On Thu, Oct 02, 2025 at 12:53:13AM -0500, Andy Chiu wrote:

Hi Yong-Xuan,

I found some issues which deserve a re-roll:

On Wed, Oct 1, 2025 at 6:15 AM Yong-Xuan Wang yongxuan.wang@sifive.com wrote:

...

Add a test case that does some basic verification of the Vector ptrace interface. This forks a child process then using ptrace to inspect and manipulate the v31 register of the child.

Signed-off-by: Yong-Xuan Wang yongxuan.wang@sifive.com

tools/testing/selftests/riscv/vector/Makefile | 5 +- .../selftests/riscv/vector/vstate_ptrace.c | 132 ++++++++++++++++++ 2 files changed, 136 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/riscv/vector/vstate_ptrace.c

diff --git a/tools/testing/selftests/riscv/vector/Makefile b/tools/testing/selftests/riscv/vector/Makefile index 6f7497f4e7b3..45f25e9dd264 100644 --- a/tools/testing/selftests/riscv/vector/Makefile +++ b/tools/testing/selftests/riscv/vector/Makefile @@ -2,7 +2,7 @@ # Copyright (C) 2021 ARM Limited # Originally tools/testing/arm64/abi/Makefile

-TEST_GEN_PROGS := v_initval vstate_prctl +TEST_GEN_PROGS := v_initval vstate_prctl vsate_ptrace

Please s/vsate_ptrace/vstate_ptrace

Otherwise we will not get the program compiled

...

TEST_GEN_PROGS_EXTENDED := vstate_exec_nolibc v_exec_initval_nolibc

include ../../lib.mk @@ -26,3 +26,6 @@ $(OUTPUT)/v_initval: v_initval.c $(OUTPUT)/sys_hwprobe.o $(OUTPUT)/v_helpers.o $(OUTPUT)/v_exec_initval_nolibc: v_exec_initval_nolibc.c $(CC) -nostdlib -static -include ../../../../include/nolibc/nolibc.h \ -Wall $(CFLAGS) $(LDFLAGS) $^ -o $@ -lgcc

+$(OUTPUT)/vstate_ptrace: vstate_ptrace.c $(OUTPUT)/sys_hwprobe.o $(OUTPUT)/v_helpers.o

•   $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
  

diff --git a/tools/testing/selftests/riscv/vector/vstate_ptrace.c b/tools/testing/selftests/riscv/vector/vstate_ptrace.c new file mode 100644 index 000000000000..8a7bcf318e59 --- /dev/null +++ b/tools/testing/selftests/riscv/vector/vstate_ptrace.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <stdio.h> +#include <stdlib.h> +#include <asm/ptrace.h> +#include <linux/elf.h> +#include <sys/ptrace.h> +#include <sys/uio.h> +#include <sys/wait.h> +#include "../../kselftest.h" +#include "v_helpers.h"

+int parent_set_val, child_set_val;

+static long do_ptrace(enum __ptrace_request op, pid_t pid, long type, size_t size, void *data) +{

•   struct iovec v_iovec = {
  

•           .iov_len = size,
  

•           .iov_base = data
  

•   };
  

•   return ptrace(op, pid, type, &v_iovec);
  

+}

+static int do_child(void) +{

•   int out;
  

•   if (ptrace(PTRACE_TRACEME, -1, NULL, NULL)) {
  

•           ksft_perror("PTRACE_TRACEME failed\n");
  

•           return EXIT_FAILURE;
  

•   }
  

•   asm volatile (".option push\n\t"
  

•           ".option        arch, +v\n\t"
  

As mentioned before, please use ".option arch, +v,-c\n\t" or ".option norvc\n\t" and +=4 when advancing the pc

arch -c should be avoided, there are cases when it does not always avoid using all compressed instructions. norvc should always do the right thing though. There is discussion at [1] about deprecating it (along with all variants of -ext).

[1] https://inbox.sourceware.org/binutils/7ecdc846-0822-4666-957f-ff818786fb44@i...

- Charlie

...

•           "vsetivli       x0, 1, e32, m1, ta, ma\n\t"
  

•           "vmv.s.x        v31, %[in]\n\t"
  

•           "ebreak\n\t"
  

•           "vmv.x.s        %[out], v31\n\t"
  

•           ".option pop\n\t"
  

•           : [out] "=r" (out)
  

•           : [in] "r" (child_set_val));
  

•   if (out != parent_set_val)
  

•           return EXIT_FAILURE;
  

•   return EXIT_SUCCESS;
  

+}

+static void do_parent(pid_t child) +{

•   int status;
  

•   void *data = NULL;
  

•   /* Attach to the child */
  

•   while (waitpid(child, &status, 0)) {
  

•           if (WIFEXITED(status)) {
  

•                   ksft_test_result(WEXITSTATUS(status) == 0, "SETREGSET vector\n");
  

•                   goto out;
  

•           } else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP)) {
  

•                   size_t size, t;
  

unused variable t

...

•                   void *data, *v31;
  

•                   struct __riscv_v_regset_state *v_regset_hdr;
  

•                   struct user_regs_struct *gpreg;
  

•                   size = sizeof(*v_regset_hdr);
  

•                   data = malloc(size);
  

•                   if (!data)
  

•                           goto out;
  

•                   v_regset_hdr = (struct __riscv_v_regset_state *)data;
  

•                   if (do_ptrace(PTRACE_GETREGSET, child, NT_RISCV_VECTOR, size, data))
  

•                           goto out;
  

•                   ksft_print_msg("vlenb %ld\n", v_regset_hdr->vlenb);
  

•                   data = realloc(data, size + v_regset_hdr->vlenb * 32);
  

realloc may give a new pointer so v_regset_hdr has to be updated here before the next use

...

•                   if (!data)
  

•                           goto out;
  

•                   v31 = (void *)(data + size + v_regset_hdr->vlenb * 31);
  

•                   size += v_regset_hdr->vlenb * 32;
  

•                   if (do_ptrace(PTRACE_GETREGSET, child, NT_RISCV_VECTOR, size, data))
  

•                           goto out;
  

•                   ksft_test_result(*(int *)v31 == child_set_val, "GETREGSET vector\n");
  

•                   *(int *)v31 = parent_set_val;
  

•                   if (do_ptrace(PTRACE_SETREGSET, child, NT_RISCV_VECTOR, size, data))
  

•                           goto out;
  

•                   /* move the pc forward */
  

•                   size = sizeof(*gpreg);
  

•                   data = realloc(data, size);
  

•                   gpreg = (struct user_regs_struct *)data;
  

•                   if (do_ptrace(PTRACE_GETREGSET, child, NT_PRSTATUS, size, data))
  

•                           goto out;
  

•                   gpreg->pc += 2;
  

•                   if (do_ptrace(PTRACE_SETREGSET, child, NT_PRSTATUS, size, data))
  

•                           goto out;
  

•           }
  

•           ptrace(PTRACE_CONT, child, NULL, NULL);
  

•   }
  

+out:

•   free(data);
  

+}

+int main(void) +{

•   pid_t child;
  

•   ksft_set_plan(2);
  

•   if (!is_vector_supported() && !is_xtheadvector_supported())
  

•           ksft_exit_skip("Vector not supported\n");
  

•   srandom(getpid());
  

•   parent_set_val = rand();
  

•   child_set_val = rand();
  

•   child = fork();
  

•   if (child < 0)
  

•           ksft_exit_fail_msg("Fork failed %d\n", child);
  

•   if (!child)
  

•           return do_child();
  

•   do_parent(child);
  

•   ksft_finished();
  

+}

2.43.0

Thanks, Andy