linux-kernel - [PATCH v2 5/6] selftests: riscv: verify initial vector state with ptrace

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Message-ID: <20251007115840.2320557-6-geomatsi@gmail.com>
Date: Tue,  7 Oct 2025 14:58:21 +0300
From: Sergey Matyukevich <geomatsi@...il.com>
To: linux-riscv@...ts.infradead.org,
	linux-kselftest@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	Paul Walmsley <pjw@...nel.org>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Alexandre Ghiti <alex@...ti.fr>,
	Oleg Nesterov <oleg@...hat.com>,
	Shuah Khan <shuah@...nel.org>,
	Jisheng Zhang <jszhang@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Thomas Huth <thuth@...hat.com>,
	Charlie Jenkins <charlie@...osinc.com>,
	Andy Chiu <andybnac@...il.com>,
	Han Gao <rabenda.cn@...il.com>,
	Samuel Holland <samuel.holland@...ive.com>,
	Nam Cao <namcao@...utronix.de>,
	Joel Granados <joel.granados@...nel.org>,
	Clément Léger <cleger@...osinc.com>,
	Conor Dooley <conor.dooley@...rochip.com>,
	Sergey Matyukevich <geomatsi@...il.com>
Subject: [PATCH v2 5/6] selftests: riscv: verify initial vector state with ptrace

Add a test case that attaches to a traced process immediately after its
first vector instructions to verify the initial vector context state.

Signed-off-by: Sergey Matyukevich <geomatsi@...il.com>
---
 .../testing/selftests/riscv/vector/v_ptrace.c | 103 ++++++++++++++++++
 1 file changed, 103 insertions(+)

diff --git a/tools/testing/selftests/riscv/vector/v_ptrace.c b/tools/testing/selftests/riscv/vector/v_ptrace.c
index ccda8a4dc49b..f452e04629ea 100644
--- a/tools/testing/selftests/riscv/vector/v_ptrace.c
+++ b/tools/testing/selftests/riscv/vector/v_ptrace.c
@@ -196,4 +196,107 @@ TEST(ptrace_rvv_invalid_vtype)
 	}
 }
 
+TEST(ptrace_rvv_early_access)
+{
+	static volatile unsigned long vstart;
+	static volatile unsigned long vtype;
+	static volatile unsigned long vlenb;
+	static volatile unsigned long vcsr;
+	static volatile unsigned long vl;
+	pid_t pid;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
+
+	chld_lock = 1;
+
+	pid = fork();
+
+	ASSERT_LE(0, pid)
+		TH_LOG("fork: %m");
+
+	if (pid == 0) {
+		while (chld_lock == 1)
+			asm volatile("" : : "g"(chld_lock) : "memory");
+
+		asm volatile("csrr %[vstart], vstart" : [vstart] "=r"(vstart));
+		asm volatile("csrr %[vl], vl" : [vl] "=r"(vl));
+		asm volatile("csrr %[vtype], vtype" : [vtype] "=r"(vtype));
+		asm volatile("csrr %[vcsr], vcsr" : [vcsr] "=r"(vcsr));
+		asm volatile("csrr %[vlenb], vlenb" : [vlenb] "=r"(vlenb));
+
+		asm volatile ("ebreak" : : : );
+	} else {
+		struct __riscv_v_regset_state *regset_data;
+		unsigned long vstart_csr;
+		unsigned long vl_csr;
+		unsigned long vtype_csr;
+		unsigned long vcsr_csr;
+		unsigned long vlenb_csr;
+		size_t regset_size;
+		struct iovec iov;
+		int status;
+
+		/* attach */
+
+		ASSERT_EQ(0, ptrace(PTRACE_ATTACH, pid, NULL, NULL));
+		ASSERT_EQ(pid, waitpid(pid, &status, 0));
+		ASSERT_TRUE(WIFSTOPPED(status));
+
+		/* unlock */
+
+		ASSERT_EQ(0, ptrace(PTRACE_POKEDATA, pid, &chld_lock, 0));
+
+		/* resume and wait for ebreak */
+
+		ASSERT_EQ(0, ptrace(PTRACE_CONT, pid, NULL, NULL));
+		ASSERT_EQ(pid, waitpid(pid, &status, 0));
+		ASSERT_TRUE(WIFSTOPPED(status));
+
+		/* read tracee vector csr regs using ptrace PEEKDATA */
+
+		errno = 0;
+		vstart_csr = ptrace(PTRACE_PEEKDATA, pid, &vstart, NULL);
+		ASSERT_FALSE((errno != 0) && (vstart_csr == -1));
+
+		errno = 0;
+		vl_csr = ptrace(PTRACE_PEEKDATA, pid, &vl, NULL);
+		ASSERT_FALSE((errno != 0) && (vl_csr == -1));
+
+		errno = 0;
+		vtype_csr = ptrace(PTRACE_PEEKDATA, pid, &vtype, NULL);
+		ASSERT_FALSE((errno != 0) && (vtype_csr == -1));
+
+		errno = 0;
+		vcsr_csr = ptrace(PTRACE_PEEKDATA, pid, &vcsr, NULL);
+		ASSERT_FALSE((errno != 0) && (vcsr_csr == -1));
+
+		errno = 0;
+		vlenb_csr = ptrace(PTRACE_PEEKDATA, pid, &vlenb, NULL);
+		ASSERT_FALSE((errno != 0) && (vlenb_csr == -1));
+
+		/* read tracee csr regs using ptrace GETREGSET */
+
+		regset_size = sizeof(*regset_data) + vlenb_csr * 32;
+		regset_data = calloc(1, regset_size);
+
+		iov.iov_base = regset_data;
+		iov.iov_len = regset_size;
+
+		ASSERT_EQ(0, ptrace(PTRACE_GETREGSET, pid, NT_RISCV_VECTOR, &iov));
+
+		/* compare */
+
+		EXPECT_EQ(vstart_csr, regset_data->vstart);
+		EXPECT_EQ(vtype_csr, regset_data->vtype);
+		EXPECT_EQ(vlenb_csr, regset_data->vlenb);
+		EXPECT_EQ(vcsr_csr, regset_data->vcsr);
+		EXPECT_EQ(vl_csr, regset_data->vl);
+
+		/* cleanup */
+
+		ASSERT_EQ(0, kill(pid, SIGKILL));
+	}
+}
+
 TEST_HARNESS_MAIN
-- 
2.51.0