP - run_ctx_off [ bpf_tramp_run_ctx ]
+ *
+ * FP - sreg_off [ callee saved reg ]
+ *
+ * [ pads ] pads for 16 bytes alignment
+ */
+
+ if (flags & (BPF_TRAMP_F_ORIG_STACK | BPF_TRAMP_F_SHARE_IPMODIFY))
+ return -ENOTSUPP;
+
+ /* extra regiters for struct arguments */
+ for (i = 0; i < m->nr_args; i++)
+ if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
+ nregs += round_up(m->arg_size[i], 8) / 8 - 1;
+
+ /* 8 arguments passed by registers */
+ if (nregs > 8)
+ return -ENOTSUPP;
+
+ /* room for parent function return address */
+ stack_size += 8;
+
+ stack_size += 8;
+ retaddr_off = stack_size;
+
+ stack_size += 8;
+ fp_off = stack_size;
+
+ save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
+ if (save_ret) {
+ stack_size += 8;
+ retval_off = stack_size;
+ }
+
+ stack_size += nregs * 8;
+ args_off = stack_size;
+
+ stack_size += 8;
+ nregs_off = stack_size;
+
+ if (flags & BPF_TRAMP_F_IP_ARG) {
+ stack_size += 8;
+ ip_off = stack_size;
+ }
+
+ stack_size += round_up(sizeof(struct bpf_tramp_run_ctx), 8);
+ run_ctx_off = stack_size;
+
+ stack_size += 8;
+ sreg_off = stack_size;
+
+ stack_size = round_up(stack_size, 16);
+
+ emit_addi(RV_REG_SP, RV_REG_SP, -stack_size, ctx);
+
+ emit_sd(RV_REG_SP, stack_size - retaddr_off, RV_REG_RA, ctx);
+ emit_sd(RV_REG_SP, stack_size - fp_off, RV_REG_FP, ctx);
+
+ emit_addi(RV_REG_FP, RV_REG_SP, stack_size, ctx);
+
+ /* callee saved register S1 to pass start time */
+ 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);
+ }
+
+ emit_li(RV_REG_T1, nregs, ctx);
+ emit_sd(RV_REG_FP, -nregs_off, RV_REG_T1, ctx);
+
+ store_args(nregs, args_off, ctx);
+
+ /* skip to actual body of traced function */
+ if (flags & BPF_TRAMP_F_SKIP_FRAME)
+ orig_call += 16;
+
+ if (flags & BPF_TRAMP_F_CALL_ORIG) {
+ emit_imm(RV_REG_A0, (const s64)im, ctx);
+ ret = emit_call((const u64)__bpf_tramp_enter, true, ctx);
+ if (ret)
+ return ret;
+ }
+
+ for (i = 0; i < fentry->nr_links; i++) {
+ ret = invoke_bpf_prog(fentry->links[i], args_off, retval_off, run_ctx_off,
+ flags & BPF_TRAMP_F_RET_FENTRY_RET, ctx);
+ if (ret)
+ return ret;
+ }
+
+ if (fmod_ret->nr_links) {
+ branches_off = kcalloc(fmod_ret->nr_links, sizeof(int), GFP_KERNEL);
+ if (!branches_off)
+ return -ENOMEM;
+
+ /* cleanup to avoid garbage return value confusion */
+ emit_sd(RV_REG_FP, -retval_off, RV_REG_ZERO, ctx);
+ for (i = 0; i < fmod_ret->nr_links; i++) {
+ ret = invoke_bpf_prog(fmod_ret->links[i], args_off, retval_off,
+ run_ctx_off, true, ctx);
+ if (ret)
+ goto out;
+ emit_ld(RV_REG_T1, -retval_off, RV_REG_FP, ctx);
+ branches_off[i] = ctx->ninsns;
+ /* nop reserved for conditional jump */
+ emit(rv_nop(), ctx);
+ }
+ }
+
+ if (flags & BPF_TRAMP_F_CALL_ORIG) {
+ restore_args(nregs, args_off, ctx);
+ ret = emit_call((const u64)orig_call, true, ctx);
+ if (ret)
+ goto out;
+ emit_sd(RV_REG_FP, -retval_off, RV_REG_A0, ctx);
+ im->ip_after_call = ctx->insns + ctx->ninsns;
+ /* 2 nops reserved for auipc+jalr pair */
+ emit(rv_nop(), ctx);
+ emit(rv_nop(), ctx);
+ }
+
+ /* update branches saved in invoke_bpf_mod_ret with bnez */
+ for (i = 0; ctx->insns && i < fmod_ret->nr_links; i++) {
+ offset = ninsns_rvoff(ctx->ninsns - branches_off[i]);
+ insn = rv_bne(RV_REG_T1, RV_REG_ZERO, offset >> 1);
+ *(u32 *)(ctx->insns + branches_off[i]) = insn;
+ }
+
+ for (i = 0; i < fexit->nr_links; i++) {
+ ret = invoke_bpf_prog(fexit->links[i], args_off, retval_off,
+ run_ctx_off, false, ctx);
+ if (ret)
+ goto out;
+ }
+
+ if (flags & BPF_TRAMP_F_CALL_ORIG) {
+ im->ip_epilogue = ctx->insns + ctx->ninsns;
+ emit_imm(RV_REG_A0, (const s64)im, ctx);
+ ret = emit_call((const u64)__bpf_tramp_exit, true, ctx);
+ if (ret)
+ goto out;
+ }
+
+ if (flags & BPF_TRAMP_F_RESTORE_REGS)
+ restore_args(nregs, args_off, ctx);
+
+ if (save_ret)
+ emit_ld(RV_REG_A0, -retval_off, RV_REG_FP, ctx);
+
+ emit_ld(RV_REG_S1, -sreg_off, RV_REG_FP, ctx);
+
+ if (flags & BPF_TRAMP_F_SKIP_FRAME)
+ /* return address of parent function */
+ emit_ld(RV_REG_RA, stack_size - 8, RV_REG_SP, ctx);
+ else
+ /* return address of traced function */
+ emit_ld(RV_REG_RA, stack_size - retaddr_off, RV_REG_SP, ctx);
+
+ emit_ld(RV_REG_FP, stack_size - fp_off, RV_REG_SP, ctx);
+ emit_addi(RV_REG_SP, RV_REG_SP, stack_size, ctx);
+
+ emit_jalr(RV_REG_ZERO, RV_REG_RA, 0, ctx);
+
+ ret = ctx->ninsns;
+out:
+ if (branches_off)
+ kfree(branches_off);
+
+ return ret;
+}
+
+int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
+ void *image_end, const struct btf_func_model *m,
+ u32 flags, struct bpf_tramp_links *tlinks,
+ void *func_addr)
+{
+ int ret;
+ struct rv_jit_context ctx;
+
+ ctx.ninsns = 0;
+ ctx.insns = NULL;
+ ret = __arch_prepare_bpf_trampoline(im, m, tlinks, func_addr, flags, &ctx);
+ if (ret < 0)
+ return ret;
+
+ if (ninsns_rvoff(ret) > (long)image_end - (long)image)
+ return -EFBIG;
+
+ ctx.ninsns = 0;
+ ctx.insns = image;
+ ret = __arch_prepare_bpf_trampoline(im, m, tlinks, func_addr, flags, &ctx);
+ if (ret < 0)
+ return ret;
+
+ bpf_flush_icache(ctx.insns, ctx.insns + ctx.ninsns);
+
+ return ninsns_rvoff(ret);
+}
+
int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
bool extra_pass)
{