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linux/arch/s390/kernel/compat_signal.c
Hendrik Brueckner b5510d9b68 s390/fpu: always enable the vector facility if it is available 
If the kernel detects that the s390 hardware supports the vector
facility, it is enabled by default at an early stage.  To force
it off, use the novx kernel parameter.  Note that there is a small
time window, where the vector facility is enabled before it is
forced to be off.

With enabling the vector facility by default, the FPU save and
restore functions can be improved.  They do not longer require
to manage expensive control register updates to enable or disable
the vector enablement control for particular processes.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-10-14 14:32:08 +02:00

548 lines
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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;
static inline void sigset_to_sigset32(unsigned long *set64,
compat_sigset_word *set32)
{
set32[0] = (compat_sigset_word) set64[0];
set32[1] = (compat_sigset_word)(set64[0] >> 32);
}
static inline void sigset32_to_sigset(compat_sigset_word *set32,
unsigned long *set64)
{
set64[0] = (unsigned long) set32[0] | ((unsigned long) set32[1] << 32);
}
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)
{
save_access_regs(current->thread.acrs);
save_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.fpu);
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;
/* Test the floating-point-control word. */
if (test_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));
fpregs_load((_s390_fp_regs *) &user_sregs.fpregs, &current->thread.fpu);
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 (MACHINE_HAS_VX) {
for (i = 0; i < __NUM_VXRS_LOW; i++)
vxrs[i] = *((__u64 *)(current->thread.fpu.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.fpu.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 (MACHINE_HAS_VX) {
if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
sizeof(sregs_ext->vxrs_low)) ||
__copy_from_user(current->thread.fpu.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.fpu.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];
compat_sigset_t cset;
sigset_t set;
if (__copy_from_user(&cset.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32))
goto badframe;
sigset32_to_sigset(cset.sig, set.sig);
set_current_blocked(&set);
save_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, 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];
compat_sigset_t cset;
sigset_t set;
if (__copy_from_user(&cset, &frame->uc.uc_sigmask, sizeof(cset)))
goto badframe;
sigset32_to_sigset(cset.sig, set.sig);
set_current_blocked(&set);
if (compat_restore_altstack(&frame->uc.uc_stack))
goto badframe;
save_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, 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 */
sigset_to_sigset32(set->sig, sc.oldmask);
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)
{
compat_sigset_t cset;
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) {
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. */
sigset_to_sigset32(set->sig, cset.sig);
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, &cset, sizeof(cset)) ||
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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