[PATCH v5 6/7] selftests: riscv: Extend vector tests for sigreturn and ptrace

Add new test cases to verify the vector state restorations at syscall
stops for ptrace and signal interfaces. Specifically:
1. Signal handler should read all ones at syscall stop and modifying
   context should success.
2. Ptrace should read all ones but any modification to NT_RISCV_VECTOR
   is silently dropped.

Signed-off-by: Andy Chiu <[email protected]>
---
Changelog v4:
 - remove timer dependency from the signal delivery (Sashiko)
 - solve 2 memory leaks in ptrace (Sashiko)
Changelog v3:
 - new patch since v3
---
 .../selftests/riscv/sigreturn/sigreturn.c     |  71 +++++++++++
 .../selftests/riscv/vector/vstate_ptrace.c    | 111 +++++++++++++++++-
 2 files changed, 178 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/riscv/sigreturn/sigreturn.c b/tools/testing/selftests/riscv/sigreturn/sigreturn.c
index e10873d95fed..647249dbd7e6 100644
--- a/tools/testing/selftests/riscv/sigreturn/sigreturn.c
+++ b/tools/testing/selftests/riscv/sigreturn/sigreturn.c
@@ -7,6 +7,7 @@
 #include "kselftest_harness.h"
 
 #define RISCV_V_MAGIC		0x53465457
+#define END_MAGIC		0
 #define DEFAULT_VALUE		2
 #define SIGNAL_HANDLER_OVERRIDE	3
 
@@ -61,6 +62,76 @@ static int vector_sigreturn(int data, void (*handler)(int, siginfo_t *, void *))
 	return after_sigreturn;
 }
 
+#define V_TEST_PATTERN_SIGNAL 0x98
+int nulled_val;
+static void sigalrm_handler(int sig, siginfo_t *info, void *vcontext)
+{
+	ucontext_t *context = vcontext;
+	struct __riscv_extra_ext_header *ext;
+	struct __riscv_ctx_hdr *hdr;
+	uint8_t *ext_ptr;
+
+	/* Find the vector context */
+	ext = (void *)(&context->uc_mcontext.__fpregs);
+	ext_ptr = (uint8_t *)ext;
+	hdr = &ext->hdr;
+
+	while (hdr->magic != END_MAGIC) {
+		if (hdr->magic == RISCV_V_MAGIC) {
+			struct __riscv_v_ext_state *v_state = (struct __riscv_v_ext_state *)(hdr + 1);
+			/* Assume a valid datap */
+			nulled_val = *(int *)v_state->datap;
+			/* Fill all vector registers with magic pattern */
+			memset(v_state->datap, V_TEST_PATTERN_SIGNAL, v_state->vlenb * 32);
+			/*
+			 * We must also set the vector configuration so that when
+			 * userspace reads v0, it uses a valid element width (e8).
+			 */
+			v_state->vl = v_state->vlenb;
+			v_state->vtype = 0; /* e8, m1, tu, mu */
+			break;
+		}
+		/* Move to the next extension header */
+		ext_ptr += hdr->size;
+		hdr = (struct __riscv_ctx_hdr *)ext_ptr;
+	}
+}
+
+TEST(test_signal_syscall_ucontext) {
+	struct sigaction sa;
+
+	/* Make sure we get V in ucontext by executing vsetvli */
+	asm volatile (
+	    ".option push\n\t"
+	    ".option		arch, +v\n\t"
+	    "vsetivli	x0, 1, e32, m1, ta, ma\n\t"
+	    ".option pop\n\t" : : :);
+
+	sa.sa_flags = SA_SIGINFO;
+	sa.sa_sigaction = sigalrm_handler;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(SIGALRM, &sa, NULL) == -1)
+		ksft_exit_fail_msg("Failed to register signal handler\n");
+
+	raise(SIGALRM);
+	/*
+	 * If the kernel successfully parsed and restored our modified ucontext,
+	 * v0 will contain V_TEST_PATTERN_SIGNAL.
+	 */
+	unsigned char v0_val;
+
+	asm volatile(
+			".option push\n\t"
+			".option arch, +zve32x\n\t"
+			"vmv.x.s %0, v0\n\t"
+			".option pop\n\t"
+			: "=r" (v0_val)
+		    );
+
+	EXPECT_EQ(v0_val, V_TEST_PATTERN_SIGNAL);
+	EXPECT_EQ(nulled_val, -1);
+}
+
 TEST(vector_restore)
 {
 	int result;
diff --git a/tools/testing/selftests/riscv/vector/vstate_ptrace.c b/tools/testing/selftests/riscv/vector/vstate_ptrace.c
index 1479abc0c9cb..863a16f6e1a3 100644
--- a/tools/testing/selftests/riscv/vector/vstate_ptrace.c
+++ b/tools/testing/selftests/riscv/vector/vstate_ptrace.c
@@ -21,6 +21,41 @@ static long do_ptrace(enum __ptrace_request op, pid_t pid, long type, size_t siz
 	return ptrace(op, pid, type, &v_iovec);
 }
 
+static int do_child_syscall_stop(void)
+{
+	int out;
+
+	if (ptrace(PTRACE_TRACEME, -1, NULL, NULL)) {
+		ksft_perror("PTRACE_TRACEME failed\n");
+		return EXIT_FAILURE;
+	}
+
+	raise(SIGSTOP);
+
+	asm volatile (".option push\n\t"
+		".option	arch, +v\n\t"
+		"vsetivli	x0, 1, e32, m1, ta, ma\n\t"
+		"vmv.s.x	v31, %[in]\n\t"
+		".option pop\n\t"
+		:
+		: [in] "r" (child_set_val));
+
+	getpid();
+
+	asm volatile (".option push\n\t"
+		".option	arch, +v\n\t"
+		"vsetivli	x0, 1, e32, m1, ta, ma\n\t"
+		"vmv.x.s	%[out], v31\n\t"
+		".option pop\n\t"
+		: [out] "=r" (out)
+		:);
+
+	if (out != -1)
+		return EXIT_FAILURE;
+
+	return EXIT_SUCCESS;
+}
+
 static int do_child(void)
 {
 	int out;
@@ -59,7 +94,7 @@ static void do_parent(pid_t child)
 			goto out;
 		} else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP)) {
 			size_t size;
-			void *data, *v31;
+			void *vctx, *v31;
 			struct __riscv_v_regset_state *v_regset_hdr;
 			struct user_regs_struct *gpreg;
 
@@ -73,9 +108,11 @@ static void do_parent(pid_t child)
 				goto out;
 
 			ksft_print_msg("vlenb %ld\n", v_regset_hdr->vlenb);
-			data = realloc(data, size + v_regset_hdr->vlenb * 32);
-			if (!data)
+			vctx = realloc(data, size + v_regset_hdr->vlenb * 32);
+			if (!vctx)
 				goto out;
+			data = vctx;
+
 			v_regset_hdr = (struct __riscv_v_regset_state *)data;
 			v31 = (void *)(data + size + v_regset_hdr->vlenb * 31);
 			size += v_regset_hdr->vlenb * 32;
@@ -109,11 +146,65 @@ static void do_parent(pid_t child)
 	free(data);
 }
 
+static void do_parent_syscall_stop(pid_t child)
+{
+	int status;
+	void *data = NULL;
+
+	while (waitpid(child, &status, 0)) {
+		if (WIFEXITED(status)) {
+			ksft_test_result(WEXITSTATUS(status) == 0,
+					 "SETREGSET vector at syscall stop\n");
+			goto out;
+		} else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGSTOP)) {
+			/* Attach to the child at syscall stop */
+			ptrace(PTRACE_SYSCALL, child, NULL, NULL);
+			continue;
+		} else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP)) {
+			size_t size;
+			void *vctx, *v31;
+			struct __riscv_v_regset_state *v_regset_hdr;
+
+			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);
+			vctx = realloc(data, size + v_regset_hdr->vlenb * 32);
+			if (!vctx)
+				goto out;
+			data = vctx;
+
+			v_regset_hdr = (struct __riscv_v_regset_state *)data;
+			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 == -1, "GETREGSET vector at syscall stop\n");
+
+			*(int *)v31 = parent_set_val;
+			if (do_ptrace(PTRACE_SETREGSET, child, NT_RISCV_VECTOR, size, data))
+				goto out;
+		}
+		ptrace(PTRACE_CONT, child, NULL, NULL);
+	}
+
+out:
+	free(data);
+}
+
 int main(void)
 {
 	pid_t child;
 
-	ksft_set_plan(2);
+	ksft_set_plan(4);
 	if (!is_vector_supported() && !is_xtheadvector_supported())
 		ksft_exit_skip("Vector not supported\n");
 
@@ -130,5 +221,17 @@ int main(void)
 
 	do_parent(child);
 
+	parent_set_val = 0x53355457;
+	child_set_val = 0x49504F21;
+
+	child = fork();
+	if (child < 0)
+		ksft_exit_fail_msg("Fork failed %d\n", child);
+
+	if (!child)
+		return do_child_syscall_stop();
+
+	do_parent_syscall_stop(child);
+
 	ksft_finished();
 }
-- 
2.43.0