[linux-block.git] / arch / s390 / kernel / compat_signal.c

// SPDX-License-Identifier: GPL-2.0
/*
 *    Copyright IBM Corp. 2000, 2006
 *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
 *               Gerhard Tonn (ton@de.ibm.com)                  
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 */

#include <linux/compat.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <asm/vdso-symbols.h>
#include <asm/access-regs.h>
#include <asm/ucontext.h>
#include <linux/uaccess.h>
#include <asm/lowcore.h>
#include <asm/fpu.h>
#include "compat_linux.h"
#include "compat_ptrace.h"
#include "entry.h"

typedef struct 
{
	__u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
	struct sigcontext32 sc;
	_sigregs32 sregs;
	int signo;
	_sigregs_ext32 sregs_ext;
	__u16 svc_insn;		/* Offset of svc_insn is NOT fixed! */
} sigframe32;

typedef struct 
{
	__u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
	__u16 svc_insn;
	compat_siginfo_t info;
	struct ucontext32 uc;
} rt_sigframe32;

/* Store registers needed to create the signal frame */
static void store_sigregs(void)
{
	save_access_regs(current->thread.acrs);
	save_user_fpu_regs();
}

/* Load registers after signal return */
static void load_sigregs(void)
{
	restore_access_regs(current->thread.acrs);
}

static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
{
	_sigregs32 user_sregs;
	int i;

	user_sregs.regs.psw.mask = (__u32)(regs->psw.mask >> 32);
	user_sregs.regs.psw.mask &= PSW32_MASK_USER | PSW32_MASK_RI;
	user_sregs.regs.psw.mask |= PSW32_USER_BITS;
	user_sregs.regs.psw.addr = (__u32) regs->psw.addr |
		(__u32)(regs->psw.mask & PSW_MASK_BA);
	for (i = 0; i < NUM_GPRS; i++)
		user_sregs.regs.gprs[i] = (__u32) regs->gprs[i];
	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
	       sizeof(user_sregs.regs.acrs));
	fpregs_store((_s390_fp_regs *) &user_sregs.fpregs, &current->thread.ufpu);
	if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs32)))
		return -EFAULT;
	return 0;
}

static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
{
	_sigregs32 user_sregs;
	int i;

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

	if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs)))
		return -EFAULT;

	if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
		return -EINVAL;

	/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
	regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
		(__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 |
		(__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 |
		(__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE);
	/* Check for invalid user address space control. */
	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
		regs->psw.mask = PSW_ASC_PRIMARY |
			(regs->psw.mask & ~PSW_MASK_ASC);
	regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN);
	for (i = 0; i < NUM_GPRS; i++)
		regs->gprs[i] = (__u64) user_sregs.regs.gprs[i];
	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
	       sizeof(current->thread.acrs));
	fpregs_load((_s390_fp_regs *)&user_sregs.fpregs, &current->thread.ufpu);

	clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
	return 0;
}

static int save_sigregs_ext32(struct pt_regs *regs,
			      _sigregs_ext32 __user *sregs_ext)
{
	__u32 gprs_high[NUM_GPRS];
	__u64 vxrs[__NUM_VXRS_LOW];
	int i;

	/* Save high gprs to signal stack */
	for (i = 0; i < NUM_GPRS; i++)
		gprs_high[i] = regs->gprs[i] >> 32;
	if (__copy_to_user(&sregs_ext->gprs_high, &gprs_high,
			   sizeof(sregs_ext->gprs_high)))
		return -EFAULT;

	/* Save vector registers to signal stack */
	if (cpu_has_vx()) {
		for (i = 0; i < __NUM_VXRS_LOW; i++)
			vxrs[i] = current->thread.ufpu.vxrs[i].low;
		if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
				   sizeof(sregs_ext->vxrs_low)) ||
		    __copy_to_user(&sregs_ext->vxrs_high,
				   current->thread.ufpu.vxrs + __NUM_VXRS_LOW,
				   sizeof(sregs_ext->vxrs_high)))
			return -EFAULT;
	}
	return 0;
}

static int restore_sigregs_ext32(struct pt_regs *regs,
				 _sigregs_ext32 __user *sregs_ext)
{
	__u32 gprs_high[NUM_GPRS];
	__u64 vxrs[__NUM_VXRS_LOW];
	int i;

	/* Restore high gprs from signal stack */
	if (__copy_from_user(&gprs_high, &sregs_ext->gprs_high,
			     sizeof(sregs_ext->gprs_high)))
		return -EFAULT;
	for (i = 0; i < NUM_GPRS; i++)
		*(__u32 *)&regs->gprs[i] = gprs_high[i];

	/* Restore vector registers from signal stack */
	if (cpu_has_vx()) {
		if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
				     sizeof(sregs_ext->vxrs_low)) ||
		    __copy_from_user(current->thread.ufpu.vxrs + __NUM_VXRS_LOW,
				     &sregs_ext->vxrs_high,
				     sizeof(sregs_ext->vxrs_high)))
			return -EFAULT;
		for (i = 0; i < __NUM_VXRS_LOW; i++)
			current->thread.ufpu.vxrs[i].low = vxrs[i];
	}
	return 0;
}

COMPAT_SYSCALL_DEFINE0(sigreturn)
{
	struct pt_regs *regs = task_pt_regs(current);
	sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
	sigset_t set;

	if (get_compat_sigset(&set, (compat_sigset_t __user *)frame->sc.oldmask))
		goto badframe;
	set_current_blocked(&set);
	save_user_fpu_regs();
	if (restore_sigregs32(regs, &frame->sregs))
		goto badframe;
	if (restore_sigregs_ext32(regs, &frame->sregs_ext))
		goto badframe;
	load_sigregs();
	return regs->gprs[2];
badframe:
	force_sig(SIGSEGV);
	return 0;
}

COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
{
	struct pt_regs *regs = task_pt_regs(current);
	rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
	sigset_t set;

	if (get_compat_sigset(&set, &frame->uc.uc_sigmask))
		goto badframe;
	set_current_blocked(&set);
	if (compat_restore_altstack(&frame->uc.uc_stack))
		goto badframe;
	save_user_fpu_regs();
	if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
		goto badframe;
	if (restore_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
		goto badframe;
	load_sigregs();
	return regs->gprs[2];
badframe:
	force_sig(SIGSEGV);
	return 0;
}	

/*
 * Set up a signal frame.
 */


/*
 * Determine which stack to use..
 */
static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
{
	unsigned long sp;

	/* Default to using normal stack */
	sp = (unsigned long) A(regs->gprs[15]);

	/* Overflow on alternate signal stack gives SIGSEGV. */
	if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
		return (void __user *) -1UL;

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (! sas_ss_flags(sp))
			sp = current->sas_ss_sp + current->sas_ss_size;
	}

	return (void __user *)((sp - frame_size) & -8ul);
}

static int setup_frame32(struct ksignal *ksig, sigset_t *set,
			 struct pt_regs *regs)
{
	int sig = ksig->sig;
	sigframe32 __user *frame;
	unsigned long restorer;
	size_t frame_size;

	/*
	 * gprs_high are always present for 31-bit compat tasks.
	 * The space for vector registers is only allocated if
	 * the machine supports it
	 */
	frame_size = sizeof(*frame) - sizeof(frame->sregs_ext.__reserved);
	if (!cpu_has_vx())
		frame_size -= sizeof(frame->sregs_ext.vxrs_low) +
			      sizeof(frame->sregs_ext.vxrs_high);
	frame = get_sigframe(&ksig->ka, regs, frame_size);
	if (frame == (void __user *) -1UL)
		return -EFAULT;

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
		return -EFAULT;

	/* Create struct sigcontext32 on the signal stack */
	if (put_compat_sigset((compat_sigset_t __user *)frame->sc.oldmask,
			      set, sizeof(compat_sigset_t)))
		return -EFAULT;
	if (__put_user(ptr_to_compat(&frame->sregs), &frame->sc.sregs))
		return -EFAULT;

	/* Store registers needed to create the signal frame */
	store_sigregs();

	/* Create _sigregs32 on the signal stack */
	if (save_sigregs32(regs, &frame->sregs))
		return -EFAULT;

	/* Place signal number on stack to allow backtrace from handler.  */
	if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
		return -EFAULT;

	/* Create _sigregs_ext32 on the signal stack */
	if (save_sigregs_ext32(regs, &frame->sregs_ext))
		return -EFAULT;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
		restorer = (unsigned long __force)
			ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
	} else {
		restorer = VDSO32_SYMBOL(current, sigreturn);
        }

	/* Set up registers for signal handler */
	regs->gprs[14] = restorer;
	regs->gprs[15] = (__force __u64) frame;
	/* Force 31 bit amode and default user address space control. */
	regs->psw.mask = PSW_MASK_BA |
		(PSW_USER_BITS & PSW_MASK_ASC) |
		(regs->psw.mask & ~PSW_MASK_ASC);
	regs->psw.addr = (__force __u64) ksig->ka.sa.sa_handler;

	regs->gprs[2] = sig;
	regs->gprs[3] = (__force __u64) &frame->sc;

	/* We forgot to include these in the sigcontext.
	   To avoid breaking binary compatibility, they are passed as args. */
	if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
	    sig == SIGTRAP || sig == SIGFPE) {
		/* set extra registers only for synchronous signals */
		regs->gprs[4] = regs->int_code & 127;
		regs->gprs[5] = regs->int_parm_long;
		regs->gprs[6] = current->thread.last_break;
	}

	return 0;
}

static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set,
			    struct pt_regs *regs)
{
	rt_sigframe32 __user *frame;
	unsigned long restorer;
	size_t frame_size;
	u32 uc_flags;

	frame_size = sizeof(*frame) -
		     sizeof(frame->uc.uc_mcontext_ext.__reserved);
	/*
	 * gprs_high are always present for 31-bit compat tasks.
	 * The space for vector registers is only allocated if
	 * the machine supports it
	 */
	uc_flags = UC_GPRS_HIGH;
	if (cpu_has_vx()) {
		uc_flags |= UC_VXRS;
	} else {
		frame_size -= sizeof(frame->uc.uc_mcontext_ext.vxrs_low) +
			      sizeof(frame->uc.uc_mcontext_ext.vxrs_high);
	}
	frame = get_sigframe(&ksig->ka, regs, frame_size);
	if (frame == (void __user *) -1UL)
		return -EFAULT;

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
		return -EFAULT;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
		restorer = (unsigned long __force)
			ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
	} else {
		restorer = VDSO32_SYMBOL(current, rt_sigreturn);
	}

	/* Create siginfo on the signal stack */
	if (copy_siginfo_to_user32(&frame->info, &ksig->info))
		return -EFAULT;

	/* Store registers needed to create the signal frame */
	store_sigregs();

	/* Create ucontext on the signal stack. */
	if (__put_user(uc_flags, &frame->uc.uc_flags) ||
	    __put_user(0, &frame->uc.uc_link) ||
	    __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
	    save_sigregs32(regs, &frame->uc.uc_mcontext) ||
	    put_compat_sigset(&frame->uc.uc_sigmask, set, sizeof(compat_sigset_t)) ||
	    save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->gprs[14] = restorer;
	regs->gprs[15] = (__force __u64) frame;
	/* Force 31 bit amode and default user address space control. */
	regs->psw.mask = PSW_MASK_BA |
		(PSW_USER_BITS & PSW_MASK_ASC) |
		(regs->psw.mask & ~PSW_MASK_ASC);
	regs->psw.addr = (__u64 __force) ksig->ka.sa.sa_handler;

	regs->gprs[2] = ksig->sig;
	regs->gprs[3] = (__force __u64) &frame->info;
	regs->gprs[4] = (__force __u64) &frame->uc;
	regs->gprs[5] = current->thread.last_break;
	return 0;
}

/*
 * OK, we're invoking a handler
 */	

void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
		     struct pt_regs *regs)
{
	int ret;

	/* Set up the stack frame */
	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
		ret = setup_rt_frame32(ksig, oldset, regs);
	else
		ret = setup_frame32(ksig, oldset, regs);

	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
}
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Copyright IBM Corp. 2000, 2006
	4	* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
	5	* Gerhard Tonn (ton@de.ibm.com)
	6	*
	7	* Copyright (C) 1991, 1992 Linus Torvalds
	8	*
	9	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
	10	*/
	11
	12	#include <linux/compat.h>
	13	#include <linux/sched.h>
	14	#include <linux/sched/task_stack.h>
	15	#include <linux/mm.h>
	16	#include <linux/smp.h>
	17	#include <linux/kernel.h>
	18	#include <linux/signal.h>
	19	#include <linux/errno.h>
	20	#include <linux/wait.h>
	21	#include <linux/ptrace.h>
	22	#include <linux/unistd.h>
	23	#include <linux/stddef.h>
	24	#include <linux/tty.h>
	25	#include <linux/personality.h>
	26	#include <linux/binfmts.h>
	27	#include <asm/vdso-symbols.h>
	28	#include <asm/access-regs.h>
	29	#include <asm/ucontext.h>
	30	#include <linux/uaccess.h>
	31	#include <asm/lowcore.h>
	32	#include <asm/fpu.h>
	33	#include "compat_linux.h"
	34	#include "compat_ptrace.h"
	35	#include "entry.h"
	36
	37	typedef struct
	38	{
	39	__u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
	40	struct sigcontext32 sc;
	41	_sigregs32 sregs;
	42	int signo;
	43	_sigregs_ext32 sregs_ext;
	44	__u16 svc_insn; /* Offset of svc_insn is NOT fixed! */
	45	} sigframe32;
	46
	47	typedef struct
	48	{
	49	__u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
	50	__u16 svc_insn;
	51	compat_siginfo_t info;
	52	struct ucontext32 uc;
	53	} rt_sigframe32;
	54
	55	/* Store registers needed to create the signal frame */
	56	static void store_sigregs(void)
	57	{
	58	save_access_regs(current->thread.acrs);
	59	save_user_fpu_regs();
	60	}
	61
	62	/* Load registers after signal return */
	63	static void load_sigregs(void)
	64	{
	65	restore_access_regs(current->thread.acrs);
	66	}
	67
	68	static int save_sigregs32(struct pt_regs regs, _sigregs32 __user sregs)
	69	{
	70	_sigregs32 user_sregs;
	71	int i;
	72
	73	user_sregs.regs.psw.mask = (__u32)(regs->psw.mask >> 32);
	74	user_sregs.regs.psw.mask &= PSW32_MASK_USER \| PSW32_MASK_RI;
	75	user_sregs.regs.psw.mask \|= PSW32_USER_BITS;
	76	user_sregs.regs.psw.addr = (__u32) regs->psw.addr \|
	77	(__u32)(regs->psw.mask & PSW_MASK_BA);
	78	for (i = 0; i < NUM_GPRS; i++)
	79	user_sregs.regs.gprs[i] = (__u32) regs->gprs[i];
	80	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
	81	sizeof(user_sregs.regs.acrs));
	82	fpregs_store((_s390_fp_regs *) &user_sregs.fpregs, &current->thread.ufpu);
	83	if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs32)))
	84	return -EFAULT;
	85	return 0;
	86	}
	87
	88	static int restore_sigregs32(struct pt_regs regs,_sigregs32 __user sregs)
	89	{
	90	_sigregs32 user_sregs;
	91	int i;
	92
	93	/* Always make any pending restarted system call return -EINTR */
	94	current->restart_block.fn = do_no_restart_syscall;
	95
	96	if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs)))
	97	return -EFAULT;
	98
	99	if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
	100	return -EINVAL;
	101
	102	/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
	103	regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER \| PSW_MASK_RI)) \|
	104	(__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 \|
	105	(__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 \|
	106	(__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE);
	107	/* Check for invalid user address space control. */
	108	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
	109	regs->psw.mask = PSW_ASC_PRIMARY \|
	110	(regs->psw.mask & ~PSW_MASK_ASC);
	111	regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN);
	112	for (i = 0; i < NUM_GPRS; i++)
	113	regs->gprs[i] = (__u64) user_sregs.regs.gprs[i];
	114	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
	115	sizeof(current->thread.acrs));
	116	fpregs_load((_s390_fp_regs *)&user_sregs.fpregs, &current->thread.ufpu);
	117
	118	clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
	119	return 0;
	120	}
	121
	122	static int save_sigregs_ext32(struct pt_regs *regs,
	123	_sigregs_ext32 __user *sregs_ext)
	124	{
	125	__u32 gprs_high[NUM_GPRS];
	126	__u64 vxrs[__NUM_VXRS_LOW];
	127	int i;
	128
	129	/* Save high gprs to signal stack */
	130	for (i = 0; i < NUM_GPRS; i++)
	131	gprs_high[i] = regs->gprs[i] >> 32;
	132	if (__copy_to_user(&sregs_ext->gprs_high, &gprs_high,
	133	sizeof(sregs_ext->gprs_high)))
	134	return -EFAULT;
	135
	136	/* Save vector registers to signal stack */
	137	if (cpu_has_vx()) {
	138	for (i = 0; i < __NUM_VXRS_LOW; i++)
	139	vxrs[i] = current->thread.ufpu.vxrs[i].low;
	140	if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
	141	sizeof(sregs_ext->vxrs_low)) \|\|
	142	__copy_to_user(&sregs_ext->vxrs_high,
	143	current->thread.ufpu.vxrs + __NUM_VXRS_LOW,
	144	sizeof(sregs_ext->vxrs_high)))
	145	return -EFAULT;
	146	}
	147	return 0;
	148	}
	149
	150	static int restore_sigregs_ext32(struct pt_regs *regs,
	151	_sigregs_ext32 __user *sregs_ext)
	152	{
	153	__u32 gprs_high[NUM_GPRS];
	154	__u64 vxrs[__NUM_VXRS_LOW];
	155	int i;
	156
	157	/* Restore high gprs from signal stack */
	158	if (__copy_from_user(&gprs_high, &sregs_ext->gprs_high,
	159	sizeof(sregs_ext->gprs_high)))
	160	return -EFAULT;
	161	for (i = 0; i < NUM_GPRS; i++)
	162	(__u32 )&regs->gprs[i] = gprs_high[i];
	163
	164	/* Restore vector registers from signal stack */
	165	if (cpu_has_vx()) {
	166	if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
	167	sizeof(sregs_ext->vxrs_low)) \|\|
	168	__copy_from_user(current->thread.ufpu.vxrs + __NUM_VXRS_LOW,
	169	&sregs_ext->vxrs_high,
	170	sizeof(sregs_ext->vxrs_high)))
	171	return -EFAULT;
	172	for (i = 0; i < __NUM_VXRS_LOW; i++)
	173	current->thread.ufpu.vxrs[i].low = vxrs[i];
	174	}
	175	return 0;
	176	}
	177
	178	COMPAT_SYSCALL_DEFINE0(sigreturn)
	179	{
	180	struct pt_regs *regs = task_pt_regs(current);
	181	sigframe32 __user frame = (sigframe32 __user )regs->gprs[15];
	182	sigset_t set;
	183
	184	if (get_compat_sigset(&set, (compat_sigset_t __user *)frame->sc.oldmask))
	185	goto badframe;
	186	set_current_blocked(&set);
	187	save_user_fpu_regs();
	188	if (restore_sigregs32(regs, &frame->sregs))
	189	goto badframe;
	190	if (restore_sigregs_ext32(regs, &frame->sregs_ext))
	191	goto badframe;
	192	load_sigregs();
	193	return regs->gprs[2];
	194	badframe:
	195	force_sig(SIGSEGV);
	196	return 0;
	197	}
	198
	199	COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
	200	{
	201	struct pt_regs *regs = task_pt_regs(current);
	202	rt_sigframe32 __user frame = (rt_sigframe32 __user )regs->gprs[15];
	203	sigset_t set;
	204
	205	if (get_compat_sigset(&set, &frame->uc.uc_sigmask))
	206	goto badframe;
	207	set_current_blocked(&set);
	208	if (compat_restore_altstack(&frame->uc.uc_stack))
	209	goto badframe;
	210	save_user_fpu_regs();
	211	if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
	212	goto badframe;
	213	if (restore_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
	214	goto badframe;
	215	load_sigregs();
	216	return regs->gprs[2];
	217	badframe:
	218	force_sig(SIGSEGV);
	219	return 0;
	220	}
	221
	222	/*
	223	* Set up a signal frame.
	224	*/
	225
	226
	227	/*
	228	* Determine which stack to use..
	229	*/
	230	static inline void __user *
	231	get_sigframe(struct k_sigaction ka, struct pt_regs regs, size_t frame_size)
	232	{
	233	unsigned long sp;
	234
	235	/* Default to using normal stack */
	236	sp = (unsigned long) A(regs->gprs[15]);
	237
	238	/* Overflow on alternate signal stack gives SIGSEGV. */
	239	if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
	240	return (void __user *) -1UL;
	241
	242	/* This is the X/Open sanctioned signal stack switching. */
	243	if (ka->sa.sa_flags & SA_ONSTACK) {
	244	if (! sas_ss_flags(sp))
	245	sp = current->sas_ss_sp + current->sas_ss_size;
	246	}
	247
	248	return (void __user *)((sp - frame_size) & -8ul);
	249	}
	250
	251	static int setup_frame32(struct ksignal ksig, sigset_t set,
	252	struct pt_regs *regs)
	253	{
	254	int sig = ksig->sig;
	255	sigframe32 __user *frame;
	256	unsigned long restorer;
	257	size_t frame_size;
	258
	259	/*
	260	* gprs_high are always present for 31-bit compat tasks.
	261	* The space for vector registers is only allocated if
	262	* the machine supports it
	263	*/
	264	frame_size = sizeof(*frame) - sizeof(frame->sregs_ext.__reserved);
	265	if (!cpu_has_vx())
	266	frame_size -= sizeof(frame->sregs_ext.vxrs_low) +
	267	sizeof(frame->sregs_ext.vxrs_high);
	268	frame = get_sigframe(&ksig->ka, regs, frame_size);
	269	if (frame == (void __user *) -1UL)
	270	return -EFAULT;
	271
	272	/* Set up backchain. */
	273	if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
	274	return -EFAULT;
	275
	276	/* Create struct sigcontext32 on the signal stack */
	277	if (put_compat_sigset((compat_sigset_t __user *)frame->sc.oldmask,
	278	set, sizeof(compat_sigset_t)))
	279	return -EFAULT;
	280	if (__put_user(ptr_to_compat(&frame->sregs), &frame->sc.sregs))
	281	return -EFAULT;
	282
	283	/* Store registers needed to create the signal frame */
	284	store_sigregs();
	285
	286	/* Create _sigregs32 on the signal stack */
	287	if (save_sigregs32(regs, &frame->sregs))
	288	return -EFAULT;
	289
	290	/* Place signal number on stack to allow backtrace from handler. */
	291	if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
	292	return -EFAULT;
	293
	294	/* Create _sigregs_ext32 on the signal stack */
	295	if (save_sigregs_ext32(regs, &frame->sregs_ext))
	296	return -EFAULT;
	297
	298	/* Set up to return from userspace. If provided, use a stub
	299	already in userspace. */
	300	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
	301	restorer = (unsigned long __force)
	302	ksig->ka.sa.sa_restorer \| PSW32_ADDR_AMODE;
	303	} else {
	304	restorer = VDSO32_SYMBOL(current, sigreturn);
	305	}
	306
	307	/* Set up registers for signal handler */
	308	regs->gprs[14] = restorer;
	309	regs->gprs[15] = (__force __u64) frame;
	310	/* Force 31 bit amode and default user address space control. */
	311	regs->psw.mask = PSW_MASK_BA \|
	312	(PSW_USER_BITS & PSW_MASK_ASC) \|
	313	(regs->psw.mask & ~PSW_MASK_ASC);
	314	regs->psw.addr = (__force __u64) ksig->ka.sa.sa_handler;
	315
	316	regs->gprs[2] = sig;
	317	regs->gprs[3] = (__force __u64) &frame->sc;
	318
	319	/* We forgot to include these in the sigcontext.
	320	To avoid breaking binary compatibility, they are passed as args. */
	321	if (sig == SIGSEGV \|\| sig == SIGBUS \|\| sig == SIGILL \|\|
	322	sig == SIGTRAP \|\| sig == SIGFPE) {
	323	/* set extra registers only for synchronous signals */
	324	regs->gprs[4] = regs->int_code & 127;
	325	regs->gprs[5] = regs->int_parm_long;
	326	regs->gprs[6] = current->thread.last_break;
	327	}
	328
	329	return 0;
	330	}
	331
	332	static int setup_rt_frame32(struct ksignal ksig, sigset_t set,
	333	struct pt_regs *regs)
	334	{
	335	rt_sigframe32 __user *frame;
	336	unsigned long restorer;
	337	size_t frame_size;
	338	u32 uc_flags;
	339
	340	frame_size = sizeof(*frame) -
	341	sizeof(frame->uc.uc_mcontext_ext.__reserved);
	342	/*
	343	* gprs_high are always present for 31-bit compat tasks.
	344	* The space for vector registers is only allocated if
	345	* the machine supports it
	346	*/
	347	uc_flags = UC_GPRS_HIGH;
	348	if (cpu_has_vx()) {
	349	uc_flags \|= UC_VXRS;
	350	} else {
	351	frame_size -= sizeof(frame->uc.uc_mcontext_ext.vxrs_low) +
	352	sizeof(frame->uc.uc_mcontext_ext.vxrs_high);
	353	}
	354	frame = get_sigframe(&ksig->ka, regs, frame_size);
	355	if (frame == (void __user *) -1UL)
	356	return -EFAULT;
	357
	358	/* Set up backchain. */
	359	if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
	360	return -EFAULT;
	361
	362	/* Set up to return from userspace. If provided, use a stub
	363	already in userspace. */
	364	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
	365	restorer = (unsigned long __force)
	366	ksig->ka.sa.sa_restorer \| PSW32_ADDR_AMODE;
	367	} else {
	368	restorer = VDSO32_SYMBOL(current, rt_sigreturn);
	369	}
	370
	371	/* Create siginfo on the signal stack */
	372	if (copy_siginfo_to_user32(&frame->info, &ksig->info))
	373	return -EFAULT;
	374
	375	/* Store registers needed to create the signal frame */
	376	store_sigregs();
	377
	378	/* Create ucontext on the signal stack. */
	379	if (__put_user(uc_flags, &frame->uc.uc_flags) \|\|
	380	__put_user(0, &frame->uc.uc_link) \|\|
	381	__compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) \|\|
	382	save_sigregs32(regs, &frame->uc.uc_mcontext) \|\|
	383	put_compat_sigset(&frame->uc.uc_sigmask, set, sizeof(compat_sigset_t)) \|\|
	384	save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
	385	return -EFAULT;
	386
	387	/* Set up registers for signal handler */
	388	regs->gprs[14] = restorer;
	389	regs->gprs[15] = (__force __u64) frame;
	390	/* Force 31 bit amode and default user address space control. */
	391	regs->psw.mask = PSW_MASK_BA \|
	392	(PSW_USER_BITS & PSW_MASK_ASC) \|
	393	(regs->psw.mask & ~PSW_MASK_ASC);
	394	regs->psw.addr = (__u64 __force) ksig->ka.sa.sa_handler;
	395
	396	regs->gprs[2] = ksig->sig;
	397	regs->gprs[3] = (__force __u64) &frame->info;
	398	regs->gprs[4] = (__force __u64) &frame->uc;
	399	regs->gprs[5] = current->thread.last_break;
	400	return 0;
	401	}
	402
	403	/*
	404	* OK, we're invoking a handler
	405	*/
	406
	407	void handle_signal32(struct ksignal ksig, sigset_t oldset,
	408	struct pt_regs *regs)
	409	{
	410	int ret;
	411
	412	/* Set up the stack frame */
	413	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
	414	ret = setup_rt_frame32(ksig, oldset, regs);
	415	else
	416	ret = setup_frame32(ksig, oldset, regs);
	417
	418	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
	419	}
	420