diff options
-rw-r--r-- | arch/x86/include/asm/segment.h | 7 | ||||
-rw-r--r-- | arch/x86/kernel/process_64.c | 71 | ||||
-rw-r--r-- | arch/x86/kernel/ptrace.c | 44 |
3 files changed, 17 insertions, 105 deletions
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h index e1a4afd..1549caa0 100644 --- a/arch/x86/include/asm/segment.h +++ b/arch/x86/include/asm/segment.h @@ -208,13 +208,6 @@ #define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3) #define __PER_CPU_SEG (GDT_ENTRY_PER_CPU*8 + 3) -/* TLS indexes for 64-bit - hardcoded in arch_prctl(): */ -#define FS_TLS 0 -#define GS_TLS 1 - -#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3) -#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3) - #endif #ifndef CONFIG_PARAVIRT diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 24d1b7f..864fe2c 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -136,25 +136,6 @@ void release_thread(struct task_struct *dead_task) } } -static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr) -{ - struct user_desc ud = { - .base_addr = addr, - .limit = 0xfffff, - .seg_32bit = 1, - .limit_in_pages = 1, - .useable = 1, - }; - struct desc_struct *desc = t->thread.tls_array; - desc += tls; - fill_ldt(desc, &ud); -} - -static inline u32 read_32bit_tls(struct task_struct *t, int tls) -{ - return get_desc_base(&t->thread.tls_array[tls]); -} - int copy_thread_tls(unsigned long clone_flags, unsigned long sp, unsigned long arg, struct task_struct *p, unsigned long tls) { @@ -554,25 +535,12 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) if (addr >= TASK_SIZE_OF(task)) return -EPERM; cpu = get_cpu(); - /* handle small bases via the GDT because that's faster to - switch. */ - if (addr <= 0xffffffff) { - set_32bit_tls(task, GS_TLS, addr); - if (doit) { - load_TLS(&task->thread, cpu); - load_gs_index(GS_TLS_SEL); - } - task->thread.gsindex = GS_TLS_SEL; - task->thread.gs = 0; - } else { - task->thread.gsindex = 0; - task->thread.gs = addr; - if (doit) { - load_gs_index(0); - ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr); - } + task->thread.gsindex = 0; + task->thread.gs = addr; + if (doit) { + load_gs_index(0); + ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr); } - put_cpu(); break; case ARCH_SET_FS: /* Not strictly needed for fs, but do it for symmetry @@ -580,25 +548,12 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) if (addr >= TASK_SIZE_OF(task)) return -EPERM; cpu = get_cpu(); - /* handle small bases via the GDT because that's faster to - switch. */ - if (addr <= 0xffffffff) { - set_32bit_tls(task, FS_TLS, addr); - if (doit) { - load_TLS(&task->thread, cpu); - loadsegment(fs, FS_TLS_SEL); - } - task->thread.fsindex = FS_TLS_SEL; - task->thread.fs = 0; - } else { - task->thread.fsindex = 0; - task->thread.fs = addr; - if (doit) { - /* set the selector to 0 to not confuse - __switch_to */ - loadsegment(fs, 0); - ret = wrmsrl_safe(MSR_FS_BASE, addr); - } + task->thread.fsindex = 0; + task->thread.fs = addr; + if (doit) { + /* set the selector to 0 to not confuse __switch_to */ + loadsegment(fs, 0); + ret = wrmsrl_safe(MSR_FS_BASE, addr); } put_cpu(); break; @@ -606,8 +561,6 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) unsigned long base; if (doit) rdmsrl(MSR_FS_BASE, base); - else if (task->thread.fsindex == FS_TLS_SEL) - base = read_32bit_tls(task, FS_TLS); else base = task->thread.fs; ret = put_user(base, (unsigned long __user *)addr); @@ -617,8 +570,6 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) unsigned long base; if (doit) rdmsrl(MSR_KERNEL_GS_BASE, base); - else if (task->thread.gsindex == GS_TLS_SEL) - base = read_32bit_tls(task, GS_TLS); else base = task->thread.gs; ret = put_user(base, (unsigned long __user *)addr); diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 0f4d2a5..e72ab40 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -303,29 +303,11 @@ static int set_segment_reg(struct task_struct *task, switch (offset) { case offsetof(struct user_regs_struct,fs): - /* - * If this is setting fs as for normal 64-bit use but - * setting fs_base has implicitly changed it, leave it. - */ - if ((value == FS_TLS_SEL && task->thread.fsindex == 0 && - task->thread.fs != 0) || - (value == 0 && task->thread.fsindex == FS_TLS_SEL && - task->thread.fs == 0)) - break; task->thread.fsindex = value; if (task == current) loadsegment(fs, task->thread.fsindex); break; case offsetof(struct user_regs_struct,gs): - /* - * If this is setting gs as for normal 64-bit use but - * setting gs_base has implicitly changed it, leave it. - */ - if ((value == GS_TLS_SEL && task->thread.gsindex == 0 && - task->thread.gs != 0) || - (value == 0 && task->thread.gsindex == GS_TLS_SEL && - task->thread.gs == 0)) - break; task->thread.gsindex = value; if (task == current) load_gs_index(task->thread.gsindex); @@ -453,31 +435,17 @@ static unsigned long getreg(struct task_struct *task, unsigned long offset) #ifdef CONFIG_X86_64 case offsetof(struct user_regs_struct, fs_base): { /* - * do_arch_prctl may have used a GDT slot instead of - * the MSR. To userland, it appears the same either - * way, except the %fs segment selector might not be 0. + * XXX: This will not behave as expected if called on + * current or if fsindex != 0. */ - unsigned int seg = task->thread.fsindex; - if (task->thread.fs != 0) - return task->thread.fs; - if (task == current) - asm("movl %%fs,%0" : "=r" (seg)); - if (seg != FS_TLS_SEL) - return 0; - return get_desc_base(&task->thread.tls_array[FS_TLS]); + return task->thread.fs; } case offsetof(struct user_regs_struct, gs_base): { /* - * Exactly the same here as the %fs handling above. + * XXX: This will not behave as expected if called on + * current or if fsindex != 0. */ - unsigned int seg = task->thread.gsindex; - if (task->thread.gs != 0) - return task->thread.gs; - if (task == current) - asm("movl %%gs,%0" : "=r" (seg)); - if (seg != GS_TLS_SEL) - return 0; - return get_desc_base(&task->thread.tls_array[GS_TLS]); + return task->thread.gs; } #endif } |