From: Martin Schwidefsky Date: Mon, 14 Apr 2014 13:11:26 +0000 (+0200) Subject: s390/uaccess: simplify control register updates X-Git-Tag: next-20140521~104^2~13 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=beef560b4cdfafb2;p=karo-tx-linux.git s390/uaccess: simplify control register updates Always switch to the kernel ASCE in switch_mm. Load the secondary space ASCE in finish_arch_post_lock_switch after checking that any pending page table operations have completed. The primary ASCE is loaded in entry[64].S. With this the update_primary_asce call can be removed from the switch_to macro and from the start of switch_mm function. Remove the load_primary argument from update_user_asce/clear_user_asce, rename update_user_asce to set_user_asce and rename update_primary_asce to load_kernel_asce. Signed-off-by: Martin Schwidefsky --- diff --git a/arch/s390/include/asm/futex.h b/arch/s390/include/asm/futex.h index 69cf5b5eddc9..a4811aa0304d 100644 --- a/arch/s390/include/asm/futex.h +++ b/arch/s390/include/asm/futex.h @@ -29,7 +29,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) int cmparg = (encoded_op << 20) >> 20; int oldval = 0, newval, ret; - update_primary_asce(current); + load_kernel_asce(); if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) oparg = 1 << oparg; @@ -79,7 +79,7 @@ static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, { int ret; - update_primary_asce(current); + load_kernel_asce(); asm volatile( " sacf 256\n" "0: cs %1,%4,0(%5)\n" diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h index 71be346d0e3c..93ec0c8e4c83 100644 --- a/arch/s390/include/asm/mmu_context.h +++ b/arch/s390/include/asm/mmu_context.h @@ -30,33 +30,31 @@ static inline int init_new_context(struct task_struct *tsk, #define destroy_context(mm) do { } while (0) -static inline void update_user_asce(struct mm_struct *mm, int load_primary) +static inline void set_user_asce(struct mm_struct *mm) { pgd_t *pgd = mm->pgd; S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd); - if (load_primary) - __ctl_load(S390_lowcore.user_asce, 1, 1); set_fs(current->thread.mm_segment); + set_thread_flag(TIF_ASCE); } -static inline void clear_user_asce(struct mm_struct *mm, int load_primary) +static inline void clear_user_asce(void) { S390_lowcore.user_asce = S390_lowcore.kernel_asce; - if (load_primary) - __ctl_load(S390_lowcore.user_asce, 1, 1); + __ctl_load(S390_lowcore.user_asce, 1, 1); __ctl_load(S390_lowcore.user_asce, 7, 7); } -static inline void update_primary_asce(struct task_struct *tsk) +static inline void load_kernel_asce(void) { unsigned long asce; __ctl_store(asce, 1, 1); if (asce != S390_lowcore.kernel_asce) __ctl_load(S390_lowcore.kernel_asce, 1, 1); - set_tsk_thread_flag(tsk, TIF_ASCE); + set_thread_flag(TIF_ASCE); } static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, @@ -64,25 +62,17 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, { int cpu = smp_processor_id(); - update_primary_asce(tsk); if (prev == next) return; if (MACHINE_HAS_TLB_LC) cpumask_set_cpu(cpu, &next->context.cpu_attach_mask); - if (atomic_inc_return(&next->context.attach_count) >> 16) { - /* Delay update_user_asce until all TLB flushes are done. */ - set_tsk_thread_flag(tsk, TIF_TLB_WAIT); - /* Clear old ASCE by loading the kernel ASCE. */ - clear_user_asce(next, 0); - } else { - cpumask_set_cpu(cpu, mm_cpumask(next)); - update_user_asce(next, 0); - if (next->context.flush_mm) - /* Flush pending TLBs */ - __tlb_flush_mm(next); - } + /* Clear old ASCE by loading the kernel ASCE. */ + __ctl_load(S390_lowcore.kernel_asce, 1, 1); + __ctl_load(S390_lowcore.kernel_asce, 7, 7); + /* Delay loading of the new ASCE to control registers CR1 & CR7 */ + set_thread_flag(TIF_ASCE); + atomic_inc(&next->context.attach_count); atomic_dec(&prev->context.attach_count); - WARN_ON(atomic_read(&prev->context.attach_count) < 0); if (MACHINE_HAS_TLB_LC) cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask); } @@ -93,15 +83,14 @@ static inline void finish_arch_post_lock_switch(void) struct task_struct *tsk = current; struct mm_struct *mm = tsk->mm; - if (!test_tsk_thread_flag(tsk, TIF_TLB_WAIT)) + if (!mm) return; preempt_disable(); - clear_tsk_thread_flag(tsk, TIF_TLB_WAIT); while (atomic_read(&mm->context.attach_count) >> 16) cpu_relax(); cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); - update_user_asce(mm, 0); + set_user_asce(mm); if (mm->context.flush_mm) __tlb_flush_mm(mm); preempt_enable(); @@ -113,7 +102,9 @@ static inline void finish_arch_post_lock_switch(void) static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next) { - switch_mm(prev, next, current); + switch_mm(prev, next, current); + cpumask_set_cpu(smp_processor_id(), mm_cpumask(next)); + set_user_asce(next); } static inline void arch_dup_mmap(struct mm_struct *oldmm, diff --git a/arch/s390/include/asm/switch_to.h b/arch/s390/include/asm/switch_to.h index e759181357fc..29c81f82705e 100644 --- a/arch/s390/include/asm/switch_to.h +++ b/arch/s390/include/asm/switch_to.h @@ -132,7 +132,6 @@ static inline void restore_access_regs(unsigned int *acrs) update_cr_regs(next); \ } \ prev = __switch_to(prev,next); \ - update_primary_asce(current); \ } while (0) #define finish_arch_switch(prev) do { \ diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h index 50630e6a35de..f3e5cad93b26 100644 --- a/arch/s390/include/asm/thread_info.h +++ b/arch/s390/include/asm/thread_info.h @@ -81,8 +81,7 @@ static inline struct thread_info *current_thread_info(void) #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ #define TIF_SIGPENDING 2 /* signal pending */ #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ -#define TIF_TLB_WAIT 4 /* wait for TLB flush completion */ -#define TIF_ASCE 5 /* primary asce needs fixup / uaccess */ +#define TIF_ASCE 5 /* user asce needs fixup / uaccess */ #define TIF_PER_TRAP 6 /* deliver sigtrap on return to user */ #define TIF_MCCK_PENDING 7 /* machine check handling is pending */ #define TIF_SYSCALL_TRACE 8 /* syscall trace active */ @@ -99,7 +98,6 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_NOTIFY_RESUME (1<active_mm == mm) - update_user_asce(mm, 1); + if (current->active_mm == mm) { + clear_user_asce(); + set_user_asce(mm); + } __tlb_flush_local(); } @@ -108,7 +110,7 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit) pgd_t *pgd; if (current->active_mm == mm) { - clear_user_asce(mm, 1); + clear_user_asce(); __tlb_flush_mm(mm); } while (mm->context.asce_limit > limit) { @@ -134,7 +136,7 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit) crst_table_free(mm, (unsigned long *) pgd); } if (current->active_mm == mm) - update_user_asce(mm, 1); + set_user_asce(mm); } #endif