* [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps
@ 2026-09-28 7:18 Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 1/4] " Chen Pei
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: Chen Pei @ 2026-09-28 7:18 UTC (permalink / raw)
To: ast, daniel, andrii, memxor, bjorn, puranjay
Cc: ihor.solodrai, eddyz87, martin.lau, song, yonghong.song, jolsa,
emil, pulehui, pjw, palmer, shuah, guoren, bpf, linux-riscv,
linux-kernel
The indirect jump instruction (BPF_JMP | BPF_JA | BPF_X, "gotox") and the
BPF_MAP_TYPE_INSN_ARRAY jump tables it consumes are core features: the
verifier accepts them on every architecture, and the x86-64, arm64 and
powerpc JITs implement them. On riscv64 a program using gotox passes
verification and then fails to load, because the JIT does not know the
opcode and CONFIG_BPF_JIT_ALWAYS_ON leaves no interpreter to fall back
onto.
This series adds the riscv64 support and turns the existing selftests on
for that architecture.
Patch 1 emits "jalr zero, rd, 0" for gotox and publishes the xlated to
jitted offsets through bpf_prog_update_insn_ptrs(), which is what fills
in the jump table addresses. Patches 2 to 4 widen the arch guards in
verifier_gotox.c, compute_live_registers.c and bpf_insn_array.c to
riscv64, the same way the other architectures were enabled.
Changes since v2:
- Pick up Pu Lehui's Reviewed-by on patch 1.
- Enable two more gotox test files for riscv64: compute_live_registers.c
and bpf_insn_array.c.
Changes since v1:
- Rebased onto bpf-next.
- Patch 1: reword the code comment to say "shift ctx->offset[] by one".
- Patch 2: collapse the multi-line #endif marker to a single line.
- Added Reviewed-by/Acked-by from Björn Töpel.
Testing
=======
Environment: QEMU virt rv64, with CONFIG_BPF_JIT=y,
CONFIG_BPF_JIT_ALWAYS_ON=y, CONFIG_DEBUG_INFO_BTF=y; selftests
cross-built with clang 23.
- test_progs -t verifier_gotox: 33/33 subtests pass.
- test_progs -t bpf_insn_array: 20/20 subtests pass.
- test_progs -t compute_live_registers: 20/20 subtests pass, including
the gotox liveness subtest.
- test_progs-cpuv4 -t bpf_gotox: 14/14 subtests pass.
Chen Pei (4):
bpf, riscv: Add support for indirect jumps
selftests/bpf: Enable gotox tests for riscv64
selftests/bpf: Enable gotox liveness test for riscv64
selftests/bpf: Enable instruction array test for riscv64
arch/riscv/net/bpf_jit_comp64.c | 5 +++++
arch/riscv/net/bpf_jit_core.c | 16 ++++++++++++++--
.../selftests/bpf/prog_tests/bpf_insn_array.c | 3 ++-
.../selftests/bpf/progs/compute_live_registers.c | 5 +++--
.../testing/selftests/bpf/progs/verifier_gotox.c | 6 ++++--
5 files changed, 28 insertions(+), 7 deletions(-)
--
2.50.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH bpf-next v3 1/4] bpf, riscv: Add support for indirect jumps
2026-09-28 7:18 [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Chen Pei
@ 2026-09-28 7:18 ` Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 2/4] selftests/bpf: Enable gotox tests for riscv64 Chen Pei
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Chen Pei @ 2026-09-28 7:18 UTC (permalink / raw)
To: ast, daniel, andrii, memxor, bjorn, puranjay
Cc: ihor.solodrai, eddyz87, martin.lau, song, yonghong.song, jolsa,
emil, pulehui, pjw, palmer, shuah, guoren, bpf, linux-riscv,
linux-kernel
Implement JIT support for the indirect jump instruction (BPF_JMP |
BPF_JA | BPF_X), a.k.a. gotox, which lets a BPF program jump through a
BPF_MAP_TYPE_INSN_ARRAY jump table.
Emit "jalr zero, rd, 0" and hand the xlated to jitted offsets to
bpf_prog_update_insn_ptrs(), which is what fills in the jump table
entries; without that call the load fails with -EFAULT in
bpf_insn_array_ready(). ctx->offset[] holds the offset of the insn
*following* insn i, as bpf_prog_fill_jited_linfo() expects, so it is
shifted by one and offset[0] comes from the prologue length. build_body()
now records both halves of a multi-insn record, so no slot keeps a
fabricated offset.
Only the RV64 JIT is covered; RV32 keeps failing to load as before.
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
---
Changes since v2:
- Pick up Pu Lehui's Reviewed-by; no code change.
Changes since v1:
- Reword the code comment to say "shift ctx->offset[] by one".
arch/riscv/net/bpf_jit_comp64.c | 5 +++++
arch/riscv/net/bpf_jit_core.c | 16 ++++++++++++++--
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index ed0a6f871dea..9de3749fb268 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -1691,6 +1691,11 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
emit_zextw(rd, rd, ctx);
break;
+ /* JUMP reg */
+ case BPF_JMP | BPF_JA | BPF_X:
+ emit_jalr(RV_REG_ZERO, rd, 0, ctx);
+ break;
+
/* JUMP off */
case BPF_JMP | BPF_JA:
case BPF_JMP32 | BPF_JA:
diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c
index 470a6ace5662..5265dd5bd39e 100644
--- a/arch/riscv/net/bpf_jit_core.c
+++ b/arch/riscv/net/bpf_jit_core.c
@@ -26,10 +26,13 @@ static int build_body(struct rv_jit_context *ctx, bool extra_pass, int *offset)
int ret;
ret = bpf_jit_emit_insn(insn, ctx, extra_pass);
- if (ret > 0)
- i++; /* skip the next instruction */
if (offset)
offset[i] = ctx->ninsns;
+ if (ret > 0) {
+ i++; /* skip the next instruction */
+ if (offset)
+ offset[i] = ctx->ninsns;
+ }
if (ret < 0)
return ret;
}
@@ -176,6 +179,15 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_pr
for (i = 0; i < prog->len; i++)
ctx->offset[i] = ninsns_rvoff(ctx->offset[i]);
bpf_prog_fill_jited_linfo(prog, ctx->offset);
+
+ /*
+ * bpf_prog_update_insn_ptrs() wants the start of each insn, so
+ * shift ctx->offset[] by one and get insn 0 from the prologue.
+ */
+ for (i = prog->len - 1; i > 0; i--)
+ ctx->offset[i] = ctx->offset[i - 1];
+ ctx->offset[0] = ninsns_rvoff(ctx->prologue_len);
+ bpf_prog_update_insn_ptrs(prog, ctx->offset, jit_data->ro_image);
out_offset:
kvfree(ctx->offset);
kfree(jit_data);
--
2.50.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH bpf-next v3 2/4] selftests/bpf: Enable gotox tests for riscv64
2026-09-28 7:18 [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 1/4] " Chen Pei
@ 2026-09-28 7:18 ` Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 3/4] selftests/bpf: Enable gotox liveness test " Chen Pei
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Chen Pei @ 2026-09-28 7:18 UTC (permalink / raw)
To: ast, daniel, andrii, memxor, bjorn, puranjay
Cc: ihor.solodrai, eddyz87, martin.lau, song, yonghong.song, jolsa,
emil, pulehui, pjw, palmer, shuah, guoren, bpf, linux-riscv,
linux-kernel
The riscv64 JIT now supports the gotox instruction and jump tables, so
run the tests in verifier_gotox.c on riscv64 too, mirroring what was done
for arm64 and powerpc.
The guard is 64-bit only because the RV32 JIT does not implement gotox.
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
---
Changes since v2:
- Unchanged.
Changes since v1:
- Collapse the multi-line #endif marker to a single line.
tools/testing/selftests/bpf/progs/verifier_gotox.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/verifier_gotox.c b/tools/testing/selftests/bpf/progs/verifier_gotox.c
index f5a9878c7b8d..96a9d914930e 100644
--- a/tools/testing/selftests/bpf/progs/verifier_gotox.c
+++ b/tools/testing/selftests/bpf/progs/verifier_gotox.c
@@ -6,7 +6,9 @@
#include "bpf_misc.h"
#include "../../../include/linux/filter.h"
-#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_powerpc)
+#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || \
+ defined(__TARGET_ARCH_powerpc) || \
+ (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64)
#define DEFINE_SIMPLE_JUMP_TABLE_PROG(NAME, SRC_REG, OFF, IMM, OUTCOME) \
\
@@ -580,6 +582,6 @@ nop_%=: \
: __clobber_all);
}
-#endif /* __TARGET_ARCH_x86 || __TARGET_ARCH_arm64 || __TARGET_ARCH_powerpc*/
+#endif /* gotox: x86, arm64, powerpc, riscv64 */
char _license[] SEC("license") = "GPL";
--
2.50.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH bpf-next v3 3/4] selftests/bpf: Enable gotox liveness test for riscv64
2026-09-28 7:18 [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 1/4] " Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 2/4] selftests/bpf: Enable gotox tests for riscv64 Chen Pei
@ 2026-09-28 7:18 ` Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 4/4] selftests/bpf: Enable instruction array " Chen Pei
2026-09-28 9:10 ` [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Pu Lehui
4 siblings, 0 replies; 6+ messages in thread
From: Chen Pei @ 2026-09-28 7:18 UTC (permalink / raw)
To: ast, daniel, andrii, memxor, bjorn, puranjay
Cc: ihor.solodrai, eddyz87, martin.lau, song, yonghong.song, jolsa,
emil, pulehui, pjw, palmer, shuah, guoren, bpf, linux-riscv,
linux-kernel
The riscv64 JIT now supports gotox, so enable the gotox liveness test in
compute_live_registers.c on riscv64 as well.
The guard is 64-bit only because the RV32 JIT does not implement gotox.
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
---
tools/testing/selftests/bpf/progs/compute_live_registers.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/compute_live_registers.c b/tools/testing/selftests/bpf/progs/compute_live_registers.c
index 941b65fe7c07..e482c10004a0 100644
--- a/tools/testing/selftests/bpf/progs/compute_live_registers.c
+++ b/tools/testing/selftests/bpf/progs/compute_live_registers.c
@@ -467,7 +467,8 @@ __naked void subprog_ret_reg_pair(void)
::: __clobber_all);
}
-#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64)
+#if defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || \
+ (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64)
SEC("socket")
__log_level(2)
@@ -506,7 +507,7 @@ void gotox(void)
: __clobber_all);
}
-#endif /* __TARGET_ARCH_x86 || __TARGET_ARCH_arm64 */
+#endif /* gotox: x86, arm64, riscv64 */
/* to retain debug info for BTF generation */
void kfunc_root(void)
--
2.50.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH bpf-next v3 4/4] selftests/bpf: Enable instruction array test for riscv64
2026-09-28 7:18 [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Chen Pei
` (2 preceding siblings ...)
2026-09-28 7:18 ` [PATCH bpf-next v3 3/4] selftests/bpf: Enable gotox liveness test " Chen Pei
@ 2026-09-28 7:18 ` Chen Pei
2026-09-28 9:10 ` [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Pu Lehui
4 siblings, 0 replies; 6+ messages in thread
From: Chen Pei @ 2026-09-28 7:18 UTC (permalink / raw)
To: ast, daniel, andrii, memxor, bjorn, puranjay
Cc: ihor.solodrai, eddyz87, martin.lau, song, yonghong.song, jolsa,
emil, pulehui, pjw, palmer, shuah, guoren, bpf, linux-riscv,
linux-kernel
As the riscv64 JIT now supports instruction array (gotox jump tables),
enable the corresponding bpf selftest for riscv64. The guard is 64-bit
only because the RV32 JIT does not implement gotox.
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
---
tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
index bfedeed24ac5..4ffe4fe6b78e 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
@@ -4,7 +4,8 @@
#include <bpf/btf.h>
#include <test_progs.h>
-#if defined(__x86_64__) || defined(__powerpc__) || defined(__aarch64__)
+#if defined(__x86_64__) || defined(__powerpc__) || defined(__aarch64__) || \
+ (defined(__riscv) && __riscv_xlen == 64)
static int map_create(__u32 map_type, __u32 max_entries)
{
const char *map_name = "insn_array";
--
2.50.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps
2026-09-28 7:18 [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Chen Pei
` (3 preceding siblings ...)
2026-09-28 7:18 ` [PATCH bpf-next v3 4/4] selftests/bpf: Enable instruction array " Chen Pei
@ 2026-09-28 9:10 ` Pu Lehui
4 siblings, 0 replies; 6+ messages in thread
From: Pu Lehui @ 2026-09-28 9:10 UTC (permalink / raw)
To: Chen Pei, ast, daniel, andrii, memxor, bjorn, puranjay
Cc: ihor.solodrai, eddyz87, martin.lau, song, yonghong.song, jolsa,
emil, pjw, palmer, shuah, guoren, bpf, linux-riscv, linux-kernel
On 2026/9/28 15:18, Chen Pei wrote:
> The indirect jump instruction (BPF_JMP | BPF_JA | BPF_X, "gotox") and the
> BPF_MAP_TYPE_INSN_ARRAY jump tables it consumes are core features: the
> verifier accepts them on every architecture, and the x86-64, arm64 and
> powerpc JITs implement them. On riscv64 a program using gotox passes
> verification and then fails to load, because the JIT does not know the
> opcode and CONFIG_BPF_JIT_ALWAYS_ON leaves no interpreter to fall back
> onto.
>
> This series adds the riscv64 support and turns the existing selftests on
> for that architecture.
>
> Patch 1 emits "jalr zero, rd, 0" for gotox and publishes the xlated to
> jitted offsets through bpf_prog_update_insn_ptrs(), which is what fills
> in the jump table addresses. Patches 2 to 4 widen the arch guards in
> verifier_gotox.c, compute_live_registers.c and bpf_insn_array.c to
> riscv64, the same way the other architectures were enabled.
>
> Changes since v2:
> - Pick up Pu Lehui's Reviewed-by on patch 1.
> - Enable two more gotox test files for riscv64: compute_live_registers.c
> and bpf_insn_array.c.
>
> Changes since v1:
> - Rebased onto bpf-next.
> - Patch 1: reword the code comment to say "shift ctx->offset[] by one".
> - Patch 2: collapse the multi-line #endif marker to a single line.
> - Added Reviewed-by/Acked-by from Björn Töpel.
>
> Testing
> =======
>
> Environment: QEMU virt rv64, with CONFIG_BPF_JIT=y,
> CONFIG_BPF_JIT_ALWAYS_ON=y, CONFIG_DEBUG_INFO_BTF=y; selftests
> cross-built with clang 23.
>
> - test_progs -t verifier_gotox: 33/33 subtests pass.
> - test_progs -t bpf_insn_array: 20/20 subtests pass.
> - test_progs -t compute_live_registers: 20/20 subtests pass, including
> the gotox liveness subtest.
> - test_progs-cpuv4 -t bpf_gotox: 14/14 subtests pass.
>
> Chen Pei (4):
> bpf, riscv: Add support for indirect jumps
> selftests/bpf: Enable gotox tests for riscv64
> selftests/bpf: Enable gotox liveness test for riscv64
> selftests/bpf: Enable instruction array test for riscv64
>
> arch/riscv/net/bpf_jit_comp64.c | 5 +++++
> arch/riscv/net/bpf_jit_core.c | 16 ++++++++++++++--
> .../selftests/bpf/prog_tests/bpf_insn_array.c | 3 ++-
> .../selftests/bpf/progs/compute_live_registers.c | 5 +++--
> .../testing/selftests/bpf/progs/verifier_gotox.c | 6 ++++--
> 5 files changed, 28 insertions(+), 7 deletions(-)
>
For this series:
Tested-by: Pu Lehui <pulehui@huawei.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-09-28 9:10 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2026-09-28 7:18 [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 1/4] " Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 2/4] selftests/bpf: Enable gotox tests for riscv64 Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 3/4] selftests/bpf: Enable gotox liveness test " Chen Pei
2026-09-28 7:18 ` [PATCH bpf-next v3 4/4] selftests/bpf: Enable instruction array " Chen Pei
2026-09-28 9:10 ` [PATCH bpf-next v3 0/4] bpf, riscv: Add support for indirect jumps Pu Lehui
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