cregit-Linux how code gets into the kernel

Release 4.14 arch/x86/kernel/signal.c

Directory: arch/x86/kernel
// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
 *  2000-2002   x86-64 support by Andi Kleen
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/tracehook.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/uaccess.h>
#include <linux/user-return-notifier.h>
#include <linux/uprobes.h>
#include <linux/context_tracking.h>

#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/fpu/internal.h>
#include <asm/fpu/signal.h>
#include <asm/vdso.h>
#include <asm/mce.h>
#include <asm/sighandling.h>
#include <asm/vm86.h>

#ifdef CONFIG_X86_64
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
#endif /* CONFIG_X86_64 */

#include <asm/syscall.h>
#include <asm/syscalls.h>

#include <asm/sigframe.h>
#include <asm/signal.h>


#define COPY(x)			do {                    \
        get_user_ex(regs->x, &sc->x);                   \
} while (0)


#define GET_SEG(seg)		({                      \
        unsigned short tmp;                             \
        get_user_ex(tmp, &sc->seg);                     \
        tmp;                                            \
})


#define COPY_SEG(seg)		do {                    \
        regs->seg = GET_SEG(seg);                       \
} while (0)


#define COPY_SEG_CPL3(seg)	do {                    \
        regs->seg = GET_SEG(seg) | 3;                   \
} while (0)

#ifdef CONFIG_X86_64
/*
 * If regs->ss will cause an IRET fault, change it.  Otherwise leave it
 * alone.  Using this generally makes no sense unless
 * user_64bit_mode(regs) would return true.
 */



static void force_valid_ss(struct pt_regs *regs)
{
	u32 ar;
	asm volatile ("lar %[old_ss], %[ar]\n\t"
                      "jz 1f\n\t"		/* If invalid: */
		      "xorl %[ar], %[ar]\n\t"	/* set ar = 0 */
		      "1:"
                      : [ar] "=r" (ar)
                      : [old_ss] "rm" ((u16)regs->ss));

	/*
         * For a valid 64-bit user context, we need DPL 3, type
         * read-write data or read-write exp-down data, and S and P
         * set.  We can't use VERW because VERW doesn't check the
         * P bit.
         */
	ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK;
	if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) &&
	    ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN))
		regs->ss = __USER_DS;
}

Contributors
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Andrew Lutomirski64100.00%1100.00%


Total64100.00%1100.00%



#endif




static int restore_sigcontext(struct pt_regs *regs,
			      struct sigcontext __user *sc,
			      unsigned long uc_flags)
{
	unsigned long buf_val;
	void __user *buf;
	unsigned int tmpflags;
	unsigned int err = 0;

	/* Always make any pending restarted system calls return -EINTR */
	current->restart_block.fn = do_no_restart_syscall;

	get_user_try {

#ifdef CONFIG_X86_32
		set_user_gs(regs, GET_SEG(gs));
		COPY_SEG(fs);
		COPY_SEG(es);
		COPY_SEG(ds);
#endif /* CONFIG_X86_32 */

		COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
		COPY(dx); COPY(cx); COPY(ip); COPY(ax);

#ifdef CONFIG_X86_64
		COPY(r8);
		COPY(r9);
		COPY(r10);
		COPY(r11);
		COPY(r12);
		COPY(r13);
		COPY(r14);
		COPY(r15);
#endif /* CONFIG_X86_64 */

		COPY_SEG_CPL3(cs);
		COPY_SEG_CPL3(ss);

#ifdef CONFIG_X86_64
		/*
                 * Fix up SS if needed for the benefit of old DOSEMU and
                 * CRIU.
                 */
		if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) &&
			     user_64bit_mode(regs)))
			force_valid_ss(regs);
#endif

		get_user_ex(tmpflags, &sc->flags);
		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
		regs->orig_ax = -1;		/* disable syscall checks */

		get_user_ex(buf_val, &sc->fpstate);
		buf = (void __user *)buf_val;
	} get_user_catch(err);

	err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32));

	force_iret();

	return err;
}


Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen12542.96%14.55%


Hiroshi Shimamoto6120.96%418.18%


H. Peter Anvin3110.65%522.73%


Andrew Lutomirski299.97%29.09%


Ingo Molnar155.15%29.09%


Brian Gerst82.75%29.09%


Andrew Morton82.75%14.55%


Tejun Heo51.72%14.55%


Linus Torvalds51.72%14.55%


Harvey Harrison20.69%14.55%


Al Viro10.34%14.55%


Masahiro Yamada10.34%14.55%


Total291100.00%22100.00%






int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
		     struct pt_regs *regs, unsigned long mask)
{
	int err = 0;

	put_user_try {

#ifdef CONFIG_X86_32
		put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
		put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
		put_user_ex(regs->es, (unsigned int __user *)&sc->es);
		put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
#endif /* CONFIG_X86_32 */

		put_user_ex(regs->di, &sc->di);
		put_user_ex(regs->si, &sc->si);
		put_user_ex(regs->bp, &sc->bp);
		put_user_ex(regs->sp, &sc->sp);
		put_user_ex(regs->bx, &sc->bx);
		put_user_ex(regs->dx, &sc->dx);
		put_user_ex(regs->cx, &sc->cx);
		put_user_ex(regs->ax, &sc->ax);
#ifdef CONFIG_X86_64
		put_user_ex(regs->r8, &sc->r8);
		put_user_ex(regs->r9, &sc->r9);
		put_user_ex(regs->r10, &sc->r10);
		put_user_ex(regs->r11, &sc->r11);
		put_user_ex(regs->r12, &sc->r12);
		put_user_ex(regs->r13, &sc->r13);
		put_user_ex(regs->r14, &sc->r14);
		put_user_ex(regs->r15, &sc->r15);
#endif /* CONFIG_X86_64 */

		put_user_ex(current->thread.trap_nr, &sc->trapno);
		put_user_ex(current->thread.error_code, &sc->err);
		put_user_ex(regs->ip, &sc->ip);
#ifdef CONFIG_X86_32
		put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
		put_user_ex(regs->flags, &sc->flags);
		put_user_ex(regs->sp, &sc->sp_at_signal);
		put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
#else /* !CONFIG_X86_32 */
		put_user_ex(regs->flags, &sc->flags);
		put_user_ex(regs->cs, &sc->cs);
		put_user_ex(0, &sc->gs);
		put_user_ex(0, &sc->fs);
		put_user_ex(regs->ss, &sc->ss);
#endif /* CONFIG_X86_32 */

		put_user_ex(fpstate, &sc->fpstate);

		/* non-iBCS2 extensions.. */
		put_user_ex(mask, &sc->oldmask);
		put_user_ex(current->thread.cr2, &sc->cr2);
	} put_user_catch(err);

	return err;
}


Contributors
PersonTokensPropCommitsCommitProp
Hiroshi Shimamoto26450.97%423.53%


Andi Kleen21942.28%423.53%


Andrew Lutomirski142.70%211.76%


Bryan Ford91.74%15.88%


Tejun Heo40.77%15.88%


Al Viro30.58%15.88%


Linus Torvalds20.39%15.88%


Harvey Harrison10.19%15.88%


H. Peter Anvin10.19%15.88%


Srikar Dronamraju10.19%15.88%


Total518100.00%17100.00%



/*
 * Set up a signal frame.
 */

/*
 * Determine which stack to use..
 */



static unsigned long align_sigframe(unsigned long sp)
{
#ifdef CONFIG_X86_32
	/*
         * Align the stack pointer according to the i386 ABI,
         * i.e. so that on function entry ((sp + 4) & 15) == 0.
         */
	sp = ((sp + 4) & -16ul) - 4;
#else /* !CONFIG_X86_32 */
	sp = round_down(sp, 16) - 8;
#endif
	return sp;
}


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Hiroshi Shimamoto49100.00%1100.00%


Total49100.00%1100.00%





static void __user *

get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
	     void __user **fpstate)
{
	/* Default to using normal stack */
	unsigned long math_size = 0;
	unsigned long sp = regs->sp;
	unsigned long buf_fx = 0;
	int onsigstack = on_sig_stack(sp);
	struct fpu *fpu = &current->thread.fpu;

	/* redzone */
	if (IS_ENABLED(CONFIG_X86_64))
		sp -= 128;

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (sas_ss_flags(sp) == 0)
			sp = current->sas_ss_sp + current->sas_ss_size;
	} else if (IS_ENABLED(CONFIG_X86_32) &&
		   !onsigstack &&
		   regs->ss != __USER_DS &&
		   !(ka->sa.sa_flags & SA_RESTORER) &&
		   ka->sa.sa_restorer) {
		/* This is the legacy signal stack switching. */
		sp = (unsigned long) ka->sa.sa_restorer;
	}

	if (fpu->initialized) {
		sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),
					  &buf_fx, &math_size);
		*fpstate = (void __user *)sp;
	}

	sp = align_sigframe(sp - frame_size);

	/*
         * If we are on the alternate signal stack and would overflow it, don't.
         * Return an always-bogus address instead so we will die with SIGSEGV.
         */
	if (onsigstack && !likely(on_sig_stack(sp)))
		return (void __user *)-1L;

	/* save i387 and extended state */
	if (fpu->initialized &&
	    copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0)
		return (void __user *)-1L;

	return (void __user *)sp;
}


Contributors
PersonTokensPropCommitsCommitProp
Hiroshi Shimamoto19471.85%743.75%


Suresh B. Siddha4416.30%212.50%


Ingo Molnar207.41%531.25%


Stas Sergeev93.33%16.25%


Masahiro Yamada31.11%16.25%


Total270100.00%16100.00%



#ifdef CONFIG_X86_32
static const struct {
	
u16 poplmovl;
	
u32 val;
	
u16 int80;

} __attribute__((packed)) retcode = {
	0xb858,		/* popl %eax; movl $..., %eax */
	__NR_sigreturn,
	0x80cd,		/* int $0x80 */
};

static const struct {
	
u8  movl;
	
u32 val;
	
u16 int80;
	
u8  pad;

} __attribute__((packed)) rt_retcode = {
	0xb8,		/* movl $..., %eax */
	__NR_rt_sigreturn,
	0x80cd,		/* int $0x80 */
	0
};



static int

__setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
	      struct pt_regs *regs)
{
	struct sigframe __user *frame;
	void __user *restorer;
	int err = 0;
	void __user *fpstate = NULL;

	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	if (__put_user(sig, &frame->sig))
		return -EFAULT;

	if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
		return -EFAULT;

	if (_NSIG_WORDS > 1) {
		if (__copy_to_user(&frame->extramask, &set->sig[1],
				   sizeof(frame->extramask)))
			return -EFAULT;
	}

	if (current->mm->context.vdso)
		restorer = current->mm->context.vdso +
			vdso_image_32.sym___kernel_sigreturn;
	else
		restorer = &frame->retcode;
	if (ksig->ka.sa.sa_flags & SA_RESTORER)
		restorer = ksig->ka.sa.sa_restorer;

	/* Set up to return from userspace.  */
	err |= __put_user(restorer, &frame->pretcode);

	/*
         * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
         *
         * WE DO NOT USE IT ANY MORE! It's only left here for historical
         * reasons and because gdb uses it as a signature to notice
         * signal handler stack frames.
         */
	err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp = (unsigned long)frame;
	regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
	regs->ax = (unsigned long)sig;
	regs->dx = 0;
	regs->cx = 0;

	regs->ds = __USER_DS;
	regs->es = __USER_DS;
	regs->ss = __USER_DS;
	regs->cs = __USER_CS;

	return 0;
}


Contributors
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Hiroshi Shimamoto32294.71%125.00%


Al Viro144.12%125.00%


Andrew Lutomirski41.18%250.00%


Total340100.00%4100.00%






static int __setup_rt_frame(int sig, struct ksignal *ksig,
			    sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	void __user *restorer;
	int err = 0;
	void __user *fpstate = NULL;

	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	put_user_try {
		put_user_ex(sig, &frame->sig);
		put_user_ex(&frame->info, &frame->pinfo);
		put_user_ex(&frame->uc, &frame->puc);

		/* Create the ucontext.  */
		if (boot_cpu_has(X86_FEATURE_XSAVE))
			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
		else
			put_user_ex(0, &frame->uc.uc_flags);
		put_user_ex(0, &frame->uc.uc_link);
		save_altstack_ex(&frame->uc.uc_stack, regs->sp);

		/* Set up to return from userspace.  */
		restorer = current->mm->context.vdso +
			vdso_image_32.sym___kernel_rt_sigreturn;
		if (ksig->ka.sa.sa_flags & SA_RESTORER)
			restorer = ksig->ka.sa.sa_restorer;
		put_user_ex(restorer, &frame->pretcode);

		/*
                 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
                 *
                 * WE DO NOT USE IT ANY MORE! It's only left here for historical
                 * reasons and because gdb uses it as a signature to notice
                 * signal handler stack frames.
                 */
		put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
	} put_user_catch(err);
	
	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
				regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp = (unsigned long)frame;
	regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
	regs->ax = (unsigned long)sig;
	regs->dx = (unsigned long)&frame->info;
	regs->cx = (unsigned long)&frame->uc;

	regs->ds = __USER_DS;
	regs->es = __USER_DS;
	regs->ss = __USER_DS;
	regs->cs = __USER_CS;

	return 0;
}

Contributors
PersonTokensPropCommitsCommitProp
Hiroshi Shimamoto33380.24%220.00%


H. Peter Anvin5513.25%110.00%


Al Viro194.58%330.00%


Borislav Petkov40.96%110.00%


Andrew Lutomirski40.96%330.00%


Total415100.00%10100.00%



#else /* !CONFIG_X86_32 */



static unsigned long frame_uc_flags(struct pt_regs *regs)
{
	unsigned long flags;

	if (boot_cpu_has(X86_FEATURE_XSAVE))
		flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS;
	else
		flags = UC_SIGCONTEXT_SS;

	if (likely(user_64bit_mode(regs)))
		flags |= UC_STRICT_RESTORE_SS;

	return flags;
}


Contributors
PersonTokensPropCommitsCommitProp
Andrew Lutomirski4792.16%150.00%


Borislav Petkov47.84%150.00%


Total51100.00%2100.00%






static int __setup_rt_frame(int sig, struct ksignal *ksig,
			    sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	void __user *fp = NULL;
	int err = 0;

	frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
		if (copy_siginfo_to_user(&frame->info, &ksig->info))
			return -EFAULT;
	}

	put_user_try {
		/* Create the ucontext.  */
		put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags);
		put_user_ex(0, &frame->uc.uc_link);
		save_altstack_ex(&frame->uc.uc_stack, regs->sp);

		/* Set up to return from userspace.  If provided, use a stub
                   already in userspace.  */
		/* x86-64 should always use SA_RESTORER. */
		if (ksig->ka.sa.sa_flags & SA_RESTORER) {
			put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
		} else {
			/* could use a vstub here */
			err |= -EFAULT;
		}
	} put_user_catch(err);

	err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->di = sig;
	/* In case the signal handler was declared without prototypes */
	regs->ax = 0;

	/* This also works for non SA_SIGINFO handlers because they expect the
           next argument after the signal number on the stack. */
	regs->si = (unsigned long)&frame->info;
	regs->dx = (unsigned long)&frame->uc;
	regs->ip = (unsigned long) ksig->ka.sa.sa_handler;

	regs->sp = (unsigned long)frame;

	/*
         * Set up the CS and SS registers to run signal handlers in
         * 64-bit mode, even if the handler happens to be interrupting
         * 32-bit or 16-bit code.
         *
         * SS is subtle.  In 64-bit mode, we don't need any particular
         * SS descriptor, but we do need SS to be valid.  It's possible
         * that the old SS is entirely bogus -- this can happen if the
         * signal we're trying to deliver is #GP or #SS caused by a bad
         * SS value.  We also have a compatbility issue here: DOSEMU
         * relies on the contents of the SS register indicating the
         * SS value at the time of the signal, even though that code in
         * DOSEMU predates sigreturn's ability to restore SS.  (DOSEMU
         * avoids relying on sigreturn to restore SS; instead it uses
         * a trampoline.)  So we do our best: if the old SS was valid,
         * we keep it.  Otherwise we replace it.
         */
	regs->cs = __USER_CS;

	if (unlikely(regs->ss != __USER_DS))
		force_valid_ss(regs);

	return 0;
}

Contributors
PersonTokensPropCommitsCommitProp
Hiroshi Shimamoto25572.86%642.86%


H. Peter Anvin4312.29%17.14%


Al Viro226.29%321.43%


Andrew Lutomirski205.71%214.29%


Andi Kleen102.86%214.29%


Total350100.00%14100.00%



#endif /* CONFIG_X86_32 */




static int x32_setup_rt_frame(struct ksignal *ksig,
			      compat_sigset_t *set,
			      struct pt_regs *regs)
{
#ifdef CONFIG_X86_X32_ABI
	struct rt_sigframe_x32 __user *frame;
	void __user *restorer;
	int err = 0;
	void __user *fpstate = NULL;

	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
		if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true))
			return -EFAULT;
	}

	put_user_try {
		/* Create the ucontext.  */
		put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags);
		put_user_ex(0, &frame->uc.uc_link);
		compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
		put_user_ex(0, &frame->uc.uc__pad0);

		if (ksig->ka.sa.sa_flags & SA_RESTORER) {
			restorer = ksig->ka.sa.sa_restorer;
		} else {
			/* could use a vstub here */
			restorer = NULL;
			err |= -EFAULT;
		}
		put_user_ex(restorer, &frame->pretcode);
	} put_user_catch(err);

	err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
				regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp = (unsigned long) frame;
	regs->ip = (unsigned long) ksig->ka.sa.sa_handler;

	/* We use the x32 calling convention here... */
	regs->di = ksig->sig;
	regs->si = (unsigned long) &frame->info;
	regs->dx = (unsigned long) &frame->uc;

	loadsegment(ds, __USER_DS);
	loadsegment(es, __USER_DS);

	regs->cs = __USER_CS;
	regs->ss = __USER_DS;
#endif	/* CONFIG_X86_X32_ABI */

	return 0;
}


Contributors
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Suresh B. Siddha18348.67%19.09%


Hiroshi Shimamoto13435.64%436.36%


H. Peter Anvin297.71%19.09%


Al Viro246.38%327.27%


Andrew Lutomirski30.80%19.09%


Dmitry Safonov30.80%19.09%


Total376100.00%11100.00%



/*
 * Do a signal return; undo the signal stack.
 */
#ifdef CONFIG_X86_32



asmlinkage unsigned long sys_sigreturn(void)
{
	struct pt_regs *regs = current_pt_regs();
	struct sigframe __user *frame;
	sigset_t set;

	frame = (struct sigframe __user *)(regs->sp - 8);

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
		&& __copy_from_user(&set.sig[1], &frame->extramask,
				    sizeof(frame->extramask))))
		goto badframe;

	set_current_blocked(&set);

	/*
         * x86_32 has no uc_flags bits relevant to restore_sigcontext.
         * Save a few cycles by skipping the __get_user.
         */
	if (restore_sigcontext(regs, &frame->sc, 0))
		goto badframe;
	return regs->ax;

badframe:
	signal_fault(regs, frame, "sigreturn");

	return 0;
}

Contributors
PersonTokensPropCommitsCommitProp
Suresh B. Siddha7045.16%16.67%


Andi Kleen3522.58%426.67%


Hiroshi Shimamoto3019.35%426.67%


Al Viro106.45%320.00%


H. Peter Anvin53.23%16.67%


Andrew Lutomirski31.94%16.67%


Brian Gerst21.29%16.67%


Total155100.00%15100.00%



#endif /* CONFIG_X86_32 */




asmlinkage long sys_rt_sigreturn(void)
{
	struct pt_regs *regs = current_pt_regs();
	struct rt_sigframe __user *frame;
	sigset_t set;
	unsigned long uc_flags;

	frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;
	if (__get_user(uc_flags, &frame->uc.uc_flags))
		goto badframe;

	set_current_blocked(&set);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
		goto badframe;

	if (restore_altstack(&frame->uc.uc_stack))
		goto badframe;

	return regs->ax;

badframe:
	signal_fault(regs, frame, "rt_sigreturn");
	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Hiroshi Shimamoto4426.51%214.29%


Andi Kleen4225.30%428.57%


Suresh B. Siddha4225.30%17.14%


Andrew Lutomirski2313.86%17.14%


Al Viro106.02%321.43%


Brian Gerst21.20%17.14%


Roland McGrath21.20%17.14%


Oleg Nesterov10.60%17.14%


Total166100.00%14100.00%






static inline int is_ia32_compat_frame(struct ksignal *ksig)
{
	return IS_ENABLED(CONFIG_IA32_EMULATION) &&
		ksig->ka.sa.sa_flags & SA_IA32_ABI;
}


Contributors
PersonTokensPropCommitsCommitProp
Ingo Molnar1450.00%133.33%


Dmitry Safonov1346.43%133.33%


Masahiro Yamada13.57%133.33%


Total28100.00%3100.00%






static inline int is_ia32_frame(struct ksignal *ksig)
{
	return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);
}


Contributors
PersonTokensPropCommitsCommitProp
Ingo Molnar1565.22%133.33%


Dmitry Safonov730.43%133.33%


Masahiro Yamada14.35%133.33%


Total23100.00%3100.00%






static inline int is_x32_frame(struct ksignal *ksig)
{
	return IS_ENABLED(CONFIG_X86_X32_ABI) &&
		ksig->ka.sa.sa_flags & SA_X32_ABI;
}


Contributors
PersonTokensPropCommitsCommitProp
Ingo Molnar1450.00%133.33%


Dmitry Safonov1346.43%133.33%


Masahiro Yamada13.57%133.33%


Total28100.00%3100.00%





static int

setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
{
	int usig = ksig->sig;
	sigset_t *set = sigmask_to_save();
	compat_sigset_t *cset = (compat_sigset_t *) set;

	/* Set up the stack frame */
	if (is_ia32_frame(ksig)) {
		if (ksig->ka.sa.sa_flags & SA_SIGINFO)
			return ia32_setup_rt_frame(usig, ksig, cset, regs);
		else
			return ia32_setup_frame(usig, ksig, cset, regs);
	} else if (is_x32_frame(ksig)) {
		return x32_setup_rt_frame(ksig, cset, regs);
	} else {
		return __setup_rt_frame(ksig->sig, ksig, set, regs);
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Hiroshi Shimamoto6048.39%433.33%


Al Viro2217.74%325.00%


H. Peter Anvin1512.10%18.33%


Suresh B. Siddha1512.10%18.33%


Dmitry Safonov64.84%18.33%


Oleg Nesterov54.03%18.33%


Andi Kleen10.81%18.33%


Total124100.00%12100.00%





static void

handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
	bool stepping, failed;
	struct fpu *fpu = &current->thread.fpu;

	if (v8086_mode(regs))
		save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL);

	/* Are we from a system call? */
	if (syscall_get_nr(current, regs) >= 0) {
		/* If so, check system call restarting.. */
		switch (syscall_get_error(current, regs)) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->ax = -EINTR;
			break;

		case -ERESTARTSYS:
			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
				regs->ax = -EINTR;
				break;
			}
		/* fallthrough */
		case -ERESTARTNOINTR:
			regs->ax = regs->orig_ax;
			regs->ip -= 2;
			break;
		}
	}

	/*
         * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
         * so that register information in the sigcontext is correct and
         * then notify the tracer before entering the signal handler.
         */
	stepping = test_thread_flag(TIF_SINGLESTEP);
	if (stepping)
		user_disable_single_step(current);

	failed = (setup_rt_frame(ksig, regs) < 0);
	if (!failed) {
		/*
                 * Clear the direction flag as per the ABI for function entry.
                 *
                 * Clear RF when entering the signal handler, because
                 * it might disable possible debug exception from the
                 * signal handler.
                 *
                 * Clear TF for the case when it wasn't set by debugger to
                 * avoid the recursive send_sigtrap() in SIGTRAP handler.
                 */
		regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
		/*
                 * Ensure the signal handler starts with the new fpu state.
                 */
		if (fpu->initialized)
			fpu__clear(fpu);
	}
	signal_setup_done(failed, ksig, stepping);
}


Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen9544.19%520.83%


Al Viro2612.09%28.33%


Roland McGrath2411.16%520.83%


Oleg Nesterov2310.70%28.33%


Brian Gerst198.84%14.17%


Ingo Molnar177.91%520.83%


Jiri Olsa52.33%28.33%


H. Peter Anvin52.33%14.17%


Hiroshi Shimamoto10.47%14.17%


Total215100.00%24100.00%






static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
{
	/*
         * This function is fundamentally broken as currently
         * implemented.
         *
         * The idea is that we want to trigger a call to the
         * restart_block() syscall and that we want in_ia32_syscall(),
         * in_x32_syscall(), etc. to match whatever they were in the
         * syscall being restarted.  We assume that the syscall
         * instruction at (regs->ip - 2) matches whatever syscall
         * instruction we used to enter in the first place.
         *
         * The problem is that we can get here when ptrace pokes
         * syscall-like values into regs even if we're not in a syscall
         * at all.
         *
         * For now, we maintain historical behavior and guess based on
         * stored state.  We could do better by saving the actual
         * syscall arch in restart_block or (with caveats on x32) by
         * checking if regs->ip points to 'int $0x80'.  The current
         * behavior is incorrect if a tracer has a different bitness
         * than the tracee.
         */
#ifdef CONFIG_IA32_EMULATION
	if (current->thread.status & (TS_COMPAT|TS_I386_REGS_POKED))
		return __NR_ia32_restart_syscall;
#endif
#ifdef CONFIG_X86_X32_ABI
	return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
#else
	return __NR_restart_syscall;
#endif
}


Contributors
PersonTokensPropCommitsCommitProp
Dmitry V. Levin4374.14%240.00%


Andrew Lutomirski1322.41%240.00%


Hiroshi Shimamoto23.45%120.00%


Total58100.00%5100.00%



/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 */



void do_signal(struct pt_regs *regs)
{
	struct ksignal ksig;

	if (get_signal(&ksig)) {
		/* Whee! Actually deliver the signal.  */
		handle_signal(&ksig, regs);
		return;
	}

	/* Did we come from a system call? */
	if (syscall_get_nr(current, regs) >= 0) {
		/* Restart the system call - no handlers present */
		switch (syscall_get_error(current, regs)) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->ax = regs->orig_ax;
			regs->ip -= 2;
			break;

		case -ERESTART_RESTARTBLOCK:
			regs->ax = get_nr_restart_syscall(regs);
			regs->ip -= 2;
			break;
		}
	}

	/*
         * If there's no signal to deliver, we just put the saved sigmask
         * back.
         */
	restore_saved_sigmask();
}


Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen6861.26%428.57%


Roland McGrath1210.81%321.43%


Andrew Morton1210.81%17.14%


Al Viro87.21%214.29%


H. Peter Anvin54.50%17.14%


Dmitry V. Levin43.60%17.14%


Harvey Harrison10.90%17.14%


Hiroshi Shimamoto10.90%17.14%


Total111100.00%14100.00%






void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
{
	struct task_struct *me = current;

	if (show_unhandled_signals && printk_ratelimit()) {
		printk("%s"
		       "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
		       task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
		       me->comm, me->pid, where, frame,
		       regs->ip, regs->sp, regs->orig_ax);
		print_vma_addr(KERN_CONT " in ", regs->ip);
		pr_cont("\n");
	}

	force_sig(SIGSEGV, me);
}


Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen7677.55%225.00%


Hiroshi Shimamoto1212.24%112.50%


Masoud Asgharifard Sharbiani44.08%112.50%


H. Peter Anvin33.06%112.50%


Al Viro11.02%112.50%


Joe Perches11.02%112.50%


Markus Trippelsdorf11.02%112.50%


Total98100.00%8100.00%



#ifdef CONFIG_X86_X32_ABI



asmlinkage long sys32_x32_rt_sigreturn(void)
{
	struct pt_regs *regs = current_pt_regs();
	struct rt_sigframe_x32 __user *frame;
	sigset_t set;
	unsigned long uc_flags;

	frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;
	if (__get_user(uc_flags, &frame->uc.uc_flags))
		goto badframe;

	set_current_blocked(&set);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
		goto badframe;

	if (compat_restore_altstack(&frame->uc.uc_stack))
		goto badframe;

	return regs->ax;

badframe:
	signal_fault(regs, frame, "x32 rt_sigreturn");
	return 0;
}

Contributors
PersonTokensPropCommitsCommitProp
H. Peter Anvin13079.75%120.00%


Andrew Lutomirski2314.11%120.00%


Al Viro84.91%240.00%


Brian Gerst21.23%120.00%


Total163100.00%5100.00%



#endif

Overall Contributors
PersonTokensPropCommitsCommitProp
Hiroshi Shimamoto187545.48%2721.77%


Andi Kleen71117.24%1512.10%


Suresh B. Siddha3618.76%21.61%


H. Peter Anvin3308.00%75.65%


Andrew Lutomirski2536.14%97.26%


Al Viro1684.07%97.26%


Ingo Molnar1022.47%1310.48%


Dmitry V. Levin471.14%21.61%


Dmitry Safonov451.09%10.81%


Roland McGrath441.07%64.84%


Brian Gerst360.87%43.23%


Oleg Nesterov290.70%43.23%


Andrew Morton200.49%10.81%


Tejun Heo160.39%10.81%


Bryan Ford90.22%10.81%


Stas Sergeev90.22%10.81%


Linus Torvalds90.22%21.61%


Joe Perches80.19%10.81%


Harvey Harrison80.19%43.23%


Borislav Petkov80.19%10.81%


Masahiro Yamada70.17%10.81%


Jiri Olsa50.12%21.61%


Masoud Asgharifard Sharbiani40.10%10.81%


Srikar Dronamraju40.10%21.61%


Frédéric Weisbecker30.07%10.81%


Jaswinder Singh Rajput30.07%10.81%


Avi Kivity30.07%10.81%


Oliver Korpilla30.07%10.81%


Markus Trippelsdorf10.02%10.81%


Greg Kroah-Hartman10.02%10.81%


Dave Jones10.02%10.81%


Total4123100.00%124100.00%


Directory: arch/x86/kernel



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