diff options
| -rw-r--r-- | arch/x86/kernel/tls.c | 89 | ||||
| -rw-r--r-- | include/asm-x86/desc.h | 11 |
2 files changed, 54 insertions, 46 deletions
diff --git a/arch/x86/kernel/tls.c b/arch/x86/kernel/tls.c index 98f428be8e8..f11c92a3faa 100644 --- a/arch/x86/kernel/tls.c +++ b/arch/x86/kernel/tls.c @@ -24,6 +24,29 @@ static int get_free_idx(void) return -ESRCH; } +static void set_tls_desc(struct task_struct *p, int idx, + const struct user_desc *info) +{ + struct thread_struct *t = &p->thread; + struct desc_struct *desc = &t->tls_array[idx - GDT_ENTRY_TLS_MIN]; + int cpu; + + /* + * We must not get preempted while modifying the TLS. + */ + cpu = get_cpu(); + + if (LDT_empty(info)) + desc->a = desc->b = 0; + else + fill_ldt(desc, info); + + if (t == ¤t->thread) + load_TLS(t, cpu); + + put_cpu(); +} + /* * Set a given TLS descriptor: */ @@ -31,10 +54,7 @@ int do_set_thread_area(struct task_struct *p, int idx, struct user_desc __user *u_info, int can_allocate) { - struct thread_struct *t = &p->thread; struct user_desc info; - u32 *desc; - int cpu; if (copy_from_user(&info, u_info, sizeof(info))) return -EFAULT; @@ -57,23 +77,8 @@ int do_set_thread_area(struct task_struct *p, int idx, if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) return -EINVAL; - desc = (u32 *) &t->tls_array[idx - GDT_ENTRY_TLS_MIN]; + set_tls_desc(p, idx, &info); - /* - * We must not get preempted while modifying the TLS. - */ - cpu = get_cpu(); - - if (LDT_empty(&info)) { - desc[0] = 0; - desc[1] = 0; - } else - fill_ldt((struct desc_struct *)desc, &info); - - if (t == ¤t->thread) - load_TLS(t, cpu); - - put_cpu(); return 0; } @@ -87,42 +92,38 @@ asmlinkage int sys_set_thread_area(struct user_desc __user *u_info) * Get the current Thread-Local Storage area: */ -#define GET_LIMIT(desc) (((desc)[0] & 0x0ffff) | ((desc)[1] & 0xf0000)) -#define GET_32BIT(desc) (((desc)[1] >> 22) & 1) -#define GET_CONTENTS(desc) (((desc)[1] >> 10) & 3) -#define GET_WRITABLE(desc) (((desc)[1] >> 9) & 1) -#define GET_LIMIT_PAGES(desc) (((desc)[1] >> 23) & 1) -#define GET_PRESENT(desc) (((desc)[1] >> 15) & 1) -#define GET_USEABLE(desc) (((desc)[1] >> 20) & 1) -#define GET_LONGMODE(desc) (((desc)[1] >> 21) & 1) +static void fill_user_desc(struct user_desc *info, int idx, + const struct desc_struct *desc) + +{ + memset(info, 0, sizeof(*info)); + info->entry_number = idx; + info->base_addr = get_desc_base(desc); + info->limit = get_desc_limit(desc); + info->seg_32bit = desc->d; + info->contents = desc->type >> 2; + info->read_exec_only = !(desc->type & 2); + info->limit_in_pages = desc->g; + info->seg_not_present = !desc->p; + info->useable = desc->avl; +#ifdef CONFIG_X86_64 + info->lm = desc->l; +#endif +} int do_get_thread_area(struct task_struct *p, int idx, struct user_desc __user *u_info) { - struct thread_struct *t = &p->thread; struct user_desc info; - u32 *desc; if (idx == -1 && get_user(idx, &u_info->entry_number)) return -EFAULT; + if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) return -EINVAL; - desc = (u32 *) &t->tls_array[idx - GDT_ENTRY_TLS_MIN]; - - memset(&info, 0, sizeof(struct user_desc)); - info.entry_number = idx; - info.base_addr = get_desc_base((struct desc_struct *)desc); - info.limit = GET_LIMIT(desc); - info.seg_32bit = GET_32BIT(desc); - info.contents = GET_CONTENTS(desc); - info.read_exec_only = !GET_WRITABLE(desc); - info.limit_in_pages = GET_LIMIT_PAGES(desc); - info.seg_not_present = !GET_PRESENT(desc); - info.useable = GET_USEABLE(desc); -#ifdef CONFIG_X86_64 - info.lm = GET_LONGMODE(desc); -#endif + fill_user_desc(&info, idx, + &p->thread.tls_array[idx - GDT_ENTRY_TLS_MIN]); if (copy_to_user(u_info, &info, sizeof(info))) return -EFAULT; diff --git a/include/asm-x86/desc.h b/include/asm-x86/desc.h index e17581ad882..5b6a05d3a77 100644 --- a/include/asm-x86/desc.h +++ b/include/asm-x86/desc.h @@ -7,7 +7,8 @@ #include <asm/mmu.h> #include <linux/smp.h> -static inline void fill_ldt(struct desc_struct *desc, struct user_desc *info) +static inline void fill_ldt(struct desc_struct *desc, + const struct user_desc *info) { desc->limit0 = info->limit & 0x0ffff; desc->base0 = info->base_addr & 0x0000ffff; @@ -275,10 +276,16 @@ static inline void load_LDT(mm_context_t *pc) preempt_enable(); } -static inline unsigned long get_desc_base(struct desc_struct *desc) +static inline unsigned long get_desc_base(const struct desc_struct *desc) { return desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24); } + +static inline unsigned long get_desc_limit(const struct desc_struct *desc) +{ + return desc->limit0 | (desc->limit << 16); +} + static inline void _set_gate(int gate, unsigned type, void *addr, unsigned dpl, unsigned ist, unsigned seg) { |