diff options
Diffstat (limited to 'arch/arm64/kernel/fpsimd.c')
-rw-r--r-- | arch/arm64/kernel/fpsimd.c | 376 |
1 files changed, 165 insertions, 211 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 8370d55f0353..c37f02d7194e 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -119,7 +119,7 @@ * whatever is in the FPSIMD registers is not saved to memory, but discarded. */ -static DEFINE_PER_CPU(struct cpu_fp_state, fpsimd_last_state); +DEFINE_PER_CPU(struct cpu_fp_state, fpsimd_last_state); __ro_after_init struct vl_info vl_info[ARM64_VEC_MAX] = { #ifdef CONFIG_ARM64_SVE @@ -180,12 +180,12 @@ static inline void set_sve_default_vl(int val) set_default_vl(ARM64_VEC_SVE, val); } -static void __percpu *efi_sve_state; +static u8 *efi_sve_state; #else /* ! CONFIG_ARM64_SVE */ /* Dummy declaration for code that will be optimised out: */ -extern void __percpu *efi_sve_state; +extern u8 *efi_sve_state; #endif /* ! CONFIG_ARM64_SVE */ @@ -359,20 +359,15 @@ static void task_fpsimd_load(void) WARN_ON(preemptible()); WARN_ON(test_thread_flag(TIF_KERNEL_FPSTATE)); - if (system_supports_fpmr()) - write_sysreg_s(current->thread.uw.fpmr, SYS_FPMR); - if (system_supports_sve() || system_supports_sme()) { switch (current->thread.fp_type) { case FP_STATE_FPSIMD: /* Stop tracking SVE for this task until next use. */ - if (test_and_clear_thread_flag(TIF_SVE)) - sve_user_disable(); + clear_thread_flag(TIF_SVE); break; case FP_STATE_SVE: - if (!thread_sm_enabled(¤t->thread) && - !WARN_ON_ONCE(!test_and_set_thread_flag(TIF_SVE))) - sve_user_enable(); + if (!thread_sm_enabled(¤t->thread)) + WARN_ON_ONCE(!test_and_set_thread_flag(TIF_SVE)); if (test_thread_flag(TIF_SVE)) sve_set_vq(sve_vq_from_vl(task_get_sve_vl(current)) - 1); @@ -413,6 +408,9 @@ static void task_fpsimd_load(void) restore_ffr = system_supports_fa64(); } + if (system_supports_fpmr()) + write_sysreg_s(current->thread.uw.fpmr, SYS_FPMR); + if (restore_sve_regs) { WARN_ON_ONCE(current->thread.fp_type != FP_STATE_SVE); sve_load_state(sve_pffr(¤t->thread), @@ -453,12 +451,15 @@ static void fpsimd_save_user_state(void) *(last->fpmr) = read_sysreg_s(SYS_FPMR); /* - * If a task is in a syscall the ABI allows us to only - * preserve the state shared with FPSIMD so don't bother - * saving the full SVE state in that case. + * Save SVE state if it is live. + * + * The syscall ABI discards live SVE state at syscall entry. When + * entering a syscall, fpsimd_syscall_enter() sets to_save to + * FP_STATE_FPSIMD to allow the SVE state to be lazily discarded until + * either new SVE state is loaded+bound or fpsimd_syscall_exit() is + * called prior to a return to userspace. */ - if ((last->to_save == FP_STATE_CURRENT && test_thread_flag(TIF_SVE) && - !in_syscall(current_pt_regs())) || + if ((last->to_save == FP_STATE_CURRENT && test_thread_flag(TIF_SVE)) || last->to_save == FP_STATE_SVE) { save_sve_regs = true; save_ffr = true; @@ -651,7 +652,7 @@ static void __fpsimd_to_sve(void *sst, struct user_fpsimd_state const *fst, * task->thread.uw.fpsimd_state must be up to date before calling this * function. */ -static void fpsimd_to_sve(struct task_struct *task) +static inline void fpsimd_to_sve(struct task_struct *task) { unsigned int vq; void *sst = task->thread.sve_state; @@ -675,7 +676,7 @@ static void fpsimd_to_sve(struct task_struct *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) +static inline void sve_to_fpsimd(struct task_struct *task) { unsigned int vq, vl; void const *sst = task->thread.sve_state; @@ -694,44 +695,39 @@ static void sve_to_fpsimd(struct task_struct *task) } } -void cpu_enable_fpmr(const struct arm64_cpu_capabilities *__always_unused p) +static inline void __fpsimd_zero_vregs(struct user_fpsimd_state *fpsimd) { - write_sysreg_s(read_sysreg_s(SYS_SCTLR_EL1) | SCTLR_EL1_EnFPM_MASK, - SYS_SCTLR_EL1); + memset(&fpsimd->vregs, 0, sizeof(fpsimd->vregs)); } -#ifdef CONFIG_ARM64_SVE /* - * Call __sve_free() directly only if you know task can't be scheduled - * or preempted. + * Simulate the effects of an SMSTOP SM instruction. */ -static void __sve_free(struct task_struct *task) +void task_smstop_sm(struct task_struct *task) { - kfree(task->thread.sve_state); - task->thread.sve_state = NULL; -} + if (!thread_sm_enabled(&task->thread)) + return; -static void sve_free(struct task_struct *task) -{ - WARN_ON(test_tsk_thread_flag(task, TIF_SVE)); + __fpsimd_zero_vregs(&task->thread.uw.fpsimd_state); + task->thread.uw.fpsimd_state.fpsr = 0x0800009f; + if (system_supports_fpmr()) + task->thread.uw.fpmr = 0; - __sve_free(task); + task->thread.svcr &= ~SVCR_SM_MASK; + task->thread.fp_type = FP_STATE_FPSIMD; } -/* - * Return how many bytes of memory are required to store the full SVE - * state for task, given task's currently configured vector length. - */ -size_t sve_state_size(struct task_struct const *task) +void cpu_enable_fpmr(const struct arm64_cpu_capabilities *__always_unused p) { - unsigned int vl = 0; - - if (system_supports_sve()) - vl = task_get_sve_vl(task); - if (system_supports_sme()) - vl = max(vl, task_get_sme_vl(task)); + write_sysreg_s(read_sysreg_s(SYS_SCTLR_EL1) | SCTLR_EL1_EnFPM_MASK, + SYS_SCTLR_EL1); +} - return SVE_SIG_REGS_SIZE(sve_vq_from_vl(vl)); +#ifdef CONFIG_ARM64_SVE +static void sve_free(struct task_struct *task) +{ + kfree(task->thread.sve_state); + task->thread.sve_state = NULL; } /* @@ -758,69 +754,34 @@ void sve_alloc(struct task_struct *task, bool flush) kzalloc(sve_state_size(task), GFP_KERNEL); } - -/* - * Force the FPSIMD state shared with SVE to be updated in the SVE state - * even if the SVE state is the current active state. - * - * This should only be called by ptrace. task must be non-runnable. - * task->thread.sve_state must point to at least sve_state_size(task) - * bytes of allocated kernel memory. - */ -void fpsimd_force_sync_to_sve(struct task_struct *task) -{ - fpsimd_to_sve(task); -} - -/* - * Ensure that task->thread.sve_state is up to date with respect to - * the user task, irrespective of when SVE is in use or not. - * - * This should only be called by ptrace. task must be non-runnable. - * task->thread.sve_state must point to at least sve_state_size(task) - * bytes of allocated kernel memory. - */ -void fpsimd_sync_to_sve(struct task_struct *task) -{ - if (!test_tsk_thread_flag(task, TIF_SVE) && - !thread_sm_enabled(&task->thread)) - fpsimd_to_sve(task); -} - /* - * Ensure that task->thread.uw.fpsimd_state is up to date with respect to - * the user task, irrespective of whether SVE is in use or not. + * Ensure that task->thread.uw.fpsimd_state is up to date with respect to the + * task's currently effective FPSIMD/SVE state. * - * This should only be called by ptrace. task must be non-runnable. - * task->thread.sve_state must point to at least sve_state_size(task) - * bytes of allocated kernel memory. + * The task's FPSIMD/SVE/SME state must not be subject to concurrent + * manipulation. */ -void sve_sync_to_fpsimd(struct task_struct *task) +void fpsimd_sync_from_effective_state(struct task_struct *task) { if (task->thread.fp_type == FP_STATE_SVE) sve_to_fpsimd(task); } /* - * Ensure that task->thread.sve_state is up to date with respect to - * the task->thread.uw.fpsimd_state. + * Ensure that the task's currently effective FPSIMD/SVE state is up to date + * with respect to task->thread.uw.fpsimd_state, zeroing any effective + * non-FPSIMD (S)SVE state. * - * This should only be called by ptrace to merge new FPSIMD register - * values into a task for which SVE is currently active. - * task must be non-runnable. - * task->thread.sve_state must point to at least sve_state_size(task) - * bytes of allocated kernel memory. - * task->thread.uw.fpsimd_state must already have been initialised with - * the new FPSIMD register values to be merged in. + * The task's FPSIMD/SVE/SME state must not be subject to concurrent + * manipulation. */ -void sve_sync_from_fpsimd_zeropad(struct task_struct *task) +void fpsimd_sync_to_effective_state_zeropad(struct task_struct *task) { unsigned int vq; void *sst = task->thread.sve_state; struct user_fpsimd_state const *fst = &task->thread.uw.fpsimd_state; - if (!test_tsk_thread_flag(task, TIF_SVE) && - !thread_sm_enabled(&task->thread)) + if (task->thread.fp_type != FP_STATE_SVE) return; vq = sve_vq_from_vl(thread_get_cur_vl(&task->thread)); @@ -829,10 +790,73 @@ void sve_sync_from_fpsimd_zeropad(struct task_struct *task) __fpsimd_to_sve(sst, fst, vq); } +static int change_live_vector_length(struct task_struct *task, + enum vec_type type, + unsigned long vl) +{ + unsigned int sve_vl = task_get_sve_vl(task); + unsigned int sme_vl = task_get_sme_vl(task); + void *sve_state = NULL, *sme_state = NULL; + + if (type == ARM64_VEC_SME) + sme_vl = vl; + else + sve_vl = vl; + + /* + * Allocate the new sve_state and sme_state before freeing the old + * copies so that allocation failure can be handled without needing to + * mutate the task's state in any way. + * + * Changes to the SVE vector length must not discard live ZA state or + * clear PSTATE.ZA, as userspace code which is unaware of the AAPCS64 + * ZA lazy saving scheme may attempt to change the SVE vector length + * while unsaved/dormant ZA state exists. + */ + sve_state = kzalloc(__sve_state_size(sve_vl, sme_vl), GFP_KERNEL); + if (!sve_state) + goto out_mem; + + if (type == ARM64_VEC_SME) { + sme_state = kzalloc(__sme_state_size(sme_vl), GFP_KERNEL); + if (!sme_state) + goto out_mem; + } + + if (task == current) + fpsimd_save_and_flush_current_state(); + else + fpsimd_flush_task_state(task); + + /* + * Always preserve PSTATE.SM and the effective FPSIMD state, zeroing + * other SVE state. + */ + fpsimd_sync_from_effective_state(task); + task_set_vl(task, type, vl); + kfree(task->thread.sve_state); + task->thread.sve_state = sve_state; + fpsimd_sync_to_effective_state_zeropad(task); + + if (type == ARM64_VEC_SME) { + task->thread.svcr &= ~SVCR_ZA_MASK; + kfree(task->thread.sme_state); + task->thread.sme_state = sme_state; + } + + return 0; + +out_mem: + kfree(sve_state); + kfree(sme_state); + return -ENOMEM; +} + int vec_set_vector_length(struct task_struct *task, enum vec_type type, unsigned long vl, unsigned long flags) { - bool free_sme = false; + bool onexec = flags & PR_SVE_SET_VL_ONEXEC; + bool inherit = flags & PR_SVE_VL_INHERIT; if (flags & ~(unsigned long)(PR_SVE_VL_INHERIT | PR_SVE_SET_VL_ONEXEC)) @@ -852,71 +876,17 @@ int vec_set_vector_length(struct task_struct *task, enum vec_type type, vl = find_supported_vector_length(type, vl); - if (flags & (PR_SVE_VL_INHERIT | - PR_SVE_SET_VL_ONEXEC)) + if (!onexec && vl != task_get_vl(task, type)) { + if (change_live_vector_length(task, type, vl)) + return -ENOMEM; + } + + if (onexec || inherit) task_set_vl_onexec(task, type, vl); else /* Reset VL to system default on next exec: */ task_set_vl_onexec(task, type, 0); - /* Only actually set the VL if not deferred: */ - if (flags & PR_SVE_SET_VL_ONEXEC) - goto out; - - if (vl == task_get_vl(task, type)) - goto out; - - /* - * To ensure the FPSIMD bits of the SVE vector registers are preserved, - * write any live register state back to task_struct, and convert to a - * regular FPSIMD thread. - */ - if (task == current) { - get_cpu_fpsimd_context(); - - fpsimd_save_user_state(); - } - - fpsimd_flush_task_state(task); - if (test_and_clear_tsk_thread_flag(task, TIF_SVE) || - thread_sm_enabled(&task->thread)) { - sve_to_fpsimd(task); - task->thread.fp_type = FP_STATE_FPSIMD; - } - - if (system_supports_sme()) { - if (type == ARM64_VEC_SME || - !(task->thread.svcr & (SVCR_SM_MASK | SVCR_ZA_MASK))) { - /* - * We are changing the SME VL or weren't using - * SME anyway, discard the state and force a - * reallocation. - */ - task->thread.svcr &= ~(SVCR_SM_MASK | - SVCR_ZA_MASK); - clear_tsk_thread_flag(task, TIF_SME); - free_sme = true; - } - } - - if (task == current) - put_cpu_fpsimd_context(); - - task_set_vl(task, type, vl); - - /* - * Free the changed states if they are not in use, SME will be - * reallocated to the correct size on next use and we just - * allocate SVE now in case it is needed for use in streaming - * mode. - */ - sve_free(task); - sve_alloc(task, true); - - if (free_sme) - sme_free(task); - -out: update_tsk_thread_flag(task, vec_vl_inherit_flag(type), flags & PR_SVE_VL_INHERIT); @@ -1131,15 +1101,15 @@ static void __init sve_efi_setup(void) if (!sve_vl_valid(max_vl)) goto fail; - efi_sve_state = __alloc_percpu( - SVE_SIG_REGS_SIZE(sve_vq_from_vl(max_vl)), SVE_VQ_BYTES); + efi_sve_state = kmalloc(SVE_SIG_REGS_SIZE(sve_vq_from_vl(max_vl)), + GFP_KERNEL); if (!efi_sve_state) goto fail; return; fail: - panic("Cannot allocate percpu memory for EFI SVE save/restore"); + panic("Cannot allocate memory for EFI SVE save/restore"); } void cpu_enable_sve(const struct arm64_cpu_capabilities *__always_unused p) @@ -1212,7 +1182,7 @@ void __init sve_setup(void) */ void fpsimd_release_task(struct task_struct *dead_task) { - __sve_free(dead_task); + sve_free(dead_task); sme_free(dead_task); } @@ -1436,7 +1406,7 @@ void do_sme_acc(unsigned long esr, struct pt_regs *regs) * If this not a trap due to SME being disabled then something * is being used in the wrong mode, report as SIGILL. */ - if (ESR_ELx_ISS(esr) != ESR_ELx_SME_ISS_SME_DISABLED) { + if (ESR_ELx_SME_ISS_SMTC(esr) != ESR_ELx_SME_ISS_SMTC_SME_DISABLED) { force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); return; } @@ -1460,6 +1430,8 @@ void do_sme_acc(unsigned long esr, struct pt_regs *regs) sme_set_vq(vq_minus_one); fpsimd_bind_task_to_cpu(); + } else { + fpsimd_flush_task_state(current); } put_cpu_fpsimd_context(); @@ -1573,8 +1545,8 @@ void fpsimd_thread_switch(struct task_struct *next) fpsimd_save_user_state(); if (test_tsk_thread_flag(next, TIF_KERNEL_FPSTATE)) { - fpsimd_load_kernel_state(next); fpsimd_flush_cpu_state(); + fpsimd_load_kernel_state(next); } else { /* * Fix up TIF_FOREIGN_FPSTATE to correctly describe next's @@ -1661,6 +1633,9 @@ void fpsimd_flush_thread(void) current->thread.svcr = 0; } + if (system_supports_fpmr()) + current->thread.uw.fpmr = 0; + current->thread.fp_type = FP_STATE_FPSIMD; put_cpu_fpsimd_context(); @@ -1683,18 +1658,6 @@ void fpsimd_preserve_current_state(void) } /* - * Like fpsimd_preserve_current_state(), but ensure that - * current->thread.uw.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 (current->thread.fp_type == FP_STATE_SVE) - sve_to_fpsimd(current); -} - -/* * Associate current's FPSIMD context with this cpu * The caller must have ownership of the cpu FPSIMD context before calling * this function. @@ -1786,30 +1749,14 @@ void fpsimd_restore_current_state(void) put_cpu_fpsimd_context(); } -/* - * Load an updated userland FPSIMD state for 'current' from memory and set the - * flag that indicates that the FPSIMD register contents are the most recent - * FPSIMD state of 'current'. This is used by the signal code to restore the - * register state when returning from a signal handler in FPSIMD only cases, - * any SVE context will be discarded. - */ void fpsimd_update_current_state(struct user_fpsimd_state const *state) { if (WARN_ON(!system_supports_fpsimd())) return; - get_cpu_fpsimd_context(); - current->thread.uw.fpsimd_state = *state; - if (test_thread_flag(TIF_SVE)) + if (current->thread.fp_type == FP_STATE_SVE) fpsimd_to_sve(current); - - task_fpsimd_load(); - fpsimd_bind_task_to_cpu(); - - clear_thread_flag(TIF_FOREIGN_FPSTATE); - - put_cpu_fpsimd_context(); } /* @@ -1839,6 +1786,17 @@ void fpsimd_flush_task_state(struct task_struct *t) barrier(); } +void fpsimd_save_and_flush_current_state(void) +{ + if (!system_supports_fpsimd()) + return; + + get_cpu_fpsimd_context(); + fpsimd_save_user_state(); + fpsimd_flush_task_state(current); + put_cpu_fpsimd_context(); +} + /* * Save the FPSIMD state to memory and invalidate cpu view. * This function must be called with preemption disabled. @@ -1948,10 +1906,10 @@ EXPORT_SYMBOL_GPL(kernel_neon_end); #ifdef CONFIG_EFI -static DEFINE_PER_CPU(struct user_fpsimd_state, efi_fpsimd_state); -static DEFINE_PER_CPU(bool, efi_fpsimd_state_used); -static DEFINE_PER_CPU(bool, efi_sve_state_used); -static DEFINE_PER_CPU(bool, efi_sm_state); +static struct user_fpsimd_state efi_fpsimd_state; +static bool efi_fpsimd_state_used; +static bool efi_sve_state_used; +static bool efi_sm_state; /* * EFI runtime services support functions @@ -1984,18 +1942,16 @@ void __efi_fpsimd_begin(void) * If !efi_sve_state, SVE can't be in use yet and doesn't need * preserving: */ - if (system_supports_sve() && likely(efi_sve_state)) { - char *sve_state = this_cpu_ptr(efi_sve_state); + if (system_supports_sve() && efi_sve_state != NULL) { bool ffr = true; u64 svcr; - __this_cpu_write(efi_sve_state_used, true); + efi_sve_state_used = true; if (system_supports_sme()) { svcr = read_sysreg_s(SYS_SVCR); - __this_cpu_write(efi_sm_state, - svcr & SVCR_SM_MASK); + efi_sm_state = svcr & SVCR_SM_MASK; /* * Unless we have FA64 FFR does not @@ -2005,19 +1961,18 @@ void __efi_fpsimd_begin(void) ffr = !(svcr & SVCR_SM_MASK); } - sve_save_state(sve_state + sve_ffr_offset(sve_max_vl()), - &this_cpu_ptr(&efi_fpsimd_state)->fpsr, - ffr); + sve_save_state(efi_sve_state + sve_ffr_offset(sve_max_vl()), + &efi_fpsimd_state.fpsr, ffr); if (system_supports_sme()) sysreg_clear_set_s(SYS_SVCR, SVCR_SM_MASK, 0); } else { - fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state)); + fpsimd_save_state(&efi_fpsimd_state); } - __this_cpu_write(efi_fpsimd_state_used, true); + efi_fpsimd_state_used = true; } } @@ -2029,12 +1984,10 @@ void __efi_fpsimd_end(void) if (!system_supports_fpsimd()) return; - if (!__this_cpu_xchg(efi_fpsimd_state_used, false)) { + if (!efi_fpsimd_state_used) { kernel_neon_end(); } else { - if (system_supports_sve() && - likely(__this_cpu_read(efi_sve_state_used))) { - char const *sve_state = this_cpu_ptr(efi_sve_state); + if (system_supports_sve() && efi_sve_state_used) { bool ffr = true; /* @@ -2043,7 +1996,7 @@ void __efi_fpsimd_end(void) * streaming mode. */ if (system_supports_sme()) { - if (__this_cpu_read(efi_sm_state)) { + if (efi_sm_state) { sysreg_clear_set_s(SYS_SVCR, 0, SVCR_SM_MASK); @@ -2057,14 +2010,15 @@ void __efi_fpsimd_end(void) } } - sve_load_state(sve_state + sve_ffr_offset(sve_max_vl()), - &this_cpu_ptr(&efi_fpsimd_state)->fpsr, - ffr); + sve_load_state(efi_sve_state + sve_ffr_offset(sve_max_vl()), + &efi_fpsimd_state.fpsr, ffr); - __this_cpu_write(efi_sve_state_used, false); + efi_sve_state_used = false; } else { - fpsimd_load_state(this_cpu_ptr(&efi_fpsimd_state)); + fpsimd_load_state(&efi_fpsimd_state); } + + efi_fpsimd_state_used = false; } } |