diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/efi.h | 4 | ||||
| -rw-r--r-- | arch/arm64/include/asm/mmu_context.h | 46 | ||||
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 51 | ||||
| -rw-r--r-- | arch/arm64/kernel/process.c | 9 |
4 files changed, 63 insertions, 47 deletions
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h index 650344d01124..c4cd5081d78b 100644 --- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -132,11 +132,9 @@ static inline void efi_set_pgd(struct mm_struct *mm) * Defer the switch to the current thread's TTBR0_EL1 * until uaccess_enable(). Restore the current * thread's saved ttbr0 corresponding to its active_mm - * (if different from init_mm). */ cpu_set_reserved_ttbr0(); - if (current->active_mm != &init_mm) - update_saved_ttbr0(current, current->active_mm); + update_saved_ttbr0(current, current->active_mm); } } } diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index 3257895a9b5e..9d155fa9a507 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -156,29 +156,21 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu); #define init_new_context(tsk,mm) ({ atomic64_set(&(mm)->context.id, 0); 0; }) -/* - * This is called when "tsk" is about to enter lazy TLB mode. - * - * mm: describes the currently active mm context - * tsk: task which is entering lazy tlb - * cpu: cpu number which is entering lazy tlb - * - * tsk->mm will be NULL - */ -static inline void -enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) -{ -} - #ifdef CONFIG_ARM64_SW_TTBR0_PAN static inline void update_saved_ttbr0(struct task_struct *tsk, struct mm_struct *mm) { - if (system_uses_ttbr0_pan()) { - BUG_ON(mm->pgd == swapper_pg_dir); - task_thread_info(tsk)->ttbr0 = - virt_to_phys(mm->pgd) | ASID(mm) << 48; - } + u64 ttbr; + + if (!system_uses_ttbr0_pan()) + return; + + if (mm == &init_mm) + ttbr = __pa_symbol(empty_zero_page); + else + ttbr = virt_to_phys(mm->pgd) | ASID(mm) << 48; + + task_thread_info(tsk)->ttbr0 = ttbr; } #else static inline void update_saved_ttbr0(struct task_struct *tsk, @@ -187,6 +179,16 @@ static inline void update_saved_ttbr0(struct task_struct *tsk, } #endif +static inline void +enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) +{ + /* + * We don't actually care about the ttbr0 mapping, so point it at the + * zero page. + */ + update_saved_ttbr0(tsk, &init_mm); +} + static inline void __switch_mm(struct mm_struct *next) { unsigned int cpu = smp_processor_id(); @@ -214,11 +216,9 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, * Update the saved TTBR0_EL1 of the scheduled-in task as the previous * value may have not been initialised yet (activate_mm caller) or the * ASID has changed since the last run (following the context switch - * of another thread of the same process). Avoid setting the reserved - * TTBR0_EL1 to swapper_pg_dir (init_mm; e.g. via idle_task_exit). + * of another thread of the same process). */ - if (next != &init_mm) - update_saved_ttbr0(tsk, next); + update_saved_ttbr0(tsk, next); } #define deactivate_mm(tsk,mm) do { } while (0) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 5084e699447a..540a1e010eb5 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -114,7 +114,12 @@ * returned from the 2nd syscall yet, TIF_FOREIGN_FPSTATE is still set so * whatever is in the FPSIMD registers is not saved to memory, but discarded. */ -static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state); +struct fpsimd_last_state_struct { + struct fpsimd_state *st; + bool sve_in_use; +}; + +static DEFINE_PER_CPU(struct fpsimd_last_state_struct, fpsimd_last_state); /* Default VL for tasks that don't set it explicitly: */ static int sve_default_vl = -1; @@ -905,7 +910,7 @@ void fpsimd_thread_switch(struct task_struct *next) */ struct fpsimd_state *st = &next->thread.fpsimd_state; - if (__this_cpu_read(fpsimd_last_state) == st + if (__this_cpu_read(fpsimd_last_state.st) == st && st->cpu == smp_processor_id()) clear_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE); else @@ -992,6 +997,21 @@ void fpsimd_signal_preserve_current_state(void) } /* + * Associate current's FPSIMD context with this cpu + * Preemption must be disabled when calling this function. + */ +static void fpsimd_bind_to_cpu(void) +{ + struct fpsimd_last_state_struct *last = + this_cpu_ptr(&fpsimd_last_state); + struct fpsimd_state *st = ¤t->thread.fpsimd_state; + + last->st = st; + last->sve_in_use = test_thread_flag(TIF_SVE); + st->cpu = smp_processor_id(); +} + +/* * 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' @@ -1004,11 +1024,8 @@ void fpsimd_restore_current_state(void) local_bh_disable(); if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) { - struct fpsimd_state *st = ¤t->thread.fpsimd_state; - task_fpsimd_load(); - __this_cpu_write(fpsimd_last_state, st); - st->cpu = smp_processor_id(); + fpsimd_bind_to_cpu(); } local_bh_enable(); @@ -1032,12 +1049,8 @@ void fpsimd_update_current_state(struct fpsimd_state *state) task_fpsimd_load(); - if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) { - struct fpsimd_state *st = ¤t->thread.fpsimd_state; - - __this_cpu_write(fpsimd_last_state, st); - st->cpu = smp_processor_id(); - } + if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) + fpsimd_bind_to_cpu(); local_bh_enable(); } @@ -1052,7 +1065,7 @@ void fpsimd_flush_task_state(struct task_struct *t) static inline void fpsimd_flush_cpu_state(void) { - __this_cpu_write(fpsimd_last_state, NULL); + __this_cpu_write(fpsimd_last_state.st, NULL); } /* @@ -1065,14 +1078,10 @@ static inline void fpsimd_flush_cpu_state(void) #ifdef CONFIG_ARM64_SVE void sve_flush_cpu_state(void) { - struct fpsimd_state *const fpstate = __this_cpu_read(fpsimd_last_state); - struct task_struct *tsk; - - if (!fpstate) - return; + struct fpsimd_last_state_struct const *last = + this_cpu_ptr(&fpsimd_last_state); - tsk = container_of(fpstate, struct task_struct, thread.fpsimd_state); - if (test_tsk_thread_flag(tsk, TIF_SVE)) + if (last->st && last->sve_in_use) fpsimd_flush_cpu_state(); } #endif /* CONFIG_ARM64_SVE */ @@ -1267,7 +1276,7 @@ static inline void fpsimd_pm_init(void) { } #ifdef CONFIG_HOTPLUG_CPU static int fpsimd_cpu_dead(unsigned int cpu) { - per_cpu(fpsimd_last_state, cpu) = NULL; + per_cpu(fpsimd_last_state.st, cpu) = NULL; return 0; } diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index b2adcce7bc18..6b7dcf4310ac 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -314,6 +314,15 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, clear_tsk_thread_flag(p, TIF_SVE); p->thread.sve_state = NULL; + /* + * In case p was allocated the same task_struct pointer as some + * other recently-exited task, make sure p is disassociated from + * any cpu that may have run that now-exited task recently. + * Otherwise we could erroneously skip reloading the FPSIMD + * registers for p. + */ + fpsimd_flush_task_state(p); + if (likely(!(p->flags & PF_KTHREAD))) { *childregs = *current_pt_regs(); childregs->regs[0] = 0; |