diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 5655fe1ced46a1e92a183e6d1cde1665fc97e90c..9bbd74c0ea6be964aaf409fc892e74c8da9c74da 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -63,6 +63,7 @@ extern void fpsimd_load_state(struct fpsimd_state *state);
extern void fpsimd_thread_switch(struct task_struct *next);
extern void fpsimd_flush_thread(void);
+extern void fpsimd_signal_preserve_current_state(void);
extern void fpsimd_preserve_current_state(void);
extern void fpsimd_restore_current_state(void);
extern void fpsimd_update_current_state(struct fpsimd_state *state);
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index c7531b85b303e4df7ebb2c596833db4065ff191b..e7733fb19388db6fa00de2b8bc7859d5be0b9752 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -300,6 +300,32 @@ static void fpsimd_to_sve(struct task_struct *task)
sizeof(fst->vregs[i]));
}
+/*
+ * Transfer the SVE state in task->thread.sve_state to
+ * task->thread.fpsimd_state.
+ *
+ * Task can be a non-runnable task, or current. In the latter case,
+ * softirqs (and preemption) must be disabled.
+ * task->thread.sve_state must point to at least sve_state_size(task)
+ * bytes of allocated kernel memory.
+ * task->thread.sve_state must be up to date before calling this function.
+ */
+static void sve_to_fpsimd(struct task_struct *task)
+{
+ unsigned int vq;
+ void const *sst = task->thread.sve_state;
+ struct fpsimd_state *fst = &task->thread.fpsimd_state;
+ unsigned int i;
+
+ if (!system_supports_sve())
+ return;
+
+ vq = sve_vq_from_vl(task->thread.sve_vl);
+ for (i = 0; i < 32; ++i)
+ memcpy(&fst->vregs[i], ZREG(sst, vq, i),
+ sizeof(fst->vregs[i]));
+}
+
#ifdef CONFIG_ARM64_SVE
/*
@@ -501,9 +527,6 @@ void fpsimd_flush_thread(void)
/*
* Save the userland FPSIMD state of 'current' to memory, but only if the state
* currently held in the registers does in fact belong to 'current'
- *
- * Currently, SVE tasks can't exist, so just WARN in that case.
- * Subsequent patches will add full SVE support here.
*/
void fpsimd_preserve_current_state(void)
{
@@ -511,15 +534,22 @@ void fpsimd_preserve_current_state(void)
return;
local_bh_disable();
-
- if (!test_thread_flag(TIF_FOREIGN_FPSTATE))
- fpsimd_save_state(¤t->thread.fpsimd_state);
-
- WARN_ON_ONCE(test_and_clear_thread_flag(TIF_SVE));
-
+ task_fpsimd_save();
local_bh_enable();
}
+/*
+ * Like fpsimd_preserve_current_state(), but ensure that
+ * current->thread.fpsimd_state is updated so that it can be copied to
+ * the signal frame.
+ */
+void fpsimd_signal_preserve_current_state(void)
+{
+ fpsimd_preserve_current_state();
+ if (system_supports_sve() && test_thread_flag(TIF_SVE))
+ sve_to_fpsimd(current);
+}
+
/*
* Load the userland FPSIMD state of 'current' from memory, but only if the
* FPSIMD state already held in the registers is /not/ the most recent FPSIMD
@@ -555,7 +585,12 @@ void fpsimd_update_current_state(struct fpsimd_state *state)
local_bh_disable();
- fpsimd_load_state(state);
+ if (system_supports_sve() && test_thread_flag(TIF_SVE)) {
+ current->thread.fpsimd_state = *state;
+ fpsimd_to_sve(current);
+ }
+ task_fpsimd_load();
+
if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
struct fpsimd_state *st = ¤t->thread.fpsimd_state;
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index a032906cf4f782f4e99154c51999198ccb02ff0c..b120111a46be5c7c245e5003d23420a8df80e1e2 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -64,6 +64,7 @@ struct rt_sigframe_user_layout {
unsigned long fpsimd_offset;
unsigned long esr_offset;
+ unsigned long sve_offset;
unsigned long extra_offset;
unsigned long end_offset;
};
@@ -180,9 +181,6 @@ static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state;
int err;
- /* dump the hardware registers to the fpsimd_state structure */
- fpsimd_preserve_current_state();
-
/* copy the FP and status/control registers */
err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
__put_user_error(fpsimd->fpsr, &ctx->fpsr, err);
@@ -215,6 +213,8 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
__get_user_error(fpsimd.fpsr, &ctx->fpsr, err);
__get_user_error(fpsimd.fpcr, &ctx->fpcr, err);
+ clear_thread_flag(TIF_SVE);
+
/* load the hardware registers from the fpsimd_state structure */
if (!err)
fpsimd_update_current_state(&fpsimd);
@@ -222,10 +222,118 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
return err ? -EFAULT : 0;
}
+
struct user_ctxs {
struct fpsimd_context __user *fpsimd;
+ struct sve_context __user *sve;
};
+#ifdef CONFIG_ARM64_SVE
+
+static int preserve_sve_context(struct sve_context __user *ctx)
+{
+ int err = 0;
+ u16 reserved[ARRAY_SIZE(ctx->__reserved)];
+ unsigned int vl = current->thread.sve_vl;
+ unsigned int vq = 0;
+
+ if (test_thread_flag(TIF_SVE))
+ vq = sve_vq_from_vl(vl);
+
+ memset(reserved, 0, sizeof(reserved));
+
+ __put_user_error(SVE_MAGIC, &ctx->head.magic, err);
+ __put_user_error(round_up(SVE_SIG_CONTEXT_SIZE(vq), 16),
+ &ctx->head.size, err);
+ __put_user_error(vl, &ctx->vl, err);
+ BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved));
+ err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved));
+
+ if (vq) {
+ /*
+ * This assumes that the SVE state has already been saved to
+ * the task struct by calling preserve_fpsimd_context().
+ */
+ err |= __copy_to_user((char __user *)ctx + SVE_SIG_REGS_OFFSET,
+ current->thread.sve_state,
+ SVE_SIG_REGS_SIZE(vq));
+ }
+
+ return err ? -EFAULT : 0;
+}
+
+static int restore_sve_fpsimd_context(struct user_ctxs *user)
+{
+ int err;
+ unsigned int vq;
+ struct fpsimd_state fpsimd;
+ struct sve_context sve;
+
+ if (__copy_from_user(&sve, user->sve, sizeof(sve)))
+ return -EFAULT;
+
+ if (sve.vl != current->thread.sve_vl)
+ return -EINVAL;
+
+ if (sve.head.size <= sizeof(*user->sve)) {
+ clear_thread_flag(TIF_SVE);
+ goto fpsimd_only;
+ }
+
+ vq = sve_vq_from_vl(sve.vl);
+
+ if (sve.head.size < SVE_SIG_CONTEXT_SIZE(vq))
+ return -EINVAL;
+
+ /*
+ * Careful: we are about __copy_from_user() directly into
+ * thread.sve_state with preemption enabled, so protection is
+ * needed to prevent a racing context switch from writing stale
+ * registers back over the new data.
+ */
+
+ fpsimd_flush_task_state(current);
+ barrier();
+ /* From now, fpsimd_thread_switch() won't clear TIF_FOREIGN_FPSTATE */
+
+ set_thread_flag(TIF_FOREIGN_FPSTATE);
+ barrier();
+ /* From now, fpsimd_thread_switch() won't touch thread.sve_state */
+
+ sve_alloc(current);
+ err = __copy_from_user(current->thread.sve_state,
+ (char __user const *)user->sve +
+ SVE_SIG_REGS_OFFSET,
+ SVE_SIG_REGS_SIZE(vq));
+ if (err)
+ return -EFAULT;
+
+ set_thread_flag(TIF_SVE);
+
+fpsimd_only:
+ /* copy the FP and status/control registers */
+ /* restore_sigframe() already checked that user->fpsimd != NULL. */
+ err = __copy_from_user(fpsimd.vregs, user->fpsimd->vregs,
+ sizeof(fpsimd.vregs));
+ __get_user_error(fpsimd.fpsr, &user->fpsimd->fpsr, err);
+ __get_user_error(fpsimd.fpcr, &user->fpsimd->fpcr, err);
+
+ /* load the hardware registers from the fpsimd_state structure */
+ if (!err)
+ fpsimd_update_current_state(&fpsimd);
+
+ return err ? -EFAULT : 0;
+}
+
+#else /* ! CONFIG_ARM64_SVE */
+
+/* Turn any non-optimised out attempts to use these into a link error: */
+extern int preserve_sve_context(void __user *ctx);
+extern int restore_sve_fpsimd_context(struct user_ctxs *user);
+
+#endif /* ! CONFIG_ARM64_SVE */
+
+
static int parse_user_sigframe(struct user_ctxs *user,
struct rt_sigframe __user *sf)
{
@@ -238,6 +346,7 @@ static int parse_user_sigframe(struct user_ctxs *user,
char const __user *const sfp = (char const __user *)sf;
user->fpsimd = NULL;
+ user->sve = NULL;
if (!IS_ALIGNED((unsigned long)base, 16))
goto invalid;
@@ -288,6 +397,19 @@ static int parse_user_sigframe(struct user_ctxs *user,
/* ignore */
break;
+ case SVE_MAGIC:
+ if (!system_supports_sve())
+ goto invalid;
+
+ if (user->sve)
+ goto invalid;
+
+ if (size < sizeof(*user->sve))
+ goto invalid;
+
+ user->sve = (struct sve_context __user *)head;
+ break;
+
case EXTRA_MAGIC:
if (have_extra_context)
goto invalid;
@@ -364,9 +486,6 @@ static int parse_user_sigframe(struct user_ctxs *user,
}
done:
- if (!user->fpsimd)
- goto invalid;
-
return 0;
invalid:
@@ -400,8 +519,19 @@ static int restore_sigframe(struct pt_regs *regs,
if (err == 0)
err = parse_user_sigframe(&user, sf);
- if (err == 0)
- err = restore_fpsimd_context(user.fpsimd);
+ if (err == 0) {
+ if (!user.fpsimd)
+ return -EINVAL;
+
+ if (user.sve) {
+ if (!system_supports_sve())
+ return -EINVAL;
+
+ err = restore_sve_fpsimd_context(&user);
+ } else {
+ err = restore_fpsimd_context(user.fpsimd);
+ }
+ }
return err;
}
@@ -460,6 +590,18 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user)
return err;
}
+ if (system_supports_sve()) {
+ unsigned int vq = 0;
+
+ if (test_thread_flag(TIF_SVE))
+ vq = sve_vq_from_vl(current->thread.sve_vl);
+
+ err = sigframe_alloc(user, &user->sve_offset,
+ SVE_SIG_CONTEXT_SIZE(vq));
+ if (err)
+ return err;
+ }
+
return sigframe_alloc_end(user);
}
@@ -501,6 +643,13 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user,
__put_user_error(current->thread.fault_code, &esr_ctx->esr, err);
}
+ /* Scalable Vector Extension state, if present */
+ if (system_supports_sve() && err == 0 && user->sve_offset) {
+ struct sve_context __user *sve_ctx =
+ apply_user_offset(user, user->sve_offset);
+ err |= preserve_sve_context(sve_ctx);
+ }
+
if (err == 0 && user->extra_offset) {
char __user *sfp = (char __user *)user->sigframe;
char __user *userp =
@@ -600,6 +749,8 @@ static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
struct rt_sigframe __user *frame;
int err = 0;
+ fpsimd_signal_preserve_current_state();
+
if (get_sigframe(&user, ksig, regs))
return 1;
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index e09bf5d1560606405e25175d69d8b67929f02657..22711ee8e36c566eef59319a457e3d61e0f9d39d 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -239,7 +239,7 @@ static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
* Note that this also saves V16-31, which aren't visible
* in AArch32.
*/
- fpsimd_preserve_current_state();
+ fpsimd_signal_preserve_current_state();
/* Place structure header on the stack */
__put_user_error(magic, &frame->magic, err);