cregit-Linux how code gets into the kernel

Release 4.14 arch/x86/kernel/process_64.c

Directory: arch/x86/kernel
/*
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  Pentium III FXSR, SSE support
 *      Gareth Hughes <gareth@valinux.com>, May 2000
 *
 *  X86-64 port
 *      Andi Kleen.
 *
 *      CPU hotplug support - ashok.raj@intel.com
 */

/*
 * This file handles the architecture-dependent parts of process handling..
 */

#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/fs.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/interrupt.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/ptrace.h>
#include <linux/notifier.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/prctl.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/ftrace.h>
#include <linux/syscalls.h>

#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/fpu/internal.h>
#include <asm/mmu_context.h>
#include <asm/prctl.h>
#include <asm/desc.h>
#include <asm/proto.h>
#include <asm/ia32.h>
#include <asm/syscalls.h>
#include <asm/debugreg.h>
#include <asm/switch_to.h>
#include <asm/xen/hypervisor.h>
#include <asm/vdso.h>
#include <asm/intel_rdt_sched.h>
#include <asm/unistd.h>
#ifdef CONFIG_IA32_EMULATION
/* Not included via unistd.h */
#include <asm/unistd_32_ia32.h>
#endif

__visible DEFINE_PER_CPU(unsigned long, rsp_scratch);

/* Prints also some state that isn't saved in the pt_regs */



void __show_regs(struct pt_regs *regs, int all)
{
	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
	unsigned long d0, d1, d2, d3, d6, d7;
	unsigned int fsindex, gsindex;
	unsigned int ds, cs, es;

	printk(KERN_DEFAULT "RIP: %04lx:%pS\n", regs->cs, (void *)regs->ip);
	printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx", regs->ss,
		regs->sp, regs->flags);
	if (regs->orig_ax != -1)
		pr_cont(" ORIG_RAX: %016lx\n", regs->orig_ax);
	else
		pr_cont("\n");

	printk(KERN_DEFAULT "RAX: %016lx RBX: %016lx RCX: %016lx\n",
	       regs->ax, regs->bx, regs->cx);
	printk(KERN_DEFAULT "RDX: %016lx RSI: %016lx RDI: %016lx\n",
	       regs->dx, regs->si, regs->di);
	printk(KERN_DEFAULT "RBP: %016lx R08: %016lx R09: %016lx\n",
	       regs->bp, regs->r8, regs->r9);
	printk(KERN_DEFAULT "R10: %016lx R11: %016lx R12: %016lx\n",
	       regs->r10, regs->r11, regs->r12);
	printk(KERN_DEFAULT "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);

	if (!all)
		return;

	cr0 = read_cr0();
	cr2 = read_cr2();
	cr3 = __read_cr3();
	cr4 = __read_cr4();

	printk(KERN_DEFAULT "FS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
	       fs, fsindex, gs, gsindex, shadowgs);
	printk(KERN_DEFAULT "CS:  %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds,
			es, cr0);
	printk(KERN_DEFAULT "CR2: %016lx CR3: %016lx CR4: %016lx\n", 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))) {
		printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n",
		       d0, d1, d2);
		printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n",
		       d3, d6, d7);
	}

	if (boot_cpu_has(X86_FEATURE_OSPKE))
		printk(KERN_DEFAULT "PKRU: %08x\n", read_pkru());
}


Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen21649.66%423.53%


Alan Stern6715.40%15.88%


Dave Jones5111.72%15.88%


Josh Poimboeuf306.90%317.65%


Pekka J Enberg204.60%211.76%


Glauber de Oliveira Costa184.14%15.88%


Dave Hansen163.68%15.88%


H. Peter Anvin102.30%15.88%


Nicolas Iooss51.15%15.88%


Andrew Lutomirski20.46%211.76%


Total435100.00%17100.00%






void release_thread(struct task_struct *dead_task)
{
	if (dead_task->mm) {
#ifdef CONFIG_MODIFY_LDT_SYSCALL
		if (dead_task->mm->context.ldt) {
			pr_warn("WARNING: dead process %s still has LDT? <%p/%d>\n",
				dead_task->comm,
				dead_task->mm->context.ldt->entries,
				dead_task->mm->context.ldt->nr_entries);
			BUG();
		}
#endif
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen5480.60%225.00%


Andrew Lutomirski811.94%225.00%


Jan Beulich22.99%112.50%


Borislav Petkov11.49%112.50%


Chen Gang S11.49%112.50%


Joe Perches11.49%112.50%


Total67100.00%8100.00%




enum which_selector {
	
FS,
	
GS
};

/*
 * Saves the FS or GS base for an outgoing thread if FSGSBASE extensions are
 * not available.  The goal is to be reasonably fast on non-FSGSBASE systems.
 * It's forcibly inlined because it'll generate better code and this function
 * is hot.
 */



static __always_inline void save_base_legacy(struct task_struct *prev_p,
					     unsigned short selector,
					     enum which_selector which)
{
	if (likely(selector == 0)) {
		/*
                 * On Intel (without X86_BUG_NULL_SEG), the segment base could
                 * be the pre-existing saved base or it could be zero.  On AMD
                 * (with X86_BUG_NULL_SEG), the segment base could be almost
                 * anything.
                 *
                 * This branch is very hot (it's hit twice on almost every
                 * context switch between 64-bit programs), and avoiding
                 * the RDMSR helps a lot, so we just assume that whatever
                 * value is already saved is correct.  This matches historical
                 * Linux behavior, so it won't break existing applications.
                 *
                 * To avoid leaking state, on non-X86_BUG_NULL_SEG CPUs, if we
                 * report that the base is zero, it needs to actually be zero:
                 * see the corresponding logic in load_seg_legacy.
                 */
	} else {
		/*
                 * If the selector is 1, 2, or 3, then the base is zero on
                 * !X86_BUG_NULL_SEG CPUs and could be anything on
                 * X86_BUG_NULL_SEG CPUs.  In the latter case, Linux
                 * has never attempted to preserve the base across context
                 * switches.
                 *
                 * If selector > 3, then it refers to a real segment, and
                 * saving the base isn't necessary.
                 */
		if (which == FS)
			prev_p->thread.fsbase = 0;
		else
			prev_p->thread.gsbase = 0;
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Andrew Lutomirski59100.00%1100.00%


Total59100.00%1100.00%






static __always_inline void save_fsgs(struct task_struct *task)
{
	savesegment(fs, task->thread.fsindex);
	savesegment(gs, task->thread.gsindex);
	save_base_legacy(task, task->thread.fsindex, FS);
	save_base_legacy(task, task->thread.gsindex, GS);
}


Contributors
PersonTokensPropCommitsCommitProp
Andrew Lutomirski60100.00%1100.00%


Total60100.00%1100.00%






static __always_inline void loadseg(enum which_selector which,
				    unsigned short sel)
{
	if (which == FS)
		loadsegment(fs, sel);
	else
		load_gs_index(sel);
}


Contributors
PersonTokensPropCommitsCommitProp
Andrew Lutomirski34100.00%1100.00%


Total34100.00%1100.00%






static __always_inline void load_seg_legacy(unsigned short prev_index,
					    unsigned long prev_base,
					    unsigned short next_index,
					    unsigned long next_base,
					    enum which_selector which)
{
	if (likely(next_index <= 3)) {
		/*
                 * The next task is using 64-bit TLS, is not using this
                 * segment at all, or is having fun with arcane CPU features.
                 */
		if (next_base == 0) {
			/*
                         * Nasty case: on AMD CPUs, we need to forcibly zero
                         * the base.
                         */
			if (static_cpu_has_bug(X86_BUG_NULL_SEG)) {
				loadseg(which, __USER_DS);
				loadseg(which, next_index);
			} else {
				/*
                                 * We could try to exhaustively detect cases
                                 * under which we can skip the segment load,
                                 * but there's really only one case that matters
                                 * for performance: if both the previous and
                                 * next states are fully zeroed, we can skip
                                 * the load.
                                 *
                                 * (This assumes that prev_base == 0 has no
                                 * false positives.  This is the case on
                                 * Intel-style CPUs.)
                                 */
				if (likely(prev_index | next_index | prev_base))
					loadseg(which, next_index);
			}
		} else {
			if (prev_index != next_index)
				loadseg(which, next_index);
			wrmsrl(which == FS ? MSR_FS_BASE : MSR_KERNEL_GS_BASE,
			       next_base);
		}
	} else {
		/*
                 * The next task is using a real segment.  Loading the selector
                 * is sufficient.
                 */
		loadseg(which, next_index);
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Andrew Lutomirski133100.00%1100.00%


Total133100.00%1100.00%






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;

	p->thread.sp0 = (unsigned long)task_stack_page(p) + THREAD_SIZE;
	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;
}


Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen18940.21%519.23%


Al Viro9820.85%311.54%


Brian Gerst5712.13%311.54%


Jeremy Fitzhardinge377.87%13.85%


H. Peter Anvin326.81%311.54%


Roland McGrath122.55%13.85%


Stéphane Eranian122.55%13.85%


K.Prasad91.91%13.85%


Thomas Meyer71.49%13.85%


Josh Triplett71.49%13.85%


Andrew Lutomirski51.06%27.69%


Vineet Gupta20.43%13.85%


Dmitry Safonov10.21%13.85%


Kyle Huey10.21%13.85%


Albert D. Cahalan10.21%13.85%


Total470100.00%26100.00%





static void

start_thread_common(struct pt_regs *regs, unsigned long new_ip,
		    unsigned long new_sp,
		    unsigned int _cs, unsigned int _ss, unsigned int _ds)
{
	WARN_ON_ONCE(regs != current_pt_regs());

	if (static_cpu_has(X86_BUG_NULL_SEG)) {
		/* Loading zero below won't clear the base. */
		loadsegment(fs, __USER_DS);
		load_gs_index(__USER_DS);
	}

	loadsegment(fs, 0);
	loadsegment(es, _ds);
	loadsegment(ds, _ds);
	load_gs_index(0);

	regs->ip		= new_ip;
	regs->sp		= new_sp;
	regs->cs		= _cs;
	regs->ss		= _ss;
	regs->flags		= X86_EFLAGS_IF;
	force_iret();
}


Contributors
PersonTokensPropCommitsCommitProp
Ingo Molnar4940.83%116.67%


Andrew Lutomirski3025.00%116.67%


Jeremy Fitzhardinge1915.83%116.67%


H. Peter Anvin1915.83%233.33%


Brian Gerst32.50%116.67%


Total120100.00%6100.00%





void

start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
{
	start_thread_common(regs, new_ip, new_sp,
			    __USER_CS, __USER_DS, 0);
}


Contributors
PersonTokensPropCommitsCommitProp
H. Peter Anvin3090.91%150.00%


Ingo Molnar39.09%150.00%


Total33100.00%2100.00%



#ifdef CONFIG_COMPAT



void compat_start_thread(struct pt_regs *regs, u32 new_ip, u32 new_sp)
{
	start_thread_common(regs, new_ip, new_sp,
			    test_thread_flag(TIF_X32)
			    ? __USER_CS : __USER32_CS,
			    __USER_DS, __USER_DS);
}

Contributors
PersonTokensPropCommitsCommitProp
H. Peter Anvin3797.37%375.00%


Brian Gerst12.63%125.00%


Total38100.00%4100.00%



#endif

/*
 *      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
 *
 * Kprobes not supported here. Set the probe on schedule instead.
 * Function graph tracer not supported too.
 */
__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;
        struct thread_struct *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);

	WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ENTRY) &&
		     this_cpu_read(irq_count) != -1);

	switch_fpu_prepare(prev_fpu, cpu);

	/* We must save %fs and %gs before load_TLS() because
         * %fs and %gs may be cleared by load_TLS().
         *
         * (e.g. xen_load_tls())
         */
	save_fsgs(prev_p);

	/*
         * Load TLS before restoring any segments so that segment loads
         * reference the correct GDT entries.
         */
	load_TLS(next, cpu);

	/*
         * Leave lazy mode, flushing any hypercalls made here.  This
         * must be done after loading TLS entries in the GDT but before
         * loading segments that might reference them, and and it must
         * be done before fpu__restore(), so the TS bit is up to
         * date.
         */
	arch_end_context_switch(next_p);

	/* Switch DS and ES.
         *
         * Reading them only returns the selectors, but writing them (if
         * nonzero) loads the full descriptor from the GDT or LDT.  The
         * LDT for next is loaded in switch_mm, and the GDT is loaded
         * above.
         *
         * We therefore need to write new values to the segment
         * registers on every context switch unless both the new and old
         * values are zero.
         *
         * Note that we don't need to do anything for CS and SS, as
         * those are saved and restored as part of pt_regs.
         */
	savesegment(es, prev->es);
	if (unlikely(next->es | prev->es))
		loadsegment(es, next->es);

	savesegment(ds, prev->ds);
	if (unlikely(next->ds | prev->ds))
		loadsegment(ds, next->ds);

	load_seg_legacy(prev->fsindex, prev->fsbase,
			next->fsindex, next->fsbase, FS);
	load_seg_legacy(prev->gsindex, prev->gsbase,
			next->gsindex, next->gsbase, GS);

	switch_fpu_finish(next_fpu, cpu);

	/*
         * Switch the PDA and FPU contexts.
         */
	this_cpu_write(current_task, next_p);

	/* Reload esp0 and ss1.  This changes current_thread_info(). */
	load_sp0(tss, next);

	/*
         * Now maybe reload the debug registers and handle I/O bitmaps
         */
	if (unlikely(task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT ||
		     task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
		__switch_to_xtra(prev_p, next_p, tss);

#ifdef CONFIG_XEN_PV
	/*
         * On Xen PV, IOPL bits in pt_regs->flags have no effect, and
         * current_pt_regs()->flags may not match the current task's
         * intended IOPL.  We need to switch it manually.
         */
	if (unlikely(static_cpu_has(X86_FEATURE_XENPV) &&
		     prev->iopl != next->iopl))
		xen_set_iopl_mask(next->iopl);
#endif

	if (static_cpu_has_bug(X86_BUG_SYSRET_SS_ATTRS)) {
		/*
                 * AMD CPUs have a misfeature: SYSRET sets the SS selector but
                 * does not update the cached descriptor.  As a result, if we
                 * do SYSRET while SS is NULL, we'll end up in user mode with
                 * SS apparently equal to __USER_DS but actually unusable.
                 *
                 * The straightforward workaround would be to fix it up just
                 * before SYSRET, but that would slow down the system call
                 * fast paths.  Instead, we ensure that SS is never NULL in
                 * system call context.  We do this by replacing NULL SS
                 * selectors at every context switch.  SYSCALL sets up a valid
                 * SS, so the only way to get NULL is to re-enter the kernel
                 * from CPL 3 through an interrupt.  Since that can't happen
                 * in the same task as a running syscall, we are guaranteed to
                 * context switch between every interrupt vector entry and a
                 * subsequent SYSRET.
                 *
                 * We read SS first because SS reads are much faster than
                 * writes.  Out of caution, we force SS to __KERNEL_DS even if
                 * it previously had a different non-NULL value.
                 */
		unsigned short ss_sel;
		savesegment(ss, ss_sel);
		if (ss_sel != __KERNEL_DS)
			loadsegment(ss, __KERNEL_DS);
	}

	/* Load the Intel cache allocation PQR MSR. */
	intel_rdt_sched_in();

	return prev_p;
}

void 
set_personality_64bit(void)
{
	/* inherit personality from parent */

	/* Make sure to be in 64bit mode */
	clear_thread_flag(TIF_IA32);
	clear_thread_flag(TIF_ADDR32);
	clear_thread_flag(TIF_X32);
	/* Pretend that this comes from a 64bit execve */
	task_pt_regs(current)->orig_ax = __NR_execve;

	/* Ensure the corresponding mm is not marked. */
	if (current->mm)
		current->mm->context.ia32_compat = 0;

	/* 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;
}




static void __set_personality_x32(void)
{
#ifdef CONFIG_X86_X32
	clear_thread_flag(TIF_IA32);
	set_thread_flag(TIF_X32);
	if (current->mm)
		current->mm->context.ia32_compat = TIF_X32;
	current->personality &= ~READ_IMPLIES_EXEC;
	/*
         * in_compat_syscall() uses the presence of the x32 syscall bit
         * flag to determine compat status.  The x86 mmap() code relies on
         * the syscall bitness so set x32 syscall bit right here to make
         * in_compat_syscall() work during exec().
         *
         * Pretend to come from a x32 execve.
         */
	task_pt_regs(current)->orig_ax = __NR_x32_execve | __X32_SYSCALL_BIT;
	current->thread.status &= ~TS_COMPAT;
#endif
}


Contributors
PersonTokensPropCommitsCommitProp
Dmitry Safonov2029.85%114.29%


H. Peter Anvin1420.90%228.57%


Oleg Nesterov1217.91%114.29%


Stephen Wilson1217.91%114.29%


Bobby Powers68.96%114.29%


Andrew Lutomirski34.48%114.29%


Total67100.00%7100.00%






static void __set_personality_ia32(void)
{
#ifdef CONFIG_IA32_EMULATION
	set_thread_flag(TIF_IA32);
	clear_thread_flag(TIF_X32);
	if (current->mm)
		current->mm->context.ia32_compat = TIF_IA32;
	current->personality |= force_personality32;
	/* Prepare the first "return" to user space */
	task_pt_regs(current)->orig_ax = __NR_ia32_execve;
	current->thread.status |= TS_COMPAT;
#endif
}


Contributors
PersonTokensPropCommitsCommitProp
H. Peter Anvin2438.10%240.00%


Dmitry Safonov2031.75%120.00%


Oleg Nesterov1625.40%120.00%


Andrew Lutomirski34.76%120.00%


Total63100.00%5100.00%






void set_personality_ia32(bool x32)
{
	/* Make sure to be in 32bit mode */
	set_thread_flag(TIF_ADDR32);

	if (x32)
		__set_personality_x32();
	else
		__set_personality_ia32();
}

Contributors
PersonTokensPropCommitsCommitProp
Dmitry Safonov2496.00%150.00%


H. Peter Anvin14.00%150.00%


Total25100.00%2100.00%




EXPORT_SYMBOL_GPL(set_personality_ia32);

#ifdef CONFIG_CHECKPOINT_RESTORE



static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr)
{
	int ret;

	ret = map_vdso_once(image, addr);
	if (ret)
		return ret;

	return (long)image->size;
}

Contributors
PersonTokensPropCommitsCommitProp
Dmitry Safonov43100.00%1100.00%


Total43100.00%1100.00%



#endif




long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
{
	int ret = 0;
	int doit = task == current;
	int cpu;

	switch (option) {
	case ARCH_SET_GS:
		if (arg2 >= TASK_SIZE_MAX)
			return -EPERM;
		cpu = get_cpu();
		task->thread.gsindex = 0;
		task->thread.gsbase = arg2;
		if (doit) {
			load_gs_index(0);
			ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, arg2);
		}
		put_cpu();
		break;
	case ARCH_SET_FS:
		/* Not strictly needed for fs, but do it for symmetry
                   with gs */
		if (arg2 >= TASK_SIZE_MAX)
			return -EPERM;
		cpu = get_cpu();
		task->thread.fsindex = 0;
		task->thread.fsbase = arg2;
		if (doit) {
			/* set the selector to 0 to not confuse __switch_to */
			loadsegment(fs, 0);
			ret = wrmsrl_safe(MSR_FS_BASE, arg2);
		}
		put_cpu();
		break;
	case ARCH_GET_FS: {
		unsigned long base;

		if (doit)
			rdmsrl(MSR_FS_BASE, base);
		else
			base = task->thread.fsbase;
		ret = put_user(base, (unsigned long __user *)arg2);
		break;
	}
	case ARCH_GET_GS: {
		unsigned long base;

		if (doit)
			rdmsrl(MSR_KERNEL_GS_BASE, base);
		else
			base = task->thread.gsbase;
		ret = put_user(base, (unsigned long __user *)arg2);
		break;
	}

#ifdef CONFIG_CHECKPOINT_RESTORE
# ifdef CONFIG_X86_X32_ABI
	case ARCH_MAP_VDSO_X32:
		return prctl_map_vdso(&vdso_image_x32, arg2);
# endif
# if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
	case ARCH_MAP_VDSO_32:
		return prctl_map_vdso(&vdso_image_32, arg2);
# endif
	case ARCH_MAP_VDSO_64:
		return prctl_map_vdso(&vdso_image_64, arg2);
#endif

	default:
		ret = -EINVAL;
		break;
	}

	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen20164.22%735.00%


Dmitry Safonov5116.29%15.00%


Andrew Lutomirski278.63%420.00%


Kyle Huey154.79%210.00%


Jeremy Fitzhardinge72.24%15.00%


John Blackwood41.28%15.00%


Mateusz Guzik30.96%15.00%


H. Peter Anvin20.64%15.00%


Al Viro20.64%15.00%


Vinson Lee10.32%15.00%


Total313100.00%20100.00%




SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
{
	long ret;

	ret = do_arch_prctl_64(current, option, arg2);
	if (ret == -EINVAL)
		ret = do_arch_prctl_common(current, option, arg2);

	return ret;
}

#ifdef CONFIG_IA32_EMULATION

COMPAT_SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
{
	return do_arch_prctl_common(current, option, arg2);
}
#endif




unsigned long KSTK_ESP(struct task_struct *task)
{
	return task_pt_regs(task)->sp;
}

Contributors
PersonTokensPropCommitsCommitProp
Stefani Seibold19100.00%1100.00%


Total19100.00%1100.00%




Overall Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen88333.69%1914.39%


Andrew Lutomirski51319.57%1914.39%


Dmitry Safonov1847.02%32.27%


H. Peter Anvin1836.98%107.58%


Al Viro1003.82%43.03%


Kyle Huey893.40%53.79%


Ingo Molnar863.28%86.06%


Jeremy Fitzhardinge823.13%32.27%


Alan Stern672.56%10.76%


Brian Gerst642.44%75.30%


Dave Jones511.95%10.76%


Josh Poimboeuf301.14%32.27%


Stephen Wilson291.11%10.76%


Oleg Nesterov281.07%10.76%


Stéphane Eranian230.88%10.76%


Pekka J Enberg200.76%21.52%


Stefani Seibold190.72%10.76%


Glauber de Oliveira Costa180.69%10.76%


Dave Hansen160.61%10.76%


Linus Torvalds140.53%53.79%


Roland McGrath120.46%10.76%


K.Prasad100.38%10.76%


Markus Metzger90.34%21.52%


Josh Triplett70.27%10.76%


Hiroshi Shimamoto70.27%10.76%


Thomas Meyer70.27%10.76%


Fenghua Yu60.23%10.76%


Bobby Powers60.23%10.76%


Nicolas Iooss50.19%10.76%


Larry Finger50.19%10.76%


John Blackwood40.15%10.76%


Gustavo Fernando Padovan40.15%10.76%


Frédéric Weisbecker40.15%10.76%


Erik Bosman30.11%10.76%


Mateusz Guzik30.11%10.76%


Christoph Hellwig30.11%10.76%


Ashok Raj30.11%10.76%


Vineet Gupta20.08%10.76%


Bibo Mao20.08%10.76%


Rusty Lynch20.08%10.76%


Alexey Dobriyan20.08%10.76%


Don Zickus20.08%10.76%


Jan Beulich20.08%10.76%


Joe Perches10.04%10.76%


Chen Gang S10.04%10.76%


Vinson Lee10.04%10.76%


Borislav Petkov10.04%10.76%


Vikas Shivappa10.04%10.76%


Paul Gortmaker10.04%10.76%


David Howells10.04%10.76%


Vitaly Kuznetsov10.04%10.76%


Rik Van Riel10.04%10.76%


Albert D. Cahalan10.04%10.76%


Jaswinder Singh Rajput10.04%10.76%


Alex Shi10.04%10.76%


Total2621100.00%132100.00%


Directory: arch/x86/kernel



Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.