diff options
Diffstat (limited to 'arch/x86_64/kernel/process.c')
| -rw-r--r-- | arch/x86_64/kernel/process.c | 770 |
1 files changed, 770 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c new file mode 100644 index 00000000000..9922d2ba24a --- /dev/null +++ b/arch/x86_64/kernel/process.c @@ -0,0 +1,770 @@ +/* + * linux/arch/x86-64/kernel/process.c + * + * Copyright (C) 1995 Linus Torvalds + * + * Pentium III FXSR, SSE support + * Gareth Hughes <gareth@valinux.com>, May 2000 + * + * X86-64 port + * Andi Kleen. + * + * $Id: process.c,v 1.38 2002/01/15 10:08:03 ak Exp $ + */ + +/* + * This file handles the architecture-dependent parts of process handling.. + */ + +#include <stdarg.h> + +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/elfcore.h> +#include <linux/smp.h> +#include <linux/slab.h> +#include <linux/user.h> +#include <linux/module.h> +#include <linux/a.out.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/irq.h> +#include <linux/ptrace.h> +#include <linux/utsname.h> +#include <linux/random.h> + +#include <asm/uaccess.h> +#include <asm/pgtable.h> +#include <asm/system.h> +#include <asm/io.h> +#include <asm/processor.h> +#include <asm/i387.h> +#include <asm/mmu_context.h> +#include <asm/pda.h> +#include <asm/prctl.h> +#include <asm/kdebug.h> +#include <asm/desc.h> +#include <asm/proto.h> +#include <asm/ia32.h> + +asmlinkage extern void ret_from_fork(void); + +unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED; + +static atomic_t hlt_counter = ATOMIC_INIT(0); + +unsigned long boot_option_idle_override = 0; +EXPORT_SYMBOL(boot_option_idle_override); + +/* + * Powermanagement idle function, if any.. + */ +void (*pm_idle)(void); +static DEFINE_PER_CPU(unsigned int, cpu_idle_state); + +void disable_hlt(void) +{ + atomic_inc(&hlt_counter); +} + +EXPORT_SYMBOL(disable_hlt); + +void enable_hlt(void) +{ + atomic_dec(&hlt_counter); +} + +EXPORT_SYMBOL(enable_hlt); + +/* + * We use this if we don't have any better + * idle routine.. + */ +void default_idle(void) +{ + if (!atomic_read(&hlt_counter)) { + local_irq_disable(); + if (!need_resched()) + safe_halt(); + else + local_irq_enable(); + } +} + +/* + * On SMP it's slightly faster (but much more power-consuming!) + * to poll the ->need_resched flag instead of waiting for the + * cross-CPU IPI to arrive. Use this option with caution. + */ +static void poll_idle (void) +{ + int oldval; + + local_irq_enable(); + + /* + * Deal with another CPU just having chosen a thread to + * run here: + */ + oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED); + + if (!oldval) { + set_thread_flag(TIF_POLLING_NRFLAG); + asm volatile( + "2:" + "testl %0,%1;" + "rep; nop;" + "je 2b;" + : : + "i" (_TIF_NEED_RESCHED), + "m" (current_thread_info()->flags)); + } else { + set_need_resched(); + } +} + +void cpu_idle_wait(void) +{ + unsigned int cpu, this_cpu = get_cpu(); + cpumask_t map; + + set_cpus_allowed(current, cpumask_of_cpu(this_cpu)); + put_cpu(); + + cpus_clear(map); + for_each_online_cpu(cpu) { + per_cpu(cpu_idle_state, cpu) = 1; + cpu_set(cpu, map); + } + + __get_cpu_var(cpu_idle_state) = 0; + + wmb(); + do { + ssleep(1); + for_each_online_cpu(cpu) { + if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu)) + cpu_clear(cpu, map); + } + cpus_and(map, map, cpu_online_map); + } while (!cpus_empty(map)); +} +EXPORT_SYMBOL_GPL(cpu_idle_wait); + +/* + * The idle thread. There's no useful work to be + * done, so just try to conserve power and have a + * low exit latency (ie sit in a loop waiting for + * somebody to say that they'd like to reschedule) + */ +void cpu_idle (void) +{ + /* endless idle loop with no priority at all */ + while (1) { + while (!need_resched()) { + void (*idle)(void); + + if (__get_cpu_var(cpu_idle_state)) + __get_cpu_var(cpu_idle_state) = 0; + + rmb(); + idle = pm_idle; + if (!idle) + idle = default_idle; + idle(); + } + + schedule(); + } +} + +/* + * This uses new MONITOR/MWAIT instructions on P4 processors with PNI, + * which can obviate IPI to trigger checking of need_resched. + * We execute MONITOR against need_resched and enter optimized wait state + * through MWAIT. Whenever someone changes need_resched, we would be woken + * up from MWAIT (without an IPI). + */ +static void mwait_idle(void) +{ + local_irq_enable(); + + if (!need_resched()) { + set_thread_flag(TIF_POLLING_NRFLAG); + do { + __monitor((void *)¤t_thread_info()->flags, 0, 0); + if (need_resched()) + break; + __mwait(0, 0); + } while (!need_resched()); + clear_thread_flag(TIF_POLLING_NRFLAG); + } +} + +void __init select_idle_routine(const struct cpuinfo_x86 *c) +{ + static int printed; + if (cpu_has(c, X86_FEATURE_MWAIT)) { + /* + * Skip, if setup has overridden idle. + * One CPU supports mwait => All CPUs supports mwait + */ + if (!pm_idle) { + if (!printed) { + printk("using mwait in idle threads.\n"); + printed = 1; + } + pm_idle = mwait_idle; + } + } +} + +static int __init idle_setup (char *str) +{ + if (!strncmp(str, "poll", 4)) { + printk("using polling idle threads.\n"); + pm_idle = poll_idle; + } + + boot_option_idle_override = 1; + return 1; +} + +__setup("idle=", idle_setup); + +/* Prints also some state that isn't saved in the pt_regs */ +void __show_regs(struct pt_regs * regs) +{ + unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs; + unsigned int fsindex,gsindex; + unsigned int ds,cs,es; + + printk("\n"); + print_modules(); + printk("Pid: %d, comm: %.20s %s %s\n", + current->pid, current->comm, print_tainted(), system_utsname.release); + printk("RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->rip); + printk_address(regs->rip); + printk("\nRSP: %04lx:%016lx EFLAGS: %08lx\n", regs->ss, regs->rsp, regs->eflags); + printk("RAX: %016lx RBX: %016lx RCX: %016lx\n", + regs->rax, regs->rbx, regs->rcx); + printk("RDX: %016lx RSI: %016lx RDI: %016lx\n", + regs->rdx, regs->rsi, regs->rdi); + printk("RBP: %016lx R08: %016lx R09: %016lx\n", + regs->rbp, regs->r8, regs->r9); + printk("R10: %016lx R11: %016lx R12: %016lx\n", + regs->r10, regs->r11, regs->r12); + printk("R13: %016lx R14: %016lx R15: %016lx\n", + regs->r13, regs->r14, regs->r15); + + asm("movl %%ds,%0" : "=r" (ds)); + asm("movl %%cs,%0" : "=r" (cs)); + asm("movl %%es,%0" : "=r" (es)); + asm("movl %%fs,%0" : "=r" (fsindex)); + asm("movl %%gs,%0" : "=r" (gsindex)); + + rdmsrl(MSR_FS_BASE, fs); + rdmsrl(MSR_GS_BASE, gs); + rdmsrl(MSR_KERNEL_GS_BASE, shadowgs); + + asm("movq %%cr0, %0": "=r" (cr0)); + asm("movq %%cr2, %0": "=r" (cr2)); + asm("movq %%cr3, %0": "=r" (cr3)); + asm("movq %%cr4, %0": "=r" (cr4)); + + printk("FS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n", + fs,fsindex,gs,gsindex,shadowgs); + printk("CS: %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds, es, cr0); + printk("CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3, cr4); +} + +void show_regs(struct pt_regs *regs) +{ + __show_regs(regs); + show_trace(®s->rsp); +} + +/* + * Free current thread data structures etc.. + */ +void exit_thread(void) +{ + struct task_struct *me = current; + struct thread_struct *t = &me->thread; + if (me->thread.io_bitmap_ptr) { + struct tss_struct *tss = &per_cpu(init_tss, get_cpu()); + + kfree(t->io_bitmap_ptr); + t->io_bitmap_ptr = NULL; + /* + * Careful, clear this in the TSS too: + */ + memset(tss->io_bitmap, 0xff, t->io_bitmap_max); + t->io_bitmap_max = 0; + put_cpu(); + } +} + +void flush_thread(void) +{ + struct task_struct *tsk = current; + struct thread_info *t = current_thread_info(); + + if (t->flags & _TIF_ABI_PENDING) + t->flags ^= (_TIF_ABI_PENDING | _TIF_IA32); + + tsk->thread.debugreg0 = 0; + tsk->thread.debugreg1 = 0; + tsk->thread.debugreg2 = 0; + tsk->thread.debugreg3 = 0; + tsk->thread.debugreg6 = 0; + tsk->thread.debugreg7 = 0; + memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); + /* + * Forget coprocessor state.. + */ + clear_fpu(tsk); + clear_used_math(); +} + +void release_thread(struct task_struct *dead_task) +{ + if (dead_task->mm) { + if (dead_task->mm->context.size) { + printk("WARNING: dead process %8s still has LDT? <%p/%d>\n", + dead_task->comm, + dead_task->mm->context.ldt, + dead_task->mm->context.size); + BUG(); + } + } +} + +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 n_desc_struct *desc = (void *)t->thread.tls_array; + desc += tls; + desc->a = LDT_entry_a(&ud); + desc->b = LDT_entry_b(&ud); +} + +static inline u32 read_32bit_tls(struct task_struct *t, int tls) +{ + struct desc_struct *desc = (void *)t->thread.tls_array; + desc += tls; + return desc->base0 | + (((u32)desc->base1) << 16) | + (((u32)desc->base2) << 24); +} + +/* + * This gets called before we allocate a new thread and copy + * the current task into it. + */ +void prepare_to_copy(struct task_struct *tsk) +{ + unlazy_fpu(tsk); +} + +int copy_thread(int nr, unsigned long clone_flags, unsigned long rsp, + unsigned long unused, + struct task_struct * p, struct pt_regs * regs) +{ + int err; + struct pt_regs * childregs; + struct task_struct *me = current; + + childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1; + + *childregs = *regs; + + childregs->rax = 0; + childregs->rsp = rsp; + if (rsp == ~0UL) { + childregs->rsp = (unsigned long)childregs; + } + + p->thread.rsp = (unsigned long) childregs; + p->thread.rsp0 = (unsigned long) (childregs+1); + p->thread.userrsp = me->thread.userrsp; + + set_ti_thread_flag(p->thread_info, TIF_FORK); + + p->thread.fs = me->thread.fs; + p->thread.gs = me->thread.gs; + + asm("movl %%gs,%0" : "=m" (p->thread.gsindex)); + asm("movl %%fs,%0" : "=m" (p->thread.fsindex)); + asm("movl %%es,%0" : "=m" (p->thread.es)); + asm("movl %%ds,%0" : "=m" (p->thread.ds)); + + if (unlikely(me->thread.io_bitmap_ptr != NULL)) { + p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); + if (!p->thread.io_bitmap_ptr) { + p->thread.io_bitmap_max = 0; + return -ENOMEM; + } + memcpy(p->thread.io_bitmap_ptr, me->thread.io_bitmap_ptr, IO_BITMAP_BYTES); + } + + /* + * Set a new TLS for the child thread? + */ + if (clone_flags & CLONE_SETTLS) { +#ifdef CONFIG_IA32_EMULATION + if (test_thread_flag(TIF_IA32)) + err = ia32_child_tls(p, childregs); + else +#endif + err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8); + 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; +} + +/* + * This special macro can be used to load a debugging register + */ +#define loaddebug(thread,r) set_debug(thread->debugreg ## r, r) + +/* + * switch_to(x,y) should switch tasks from x to y. + * + * This could still be optimized: + * - fold all the options into a flag word and test it with a single test. + * - could test fs/gs bitsliced + */ +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(init_tss, cpu); + + unlazy_fpu(prev_p); + + /* + * Reload esp0, LDT and the page table pointer: + */ + tss->rsp0 = next->rsp0; + + /* + * Switch DS and ES. + * This won't pick up thread selector changes, but I guess that is ok. + */ + asm volatile("movl %%es,%0" : "=m" (prev->es)); + if (unlikely(next->es | prev->es)) + loadsegment(es, next->es); + + asm volatile ("movl %%ds,%0" : "=m" (prev->ds)); + if (unlikely(next->ds | prev->ds)) + loadsegment(ds, next->ds); + + load_TLS(next, cpu); + + /* + * Switch FS and GS. + */ + { + unsigned fsindex; + asm volatile("movl %%fs,%0" : "=r" (fsindex)); + /* segment register != 0 always requires a reload. + also reload when it has changed. + when prev process used 64bit base always reload + to avoid an information leak. */ + if (unlikely(fsindex | next->fsindex | prev->fs)) { + loadsegment(fs, next->fsindex); + /* check if the user used a selector != 0 + * if yes clear 64bit base, since overloaded base + * is always mapped to the Null selector + */ + if (fsindex) + prev->fs = 0; + } + /* when next process has a 64bit base use it */ + if (next->fs) + wrmsrl(MSR_FS_BASE, next->fs); + prev->fsindex = fsindex; + } + { + unsigned gsindex; + asm volatile("movl %%gs,%0" : "=r" (gsindex)); + if (unlikely(gsindex | next->gsindex | prev->gs)) { + load_gs_index(next->gsindex); + if (gsindex) + prev->gs = 0; + } + if (next->gs) + wrmsrl(MSR_KERNEL_GS_BASE, next->gs); + prev->gsindex = gsindex; + } + + /* + * Switch the PDA context. + */ + prev->userrsp = read_pda(oldrsp); + write_pda(oldrsp, next->userrsp); + write_pda(pcurrent, next_p); + write_pda(kernelstack, (unsigned long)next_p->thread_info + THREAD_SIZE - PDA_STACKOFFSET); + + /* + * Now maybe reload the debug registers + */ + if (unlikely(next->debugreg7)) { + loaddebug(next, 0); + loaddebug(next, 1); + loaddebug(next, 2); + loaddebug(next, 3); + /* no 4 and 5 */ + loaddebug(next, 6); + loaddebug(next, 7); + } + + + /* + * Handle the IO bitmap + */ + if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr)) { + if (next->io_bitmap_ptr) + /* + * Copy the relevant range of the IO bitmap. + * Normally this is 128 bytes or less: + */ + memcpy(tss->io_bitmap, next->io_bitmap_ptr, + max(prev->io_bitmap_max, next->io_bitmap_max)); + else { + /* + * Clear any possible leftover bits: + */ + memset(tss->io_bitmap, 0xff, prev->io_bitmap_max); + } + } + + return prev_p; +} + +/* + * sys_execve() executes a new program. + */ +asmlinkage +long sys_execve(char __user *name, char __user * __user *argv, + char __user * __user *envp, struct pt_regs regs) +{ + long error; + char * filename; + + filename = getname(name); + error = PTR_ERR(filename); + if (IS_ERR(filename)) + return error; + error = do_execve(filename, argv, envp, ®s); + if (error == 0) { + task_lock(current); + current->ptrace &= ~PT_DTRACE; + task_unlock(current); + } + putname(filename); + return error; +} + +void set_personality_64bit(void) +{ + /* inherit personality from parent */ + + /* Make sure to be in 64bit mode */ + clear_thread_flag(TIF_IA32); + + /* TBD: overwrites user setup. Should have two bits. + But 64bit processes have always behaved this way, + so it's not too bad. The main problem is just that + 32bit childs are affected again. */ + current->personality &= ~READ_IMPLIES_EXEC; +} + +asmlinkage long sys_fork(struct pt_regs *regs) +{ + return do_fork(SIGCHLD, regs->rsp, regs, 0, NULL, NULL); +} + +asmlinkage long sys_clone(unsigned long clone_flags, unsigned long newsp, void __user *parent_tid, void __user *child_tid, struct pt_regs *regs) +{ + if (!newsp) + newsp = regs->rsp; + return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid); +} + +/* + * This is trivial, and on the face of it looks like it + * could equally well be done in user mode. + * + * Not so, for quite unobvious reasons - register pressure. + * In user mode vfork() cannot have a stack frame, and if + * done by calling the "clone()" system call directly, you + * do not have enough call-clobbered registers to hold all + * the information you need. + */ +asmlinkage long sys_vfork(struct pt_regs *regs) +{ + return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->rsp, regs, 0, + NULL, NULL); +} + +unsigned long get_wchan(struct task_struct *p) +{ + unsigned long stack; + u64 fp,rip; + int count = 0; + + if (!p || p == current || p->state==TASK_RUNNING) + return 0; + stack = (unsigned long)p->thread_info; + if (p->thread.rsp < stack || p->thread.rsp > stack+THREAD_SIZE) + return 0; + fp = *(u64 *)(p->thread.rsp); + do { + if (fp < (unsigned long)stack || fp > (unsigned long)stack+THREAD_SIZE) + return 0; + rip = *(u64 *)(fp+8); + if (!in_sched_functions(rip)) + return rip; + fp = *(u64 *)fp; + } while (count++ < 16); + return 0; +} + +long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) +{ + int ret = 0; + int doit = task == current; + int cpu; + + switch (code) { + case ARCH_SET_GS: + if (addr >= TASK_SIZE) + 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 = checking_wrmsrl(MSR_KERNEL_GS_BASE, addr); + } + } + put_cpu(); + break; + case ARCH_SET_FS: + /* Not strictly needed for fs, but do it for symmetry + with gs */ + if (addr >= TASK_SIZE) + 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); + asm volatile("movl %0,%%fs" :: "r" (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 */ + asm volatile("movl %0,%%fs" :: "r" (0)); + ret = checking_wrmsrl(MSR_FS_BASE, addr); + } + } + put_cpu(); + break; + case ARCH_GET_FS: { + unsigned long base; + if (task->thread.fsindex == FS_TLS_SEL) + base = read_32bit_tls(task, FS_TLS); + else if (doit) { + rdmsrl(MSR_FS_BASE, base); + } else + base = task->thread.fs; + ret = put_user(base, (unsigned long __user *)addr); + break; + } + case ARCH_GET_GS: { + unsigned long base; + if (task->thread.gsindex == GS_TLS_SEL) + base = read_32bit_tls(task, GS_TLS); + else if (doit) { + rdmsrl(MSR_KERNEL_GS_BASE, base); + } else + base = task->thread.gs; + ret = put_user(base, (unsigned long __user *)addr); + break; + } + + default: + ret = -EINVAL; + break; + } + + return ret; +} + +long sys_arch_prctl(int code, unsigned long addr) +{ + return do_arch_prctl(current, code, addr); +} + +/* + * Capture the user space registers if the task is not running (in user space) + */ +int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) +{ + struct pt_regs *pp, ptregs; + + pp = (struct pt_regs *)(tsk->thread.rsp0); + --pp; + + ptregs = *pp; + ptregs.cs &= 0xffff; + ptregs.ss &= 0xffff; + + elf_core_copy_regs(regs, &ptregs); + + return 1; +} + +unsigned long arch_align_stack(unsigned long sp) +{ + if (randomize_va_space) + sp -= get_random_int() % 8192; + return sp & ~0xf; +} |