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/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#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/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/suspend.h>
#include <linux/ptrace.h>
#include <linux/elf.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/sigframe.h>
#include <asm/syscalls.h>
#include <asm/vdso.h>
#include <arch/interrupts.h>
struct compat_ucontext {
compat_ulong_t uc_flags;
compat_uptr_t uc_link;
struct compat_sigaltstack uc_stack;
struct sigcontext uc_mcontext;
sigset_t uc_sigmask; /* mask last for extensibility */
};
struct compat_rt_sigframe {
unsigned char save_area[C_ABI_SAVE_AREA_SIZE]; /* caller save area */
struct compat_siginfo info;
struct compat_ucontext uc;
};
/* The assembly shim for this function arranges to ignore the return value. */
long compat_sys_rt_sigreturn(void)
{
struct pt_regs *regs = current_pt_regs();
struct compat_rt_sigframe __user *frame =
(struct compat_rt_sigframe __user *) compat_ptr(regs->sp);
sigset_t set;
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))
goto badframe;
if (compat_restore_altstack(&frame->uc.uc_stack))
goto badframe;
return 0;
badframe:
signal_fault("bad sigreturn frame", regs, frame, 0);
return 0;
}
/*
* Determine which stack to use..
*/
static inline void __user *compat_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)compat_ptr(regs->sp);
/*
* 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 (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
return (void __user __force *)-1UL;
/* 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;
}
sp -= frame_size;
/*
* Align the stack pointer according to the TILE ABI,
* i.e. so that on function entry (sp & 15) == 0.
*/
sp &= -16UL;
return (void __user *) sp;
}
int compat_setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
unsigned long restorer;
struct compat_rt_sigframe __user *frame;
int err = 0, sig = ksig->sig;
frame = compat_get_sigframe(&ksig->ka, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto err;
/* Always write at least the signal number for the stack backtracer. */
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
/* At sigreturn time, restore the callee-save registers too. */
err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
regs->flags |= PT_FLAGS_RESTORE_REGS;
} else {
err |= __put_user(ksig->info.si_signo, &frame->info.si_signo);
}
/* Create the ucontext. */
err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __compat_save_altstack(&frame->uc.uc_stack, regs->sp);
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto err;
restorer = VDSO_SYM(&__vdso_rt_sigreturn);
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ptr_to_compat_reg(ksig->ka.sa.sa_restorer);
/*
* Set up registers for signal handler.
* Registers that we don't modify keep the value they had from
* user-space at the time we took the signal.
* We always pass siginfo and mcontext, regardless of SA_SIGINFO,
* since some things rely on this (e.g. glibc's debug/segfault.c).
*/
regs->pc = ptr_to_compat_reg(ksig->ka.sa.sa_handler);
regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
regs->sp = ptr_to_compat_reg(frame);
regs->lr = restorer;
regs->regs[0] = (unsigned long) sig;
regs->regs[1] = ptr_to_compat_reg(&frame->info);
regs->regs[2] = ptr_to_compat_reg(&frame->uc);
regs->flags |= PT_FLAGS_CALLER_SAVES;
return 0;
err:
trace_unhandled_signal("bad sigreturn frame", regs,
(unsigned long)frame, SIGSEGV);
return -EFAULT;
}
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