diff options
Diffstat (limited to 'arch/x86/kernel/process_32.c')
| -rw-r--r-- | arch/x86/kernel/process_32.c | 355 |
1 files changed, 355 insertions, 0 deletions
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c new file mode 100644 index 000000000..8ed2106b0 --- /dev/null +++ b/arch/x86/kernel/process_32.c @@ -0,0 +1,355 @@ +/* + * Copyright (C) 1995 Linus Torvalds + * + * Pentium III FXSR, SSE support + * Gareth Hughes <gareth@valinux.com>, May 2000 + */ + +/* + * This file handles the architecture-dependent parts of process handling.. + */ + +#include <linux/cpu.h> +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/elfcore.h> +#include <linux/smp.h> +#include <linux/stddef.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/user.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/reboot.h> +#include <linux/mc146818rtc.h> +#include <linux/module.h> +#include <linux/kallsyms.h> +#include <linux/ptrace.h> +#include <linux/personality.h> +#include <linux/percpu.h> +#include <linux/prctl.h> +#include <linux/ftrace.h> +#include <linux/uaccess.h> +#include <linux/io.h> +#include <linux/kdebug.h> + +#include <asm/pgtable.h> +#include <asm/ldt.h> +#include <asm/processor.h> +#include <asm/i387.h> +#include <asm/fpu-internal.h> +#include <asm/desc.h> +#ifdef CONFIG_MATH_EMULATION +#include <asm/math_emu.h> +#endif + +#include <linux/err.h> + +#include <asm/tlbflush.h> +#include <asm/cpu.h> +#include <asm/idle.h> +#include <asm/syscalls.h> +#include <asm/debugreg.h> +#include <asm/switch_to.h> + +asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); +asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread"); + +/* + * Return saved PC of a blocked thread. + */ +unsigned long thread_saved_pc(struct task_struct *tsk) +{ + return ((unsigned long *)tsk->thread.sp)[3]; +} + +void __show_regs(struct pt_regs *regs, int all) +{ + unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; + unsigned long d0, d1, d2, d3, d6, d7; + unsigned long sp; + unsigned short ss, gs; + + if (user_mode(regs)) { + sp = regs->sp; + ss = regs->ss & 0xffff; + gs = get_user_gs(regs); + } else { + sp = kernel_stack_pointer(regs); + savesegment(ss, ss); + savesegment(gs, gs); + } + + printk(KERN_DEFAULT "EIP: %04x:[<%08lx>] EFLAGS: %08lx CPU: %d\n", + (u16)regs->cs, regs->ip, regs->flags, + smp_processor_id()); + print_symbol("EIP is at %s\n", regs->ip); + + printk(KERN_DEFAULT "EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n", + regs->ax, regs->bx, regs->cx, regs->dx); + printk(KERN_DEFAULT "ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n", + regs->si, regs->di, regs->bp, sp); + printk(KERN_DEFAULT " DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n", + (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss); + + if (!all) + return; + + cr0 = read_cr0(); + cr2 = read_cr2(); + cr3 = read_cr3(); + cr4 = __read_cr4_safe(); + printk(KERN_DEFAULT "CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", + cr0, cr2, cr3, cr4); + + get_debugreg(d0, 0); + get_debugreg(d1, 1); + get_debugreg(d2, 2); + get_debugreg(d3, 3); + get_debugreg(d6, 6); + get_debugreg(d7, 7); + + /* Only print out debug registers if they are in their non-default state. */ + if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && + (d6 == DR6_RESERVED) && (d7 == 0x400)) + return; + + printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", + d0, d1, d2, d3); + printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n", + d6, d7); +} + +void release_thread(struct task_struct *dead_task) +{ + BUG_ON(dead_task->mm); + release_vm86_irqs(dead_task); +} + +int copy_thread(unsigned long clone_flags, unsigned long sp, + unsigned long arg, struct task_struct *p) +{ + struct pt_regs *childregs = task_pt_regs(p); + struct task_struct *tsk; + int err; + + p->thread.sp = (unsigned long) childregs; + 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)); + p->thread.ip = (unsigned long) ret_from_kernel_thread; + task_user_gs(p) = __KERNEL_STACK_CANARY; + childregs->ds = __USER_DS; + childregs->es = __USER_DS; + childregs->fs = __KERNEL_PERCPU; + childregs->bx = sp; /* function */ + childregs->bp = arg; + childregs->orig_ax = -1; + childregs->cs = __KERNEL_CS | get_kernel_rpl(); + childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED; + p->thread.io_bitmap_ptr = NULL; + return 0; + } + *childregs = *current_pt_regs(); + childregs->ax = 0; + if (sp) + childregs->sp = sp; + + p->thread.ip = (unsigned long) ret_from_fork; + 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 *)childregs->si, 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) +{ + set_user_gs(regs, 0); + regs->fs = 0; + regs->ds = __USER_DS; + regs->es = __USER_DS; + regs->ss = __USER_DS; + regs->cs = __USER_CS; + regs->ip = new_ip; + regs->sp = new_sp; + regs->flags = X86_EFLAGS_IF; + force_iret(); +} +EXPORT_SYMBOL_GPL(start_thread); + + +/* + * switch_to(x,y) should switch tasks from x to y. + * + * We fsave/fwait so that an exception goes off at the right time + * (as a call from the fsave or fwait in effect) rather than to + * the wrong process. Lazy FP saving no longer makes any sense + * with modern CPU's, and this simplifies a lot of things (SMP + * and UP become the same). + * + * NOTE! We used to use the x86 hardware context switching. The + * reason for not using it any more becomes apparent when you + * try to recover gracefully from saved state that is no longer + * valid (stale segment register values in particular). With the + * hardware task-switch, there is no way to fix up bad state in + * a reasonable manner. + * + * The fact that Intel documents the hardware task-switching to + * be slow is a fairly red herring - this code is not noticeably + * faster. However, there _is_ some room for improvement here, + * so the performance issues may eventually be a valid point. + * More important, however, is the fact that this allows us much + * more flexibility. + * + * The return value (in %ax) will be the "prev" task after + * the task-switch, and shows up in ret_from_fork in entry.S, + * for example. + */ +__visible __notrace_funcgraph struct task_struct * +__switch_to(struct task_struct *prev_p, struct task_struct *next_p) +{ + struct thread_struct *prev = &prev_p->thread, + *next = &next_p->thread; + int cpu = smp_processor_id(); + struct tss_struct *tss = &per_cpu(cpu_tss, cpu); + fpu_switch_t fpu; + + /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ + + fpu = switch_fpu_prepare(prev_p, next_p, cpu); + + /* + * Save away %gs. No need to save %fs, as it was saved on the + * stack on entry. No need to save %es and %ds, as those are + * always kernel segments while inside the kernel. Doing this + * before setting the new TLS descriptors avoids the situation + * where we temporarily have non-reloadable segments in %fs + * and %gs. This could be an issue if the NMI handler ever + * used %fs or %gs (it does not today), or if the kernel is + * running inside of a hypervisor layer. + */ + lazy_save_gs(prev->gs); + + /* + * Load the per-thread Thread-Local Storage descriptor. + */ + load_TLS(next, cpu); + + /* + * Restore IOPL if needed. In normal use, the flags restore + * in the switch assembly will handle this. But if the kernel + * is running virtualized at a non-zero CPL, the popf will + * not restore flags, so it must be done in a separate step. + */ + if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl)) + set_iopl_mask(next->iopl); + + /* + * If it were not for PREEMPT_ACTIVE we could guarantee that the + * preempt_count of all tasks was equal here and this would not be + * needed. + */ + task_thread_info(prev_p)->saved_preempt_count = this_cpu_read(__preempt_count); + this_cpu_write(__preempt_count, task_thread_info(next_p)->saved_preempt_count); + + /* + * Now maybe handle debug registers and/or IO bitmaps + */ + if (unlikely(task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV || + task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT)) + __switch_to_xtra(prev_p, next_p, tss); + + /* + * Leave lazy mode, flushing any hypercalls made here. + * This must be done before restoring TLS segments so + * the GDT and LDT are properly updated, and must be + * done before math_state_restore, so the TS bit is up + * to date. + */ + arch_end_context_switch(next_p); + + /* + * Reload esp0, kernel_stack, and current_top_of_stack. This changes + * current_thread_info(). + */ + load_sp0(tss, next); + this_cpu_write(kernel_stack, + (unsigned long)task_stack_page(next_p) + + THREAD_SIZE); + this_cpu_write(cpu_current_top_of_stack, + (unsigned long)task_stack_page(next_p) + + THREAD_SIZE); + + /* + * Restore %gs if needed (which is common) + */ + if (prev->gs | next->gs) + lazy_load_gs(next->gs); + + switch_fpu_finish(next_p, fpu); + + this_cpu_write(current_task, next_p); + + return prev_p; +} + +#define top_esp (THREAD_SIZE - sizeof(unsigned long)) +#define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long)) + +unsigned long get_wchan(struct task_struct *p) +{ + unsigned long bp, sp, ip; + unsigned long stack_page; + int count = 0; + if (!p || p == current || p->state == TASK_RUNNING) + return 0; + stack_page = (unsigned long)task_stack_page(p); + sp = p->thread.sp; + if (!stack_page || sp < stack_page || sp > top_esp+stack_page) + return 0; + /* include/asm-i386/system.h:switch_to() pushes bp last. */ + bp = *(unsigned long *) sp; + do { + if (bp < stack_page || bp > top_ebp+stack_page) + return 0; + ip = *(unsigned long *) (bp+4); + if (!in_sched_functions(ip)) + return ip; + bp = *(unsigned long *) bp; + } while (count++ < 16); + return 0; +} + |