[PATCH bpf-next 0/2] riscv, bpf: Support indirect calls to bpf subprogs (callx)

[PATCH bpf-next 0/2] riscv, bpf: Support indirect calls to bpf subprogs (callx)

[Pu Lehui]

From: Pu Lehui <pulehui@huawei.com>

This series implements support for indirect calls to bpf subprogs on
riscv64 and enables the corresponding selftests.

Meanwhile, this series also resolves the test_verifier failures
previously captured by riscv-bpf-daily due to missing callx support [0].

[0] https://github.com/pulehui/riscv-bpf-daily/issues/11

Pu Lehui (2):
  riscv, bpf: Support indirect calls to bpf subprogs (callx)
  selftests/bpf: Enable callx related testcases for RV64

 arch/riscv/net/bpf_jit_comp64.c                      | 12 ++++++++++++
 .../selftests/bpf/prog_tests/callx_func_ptr_map.c    |  3 ++-
 .../selftests/bpf/prog_tests/callx_rodata_lskel.c    |  3 ++-
 tools/testing/selftests/bpf/progs/verifier_callx.c   |  3 ++-
 .../selftests/bpf/progs/verifier_callx_rodata.c      |  3 ++-
 5 files changed, 20 insertions(+), 4 deletions(-)

-- 
2.34.1

[PATCH bpf-next 1/2] riscv, bpf: Support indirect calls to bpf subprogs (callx)

[Pu Lehui]

From: Pu Lehui <pulehui@huawei.com>

Implement callx by emitting a jalr instruction to jump to the target
subprog address held in rd, and marking the call as it clobbers
RV_REG_RA.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
---
 arch/riscv/net/bpf_jit_comp64.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 7ce9f8460c59..88430825f4f5 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -2071,6 +2071,13 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 			emit_mv(bpf_to_rv_reg(BPF_REG_0, ctx), RV_REG_A0, ctx);
 		break;
 	}
+
+	/* indirect call to a bpf subprog via the address in rd */
+	case BPF_JMP | BPF_CALL | BPF_X:
+		mark_call(ctx);
+		emit_jalr(RV_REG_RA, rd, 0, ctx);
+		break;
+
 	/* tail call */
 	case BPF_JMP | BPF_TAIL_CALL:
 		if (emit_bpf_tail_call(i, ctx))
@@ -2397,3 +2404,8 @@ bool bpf_jit_supports_exceptions(void)
 	 */
 	return IS_ENABLED(CONFIG_FRAME_POINTER);
 }
+
+bool bpf_jit_supports_callx(void)
+{
+	return true;
+}
-- 
2.34.1

[PATCH bpf-next 2/2] selftests/bpf: Enable callx related testcases for RV64

[Pu Lehui]

From: Pu Lehui <pulehui@huawei.com>

Enable callx bpf selftests for RV64 now that the RV64 JIT supports
indirect calls to subprogs.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
---
 tools/testing/selftests/bpf/prog_tests/callx_func_ptr_map.c | 3 ++-
 tools/testing/selftests/bpf/prog_tests/callx_rodata_lskel.c | 3 ++-
 tools/testing/selftests/bpf/progs/verifier_callx.c          | 3 ++-
 tools/testing/selftests/bpf/progs/verifier_callx_rodata.c   | 3 ++-
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/callx_func_ptr_map.c b/tools/testing/selftests/bpf/prog_tests/callx_func_ptr_map.c
index 42b33d5876b1..cc63b84e4d94 100644
--- a/tools/testing/selftests/bpf/prog_tests/callx_func_ptr_map.c
+++ b/tools/testing/selftests/bpf/prog_tests/callx_func_ptr_map.c
@@ -8,7 +8,8 @@
 #include <linux/filter.h>
 #include <bpf/btf.h>
 
-#if defined(__x86_64__) || defined(__aarch64__)
+#if defined(__x86_64__) || defined(__aarch64__) || \
+    (defined(__riscv) && __riscv_xlen == 64)
 
 #define CALLEE_INSN	6
 #define DATA		0x1234
diff --git a/tools/testing/selftests/bpf/prog_tests/callx_rodata_lskel.c b/tools/testing/selftests/bpf/prog_tests/callx_rodata_lskel.c
index fc5181c5b5ba..f6ef67c3141e 100644
--- a/tools/testing/selftests/bpf/prog_tests/callx_rodata_lskel.c
+++ b/tools/testing/selftests/bpf/prog_tests/callx_rodata_lskel.c
@@ -3,7 +3,8 @@
 
 #include "callx_rodata.lskel.h"
 
-#if defined(__x86_64__) || defined(__aarch64__)
+#if defined(__x86_64__) || defined(__aarch64__) || \
+    (defined(__riscv) && __riscv_xlen == 64)
 
 static void run(int prog_fd, int expected, const char *name)
 {
diff --git a/tools/testing/selftests/bpf/progs/verifier_callx.c b/tools/testing/selftests/bpf/progs/verifier_callx.c
index bc31d0221f6a..7e59188d9fca 100644
--- a/tools/testing/selftests/bpf/progs/verifier_callx.c
+++ b/tools/testing/selftests/bpf/progs/verifier_callx.c
@@ -7,7 +7,8 @@
 #include "../../../include/linux/filter.h"
 
 /* gcc doesn't support indirect calls */
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && defined(__clang__)
+#if defined(__clang__) && (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || \
+    (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64))
 
 #define CALLX_INSN(DST, SRC, OFF, IMM) \
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL | BPF_X, DST, SRC, OFF, IMM)
diff --git a/tools/testing/selftests/bpf/progs/verifier_callx_rodata.c b/tools/testing/selftests/bpf/progs/verifier_callx_rodata.c
index db3169a1ddf6..3ebd50f9c4b6 100644
--- a/tools/testing/selftests/bpf/progs/verifier_callx_rodata.c
+++ b/tools/testing/selftests/bpf/progs/verifier_callx_rodata.c
@@ -7,7 +7,8 @@
 #include "../../../include/linux/filter.h"
 
 /* gcc doesn't support indirect calls */
-#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)) && defined(__clang__)
+#if defined(__clang__) && (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || \
+    (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64))
 
 /*
  * Read-only data with pointers to functions, where the compiler puts tables
-- 
2.34.1

Re: [PATCH bpf-next 0/2] riscv, bpf: Support indirect calls to bpf subprogs (callx)

[Pu Lehui]

This series fail to apply, I have resent a new one.


https://lore.kernel.org/all/20260930064928.1909085-1-pulehui@huaweicloud.com/T/#t

On 2026/9/29 16:54, Pu Lehui wrote:
> From: Pu Lehui <pulehui@huawei.com>
> 
> This series implements support for indirect calls to bpf subprogs on
> riscv64 and enables the corresponding selftests.
> 
> Meanwhile, this series also resolves the test_verifier failures
> previously captured by riscv-bpf-daily due to missing callx support [0].
> 
> [0] https://github.com/pulehui/riscv-bpf-daily/issues/11
> 
> Pu Lehui (2):
>    riscv, bpf: Support indirect calls to bpf subprogs (callx)
>    selftests/bpf: Enable callx related testcases for RV64
> 
>   arch/riscv/net/bpf_jit_comp64.c                      | 12 ++++++++++++
>   .../selftests/bpf/prog_tests/callx_func_ptr_map.c    |  3 ++-
>   .../selftests/bpf/prog_tests/callx_rodata_lskel.c    |  3 ++-
>   tools/testing/selftests/bpf/progs/verifier_callx.c   |  3 ++-
>   .../selftests/bpf/progs/verifier_callx_rodata.c      |  3 ++-
>   5 files changed, 20 insertions(+), 4 deletions(-)
>