cregit-Linux how code gets into the kernel

Release 4.7 arch/x86/kernel/process_32.c

Directory: arch/x86/kernel
/*
 *  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/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>
#include <asm/vm86.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]; }

Contributors

PersonTokensPropCommitsCommitProp
jens axboejens axboe2796.43%150.00%
h. peter anvinh. peter anvin13.57%150.00%
Total28100.00%2100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git8423.27%315.79%
pavel emelianovpavel emelianov8122.44%15.26%
alan sternalan stern6518.01%15.26%
dave jonesdave jones5414.96%15.26%
h. peter anvinh. peter anvin215.82%210.53%
zachary amsdenzachary amsden195.26%15.26%
harvey harrisonharvey harrison123.32%15.26%
pekka j enbergpekka j enberg71.94%210.53%
tejun heotejun heo41.11%15.26%
ingo molnaringo molnar41.11%15.26%
linus torvaldslinus torvalds41.11%15.26%
jeremy fitzhardingejeremy fitzhardinge20.55%15.26%
andy lutomirskiandy lutomirski20.55%210.53%
vincent hanquezvincent hanquez20.55%15.26%
Total361100.00%19100.00%


void release_thread(struct task_struct *dead_task) { BUG_ON(dead_task->mm); release_vm86_irqs(dead_task); }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git1359.09%450.00%
william lee irwin iiiwilliam lee irwin iii418.18%112.50%
dave jonesdave jones313.64%112.50%
ingo molnaringo molnar14.55%112.50%
zachary amsdenzachary amsden14.55%112.50%
Total22100.00%8100.00%


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 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 *)tls, 0); if (err && p->thread.io_bitmap_ptr) { kfree(p->thread.io_bitmap_ptr); p->thread.io_bitmap_max = 0; } return err; }

Contributors

PersonTokensPropCommitsCommitProp
al viroal viro14737.40%27.14%
ingo molnaringo molnar6516.54%310.71%
pre-gitpre-git5714.50%517.86%
andrew mortonandrew morton287.12%310.71%
oleg nesterovoleg nesterov205.09%13.57%
roland mcgrathroland mcgrath123.05%13.57%
stephane eranianstephane eranian123.05%13.57%
k.prasadk.prasad112.80%13.57%
benjamin lahaisebenjamin lahaise92.29%13.57%
alexey dobriyanalexey dobriyan71.78%13.57%
josh triplettjosh triplett61.53%13.57%
tejun heotejun heo51.27%13.57%
h. peter anvinh. peter anvin41.02%310.71%
vineet guptavineet gupta41.02%13.57%
albert cahalanalbert cahalan41.02%13.57%
alexander nybergalexander nyberg10.25%13.57%
linus torvaldslinus torvalds10.25%13.57%
Total393100.00%28100.00%


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(); }

Contributors

PersonTokensPropCommitsCommitProp
ingo molnaringo molnar6078.95%120.00%
al viroal viro79.21%240.00%
tejun heotejun heo79.21%120.00%
brian gerstbrian gerst22.63%120.00%
Total76100.00%5100.00%

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; struct fpu *prev_fpu = &prev->fpu; struct fpu *next_fpu = &next->fpu; int cpu = smp_processor_id(); struct tss_struct *tss = &per_cpu(cpu_tss, cpu); fpu_switch_t fpu_switch; /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ fpu_switch = switch_fpu_prepare(prev_fpu, next_fpu, 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); /* * 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 fpu__restore(), so the TS bit is up * to date. */ arch_end_context_switch(next_p); /* * Reload esp0 and cpu_current_top_of_stack. This changes * current_thread_info(). */ load_sp0(tss, next); 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_fpu, fpu_switch); this_cpu_write(current_task, next_p); return prev_p; }

Overall Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git23818.96%2621.14%
ingo molnaringo molnar17113.63%129.76%
al viroal viro16513.15%43.25%
pavel emelianovpavel emelianov816.45%10.81%
zachary amsdenzachary amsden715.66%54.07%
alan sternalan stern655.18%10.81%
dave jonesdave jones624.94%43.25%
jeremy fitzhardingejeremy fitzhardinge352.79%64.88%
jens axboejens axboe282.23%10.81%
andi kleenandi kleen282.23%21.63%
andrew mortonandrew morton282.23%32.44%
h. peter anvinh. peter anvin262.07%43.25%
andy lutomirskiandy lutomirski262.07%54.07%
oleg nesterovoleg nesterov251.99%21.63%
linus torvaldslinus torvalds251.99%86.50%
tejun heotejun heo181.43%21.63%
stephane eranianstephane eranian181.43%10.81%
andrea arcangeliandrea arcangeli171.35%21.63%
k.prasadk.prasad120.96%10.81%
harvey harrisonharvey harrison120.96%10.81%
roland mcgrathroland mcgrath120.96%10.81%
zwane mwaikambozwane mwaikambo90.72%10.81%
jaswinder singh rajputjaswinder singh rajput90.72%32.44%
benjamin lahaisebenjamin lahaise90.72%10.81%
alexey dobriyanalexey dobriyan70.56%10.81%
pekka j enbergpekka j enberg70.56%21.63%
josh triplettjosh triplett60.48%10.81%
brian gerstbrian gerst50.40%21.63%
albert cahalanalbert cahalan40.32%10.81%
vineet guptavineet gupta40.32%10.81%
william lee irwin iiiwilliam lee irwin iii40.32%10.81%
vincent hanquezvincent hanquez30.24%21.63%
rusty russellrusty russell30.24%10.81%
erik bosmanerik bosman30.24%10.81%
daniel jacobowitzdaniel jacobowitz30.24%10.81%
frederic weisbeckerfrederic weisbecker30.24%10.81%
don zickusdon zickus20.16%10.81%
thomas gleixnerthomas gleixner20.16%10.81%
david howellsdavid howells20.16%21.63%
alexander nybergalexander nyberg10.08%10.81%
denys vlasenkodenys vlasenko10.08%10.81%
kamalesh babulalkamalesh babulal10.08%10.81%
marc dionnemarc dionne10.08%10.81%
shai fultheimshai fultheim10.08%10.81%
chuck ebbertchuck ebbert10.08%10.81%
alex shialex shi10.08%10.81%
Total1255100.00%123100.00%
Directory: arch/x86/kernel
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
{% endraw %}