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alistair23-linux/arch/sh/kernel/signal_32.c
Linus Torvalds fa2e5c073a Merge branch 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc 
Pull exec domain removal from Richard Weinberger:
 "This series removes execution domain support from Linux.

  The idea behind exec domains was to support different ABIs.  The
  feature was never complete nor stable.  Let's rip it out and make the
  kernel signal handling code less complicated"

* 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc: (27 commits)
  arm64: Removed unused variable
  sparc: Fix execution domain removal
  Remove rest of exec domains.
  arch: Remove exec_domain from remaining archs
  arc: Remove signal translation and exec_domain
  xtensa: Remove signal translation and exec_domain
  xtensa: Autogenerate offsets in struct thread_info
  x86: Remove signal translation and exec_domain
  unicore32: Remove signal translation and exec_domain
  um: Remove signal translation and exec_domain
  tile: Remove signal translation and exec_domain
  sparc: Remove signal translation and exec_domain
  sh: Remove signal translation and exec_domain
  s390: Remove signal translation and exec_domain
  mn10300: Remove signal translation and exec_domain
  microblaze: Remove signal translation and exec_domain
  m68k: Remove signal translation and exec_domain
  m32r: Remove signal translation and exec_domain
  m32r: Autogenerate offsets in struct thread_info
  frv: Remove signal translation and exec_domain
  ...
2015-04-15 13:53:55 -07:00

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/*
* linux/arch/sh/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
*
* SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
*
*/
#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/elf.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/io.h>
#include <linux/tracehook.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
#include <asm/syscalls.h>
#include <asm/fpu.h>
struct fdpic_func_descriptor {
unsigned long text;
unsigned long GOT;
};
/*
* The following define adds a 64 byte gap between the signal
* stack frame and previous contents of the stack. This allows
* frame unwinding in a function epilogue but only if a frame
* pointer is used in the function. This is necessary because
* current gcc compilers (<4.3) do not generate unwind info on
* SH for function epilogues.
*/
#define UNWINDGUARD 64
/*
* Do a signal return; undo the signal stack.
*/
#define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */
#if defined(CONFIG_CPU_SH2)
#define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */
#else
#define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */
#endif
#define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */
struct sigframe
{
struct sigcontext sc;
unsigned long extramask[_NSIG_WORDS-1];
u16 retcode[8];
};
struct rt_sigframe
{
struct siginfo info;
struct ucontext uc;
u16 retcode[8];
};
#ifdef CONFIG_SH_FPU
static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
{
struct task_struct *tsk = current;
if (!(boot_cpu_data.flags & CPU_HAS_FPU))
return 0;
set_used_math();
return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0],
sizeof(long)*(16*2+2));
}
static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
struct pt_regs *regs)
{
struct task_struct *tsk = current;
if (!(boot_cpu_data.flags & CPU_HAS_FPU))
return 0;
if (!used_math())
return __put_user(0, &sc->sc_ownedfp);
if (__put_user(1, &sc->sc_ownedfp))
return -EFAULT;
/* This will cause a "finit" to be triggered by the next
attempted FPU operation by the 'current' process.
*/
clear_used_math();
unlazy_fpu(tsk, regs);
return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu,
sizeof(long)*(16*2+2));
}
#endif /* CONFIG_SH_FPU */
static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
{
unsigned int err = 0;
#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
COPY(regs[1]);
COPY(regs[2]); COPY(regs[3]);
COPY(regs[4]); COPY(regs[5]);
COPY(regs[6]); COPY(regs[7]);
COPY(regs[8]); COPY(regs[9]);
COPY(regs[10]); COPY(regs[11]);
COPY(regs[12]); COPY(regs[13]);
COPY(regs[14]); COPY(regs[15]);
COPY(gbr); COPY(mach);
COPY(macl); COPY(pr);
COPY(sr); COPY(pc);
#undef COPY
#ifdef CONFIG_SH_FPU
if (boot_cpu_data.flags & CPU_HAS_FPU) {
int owned_fp;
struct task_struct *tsk = current;
regs->sr |= SR_FD; /* Release FPU */
clear_fpu(tsk, regs);
clear_used_math();
err |= __get_user (owned_fp, &sc->sc_ownedfp);
if (owned_fp)
err |= restore_sigcontext_fpu(sc);
}
#endif
regs->tra = -1; /* disable syscall checks */
err |= __get_user(*r0_p, &sc->sc_regs[0]);
return err;
}
asmlinkage int sys_sigreturn(void)
{
struct pt_regs *regs = current_pt_regs();
struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
sigset_t set;
int r0;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
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);
if (restore_sigcontext(regs, &frame->sc, &r0))
goto badframe;
return r0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage int sys_rt_sigreturn(void)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
sigset_t set;
int r0;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return r0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
/*
* Set up a signal frame.
*/
static int
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
unsigned long mask)
{
int err = 0;
#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
COPY(regs[0]); COPY(regs[1]);
COPY(regs[2]); COPY(regs[3]);
COPY(regs[4]); COPY(regs[5]);
COPY(regs[6]); COPY(regs[7]);
COPY(regs[8]); COPY(regs[9]);
COPY(regs[10]); COPY(regs[11]);
COPY(regs[12]); COPY(regs[13]);
COPY(regs[14]); COPY(regs[15]);
COPY(gbr); COPY(mach);
COPY(macl); COPY(pr);
COPY(sr); COPY(pc);
#undef COPY
#ifdef CONFIG_SH_FPU
err |= save_sigcontext_fpu(sc, regs);
#endif
/* non-iBCS2 extensions.. */
err |= __put_user(mask, &sc->oldmask);
return err;
}
/*
* Determine which stack to use..
*/
static inline void __user *
get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
{
if (ka->sa.sa_flags & SA_ONSTACK) {
if (sas_ss_flags(sp) == 0)
sp = current->sas_ss_sp + current->sas_ss_size;
}
return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul);
}
/* These symbols are defined with the addresses in the vsyscall page.
See vsyscall-trapa.S. */
extern void __kernel_sigreturn(void);
extern void __kernel_rt_sigreturn(void);
static int setup_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct sigframe __user *frame;
int err = 0, sig = ksig->sig;
frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return -EFAULT;
err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
if (_NSIG_WORDS > 1)
err |= __copy_to_user(frame->extramask, &set->sig[1],
sizeof(frame->extramask));
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
regs->pr = (unsigned long) ksig->ka.sa.sa_restorer;
#ifdef CONFIG_VSYSCALL
} else if (likely(current->mm->context.vdso)) {
regs->pr = VDSO_SYM(&__kernel_sigreturn);
#endif
} else {
/* Generate return code (system call to sigreturn) */
err |= __put_user(MOVW(7), &frame->retcode[0]);
err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
err |= __put_user(OR_R0_R0, &frame->retcode[2]);
err |= __put_user(OR_R0_R0, &frame->retcode[3]);
err |= __put_user(OR_R0_R0, &frame->retcode[4]);
err |= __put_user(OR_R0_R0, &frame->retcode[5]);
err |= __put_user(OR_R0_R0, &frame->retcode[6]);
err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
regs->pr = (unsigned long) frame->retcode;
flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
}
if (err)
return -EFAULT;
/* Set up registers for signal handler */
regs->regs[15] = (unsigned long) frame;
regs->regs[4] = sig; /* Arg for signal handler */
regs->regs[5] = 0;
regs->regs[6] = (unsigned long) &frame->sc;
if (current->personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler;
err |= __get_user(regs->pc, &funcptr->text);
err |= __get_user(regs->regs[12], &funcptr->GOT);
} else
regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
if (err)
return -EFAULT;
pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
return 0;
}
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
int err = 0, sig = ksig->sig;
frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return -EFAULT;
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(NULL, &frame->uc.uc_link);
err |= __save_altstack(&frame->uc.uc_stack, regs->regs[15]);
err |= setup_sigcontext(&frame->uc.uc_mcontext,
regs, set->sig[0]);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
regs->pr = (unsigned long) ksig->ka.sa.sa_restorer;
#ifdef CONFIG_VSYSCALL
} else if (likely(current->mm->context.vdso)) {
regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
#endif
} else {
/* Generate return code (system call to rt_sigreturn) */
err |= __put_user(MOVW(7), &frame->retcode[0]);
err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
err |= __put_user(OR_R0_R0, &frame->retcode[2]);
err |= __put_user(OR_R0_R0, &frame->retcode[3]);
err |= __put_user(OR_R0_R0, &frame->retcode[4]);
err |= __put_user(OR_R0_R0, &frame->retcode[5]);
err |= __put_user(OR_R0_R0, &frame->retcode[6]);
err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
regs->pr = (unsigned long) frame->retcode;
flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
}
if (err)
return -EFAULT;
/* Set up registers for signal handler */
regs->regs[15] = (unsigned long) frame;
regs->regs[4] = sig; /* Arg for signal handler */
regs->regs[5] = (unsigned long) &frame->info;
regs->regs[6] = (unsigned long) &frame->uc;
if (current->personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler;
err |= __get_user(regs->pc, &funcptr->text);
err |= __get_user(regs->regs[12], &funcptr->GOT);
} else
regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
if (err)
return -EFAULT;
pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
return 0;
}
static inline void
handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs,
struct sigaction *sa)
{
/* If we're not from a syscall, bail out */
if (regs->tra < 0)
return;
/* check for system call restart.. */
switch (regs->regs[0]) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
no_system_call_restart:
regs->regs[0] = -EINTR;
break;
case -ERESTARTSYS:
if (!(sa->sa_flags & SA_RESTART))
goto no_system_call_restart;
/* fallthrough */
case -ERESTARTNOINTR:
regs->regs[0] = save_r0;
regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
break;
}
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(struct ksignal *ksig, struct pt_regs *regs, unsigned int save_r0)
{
sigset_t *oldset = sigmask_to_save();
int ret;
/* Set up the stack frame */
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
ret = setup_rt_frame(ksig, oldset, regs);
else
ret = setup_frame(ksig, oldset, regs);
signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
}
/*
* 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.
*
* Note that we go through the signals twice: once to check the signals that
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
static void do_signal(struct pt_regs *regs, unsigned int save_r0)
{
struct ksignal ksig;
/*
* We want the common case to go fast, which
* is why we may in certain cases get here from
* kernel mode. Just return without doing anything
* if so.
*/
if (!user_mode(regs))
return;
if (get_signal(&ksig)) {
handle_syscall_restart(save_r0, regs, &ksig.ka.sa);
/* Whee! Actually deliver the signal. */
handle_signal(&ksig, regs, save_r0);
return;
}
/* Did we come from a system call? */
if (regs->tra >= 0) {
/* Restart the system call - no handlers present */
if (regs->regs[0] == -ERESTARTNOHAND ||
regs->regs[0] == -ERESTARTSYS ||
regs->regs[0] == -ERESTARTNOINTR) {
regs->regs[0] = save_r0;
regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
} else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
regs->regs[3] = __NR_restart_syscall;
}
}
/*
* If there's no signal to deliver, we just put the saved sigmask
* back.
*/
restore_saved_sigmask();
}
asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
unsigned long thread_info_flags)
{
/* deal with pending signal delivery */
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs, save_r0);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
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