diff options
| -rw-r--r-- | arch/arm64/include/asm/fpsimd.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 55 | ||||
| -rw-r--r-- | arch/arm64/kernel/signal.c | 167 | ||||
| -rw-r--r-- | arch/arm64/kernel/signal32.c | 2 |
4 files changed, 206 insertions, 19 deletions
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 5655fe1ced46..9bbd74c0ea6b 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 c7531b85b303..e7733fb19388 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) { @@ -511,16 +534,23 @@ 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 * state of 'current' @@ -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 a032906cf4f7..b120111a46be 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 e09bf5d15606..22711ee8e36c 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); |