diff options
Diffstat (limited to 'arch/um/sys-i386/tls.c')
| -rw-r--r-- | arch/um/sys-i386/tls.c | 101 |
1 files changed, 48 insertions, 53 deletions
diff --git a/arch/um/sys-i386/tls.c b/arch/um/sys-i386/tls.c index fea8e5e15cc..b02266ab5c5 100644 --- a/arch/um/sys-i386/tls.c +++ b/arch/um/sys-i386/tls.c @@ -3,25 +3,12 @@ * Licensed under the GPL */ -#include "linux/kernel.h" +#include "linux/percpu.h" #include "linux/sched.h" -#include "linux/slab.h" -#include "linux/types.h" #include "asm/uaccess.h" -#include "asm/ptrace.h" -#include "asm/segment.h" -#include "asm/smp.h" -#include "asm/desc.h" -#include "choose-mode.h" -#include "kern.h" -#include "kern_util.h" -#include "mode_kern.h" #include "os.h" -#include "mode.h" - -#ifdef CONFIG_MODE_SKAS #include "skas.h" -#endif +#include "sysdep/tls.h" /* * If needed we can detect when it's uninitialized. @@ -31,8 +18,7 @@ static int host_supports_tls = -1; int host_gdt_entry_tls_min; -#ifdef CONFIG_MODE_SKAS -int do_set_thread_area_skas(struct user_desc *info) +int do_set_thread_area(struct user_desc *info) { int ret; u32 cpu; @@ -43,7 +29,7 @@ int do_set_thread_area_skas(struct user_desc *info) return ret; } -int do_get_thread_area_skas(struct user_desc *info) +int do_get_thread_area(struct user_desc *info) { int ret; u32 cpu; @@ -53,7 +39,6 @@ int do_get_thread_area_skas(struct user_desc *info) put_cpu(); return ret; } -#endif /* * sys_get_thread_area: get a yet unused TLS descriptor index. @@ -82,7 +67,8 @@ static inline void clear_user_desc(struct user_desc* info) /* Postcondition: LDT_empty(info) returns true. */ memset(info, 0, sizeof(*info)); - /* Check the LDT_empty or the i386 sys_get_thread_area code - we obtain + /* + * Check the LDT_empty or the i386 sys_get_thread_area code - we obtain * indeed an empty user_desc. */ info->read_exec_only = 1; @@ -97,10 +83,13 @@ static int load_TLS(int flags, struct task_struct *to) int idx; for (idx = GDT_ENTRY_TLS_MIN; idx < GDT_ENTRY_TLS_MAX; idx++) { - struct uml_tls_struct* curr = &to->thread.arch.tls_array[idx - GDT_ENTRY_TLS_MIN]; + struct uml_tls_struct* curr = + &to->thread.arch.tls_array[idx - GDT_ENTRY_TLS_MIN]; - /* Actually, now if it wasn't flushed it gets cleared and - * flushed to the host, which will clear it.*/ + /* + * Actually, now if it wasn't flushed it gets cleared and + * flushed to the host, which will clear it. + */ if (!curr->present) { if (!curr->flushed) { clear_user_desc(&curr->tls); @@ -124,7 +113,8 @@ out: return ret; } -/* Verify if we need to do a flush for the new process, i.e. if there are any +/* + * Verify if we need to do a flush for the new process, i.e. if there are any * present desc's, only if they haven't been flushed. */ static inline int needs_TLS_update(struct task_struct *task) @@ -133,10 +123,13 @@ static inline int needs_TLS_update(struct task_struct *task) int ret = 0; for (i = GDT_ENTRY_TLS_MIN; i < GDT_ENTRY_TLS_MAX; i++) { - struct uml_tls_struct* curr = &task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN]; + struct uml_tls_struct* curr = + &task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN]; - /* Can't test curr->present, we may need to clear a descriptor - * which had a value. */ + /* + * Can't test curr->present, we may need to clear a descriptor + * which had a value. + */ if (curr->flushed) continue; ret = 1; @@ -145,7 +138,8 @@ static inline int needs_TLS_update(struct task_struct *task) return ret; } -/* On a newly forked process, the TLS descriptors haven't yet been flushed. So +/* + * On a newly forked process, the TLS descriptors haven't yet been flushed. So * we mark them as such and the first switch_to will do the job. */ void clear_flushed_tls(struct task_struct *task) @@ -153,10 +147,13 @@ void clear_flushed_tls(struct task_struct *task) int i; for (i = GDT_ENTRY_TLS_MIN; i < GDT_ENTRY_TLS_MAX; i++) { - struct uml_tls_struct* curr = &task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN]; + struct uml_tls_struct* curr = + &task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN]; - /* Still correct to do this, if it wasn't present on the host it - * will remain as flushed as it was. */ + /* + * Still correct to do this, if it wasn't present on the host it + * will remain as flushed as it was. + */ if (!curr->present) continue; @@ -164,40 +161,33 @@ void clear_flushed_tls(struct task_struct *task) } } -/* In SKAS0 mode, currently, multiple guest threads sharing the same ->mm have a +/* + * In SKAS0 mode, currently, multiple guest threads sharing the same ->mm have a * common host process. So this is needed in SKAS0 too. * * However, if each thread had a different host process (and this was discussed * for SMP support) this won't be needed. * * And this will not need be used when (and if) we'll add support to the host - * SKAS patch. */ + * SKAS patch. + */ -int arch_switch_tls_skas(struct task_struct *from, struct task_struct *to) +int arch_switch_tls(struct task_struct *from, struct task_struct *to) { if (!host_supports_tls) return 0; - /* We have no need whatsoever to switch TLS for kernel threads; beyond + /* + * We have no need whatsoever to switch TLS for kernel threads; beyond * that, that would also result in us calling os_set_thread_area with - * userspace_pid[cpu] == 0, which gives an error. */ + * userspace_pid[cpu] == 0, which gives an error. + */ if (likely(to->mm)) return load_TLS(O_FORCE, to); return 0; } -int arch_switch_tls_tt(struct task_struct *from, struct task_struct *to) -{ - if (!host_supports_tls) - return 0; - - if (needs_TLS_update(to)) - return load_TLS(0, to); - - return 0; -} - static int set_tls_entry(struct task_struct* task, struct user_desc *info, int idx, int flushed) { @@ -251,17 +241,20 @@ static int get_tls_entry(struct task_struct* task, struct user_desc *info, int i *info = t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls; out: - /* Temporary debugging check, to make sure that things have been + /* + * Temporary debugging check, to make sure that things have been * flushed. This could be triggered if load_TLS() failed. */ - if (unlikely(task == current && !t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed)) { + if (unlikely(task == current && + !t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed)) { printk(KERN_ERR "get_tls_entry: task with pid %d got here " "without flushed TLS.", current->pid); } return 0; clear: - /* When the TLS entry has not been set, the values read to user in the + /* + * When the TLS entry has not been set, the values read to user in the * tls_array are 0 (because it's cleared at boot, see * arch/i386/kernel/head.S:cpu_gdt_table). Emulate that. */ @@ -293,7 +286,7 @@ asmlinkage int sys_set_thread_area(struct user_desc __user *user_desc) return -EFAULT; } - ret = CHOOSE_MODE_PROC(do_set_thread_area_tt, do_set_thread_area_skas, &info); + ret = do_set_thread_area(&info); if (ret) return ret; return set_tls_entry(current, &info, idx, 1); @@ -363,8 +356,10 @@ out: } -/* XXX: This part is probably common to i386 and x86-64. Don't create a common - * file for now, do that when implementing x86-64 support.*/ +/* + * XXX: This part is probably common to i386 and x86-64. Don't create a common + * file for now, do that when implementing x86-64 support. + */ static int __init __setup_host_supports_tls(void) { check_host_supports_tls(&host_supports_tls, &host_gdt_entry_tls_min); |