550 lines
14 KiB
C
550 lines
14 KiB
C
/*
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* Copyright (C) 1995 Linus Torvalds
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*
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* Pentium III FXSR, SSE support
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*
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* X86-64 port
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* Andi Kleen.
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*
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* CPU hotplug support - ashok.raj@intel.com
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*/
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/*
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* This file handles the architecture-dependent parts of process handling..
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*/
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#include <linux/cpu.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/elfcore.h>
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#include <linux/smp.h>
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#include <linux/slab.h>
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#include <linux/user.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/ptrace.h>
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#include <linux/notifier.h>
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#include <linux/kprobes.h>
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#include <linux/kdebug.h>
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#include <linux/prctl.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/ftrace.h>
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#include <asm/pgtable.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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#include <asm/fpu-internal.h>
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#include <asm/mmu_context.h>
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#include <asm/prctl.h>
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#include <asm/desc.h>
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#include <asm/proto.h>
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#include <asm/ia32.h>
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#include <asm/idle.h>
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#include <asm/syscalls.h>
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#include <asm/debugreg.h>
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#include <asm/switch_to.h>
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asmlinkage extern void ret_from_fork(void);
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DEFINE_PER_CPU(unsigned long, old_rsp);
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/* Prints also some state that isn't saved in the pt_regs */
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void __show_regs(struct pt_regs *regs, int all)
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{
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unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
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unsigned long d0, d1, d2, d3, d6, d7;
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unsigned int fsindex, gsindex;
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unsigned int ds, cs, es;
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printk(KERN_DEFAULT "RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip);
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printk_address(regs->ip, 1);
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printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx\n", regs->ss,
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regs->sp, regs->flags);
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printk(KERN_DEFAULT "RAX: %016lx RBX: %016lx RCX: %016lx\n",
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regs->ax, regs->bx, regs->cx);
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printk(KERN_DEFAULT "RDX: %016lx RSI: %016lx RDI: %016lx\n",
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regs->dx, regs->si, regs->di);
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printk(KERN_DEFAULT "RBP: %016lx R08: %016lx R09: %016lx\n",
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regs->bp, regs->r8, regs->r9);
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printk(KERN_DEFAULT "R10: %016lx R11: %016lx R12: %016lx\n",
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regs->r10, regs->r11, regs->r12);
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printk(KERN_DEFAULT "R13: %016lx R14: %016lx R15: %016lx\n",
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regs->r13, regs->r14, regs->r15);
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asm("movl %%ds,%0" : "=r" (ds));
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asm("movl %%cs,%0" : "=r" (cs));
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asm("movl %%es,%0" : "=r" (es));
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asm("movl %%fs,%0" : "=r" (fsindex));
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asm("movl %%gs,%0" : "=r" (gsindex));
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rdmsrl(MSR_FS_BASE, fs);
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rdmsrl(MSR_GS_BASE, gs);
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rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
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if (!all)
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return;
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cr0 = read_cr0();
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cr2 = read_cr2();
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cr3 = read_cr3();
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cr4 = read_cr4();
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printk(KERN_DEFAULT "FS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
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fs, fsindex, gs, gsindex, shadowgs);
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printk(KERN_DEFAULT "CS: %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds,
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es, cr0);
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printk(KERN_DEFAULT "CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3,
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cr4);
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get_debugreg(d0, 0);
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get_debugreg(d1, 1);
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get_debugreg(d2, 2);
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printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
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get_debugreg(d3, 3);
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get_debugreg(d6, 6);
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get_debugreg(d7, 7);
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printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
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}
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void release_thread(struct task_struct *dead_task)
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{
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if (dead_task->mm) {
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if (dead_task->mm->context.size) {
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pr_warn("WARNING: dead process %s still has LDT? <%p/%d>\n",
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dead_task->comm,
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dead_task->mm->context.ldt,
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dead_task->mm->context.size);
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BUG();
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}
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}
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}
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static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
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{
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struct user_desc ud = {
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.base_addr = addr,
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.limit = 0xfffff,
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.seg_32bit = 1,
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.limit_in_pages = 1,
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.useable = 1,
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};
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struct desc_struct *desc = t->thread.tls_array;
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desc += tls;
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fill_ldt(desc, &ud);
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}
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static inline u32 read_32bit_tls(struct task_struct *t, int tls)
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{
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return get_desc_base(&t->thread.tls_array[tls]);
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}
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int copy_thread(unsigned long clone_flags, unsigned long sp,
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unsigned long arg, struct task_struct *p)
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{
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int err;
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struct pt_regs *childregs;
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struct task_struct *me = current;
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p->thread.sp0 = (unsigned long)task_stack_page(p) + THREAD_SIZE;
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childregs = task_pt_regs(p);
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p->thread.sp = (unsigned long) childregs;
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p->thread.usersp = me->thread.usersp;
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set_tsk_thread_flag(p, TIF_FORK);
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p->fpu_counter = 0;
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p->thread.io_bitmap_ptr = NULL;
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savesegment(gs, p->thread.gsindex);
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p->thread.gs = p->thread.gsindex ? 0 : me->thread.gs;
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savesegment(fs, p->thread.fsindex);
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p->thread.fs = p->thread.fsindex ? 0 : me->thread.fs;
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savesegment(es, p->thread.es);
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savesegment(ds, p->thread.ds);
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memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
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if (unlikely(p->flags & PF_KTHREAD)) {
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/* kernel thread */
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memset(childregs, 0, sizeof(struct pt_regs));
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childregs->sp = (unsigned long)childregs;
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childregs->ss = __KERNEL_DS;
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childregs->bx = sp; /* function */
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childregs->bp = arg;
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childregs->orig_ax = -1;
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childregs->cs = __KERNEL_CS | get_kernel_rpl();
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childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1;
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return 0;
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}
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*childregs = *current_pt_regs();
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childregs->ax = 0;
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if (sp)
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childregs->sp = sp;
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err = -ENOMEM;
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memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
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if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
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p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
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IO_BITMAP_BYTES, GFP_KERNEL);
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if (!p->thread.io_bitmap_ptr) {
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p->thread.io_bitmap_max = 0;
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return -ENOMEM;
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}
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set_tsk_thread_flag(p, TIF_IO_BITMAP);
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}
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/*
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* Set a new TLS for the child thread?
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*/
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if (clone_flags & CLONE_SETTLS) {
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#ifdef CONFIG_IA32_EMULATION
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if (test_thread_flag(TIF_IA32))
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err = do_set_thread_area(p, -1,
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(struct user_desc __user *)childregs->si, 0);
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else
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#endif
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err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);
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if (err)
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goto out;
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}
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err = 0;
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out:
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if (err && p->thread.io_bitmap_ptr) {
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kfree(p->thread.io_bitmap_ptr);
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p->thread.io_bitmap_max = 0;
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}
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return err;
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}
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static void
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start_thread_common(struct pt_regs *regs, unsigned long new_ip,
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unsigned long new_sp,
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unsigned int _cs, unsigned int _ss, unsigned int _ds)
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{
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loadsegment(fs, 0);
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loadsegment(es, _ds);
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loadsegment(ds, _ds);
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load_gs_index(0);
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current->thread.usersp = new_sp;
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regs->ip = new_ip;
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regs->sp = new_sp;
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this_cpu_write(old_rsp, new_sp);
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regs->cs = _cs;
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regs->ss = _ss;
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regs->flags = X86_EFLAGS_IF;
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}
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void
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start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
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{
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start_thread_common(regs, new_ip, new_sp,
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__USER_CS, __USER_DS, 0);
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}
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#ifdef CONFIG_IA32_EMULATION
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void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp)
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{
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start_thread_common(regs, new_ip, new_sp,
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test_thread_flag(TIF_X32)
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? __USER_CS : __USER32_CS,
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__USER_DS, __USER_DS);
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}
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#endif
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/*
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* switch_to(x,y) should switch tasks from x to y.
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*
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* This could still be optimized:
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* - fold all the options into a flag word and test it with a single test.
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* - could test fs/gs bitsliced
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*
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* Kprobes not supported here. Set the probe on schedule instead.
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* Function graph tracer not supported too.
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*/
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__notrace_funcgraph struct task_struct *
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__switch_to(struct task_struct *prev_p, struct task_struct *next_p)
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{
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struct thread_struct *prev = &prev_p->thread;
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struct thread_struct *next = &next_p->thread;
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int cpu = smp_processor_id();
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struct tss_struct *tss = &per_cpu(init_tss, cpu);
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unsigned fsindex, gsindex;
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fpu_switch_t fpu;
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fpu = switch_fpu_prepare(prev_p, next_p, cpu);
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/*
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* Reload esp0, LDT and the page table pointer:
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*/
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load_sp0(tss, next);
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/*
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* Switch DS and ES.
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* This won't pick up thread selector changes, but I guess that is ok.
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*/
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savesegment(es, prev->es);
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if (unlikely(next->es | prev->es))
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loadsegment(es, next->es);
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savesegment(ds, prev->ds);
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if (unlikely(next->ds | prev->ds))
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loadsegment(ds, next->ds);
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/* We must save %fs and %gs before load_TLS() because
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* %fs and %gs may be cleared by load_TLS().
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*
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* (e.g. xen_load_tls())
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*/
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savesegment(fs, fsindex);
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savesegment(gs, gsindex);
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load_TLS(next, cpu);
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/*
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* Leave lazy mode, flushing any hypercalls made here.
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* This must be done before restoring TLS segments so
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* the GDT and LDT are properly updated, and must be
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* done before math_state_restore, so the TS bit is up
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* to date.
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*/
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arch_end_context_switch(next_p);
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/*
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* Switch FS and GS.
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*
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* Segment register != 0 always requires a reload. Also
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* reload when it has changed. When prev process used 64bit
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* base always reload to avoid an information leak.
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*/
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if (unlikely(fsindex | next->fsindex | prev->fs)) {
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loadsegment(fs, next->fsindex);
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/*
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* Check if the user used a selector != 0; if yes
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* clear 64bit base, since overloaded base is always
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* mapped to the Null selector
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*/
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if (fsindex)
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prev->fs = 0;
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}
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/* when next process has a 64bit base use it */
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if (next->fs)
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wrmsrl(MSR_FS_BASE, next->fs);
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prev->fsindex = fsindex;
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if (unlikely(gsindex | next->gsindex | prev->gs)) {
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load_gs_index(next->gsindex);
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if (gsindex)
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prev->gs = 0;
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}
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if (next->gs)
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wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
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prev->gsindex = gsindex;
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switch_fpu_finish(next_p, fpu);
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/*
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* Switch the PDA and FPU contexts.
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*/
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prev->usersp = this_cpu_read(old_rsp);
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this_cpu_write(old_rsp, next->usersp);
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this_cpu_write(current_task, next_p);
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this_cpu_write(kernel_stack,
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(unsigned long)task_stack_page(next_p) +
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THREAD_SIZE - KERNEL_STACK_OFFSET);
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/*
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* Now maybe reload the debug registers and handle I/O bitmaps
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*/
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if (unlikely(task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT ||
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task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
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__switch_to_xtra(prev_p, next_p, tss);
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return prev_p;
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}
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void set_personality_64bit(void)
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{
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/* inherit personality from parent */
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/* Make sure to be in 64bit mode */
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clear_thread_flag(TIF_IA32);
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clear_thread_flag(TIF_ADDR32);
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clear_thread_flag(TIF_X32);
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/* Ensure the corresponding mm is not marked. */
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if (current->mm)
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current->mm->context.ia32_compat = 0;
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/* TBD: overwrites user setup. Should have two bits.
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But 64bit processes have always behaved this way,
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so it's not too bad. The main problem is just that
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32bit childs are affected again. */
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current->personality &= ~READ_IMPLIES_EXEC;
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}
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void set_personality_ia32(bool x32)
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{
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/* inherit personality from parent */
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/* Make sure to be in 32bit mode */
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set_thread_flag(TIF_ADDR32);
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/* Mark the associated mm as containing 32-bit tasks. */
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if (current->mm)
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current->mm->context.ia32_compat = 1;
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if (x32) {
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clear_thread_flag(TIF_IA32);
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set_thread_flag(TIF_X32);
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current->personality &= ~READ_IMPLIES_EXEC;
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/* is_compat_task() uses the presence of the x32
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syscall bit flag to determine compat status */
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current_thread_info()->status &= ~TS_COMPAT;
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} else {
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set_thread_flag(TIF_IA32);
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clear_thread_flag(TIF_X32);
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current->personality |= force_personality32;
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/* Prepare the first "return" to user space */
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current_thread_info()->status |= TS_COMPAT;
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}
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}
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EXPORT_SYMBOL_GPL(set_personality_ia32);
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unsigned long get_wchan(struct task_struct *p)
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{
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unsigned long stack;
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u64 fp, ip;
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int count = 0;
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if (!p || p == current || p->state == TASK_RUNNING)
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return 0;
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stack = (unsigned long)task_stack_page(p);
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if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE)
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return 0;
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fp = *(u64 *)(p->thread.sp);
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do {
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if (fp < (unsigned long)stack ||
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fp >= (unsigned long)stack+THREAD_SIZE)
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return 0;
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ip = *(u64 *)(fp+8);
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if (!in_sched_functions(ip))
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return ip;
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fp = *(u64 *)fp;
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} while (count++ < 16);
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return 0;
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}
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long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
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{
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int ret = 0;
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int doit = task == current;
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int cpu;
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switch (code) {
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case ARCH_SET_GS:
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if (addr >= TASK_SIZE_OF(task))
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return -EPERM;
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cpu = get_cpu();
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/* handle small bases via the GDT because that's faster to
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switch. */
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if (addr <= 0xffffffff) {
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set_32bit_tls(task, GS_TLS, addr);
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if (doit) {
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load_TLS(&task->thread, cpu);
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load_gs_index(GS_TLS_SEL);
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}
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task->thread.gsindex = GS_TLS_SEL;
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task->thread.gs = 0;
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} else {
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task->thread.gsindex = 0;
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task->thread.gs = addr;
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if (doit) {
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load_gs_index(0);
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ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
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}
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}
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put_cpu();
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break;
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case ARCH_SET_FS:
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/* Not strictly needed for fs, but do it for symmetry
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with gs */
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if (addr >= TASK_SIZE_OF(task))
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return -EPERM;
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cpu = get_cpu();
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/* handle small bases via the GDT because that's faster to
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switch. */
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if (addr <= 0xffffffff) {
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set_32bit_tls(task, FS_TLS, addr);
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if (doit) {
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load_TLS(&task->thread, cpu);
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loadsegment(fs, FS_TLS_SEL);
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}
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task->thread.fsindex = FS_TLS_SEL;
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task->thread.fs = 0;
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} else {
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|
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;
|
|
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;
|
|
unsigned gsindex;
|
|
if (task->thread.gsindex == GS_TLS_SEL)
|
|
base = read_32bit_tls(task, GS_TLS);
|
|
else if (doit) {
|
|
savesegment(gs, gsindex);
|
|
if (gsindex)
|
|
rdmsrl(MSR_KERNEL_GS_BASE, base);
|
|
else
|
|
base = task->thread.gs;
|
|
} 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);
|
|
}
|
|
|
|
unsigned long KSTK_ESP(struct task_struct *task)
|
|
{
|
|
return (test_tsk_thread_flag(task, TIF_IA32)) ?
|
|
(task_pt_regs(task)->sp) : ((task)->thread.usersp);
|
|
}
|