[bpf-next PATCH 0/2] bpf, riscv: Add BPF stack arguments support for RV64 JIT

[bpf-next PATCH 0/2] bpf, riscv: Add BPF stack arguments support for RV64 JIT

[Feng Jiang]

Port the BPF stack argument feature (BPF_REG_PARAMS / r11) to the
RV64 JIT, matching what x86 and arm64 already do.

BPF-to-BPF calls keep all extra arguments on the stack.  For kfunc
calls, the JIT loads arguments 6-8 into A5-A7 at the call site to
satisfy the RISC-V C calling convention.

Tested on riscv64 QEMU with LLVM main [1]; BPF-to-BPF and kfunc
selftests pass.

[1] https://github.com/llvm/llvm-project/pull/189060

Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
---
Feng Jiang (2):
      bpf, riscv: Add BPF stack arguments support for RV64 JIT
      selftests/bpf: Enable stack argument tests for riscv

 arch/riscv/net/bpf_jit.h                           |  1 +
 arch/riscv/net/bpf_jit_comp64.c                    | 75 +++++++++++++++++++++-
 arch/riscv/net/bpf_jit_core.c                      |  4 ++
 .../selftests/bpf/progs/btf__stack_arg_precision.c |  2 +-
 .../bpf/progs/btf__verifier_stack_arg_order.c      |  2 +-
 tools/testing/selftests/bpf/progs/exceptions.c     |  2 +-
 tools/testing/selftests/bpf/progs/stack_arg.c      |  2 +-
 .../testing/selftests/bpf/progs/stack_arg_kfunc.c  |  2 +-
 .../selftests/bpf/progs/stack_arg_precision.c      |  2 +-
 .../selftests/bpf/progs/verifier_stack_arg.c       |  2 +-
 .../selftests/bpf/progs/verifier_stack_arg_order.c |  2 +-
 11 files changed, 85 insertions(+), 11 deletions(-)
---
base-commit: d114bb98936770c501c958bf2bc5fb6b7c0bad7b
change-id: 20260728-bpf-riscv-stack-args-6350d066a1e9

Best regards,
-- 
Feng Jiang <jiangfeng@kylinos.cn>

[bpf-next PATCH 0/2] bpf, riscv: Add BPF stack arguments support for RV64 JIT

[Feng Jiang]

Port the BPF stack argument feature (BPF_REG_PARAMS / r11) to the
RV64 JIT, matching what x86 and arm64 already do.

BPF-to-BPF calls keep all extra arguments on the stack.  For kfunc
calls, the JIT loads arguments 6-8 into A5-A7 at the call site to
satisfy the RISC-V C calling convention.

Tested on riscv64 QEMU with LLVM main [1]; BPF-to-BPF and kfunc
selftests pass.

[1] https://github.com/llvm/llvm-project/pull/189060

Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
---
Feng Jiang (2):
      bpf, riscv: Add BPF stack arguments support for RV64 JIT
      selftests/bpf: Enable stack argument tests for riscv

 arch/riscv/net/bpf_jit.h                           |  1 +
 arch/riscv/net/bpf_jit_comp64.c                    | 75 +++++++++++++++++++++-
 arch/riscv/net/bpf_jit_core.c                      |  4 ++
 .../selftests/bpf/progs/btf__stack_arg_precision.c |  2 +-
 .../bpf/progs/btf__verifier_stack_arg_order.c      |  2 +-
 tools/testing/selftests/bpf/progs/exceptions.c     |  2 +-
 tools/testing/selftests/bpf/progs/stack_arg.c      |  2 +-
 .../testing/selftests/bpf/progs/stack_arg_kfunc.c  |  2 +-
 .../selftests/bpf/progs/stack_arg_precision.c      |  2 +-
 .../selftests/bpf/progs/verifier_stack_arg.c       |  2 +-
 .../selftests/bpf/progs/verifier_stack_arg_order.c |  2 +-
 11 files changed, 85 insertions(+), 11 deletions(-)
---
base-commit: d114bb98936770c501c958bf2bc5fb6b7c0bad7b
change-id: 20260728-bpf-riscv-stack-args-6350d066a1e9

Best regards,
-- 
Feng Jiang <jiangfeng@kylinos.cn>


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[bpf-next PATCH 1/2] bpf, riscv: Add BPF stack arguments support for RV64 JIT

[Feng Jiang]

Add bpf_jit_supports_stack_args() for the RV64 JIT so BPF subprograms
and kfuncs can receive more than 5 arguments via the stack
(BPF_REG_PARAMS / r11).

For BPF-to-BPF calls the caller writes outgoing arguments at the
bottom of its frame (SP-relative). The callee reads them with
FP-relative loads. Its FP is set to the caller SP in the prologue,
so the offsets match.

The RISC-V ABI puts arguments 6-8 in A5-A7 and arguments 9+ at
SP+0. Before each kfunc call, load arguments 6-8 from the outgoing
area into A5-A7 and copy any remaining arguments down so argument 9
lands at SP+0.

A5 (BPF_REG_0), A6 (TCC) and A7 are safe to clobber here: R0 is not
live before a call, TCC is backed up on the stack, and A7 is unused
by the JIT.

Limit the existing kfunc sign-extension loop to MAX_BPF_FUNC_REG_ARGS
iterations; otherwise idx >= 5 resolves to S1-S5 (BPF_R6-FP) and
corrupts callee-saved registers.

Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
---
 arch/riscv/net/bpf_jit.h        |  1 +
 arch/riscv/net/bpf_jit_comp64.c | 75 +++++++++++++++++++++++++++++++++++++++--
 arch/riscv/net/bpf_jit_core.c   |  4 +++
 3 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h
index 419b9d795f2a..9eb4e149505d 100644
--- a/arch/riscv/net/bpf_jit.h
+++ b/arch/riscv/net/bpf_jit.h
@@ -82,6 +82,7 @@ struct rv_jit_context {
 	unsigned long flags;
 	int stack_size;
 	int tcc_offset;
+	u16 stack_arg_size;
 	u64 arena_vm_start;
 	u64 user_vm_start;
 };
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 6b9972b07c1b..b3f4bf9e1e7f 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -1815,18 +1815,39 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 
 		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
 			const struct btf_func_model *fm;
-			int idx;
+			int idx, nargs;
 
 			fm = bpf_jit_find_kfunc_model(ctx->prog, insn);
 			if (!fm)
 				return -EINVAL;
 
-			for (idx = 0; idx < fm->nr_args; idx++) {
+			nargs = min_t(int, fm->nr_args, MAX_BPF_FUNC_REG_ARGS);
+			for (idx = 0; idx < nargs; idx++) {
 				u8 reg = bpf_to_rv_reg(BPF_REG_1 + idx, ctx);
 
 				if (fm->arg_size[idx] == sizeof(int))
 					emit_sextw(reg, reg, ctx);
 			}
+
+			/* BPF stack args -> RISC-V ABI: args 6-8 in A5-A7, 9+ at SP+0 */
+			if (fm->nr_args > MAX_BPF_FUNC_REG_ARGS) {
+				int n_stack = fm->nr_args - MAX_BPF_FUNC_REG_ARGS;
+				int n_reg = min_t(int, n_stack,
+						  RV_MAX_REG_ARGS - MAX_BPF_FUNC_REG_ARGS);
+
+				for (idx = 0; idx < n_reg; idx++) {
+					int sz = fm->arg_size[MAX_BPF_FUNC_REG_ARGS + idx];
+
+					emit_ld(RV_REG_A5 + idx, idx * 8, RV_REG_SP, ctx);
+					if (sz == sizeof(int))
+						emit_sextw(RV_REG_A5 + idx, RV_REG_A5 + idx, ctx);
+				}
+
+				for (idx = 0; idx < n_stack - n_reg; idx++) {
+					emit_ld(RV_REG_T1, (n_reg + idx) * 8, RV_REG_SP, ctx);
+					emit_sd(RV_REG_SP, idx * 8, RV_REG_T1, ctx);
+				}
+			}
 		}
 
 		/* restore TCC to RV_REG_TCC before bpf2bpf call */
@@ -1891,6 +1912,21 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_LDX | BPF_MEM | BPF_H:
 	case BPF_LDX | BPF_MEM | BPF_W:
 	case BPF_LDX | BPF_MEM | BPF_DW:
+		if (insn->src_reg == BPF_REG_PARAMS) {
+			int idx = off / 8 - 1;
+
+			if (is_12b_int(idx * 8)) {
+				emit_ldx_insn(rd, idx * 8, RV_REG_FP, BPF_SIZE(code), false, ctx);
+			} else {
+				emit_imm(RV_REG_T1, idx * 8, ctx);
+				emit_add(RV_REG_T1, RV_REG_T1, RV_REG_FP, ctx);
+				emit_ldx_insn(rd, 0, RV_REG_T1, BPF_SIZE(code), false, ctx);
+			}
+			if (BPF_SIZE(code) != BPF_DW && insn_is_zext(&insn[1]))
+				return 1;
+			break;
+		}
+		fallthrough;
 	case BPF_LDX | BPF_PROBE_MEM | BPF_B:
 	case BPF_LDX | BPF_PROBE_MEM | BPF_H:
 	case BPF_LDX | BPF_PROBE_MEM | BPF_W:
@@ -1938,6 +1974,20 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ST | BPF_MEM | BPF_H:
 	case BPF_ST | BPF_MEM | BPF_W:
 	case BPF_ST | BPF_MEM | BPF_DW:
+		if (insn->dst_reg == BPF_REG_PARAMS) {
+			int idx = -off / 8 - 1;
+
+			emit_imm(RV_REG_T1, imm, ctx);
+			if (is_12b_int(idx * 8)) {
+				emit_stx_insn(RV_REG_SP, idx * 8, RV_REG_T1, BPF_SIZE(code), ctx);
+			} else {
+				emit_imm(RV_REG_T2, idx * 8, ctx);
+				emit_add(RV_REG_T2, RV_REG_SP, RV_REG_T2, ctx);
+				emit_stx_insn(RV_REG_T2, 0, RV_REG_T1, BPF_SIZE(code), ctx);
+			}
+			break;
+		}
+		fallthrough;
 	/* ST | PROBE_MEM32: *(size *)(dst + RV_REG_ARENA + off) = imm */
 	case BPF_ST | BPF_PROBE_MEM32 | BPF_B:
 	case BPF_ST | BPF_PROBE_MEM32 | BPF_H:
@@ -1960,6 +2010,19 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_STX | BPF_MEM | BPF_H:
 	case BPF_STX | BPF_MEM | BPF_W:
 	case BPF_STX | BPF_MEM | BPF_DW:
+		if (insn->dst_reg == BPF_REG_PARAMS) {
+			int idx = -off / 8 - 1;
+
+			if (is_12b_int(idx * 8)) {
+				emit_stx_insn(RV_REG_SP, idx * 8, rs, BPF_SIZE(code), ctx);
+			} else {
+				emit_imm(RV_REG_T1, idx * 8, ctx);
+				emit_add(RV_REG_T1, RV_REG_SP, RV_REG_T1, ctx);
+				emit_stx_insn(RV_REG_T1, 0, rs, BPF_SIZE(code), ctx);
+			}
+			break;
+		}
+		fallthrough;
 	/* STX | PROBE_MEM32: *(size *)(dst + RV_REG_ARENA + off) = src */
 	case BPF_STX | BPF_PROBE_MEM32 | BPF_B:
 	case BPF_STX | BPF_PROBE_MEM32 | BPF_H:
@@ -2036,6 +2099,7 @@ void bpf_jit_build_prologue(struct rv_jit_context *ctx, bool is_subprog)
 
 	stack_adjust = round_up(stack_adjust, STACK_ALIGN);
 	stack_adjust += bpf_stack_adjust;
+	stack_adjust += ctx->stack_arg_size;
 
 	store_offset = stack_adjust - 8;
 
@@ -2093,7 +2157,7 @@ void bpf_jit_build_prologue(struct rv_jit_context *ctx, bool is_subprog)
 	emit_addi(RV_REG_FP, RV_REG_SP, stack_adjust, ctx);
 
 	if (bpf_stack_adjust)
-		emit_addi(RV_REG_S5, RV_REG_SP, bpf_stack_adjust, ctx);
+		emit_addi(RV_REG_S5, RV_REG_SP, ctx->stack_arg_size + bpf_stack_adjust, ctx);
 
 	ctx->stack_size = stack_adjust;
 
@@ -2171,3 +2235,8 @@ bool bpf_jit_supports_timed_may_goto(void)
 {
 	return true;
 }
+
+bool bpf_jit_supports_stack_args(void)
+{
+	return true;
+}
diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c
index cbfcd287ea16..844a0f3e0fa9 100644
--- a/arch/riscv/net/bpf_jit_core.c
+++ b/arch/riscv/net/bpf_jit_core.c
@@ -72,6 +72,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_pr
 	ctx->arena_vm_start = bpf_arena_get_kern_vm_start(prog->aux->arena);
 	ctx->user_vm_start = bpf_arena_get_user_vm_start(prog->aux->arena);
 	ctx->prog = prog;
+
+	ctx->stack_arg_size = round_up(bpf_out_stack_arg_cnt(env, prog) *
+				       sizeof(u64), STACK_ALIGN);
+
 	ctx->offset = kvzalloc_objs(int, prog->len);
 	if (!ctx->offset)
 		goto out_offset;

-- 
2.53.0

[bpf-next PATCH 1/2] bpf, riscv: Add BPF stack arguments support for RV64 JIT

[Feng Jiang]

Add bpf_jit_supports_stack_args() for the RV64 JIT so BPF subprograms
and kfuncs can receive more than 5 arguments via the stack
(BPF_REG_PARAMS / r11).

For BPF-to-BPF calls the caller writes outgoing arguments at the
bottom of its frame (SP-relative). The callee reads them with
FP-relative loads. Its FP is set to the caller SP in the prologue,
so the offsets match.

The RISC-V ABI puts arguments 6-8 in A5-A7 and arguments 9+ at
SP+0. Before each kfunc call, load arguments 6-8 from the outgoing
area into A5-A7 and copy any remaining arguments down so argument 9
lands at SP+0.

A5 (BPF_REG_0), A6 (TCC) and A7 are safe to clobber here: R0 is not
live before a call, TCC is backed up on the stack, and A7 is unused
by the JIT.

Limit the existing kfunc sign-extension loop to MAX_BPF_FUNC_REG_ARGS
iterations; otherwise idx >= 5 resolves to S1-S5 (BPF_R6-FP) and
corrupts callee-saved registers.

Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
---
 arch/riscv/net/bpf_jit.h        |  1 +
 arch/riscv/net/bpf_jit_comp64.c | 75 +++++++++++++++++++++++++++++++++++++++--
 arch/riscv/net/bpf_jit_core.c   |  4 +++
 3 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h
index 419b9d795f2a..9eb4e149505d 100644
--- a/arch/riscv/net/bpf_jit.h
+++ b/arch/riscv/net/bpf_jit.h
@@ -82,6 +82,7 @@ struct rv_jit_context {
 	unsigned long flags;
 	int stack_size;
 	int tcc_offset;
+	u16 stack_arg_size;
 	u64 arena_vm_start;
 	u64 user_vm_start;
 };
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 6b9972b07c1b..b3f4bf9e1e7f 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -1815,18 +1815,39 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 
 		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
 			const struct btf_func_model *fm;
-			int idx;
+			int idx, nargs;
 
 			fm = bpf_jit_find_kfunc_model(ctx->prog, insn);
 			if (!fm)
 				return -EINVAL;
 
-			for (idx = 0; idx < fm->nr_args; idx++) {
+			nargs = min_t(int, fm->nr_args, MAX_BPF_FUNC_REG_ARGS);
+			for (idx = 0; idx < nargs; idx++) {
 				u8 reg = bpf_to_rv_reg(BPF_REG_1 + idx, ctx);
 
 				if (fm->arg_size[idx] == sizeof(int))
 					emit_sextw(reg, reg, ctx);
 			}
+
+			/* BPF stack args -> RISC-V ABI: args 6-8 in A5-A7, 9+ at SP+0 */
+			if (fm->nr_args > MAX_BPF_FUNC_REG_ARGS) {
+				int n_stack = fm->nr_args - MAX_BPF_FUNC_REG_ARGS;
+				int n_reg = min_t(int, n_stack,
+						  RV_MAX_REG_ARGS - MAX_BPF_FUNC_REG_ARGS);
+
+				for (idx = 0; idx < n_reg; idx++) {
+					int sz = fm->arg_size[MAX_BPF_FUNC_REG_ARGS + idx];
+
+					emit_ld(RV_REG_A5 + idx, idx * 8, RV_REG_SP, ctx);
+					if (sz == sizeof(int))
+						emit_sextw(RV_REG_A5 + idx, RV_REG_A5 + idx, ctx);
+				}
+
+				for (idx = 0; idx < n_stack - n_reg; idx++) {
+					emit_ld(RV_REG_T1, (n_reg + idx) * 8, RV_REG_SP, ctx);
+					emit_sd(RV_REG_SP, idx * 8, RV_REG_T1, ctx);
+				}
+			}
 		}
 
 		/* restore TCC to RV_REG_TCC before bpf2bpf call */
@@ -1891,6 +1912,21 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_LDX | BPF_MEM | BPF_H:
 	case BPF_LDX | BPF_MEM | BPF_W:
 	case BPF_LDX | BPF_MEM | BPF_DW:
+		if (insn->src_reg == BPF_REG_PARAMS) {
+			int idx = off / 8 - 1;
+
+			if (is_12b_int(idx * 8)) {
+				emit_ldx_insn(rd, idx * 8, RV_REG_FP, BPF_SIZE(code), false, ctx);
+			} else {
+				emit_imm(RV_REG_T1, idx * 8, ctx);
+				emit_add(RV_REG_T1, RV_REG_T1, RV_REG_FP, ctx);
+				emit_ldx_insn(rd, 0, RV_REG_T1, BPF_SIZE(code), false, ctx);
+			}
+			if (BPF_SIZE(code) != BPF_DW && insn_is_zext(&insn[1]))
+				return 1;
+			break;
+		}
+		fallthrough;
 	case BPF_LDX | BPF_PROBE_MEM | BPF_B:
 	case BPF_LDX | BPF_PROBE_MEM | BPF_H:
 	case BPF_LDX | BPF_PROBE_MEM | BPF_W:
@@ -1938,6 +1974,20 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ST | BPF_MEM | BPF_H:
 	case BPF_ST | BPF_MEM | BPF_W:
 	case BPF_ST | BPF_MEM | BPF_DW:
+		if (insn->dst_reg == BPF_REG_PARAMS) {
+			int idx = -off / 8 - 1;
+
+			emit_imm(RV_REG_T1, imm, ctx);
+			if (is_12b_int(idx * 8)) {
+				emit_stx_insn(RV_REG_SP, idx * 8, RV_REG_T1, BPF_SIZE(code), ctx);
+			} else {
+				emit_imm(RV_REG_T2, idx * 8, ctx);
+				emit_add(RV_REG_T2, RV_REG_SP, RV_REG_T2, ctx);
+				emit_stx_insn(RV_REG_T2, 0, RV_REG_T1, BPF_SIZE(code), ctx);
+			}
+			break;
+		}
+		fallthrough;
 	/* ST | PROBE_MEM32: *(size *)(dst + RV_REG_ARENA + off) = imm */
 	case BPF_ST | BPF_PROBE_MEM32 | BPF_B:
 	case BPF_ST | BPF_PROBE_MEM32 | BPF_H:
@@ -1960,6 +2010,19 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_STX | BPF_MEM | BPF_H:
 	case BPF_STX | BPF_MEM | BPF_W:
 	case BPF_STX | BPF_MEM | BPF_DW:
+		if (insn->dst_reg == BPF_REG_PARAMS) {
+			int idx = -off / 8 - 1;
+
+			if (is_12b_int(idx * 8)) {
+				emit_stx_insn(RV_REG_SP, idx * 8, rs, BPF_SIZE(code), ctx);
+			} else {
+				emit_imm(RV_REG_T1, idx * 8, ctx);
+				emit_add(RV_REG_T1, RV_REG_SP, RV_REG_T1, ctx);
+				emit_stx_insn(RV_REG_T1, 0, rs, BPF_SIZE(code), ctx);
+			}
+			break;
+		}
+		fallthrough;
 	/* STX | PROBE_MEM32: *(size *)(dst + RV_REG_ARENA + off) = src */
 	case BPF_STX | BPF_PROBE_MEM32 | BPF_B:
 	case BPF_STX | BPF_PROBE_MEM32 | BPF_H:
@@ -2036,6 +2099,7 @@ void bpf_jit_build_prologue(struct rv_jit_context *ctx, bool is_subprog)
 
 	stack_adjust = round_up(stack_adjust, STACK_ALIGN);
 	stack_adjust += bpf_stack_adjust;
+	stack_adjust += ctx->stack_arg_size;
 
 	store_offset = stack_adjust - 8;
 
@@ -2093,7 +2157,7 @@ void bpf_jit_build_prologue(struct rv_jit_context *ctx, bool is_subprog)
 	emit_addi(RV_REG_FP, RV_REG_SP, stack_adjust, ctx);
 
 	if (bpf_stack_adjust)
-		emit_addi(RV_REG_S5, RV_REG_SP, bpf_stack_adjust, ctx);
+		emit_addi(RV_REG_S5, RV_REG_SP, ctx->stack_arg_size + bpf_stack_adjust, ctx);
 
 	ctx->stack_size = stack_adjust;
 
@@ -2171,3 +2235,8 @@ bool bpf_jit_supports_timed_may_goto(void)
 {
 	return true;
 }
+
+bool bpf_jit_supports_stack_args(void)
+{
+	return true;
+}
diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c
index cbfcd287ea16..844a0f3e0fa9 100644
--- a/arch/riscv/net/bpf_jit_core.c
+++ b/arch/riscv/net/bpf_jit_core.c
@@ -72,6 +72,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_pr
 	ctx->arena_vm_start = bpf_arena_get_kern_vm_start(prog->aux->arena);
 	ctx->user_vm_start = bpf_arena_get_user_vm_start(prog->aux->arena);
 	ctx->prog = prog;
+
+	ctx->stack_arg_size = round_up(bpf_out_stack_arg_cnt(env, prog) *
+				       sizeof(u64), STACK_ALIGN);
+
 	ctx->offset = kvzalloc_objs(int, prog->len);
 	if (!ctx->offset)
 		goto out_offset;

-- 
2.53.0


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[bpf-next PATCH 2/2] selftests/bpf: Enable stack argument tests for riscv

[Feng Jiang]

Add __TARGET_ARCH_riscv to the architecture guard in all stack
argument selftests so the real test cases are compiled for RISC-V.

Keep the __BPF_FEATURE_STACK_ARGUMENT gate, defined by clang with
BPF stack argument support [1].

[1] https://github.com/llvm/llvm-project/pull/189060

Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
---
 tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c      | 2 +-
 tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c | 2 +-
 tools/testing/selftests/bpf/progs/exceptions.c                    | 2 +-
 tools/testing/selftests/bpf/progs/stack_arg.c                     | 2 +-
 tools/testing/selftests/bpf/progs/stack_arg_kfunc.c               | 2 +-
 tools/testing/selftests/bpf/progs/stack_arg_precision.c           | 2 +-
 tools/testing/selftests/bpf/progs/verifier_stack_arg.c            | 2 +-
 tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c      | 2 +-
 8 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c b/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
index 8d38aafe66a2..c8540d30e293 100644
--- a/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
+++ b/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
@@ -4,7 +4,7 @@
 #include <bpf/bpf_helpers.h>
 #include "../test_kmods/bpf_testmod_kfunc.h"
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 long subprog_call_mem_kfunc(long a, long b, long c, long d, long e, long size)
diff --git a/tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c b/tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c
index 99bc115f8380..d1c382693fed 100644
--- a/tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c
+++ b/tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c
@@ -3,7 +3,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 int subprog_bad_order_6args(int a, int b, int c, int d, int e, int f)
diff --git a/tools/testing/selftests/bpf/progs/exceptions.c b/tools/testing/selftests/bpf/progs/exceptions.c
index c8d716fbd419..dc5d422a82a5 100644
--- a/tools/testing/selftests/bpf/progs/exceptions.c
+++ b/tools/testing/selftests/bpf/progs/exceptions.c
@@ -379,7 +379,7 @@ int exception_bad_assert_range_with(struct __sk_buff *ctx)
 	return 1;
 }
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) \
 	&& defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 const volatile bool has_stack_arg = true;
diff --git a/tools/testing/selftests/bpf/progs/stack_arg.c b/tools/testing/selftests/bpf/progs/stack_arg.c
index 944e3bb603e7..8ba4991bbabd 100644
--- a/tools/testing/selftests/bpf/progs/stack_arg.c
+++ b/tools/testing/selftests/bpf/progs/stack_arg.c
@@ -21,7 +21,7 @@ struct {
 
 int timer_result;
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 const volatile bool has_stack_arg = true;
diff --git a/tools/testing/selftests/bpf/progs/stack_arg_kfunc.c b/tools/testing/selftests/bpf/progs/stack_arg_kfunc.c
index 345f2da2e361..6a22255fcaa7 100644
--- a/tools/testing/selftests/bpf/progs/stack_arg_kfunc.c
+++ b/tools/testing/selftests/bpf/progs/stack_arg_kfunc.c
@@ -6,7 +6,7 @@
 #include "bpf_kfuncs.h"
 #include "../test_kmods/bpf_testmod_kfunc.h"
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 const volatile bool has_stack_arg = true;
diff --git a/tools/testing/selftests/bpf/progs/stack_arg_precision.c b/tools/testing/selftests/bpf/progs/stack_arg_precision.c
index bee2eeec021d..cffa0dfb6f52 100644
--- a/tools/testing/selftests/bpf/progs/stack_arg_precision.c
+++ b/tools/testing/selftests/bpf/progs/stack_arg_precision.c
@@ -6,7 +6,7 @@
 #include "../test_kmods/bpf_testmod_kfunc.h"
 #include "bpf_misc.h"
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 /* Force kfunc extern BTF generation for inline asm call below.
diff --git a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c
index 7e0ce5db28a0..b2a724a2790e 100644
--- a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c
+++ b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c
@@ -12,7 +12,7 @@ struct {
 	__type(value, long long);
 } map_hash_8b SEC(".maps");
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 __noinline __used
diff --git a/tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c b/tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c
index c9fe4857da3f..ed260041d827 100644
--- a/tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c
+++ b/tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c
@@ -5,7 +5,7 @@
 #include <bpf/bpf_helpers.h>
 #include "bpf_misc.h"
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 __noinline __used __naked

-- 
2.53.0

[bpf-next PATCH 2/2] selftests/bpf: Enable stack argument tests for riscv

[Feng Jiang]

Add __TARGET_ARCH_riscv to the architecture guard in all stack
argument selftests so the real test cases are compiled for RISC-V.

Keep the __BPF_FEATURE_STACK_ARGUMENT gate, defined by clang with
BPF stack argument support [1].

[1] https://github.com/llvm/llvm-project/pull/189060

Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
---
 tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c      | 2 +-
 tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c | 2 +-
 tools/testing/selftests/bpf/progs/exceptions.c                    | 2 +-
 tools/testing/selftests/bpf/progs/stack_arg.c                     | 2 +-
 tools/testing/selftests/bpf/progs/stack_arg_kfunc.c               | 2 +-
 tools/testing/selftests/bpf/progs/stack_arg_precision.c           | 2 +-
 tools/testing/selftests/bpf/progs/verifier_stack_arg.c            | 2 +-
 tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c      | 2 +-
 8 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c b/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
index 8d38aafe66a2..c8540d30e293 100644
--- a/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
+++ b/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
@@ -4,7 +4,7 @@
 #include <bpf/bpf_helpers.h>
 #include "../test_kmods/bpf_testmod_kfunc.h"
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 long subprog_call_mem_kfunc(long a, long b, long c, long d, long e, long size)
diff --git a/tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c b/tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c
index 99bc115f8380..d1c382693fed 100644
--- a/tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c
+++ b/tools/testing/selftests/bpf/progs/btf__verifier_stack_arg_order.c
@@ -3,7 +3,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 int subprog_bad_order_6args(int a, int b, int c, int d, int e, int f)
diff --git a/tools/testing/selftests/bpf/progs/exceptions.c b/tools/testing/selftests/bpf/progs/exceptions.c
index c8d716fbd419..dc5d422a82a5 100644
--- a/tools/testing/selftests/bpf/progs/exceptions.c
+++ b/tools/testing/selftests/bpf/progs/exceptions.c
@@ -379,7 +379,7 @@ int exception_bad_assert_range_with(struct __sk_buff *ctx)
 	return 1;
 }
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) \
 	&& defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 const volatile bool has_stack_arg = true;
diff --git a/tools/testing/selftests/bpf/progs/stack_arg.c b/tools/testing/selftests/bpf/progs/stack_arg.c
index 944e3bb603e7..8ba4991bbabd 100644
--- a/tools/testing/selftests/bpf/progs/stack_arg.c
+++ b/tools/testing/selftests/bpf/progs/stack_arg.c
@@ -21,7 +21,7 @@ struct {
 
 int timer_result;
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 const volatile bool has_stack_arg = true;
diff --git a/tools/testing/selftests/bpf/progs/stack_arg_kfunc.c b/tools/testing/selftests/bpf/progs/stack_arg_kfunc.c
index 345f2da2e361..6a22255fcaa7 100644
--- a/tools/testing/selftests/bpf/progs/stack_arg_kfunc.c
+++ b/tools/testing/selftests/bpf/progs/stack_arg_kfunc.c
@@ -6,7 +6,7 @@
 #include "bpf_kfuncs.h"
 #include "../test_kmods/bpf_testmod_kfunc.h"
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 const volatile bool has_stack_arg = true;
diff --git a/tools/testing/selftests/bpf/progs/stack_arg_precision.c b/tools/testing/selftests/bpf/progs/stack_arg_precision.c
index bee2eeec021d..cffa0dfb6f52 100644
--- a/tools/testing/selftests/bpf/progs/stack_arg_precision.c
+++ b/tools/testing/selftests/bpf/progs/stack_arg_precision.c
@@ -6,7 +6,7 @@
 #include "../test_kmods/bpf_testmod_kfunc.h"
 #include "bpf_misc.h"
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 /* Force kfunc extern BTF generation for inline asm call below.
diff --git a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c
index 7e0ce5db28a0..b2a724a2790e 100644
--- a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c
+++ b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c
@@ -12,7 +12,7 @@ struct {
 	__type(value, long long);
 } map_hash_8b SEC(".maps");
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 __noinline __used
diff --git a/tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c b/tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c
index c9fe4857da3f..ed260041d827 100644
--- a/tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c
+++ b/tools/testing/selftests/bpf/progs/verifier_stack_arg_order.c
@@ -5,7 +5,7 @@
 #include <bpf/bpf_helpers.h>
 #include "bpf_misc.h"
 
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
+#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
 	defined(__BPF_FEATURE_STACK_ARGUMENT)
 
 __noinline __used __naked

-- 
2.53.0


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

Re: [bpf-next PATCH 2/2] selftests/bpf: Enable stack argument tests for riscv

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Stack argument selftests are incorrectly enabled for 32-bit RISC-V (RV32) targets, leading to test regressions.
--

--- Patch [2]: [bpf-next PATCH 2/2] selftests/bpf: Enable stack argument tests for riscv ---
commit 4c9f49e3a0c01bc5c673e83a3a3e5b7f61947d45
Author: Feng Jiang <jiangfeng@kylinos.cn>

selftests/bpf: Enable stack argument tests for riscv

This commit adds __TARGET_ARCH_riscv to the architecture guard in all stack
argument selftests so the real test cases are compiled for RISC-V. It keeps
the __BPF_FEATURE_STACK_ARGUMENT gate defined by clang.

Link: https://github.com/llvm/llvm-project/pull/189060

> diff --git a/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c b/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
> index 8d38aafe66a28..c8540d30e293d 100644
> --- a/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
> +++ b/tools/testing/selftests/bpf/progs/btf__stack_arg_precision.c
> @@ -4,7 +4,7 @@
>  #include <bpf/bpf_helpers.h>
>  #include "../test_kmods/bpf_testmod_kfunc.h"
>  
> -#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && \
> +#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_riscv)) && \
>  	defined(__BPF_FEATURE_STACK_ARGUMENT)

[Severity: Medium]
Does this incorrectly enable the tests for 32-bit RISC-V (RV32) as well?

The BPF selftests build system defines __TARGET_ARCH_riscv for both RV32
and RV64, but BPF stack arguments are only supported in the RV64 JIT.

If these tests are compiled and run on RV32, the verifier will likely reject
programs with more than 5 arguments (returning -ENOTSUPP or -EINVAL),
causing test regressions on that architecture.

Could this be restricted to RV64 by using
(defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64) across all of the
modified selftest files?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260812-bpf-riscv-stack-args-v1-0-67b246806e59@kylinos.cn?part=2

Re: [bpf-next PATCH 1/2] bpf, riscv: Add BPF stack arguments support for RV64 JIT

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Missing sign-extension for 32-bit kfunc arguments passed on the stack
--

--- Patch [1]: [bpf-next PATCH 1/2] bpf, riscv: Add BPF stack arguments support for RV64 JIT ---
commit c291f39756942d05aeab1b370b77119f4235a7f8
Author: Feng Jiang <jiangfeng@kylinos.cn>

bpf, riscv: Add BPF stack arguments support for RV64 JIT

This commit adds support for passing BPF stack arguments to BPF subprograms
and kfuncs in the RV64 JIT. It implements the RISC-V ABI requirement of
putting arguments 6-8 in registers A5-A7 and arguments 9+ on the stack.

> diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
> index 6b9972b07c1b0..b3f4bf9e1e7f2 100644
> --- a/arch/riscv/net/bpf_jit_comp64.c
> +++ b/arch/riscv/net/bpf_jit_comp64.c
[ ... ]
> @@ -1815,18 +1815,39 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
[ ... ]
>  		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
>  			const struct btf_func_model *fm;
> -			int idx;
> +			int idx, nargs;
>  
>  			fm = bpf_jit_find_kfunc_model(ctx->prog, insn);
>  			if (!fm)
>  				return -EINVAL;
>  
> -			for (idx = 0; idx < fm->nr_args; idx++) {
> +			nargs = min_t(int, fm->nr_args, MAX_BPF_FUNC_REG_ARGS);
> +			for (idx = 0; idx < nargs; idx++) {
>  				u8 reg = bpf_to_rv_reg(BPF_REG_1 + idx, ctx);
>  
>  				if (fm->arg_size[idx] == sizeof(int))
>  					emit_sextw(reg, reg, ctx);
>  			}
> +
> +			/* BPF stack args -> RISC-V ABI: args 6-8 in A5-A7, 9+ at SP+0 */
> +			if (fm->nr_args > MAX_BPF_FUNC_REG_ARGS) {
> +				int n_stack = fm->nr_args - MAX_BPF_FUNC_REG_ARGS;
> +				int n_reg = min_t(int, n_stack,
> +						  RV_MAX_REG_ARGS - MAX_BPF_FUNC_REG_ARGS);
> +
> +				for (idx = 0; idx < n_reg; idx++) {
> +					int sz = fm->arg_size[MAX_BPF_FUNC_REG_ARGS + idx];
> +
> +					emit_ld(RV_REG_A5 + idx, idx * 8, RV_REG_SP, ctx);
> +					if (sz == sizeof(int))
> +						emit_sextw(RV_REG_A5 + idx, RV_REG_A5 + idx, ctx);
> +				}
> +
> +				for (idx = 0; idx < n_stack - n_reg; idx++) {
> +					emit_ld(RV_REG_T1, (n_reg + idx) * 8, RV_REG_SP, ctx);
> +					emit_sd(RV_REG_SP, idx * 8, RV_REG_T1, ctx);
> +				}

[Severity: High]
Does this loop need to sign-extend 32-bit integer arguments passed on the
stack?

The RISC-V RV64 C ABI requires scalars narrower than 64 bits to be
sign-extended to 64 bits when passed on the stack. BPF ALU32 operations
zero-extend values, so if a negative 32-bit integer is passed on the stack
(argument 9 or above), its upper 32 bits will be zero instead of ones.

The preceding loops for register arguments (both BPF_REG_1-5 and A5-A7)
check fm->arg_size[idx] == sizeof(int) and use emit_sextw(). Is a similar
check needed here before writing the argument to the stack?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260812-bpf-riscv-stack-args-v1-0-67b246806e59@kylinos.cn?part=1