linux-kernel - [PATCH v2 3/6] selftests: riscv: set invalid vtype using ptrace

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Message-ID: <20251007115840.2320557-4-geomatsi@gmail.com>
Date: Tue,  7 Oct 2025 14:58:19 +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 3/6] selftests: riscv: set invalid vtype using ptrace

Add a test case that attempts to set invalid vtype value using ptrace
and verifies that the 'vill' bit is set as required by the RISC-V
Vector specification v1.0, Section 3.4.1.

Signed-off-by: Sergey Matyukevich <geomatsi@...il.com>
---
 .../testing/selftests/riscv/vector/v_ptrace.c | 112 ++++++++++++++++++
 1 file changed, 112 insertions(+)

diff --git a/tools/testing/selftests/riscv/vector/v_ptrace.c b/tools/testing/selftests/riscv/vector/v_ptrace.c
index 6a8d56a5c4f4..ccda8a4dc49b 100644
--- a/tools/testing/selftests/riscv/vector/v_ptrace.c
+++ b/tools/testing/selftests/riscv/vector/v_ptrace.c
@@ -84,4 +84,116 @@ TEST(ptrace_rvv_not_enabled)
 	}
 }
 
+TEST(ptrace_rvv_invalid_vtype)
+{
+	static volatile unsigned long vtype;
+	unsigned long vlenb;
+	unsigned long reg;
+	pid_t pid;
+
+	if (!is_vector_supported())
+		SKIP(return, "Vector not supported");
+
+	asm volatile("csrr %[vlenb], vlenb" : [vlenb] "=r"(vlenb));
+
+	if (vlenb > 16)
+		SKIP(return, "This test does not support VLEN > 128");
+
+	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(".option arch, +v\n");
+		asm(".option arch, +c\n");
+		asm volatile("vsetvli x0, x0, e8, m8, tu, mu\n");
+
+		while (1) {
+			asm volatile ("c.ebreak");
+			asm volatile("csrr %[vtype], vtype" : [vtype] "=r"(vtype) : :);
+			asm volatile ("c.ebreak");
+		}
+	} else {
+		struct __riscv_v_regset_state *regset_data;
+		struct user_regs_struct regs;
+		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 the 1st c.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 GETREGSET */
+
+		regset_size = sizeof(*regset_data) + vlenb * 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));
+
+		/* set invalid vtype 0x1d = (5 | 3 << 3):
+		 * - LMUL: 1/8
+		 * - SEW:  64
+		 *   - invalid configuration for VLENB <= 128
+		 */
+		regset_data->vtype = 0x1d;
+		ASSERT_EQ(0, ptrace(PTRACE_SETREGSET, pid, NT_RISCV_VECTOR, &iov));
+
+		/* skip 1st c.ebreak, then resume and wait for the 2nd c.ebreak */
+
+		iov.iov_base = &regs;
+		iov.iov_len = sizeof(regs);
+
+		ASSERT_EQ(0, ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov));
+		regs.pc += 2;
+		ASSERT_EQ(0, ptrace(PTRACE_SETREGSET, pid, NT_PRSTATUS, &iov));
+
+		ASSERT_EQ(0, ptrace(PTRACE_CONT, pid, NULL, NULL));
+		ASSERT_EQ(pid, waitpid(pid, &status, 0));
+		ASSERT_TRUE(WIFSTOPPED(status));
+
+		/* read tracee vtype using ptrace GETREGSET */
+
+		iov.iov_base = regset_data;
+		iov.iov_len = regset_size;
+		ASSERT_EQ(0, ptrace(PTRACE_GETREGSET, pid, NT_RISCV_VECTOR, &iov));
+
+		/* read tracee vtype ptrace PEEKDATA */
+
+		errno = 0;
+		reg = ptrace(PTRACE_PEEKDATA, pid, &vtype, NULL);
+		ASSERT_FALSE((errno != 0) && (reg == -1));
+
+		/* verify that V state is illegal */
+
+		EXPECT_EQ(reg, regset_data->vtype);
+		EXPECT_EQ(1UL, (regset_data->vtype >> (__riscv_xlen - 1)));
+
+		/* cleanup */
+
+		ASSERT_EQ(0, kill(pid, SIGKILL));
+	}
+}
+
 TEST_HARNESS_MAIN
-- 
2.51.0