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linux/arch/s390/kernel/compat_signal.c

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/*
* 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/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/ucontext.h>
#include <asm/uaccess.h>
#include <asm/lowcore.h>
#include <asm/switch_to.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;
int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
{
int err;
/* If you change siginfo_t structure, please be sure
this code is fixed accordingly.
It should never copy any pad contained in the structure
to avoid security leaks, but must copy the generic
3 ints plus the relevant union member.
This routine must convert siginfo from 64bit to 32bit as well
at the same time. */
err = __put_user(from->si_signo, &to->si_signo);
err |= __put_user(from->si_errno, &to->si_errno);
err |= __put_user((short)from->si_code, &to->si_code);
if (from->si_code < 0)
err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
else {
switch (from->si_code >> 16) {
case __SI_RT >> 16: /* This is not generated by the kernel as of now. */
case __SI_MESGQ >> 16:
err |= __put_user(from->si_int, &to->si_int);
/* fallthrough */
case __SI_KILL >> 16:
err |= __put_user(from->si_pid, &to->si_pid);
err |= __put_user(from->si_uid, &to->si_uid);
break;
case __SI_CHLD >> 16:
err |= __put_user(from->si_pid, &to->si_pid);
err |= __put_user(from->si_uid, &to->si_uid);
err |= __put_user(from->si_utime, &to->si_utime);
err |= __put_user(from->si_stime, &to->si_stime);
err |= __put_user(from->si_status, &to->si_status);
break;
case __SI_FAULT >> 16:
err |= __put_user((unsigned long) from->si_addr,
&to->si_addr);
break;
case __SI_POLL >> 16:
err |= __put_user(from->si_band, &to->si_band);
err |= __put_user(from->si_fd, &to->si_fd);
break;
case __SI_TIMER >> 16:
err |= __put_user(from->si_tid, &to->si_tid);
err |= __put_user(from->si_overrun, &to->si_overrun);
err |= __put_user(from->si_int, &to->si_int);
break;
default:
break;
}
}
return err ? -EFAULT : 0;
}
int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
{
int err;
u32 tmp;
err = __get_user(to->si_signo, &from->si_signo);
err |= __get_user(to->si_errno, &from->si_errno);
err |= __get_user(to->si_code, &from->si_code);
if (to->si_code < 0)
err |= __copy_from_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
else {
switch (to->si_code >> 16) {
case __SI_RT >> 16: /* This is not generated by the kernel as of now. */
case __SI_MESGQ >> 16:
err |= __get_user(to->si_int, &from->si_int);
/* fallthrough */
case __SI_KILL >> 16:
err |= __get_user(to->si_pid, &from->si_pid);
err |= __get_user(to->si_uid, &from->si_uid);
break;
case __SI_CHLD >> 16:
err |= __get_user(to->si_pid, &from->si_pid);
err |= __get_user(to->si_uid, &from->si_uid);
err |= __get_user(to->si_utime, &from->si_utime);
err |= __get_user(to->si_stime, &from->si_stime);
err |= __get_user(to->si_status, &from->si_status);
break;
case __SI_FAULT >> 16:
err |= __get_user(tmp, &from->si_addr);
to->si_addr = (void __force __user *)
(u64) (tmp & PSW32_ADDR_INSN);
break;
case __SI_POLL >> 16:
err |= __get_user(to->si_band, &from->si_band);
err |= __get_user(to->si_fd, &from->si_fd);
break;
case __SI_TIMER >> 16:
err |= __get_user(to->si_tid, &from->si_tid);
err |= __get_user(to->si_overrun, &from->si_overrun);
err |= __get_user(to->si_int, &from->si_int);
break;
default:
break;
}
}
return err ? -EFAULT : 0;
}
/* Store registers needed to create the signal frame */
static void store_sigregs(void)
{
int i;
save_access_regs(current->thread.acrs);
save_fp_ctl(&current->thread.fp_regs.fpc);
if (current->thread.vxrs) {
save_vx_regs(current->thread.vxrs);
for (i = 0; i < __NUM_FPRS; i++)
current->thread.fp_regs.fprs[i] =
*(freg_t *)(current->thread.vxrs + i);
} else
save_fp_regs(current->thread.fp_regs.fprs);
}
/* Load registers after signal return */
static void load_sigregs(void)
{
int i;
restore_access_regs(current->thread.acrs);
/* restore_fp_ctl is done in restore_sigregs */
if (current->thread.vxrs) {
for (i = 0; i < __NUM_FPRS; i++)
*(freg_t *)(current->thread.vxrs + i) =
current->thread.fp_regs.fprs[i];
restore_vx_regs(current->thread.vxrs);
} else
restore_fp_regs(current->thread.fp_regs.fprs);
}
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));
memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
sizeof(user_sregs.fpregs));
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;
/* Alwys 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;
/* Loading the floating-point-control word can fail. Do that first. */
if (restore_fp_ctl(&user_sregs.fpregs.fpc))
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));
memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
sizeof(current->thread.fp_regs));
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 (current->thread.vxrs) {
for (i = 0; i < __NUM_VXRS_LOW; i++)
vxrs[i] = *((__u64 *)(current->thread.vxrs + i) + 1);
if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
sizeof(sregs_ext->vxrs_low)) ||
__copy_to_user(&sregs_ext->vxrs_high,
current->thread.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 (current->thread.vxrs) {
if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
sizeof(sregs_ext->vxrs_low)) ||
__copy_from_user(current->thread.vxrs + __NUM_VXRS_LOW,
&sregs_ext->vxrs_high,
sizeof(sregs_ext->vxrs_high)))
return -EFAULT;
for (i = 0; i < __NUM_VXRS_LOW; i++)
*((__u64 *)(current->thread.vxrs + i) + 1) = 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 (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32))
goto badframe;
set_current_blocked(&set);
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, current);
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 (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (compat_restore_altstack(&frame->uc.uc_stack))
goto badframe;
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, current);
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;
struct sigcontext32 sc;
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 (!MACHINE_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 */
memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE32);
sc.sregs = (__u32)(unsigned long __force) &frame->sregs;
if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc)))
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 {
/* Signal frames without vectors registers are short ! */
__u16 __user *svc = (void __user *) frame + frame_size - 2;
if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
return -EFAULT;
restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
}
/* 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] = task_thread_info(current)->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 (MACHINE_HAS_VX) {
if (current->thread.vxrs)
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 {
__u16 __user *svc = &frame->svc_insn;
if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
return -EFAULT;
restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
}
/* 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) ||
__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) ||
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] = task_thread_info(current)->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));
}
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