The following commit has been merged into the x86/iopl branch of tip: Commit-ID: 2fff071d28b54f050f62654dad4ec111b8416d8e Gitweb: https://git.kernel.org/tip/2fff071d28b54f050f62654dad4ec111b8416d8e Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Mon, 11 Nov 2019 23:03:16 +01:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Sat, 16 Nov 2019 11:23:59 +01:00 x86/process: Unify copy_thread_tls() While looking at the TSS io bitmap it turned out that any change in that area would require identical changes to copy_thread_tls(). The 32 and 64 bit variants share sufficient code to consolidate them into a common function to avoid duplication of upcoming modifications. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Andy Lutomirski <luto@xxxxxxxxxx> --- arch/x86/include/asm/ptrace.h | 6 ++- arch/x86/include/asm/switch_to.h | 10 +++- arch/x86/kernel/process.c | 100 ++++++++++++++++++++++++++++++- arch/x86/kernel/process_32.c | 68 +-------------------- arch/x86/kernel/process_64.c | 75 +----------------------- 5 files changed, 116 insertions(+), 143 deletions(-) diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 332eb35..5057a8e 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -361,5 +361,11 @@ extern int do_get_thread_area(struct task_struct *p, int idx, extern int do_set_thread_area(struct task_struct *p, int idx, struct user_desc __user *info, int can_allocate); +#ifdef CONFIG_X86_64 +# define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t) +#else +# define do_set_thread_area_64(p, s, t) (0) +#endif + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_PTRACE_H */ diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h index 18a4b68..0e059b7 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -103,7 +103,17 @@ static inline void update_task_stack(struct task_struct *task) if (static_cpu_has(X86_FEATURE_XENPV)) load_sp0(task_top_of_stack(task)); #endif +} +static inline void kthread_frame_init(struct inactive_task_frame *frame, + unsigned long fun, unsigned long arg) +{ + frame->bx = fun; +#ifdef CONFIG_X86_32 + frame->di = arg; +#else + frame->r12 = arg; +#endif } #endif /* _ASM_X86_SWITCH_TO_H */ diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 5e94c43..7e07f0b 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -132,6 +132,106 @@ void exit_thread(struct task_struct *tsk) fpu__drop(fpu); } +static int set_new_tls(struct task_struct *p, unsigned long tls) +{ + struct user_desc __user *utls = (struct user_desc __user *)tls; + + if (in_ia32_syscall()) + return do_set_thread_area(p, -1, utls, 0); + else + return do_set_thread_area_64(p, ARCH_SET_FS, tls); +} + +static inline int copy_io_bitmap(struct task_struct *tsk) +{ + if (likely(!test_tsk_thread_flag(current, TIF_IO_BITMAP))) + return 0; + + tsk->thread.io_bitmap_ptr = kmemdup(current->thread.io_bitmap_ptr, + IO_BITMAP_BYTES, GFP_KERNEL); + if (!tsk->thread.io_bitmap_ptr) { + tsk->thread.io_bitmap_max = 0; + return -ENOMEM; + } + set_tsk_thread_flag(tsk, TIF_IO_BITMAP); + return 0; +} + +static inline void free_io_bitmap(struct task_struct *tsk) +{ + if (tsk->thread.io_bitmap_ptr) { + kfree(tsk->thread.io_bitmap_ptr); + tsk->thread.io_bitmap_ptr = NULL; + tsk->thread.io_bitmap_max = 0; + } +} + +int copy_thread_tls(unsigned long clone_flags, unsigned long sp, + unsigned long arg, struct task_struct *p, unsigned long tls) +{ + struct inactive_task_frame *frame; + struct fork_frame *fork_frame; + struct pt_regs *childregs; + int ret; + + childregs = task_pt_regs(p); + fork_frame = container_of(childregs, struct fork_frame, regs); + frame = &fork_frame->frame; + + frame->bp = 0; + frame->ret_addr = (unsigned long) ret_from_fork; + p->thread.sp = (unsigned long) fork_frame; + p->thread.io_bitmap_ptr = NULL; + memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); + +#ifdef CONFIG_X86_64 + savesegment(gs, p->thread.gsindex); + p->thread.gsbase = p->thread.gsindex ? 0 : current->thread.gsbase; + savesegment(fs, p->thread.fsindex); + p->thread.fsbase = p->thread.fsindex ? 0 : current->thread.fsbase; + savesegment(es, p->thread.es); + savesegment(ds, p->thread.ds); +#else + p->thread.sp0 = (unsigned long) (childregs + 1); + /* + * Clear all status flags including IF and set fixed bit. 64bit + * does not have this initialization as the frame does not contain + * flags. The flags consistency (especially vs. AC) is there + * ensured via objtool, which lacks 32bit support. + */ + frame->flags = X86_EFLAGS_FIXED; +#endif + + /* Kernel thread ? */ + if (unlikely(p->flags & PF_KTHREAD)) { + memset(childregs, 0, sizeof(struct pt_regs)); + kthread_frame_init(frame, sp, arg); + return 0; + } + + frame->bx = 0; + *childregs = *current_pt_regs(); + childregs->ax = 0; + if (sp) + childregs->sp = sp; + +#ifdef CONFIG_X86_32 + task_user_gs(p) = get_user_gs(current_pt_regs()); +#endif + + ret = copy_io_bitmap(p); + if (ret) + return ret; + + /* Set a new TLS for the child thread? */ + if (clone_flags & CLONE_SETTLS) { + ret = set_new_tls(p, tls); + if (ret) + free_io_bitmap(p); + } + return ret; +} + void flush_thread(void) { struct task_struct *tsk = current; diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index b8ceec4..6c7d905 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -112,74 +112,6 @@ void release_thread(struct task_struct *dead_task) release_vm86_irqs(dead_task); } -int copy_thread_tls(unsigned long clone_flags, unsigned long sp, - unsigned long arg, struct task_struct *p, unsigned long tls) -{ - struct pt_regs *childregs = task_pt_regs(p); - struct fork_frame *fork_frame = container_of(childregs, struct fork_frame, regs); - struct inactive_task_frame *frame = &fork_frame->frame; - struct task_struct *tsk; - int err; - - /* - * For a new task use the RESET flags value since there is no before. - * All the status flags are zero; DF and all the system flags must also - * be 0, specifically IF must be 0 because we context switch to the new - * task with interrupts disabled. - */ - frame->flags = X86_EFLAGS_FIXED; - frame->bp = 0; - frame->ret_addr = (unsigned long) ret_from_fork; - p->thread.sp = (unsigned long) fork_frame; - p->thread.sp0 = (unsigned long) (childregs+1); - memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); - - if (unlikely(p->flags & PF_KTHREAD)) { - /* kernel thread */ - memset(childregs, 0, sizeof(struct pt_regs)); - frame->bx = sp; /* function */ - frame->di = arg; - p->thread.io_bitmap_ptr = NULL; - return 0; - } - frame->bx = 0; - *childregs = *current_pt_regs(); - childregs->ax = 0; - if (sp) - childregs->sp = sp; - - task_user_gs(p) = get_user_gs(current_pt_regs()); - - p->thread.io_bitmap_ptr = NULL; - tsk = current; - err = -ENOMEM; - - if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) { - p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr, - IO_BITMAP_BYTES, GFP_KERNEL); - if (!p->thread.io_bitmap_ptr) { - p->thread.io_bitmap_max = 0; - return -ENOMEM; - } - set_tsk_thread_flag(p, TIF_IO_BITMAP); - } - - err = 0; - - /* - * Set a new TLS for the child thread? - */ - if (clone_flags & CLONE_SETTLS) - err = do_set_thread_area(p, -1, - (struct user_desc __user *)tls, 0); - - if (err && p->thread.io_bitmap_ptr) { - kfree(p->thread.io_bitmap_ptr); - p->thread.io_bitmap_max = 0; - } - return err; -} - void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) { diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index af64519..e93a1b8 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -371,81 +371,6 @@ void x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase) task->thread.gsbase = gsbase; } -int copy_thread_tls(unsigned long clone_flags, unsigned long sp, - unsigned long arg, struct task_struct *p, unsigned long tls) -{ - int err; - struct pt_regs *childregs; - struct fork_frame *fork_frame; - struct inactive_task_frame *frame; - struct task_struct *me = current; - - childregs = task_pt_regs(p); - fork_frame = container_of(childregs, struct fork_frame, regs); - frame = &fork_frame->frame; - - frame->bp = 0; - frame->ret_addr = (unsigned long) ret_from_fork; - p->thread.sp = (unsigned long) fork_frame; - p->thread.io_bitmap_ptr = NULL; - - savesegment(gs, p->thread.gsindex); - p->thread.gsbase = p->thread.gsindex ? 0 : me->thread.gsbase; - savesegment(fs, p->thread.fsindex); - p->thread.fsbase = p->thread.fsindex ? 0 : me->thread.fsbase; - savesegment(es, p->thread.es); - savesegment(ds, p->thread.ds); - memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); - - if (unlikely(p->flags & PF_KTHREAD)) { - /* kernel thread */ - memset(childregs, 0, sizeof(struct pt_regs)); - frame->bx = sp; /* function */ - frame->r12 = arg; - return 0; - } - frame->bx = 0; - *childregs = *current_pt_regs(); - - childregs->ax = 0; - if (sp) - childregs->sp = sp; - - err = -ENOMEM; - if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) { - p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr, - IO_BITMAP_BYTES, GFP_KERNEL); - if (!p->thread.io_bitmap_ptr) { - p->thread.io_bitmap_max = 0; - return -ENOMEM; - } - set_tsk_thread_flag(p, TIF_IO_BITMAP); - } - - /* - * Set a new TLS for the child thread? - */ - if (clone_flags & CLONE_SETTLS) { -#ifdef CONFIG_IA32_EMULATION - if (in_ia32_syscall()) - err = do_set_thread_area(p, -1, - (struct user_desc __user *)tls, 0); - else -#endif - err = do_arch_prctl_64(p, ARCH_SET_FS, tls); - if (err) - goto out; - } - err = 0; -out: - if (err && p->thread.io_bitmap_ptr) { - kfree(p->thread.io_bitmap_ptr); - p->thread.io_bitmap_max = 0; - } - - return err; -} - static void start_thread_common(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp,
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