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.
Signed-off-by: Charlie Jenkins <[email protected]>
---
These tests came about to highlight the bug fixed in
https://lore.kernel.org/lkml/[email protected]/
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
--
- Charlie
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
>
> Signed-off-by: Charlie Jenkins <[email protected]>
> ---
> These tests came about to highlight the bug fixed in
> https://lore.kernel.org/lkml/[email protected]/
> 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
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 <[email protected]>
> > ---
> > These tests came about to highlight the bug fixed in
> > https://lore.kernel.org/lkml/[email protected]/
> > 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
>
Charlie Jenkins <[email protected]> writes:
> 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.
>
> Signed-off-by: Charlie Jenkins <[email protected]>
Nice!
Reviewed-by: Björn Töpel <[email protected]>
On Thu, Apr 4, 2024 at 1:47 PM Björn Töpel <[email protected]> wrote:
>
> Charlie Jenkins <[email protected]> writes:
>
> > 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.
> >
> > Signed-off-by: Charlie Jenkins <[email protected]>
>
> Nice!
>
> Reviewed-by: Björn Töpel <[email protected]>
Thanks!
Reviewed-by: Andy Chiu <[email protected]>
Tested-by: Andy Chiu <[email protected]>