On Wed, Apr 03, 2024 at 05:27:23PM -0700, Vineet Gupta wrote:
On 4/3/24 16:50, Charlie Jenkins wrote:
Add two tests to check vector save/restore when a signal is received during a vector routine. One test ensures that a value is not clobbered during signal handling. The other verifies that vector registers modified in the signal handler are properly reflected when the signal handling is complete.
Hmm, isn't this testing two contradictory things ?
We do want V regs to be not clobbered across a handled signal, o/w V enabled code would just not work at all. That implies that anything done by signal handler should just be discarded - no ?
Am I missing something.
-Vineet
This is referring to the user-implemented signal handler. The test in question is testing the ability of the user-implemented signal handler to be able to modify the vector registers. In the test:
static void vector_override(int sig_no, siginfo_t *info, void *vcontext) { ...
*(int *)v_ext_state->datap = SIGNAL_HANDLER_OVERRIDE;
... }
This line is changing the saved state of the user program's vector registers.
When the signal handling concludes and the original user program resumes execution, the content of the user-context registers that were modified by the signal handler should be restored into the hardware registers. Hence the test case checks that the v0 register contains the value SIGNAL_HANDLER_OVERRIDE.
EXPECT_EQ(SIGNAL_HANDLER_OVERRIDE, result);
- Charlie
Signed-off-by: Charlie Jenkins charlie@rivosinc.com
These tests came about to highlight the bug fixed in https://lore.kernel.org/lkml/20240403072638.567446-1-bjorn@kernel.org/ and will only pass with that fix applied.
tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/sigreturn/.gitignore | 1 + tools/testing/selftests/riscv/sigreturn/Makefile | 12 ++++ .../testing/selftests/riscv/sigreturn/sigreturn.c | 82 ++++++++++++++++++++++ 4 files changed, 96 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/riscv/Makefile b/tools/testing/selftests/riscv/Makefile index 4a9ff515a3a0..7ce03d832b64 100644 --- a/tools/testing/selftests/riscv/Makefile +++ b/tools/testing/selftests/riscv/Makefile @@ -5,7 +5,7 @@ ARCH ?= $(shell uname -m 2>/dev/null || echo not) ifneq (,$(filter $(ARCH),riscv)) -RISCV_SUBTARGETS ?= hwprobe vector mm +RISCV_SUBTARGETS ?= hwprobe vector mm sigreturn else RISCV_SUBTARGETS := endif diff --git a/tools/testing/selftests/riscv/sigreturn/.gitignore b/tools/testing/selftests/riscv/sigreturn/.gitignore new file mode 100644 index 000000000000..35002b8ae780 --- /dev/null +++ b/tools/testing/selftests/riscv/sigreturn/.gitignore @@ -0,0 +1 @@ +sigreturn diff --git a/tools/testing/selftests/riscv/sigreturn/Makefile b/tools/testing/selftests/riscv/sigreturn/Makefile new file mode 100644 index 000000000000..eb8bac9279a8 --- /dev/null +++ b/tools/testing/selftests/riscv/sigreturn/Makefile @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2021 ARM Limited +# Originally tools/testing/arm64/abi/Makefile
+CFLAGS += -I$(top_srcdir)/tools/include
+TEST_GEN_PROGS := sigreturn
+include ../../lib.mk
+$(OUTPUT)/sigreturn: sigreturn.c
- $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
diff --git a/tools/testing/selftests/riscv/sigreturn/sigreturn.c b/tools/testing/selftests/riscv/sigreturn/sigreturn.c new file mode 100644 index 000000000000..62397d5934f1 --- /dev/null +++ b/tools/testing/selftests/riscv/sigreturn/sigreturn.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <ucontext.h> +#include <linux/ptrace.h> +#include "../../kselftest_harness.h"
+#define RISCV_V_MAGIC 0x53465457 +#define DEFAULT_VALUE 2 +#define SIGNAL_HANDLER_OVERRIDE 3
+static void simple_handle(int sig_no, siginfo_t *info, void *vcontext) +{
- ucontext_t *context = vcontext;
- context->uc_mcontext.__gregs[REG_PC] = context->uc_mcontext.__gregs[REG_PC] + 4;
+}
+static void vector_override(int sig_no, siginfo_t *info, void *vcontext) +{
- ucontext_t *context = vcontext;
- // vector state
- struct __riscv_extra_ext_header *ext;
- struct __riscv_v_ext_state *v_ext_state;
- /* Find the vector context. */
- ext = (void *)(&context->uc_mcontext.__fpregs);
- if (ext->hdr.magic != RISCV_V_MAGIC) {
fprintf(stderr, "bad vector magic: %x\n", ext->hdr.magic);abort();- }
- v_ext_state = (void *)((char *)(ext) + sizeof(*ext));
- *(int *)v_ext_state->datap = SIGNAL_HANDLER_OVERRIDE;
- context->uc_mcontext.__gregs[REG_PC] = context->uc_mcontext.__gregs[REG_PC] + 4;
+}
+static int vector_sigreturn(int data, void (*handler)(int, siginfo_t *, void *)) +{
- int after_sigreturn;
- struct sigaction sig_action = {
.sa_sigaction = handler,.sa_flags = SA_SIGINFO- };
- sigaction(SIGSEGV, &sig_action, 0);
- asm(".option push \n\
.option arch, +v \n\vsetivli x0, 1, e32, ta, ma \n\vmv.s.x v0, %1 \n\# Generate SIGSEGV \n\lw a0, 0(x0) \n\vmv.x.s %0, v0 \n\.option pop" : "=r" (after_sigreturn) : "r" (data));- return after_sigreturn;
+}
+TEST(vector_restore) +{
- int result;
- result = vector_sigreturn(DEFAULT_VALUE, &simple_handle);
- EXPECT_EQ(DEFAULT_VALUE, result);
+}
+TEST(vector_restore_signal_handler_override) +{
- int result;
- result = vector_sigreturn(DEFAULT_VALUE, &vector_override);
- EXPECT_EQ(SIGNAL_HANDLER_OVERRIDE, result);
+}
+TEST_HARNESS_MAIN
base-commit: 4cece764965020c22cff7665b18a012006359095 change-id: 20240403-vector_sigreturn_tests-8118f0ac54fa