326 lines
8.2 KiB
C
326 lines
8.2 KiB
C
/*
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* Signal handling
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*
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* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2008-2009 PetaLogix
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* Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
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* Copyright (C) 2001 NEC Corporation
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* Copyright (C) 2001 Miles Bader <miles@gnu.org>
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* Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
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* Copyright (C) 1991,1992 Linus Torvalds
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*
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* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
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*
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* This file was was derived from the sh version, arch/sh/kernel/signal.c
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*
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* This file is subject to the terms and conditions of the GNU General
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* Public License. See the file COPYING in the main directory of this
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* archive for more details.
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/errno.h>
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#include <linux/wait.h>
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#include <linux/ptrace.h>
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#include <linux/unistd.h>
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#include <linux/stddef.h>
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#include <linux/personality.h>
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#include <linux/percpu.h>
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#include <linux/linkage.h>
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#include <linux/tracehook.h>
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#include <asm/entry.h>
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#include <asm/ucontext.h>
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#include <linux/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <linux/syscalls.h>
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#include <asm/cacheflush.h>
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#include <asm/syscalls.h>
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/*
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* Do a signal return; undo the signal stack.
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*/
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struct sigframe {
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struct sigcontext sc;
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unsigned long extramask[_NSIG_WORDS-1];
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unsigned long tramp[2]; /* signal trampoline */
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};
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struct rt_sigframe {
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struct siginfo info;
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struct ucontext uc;
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unsigned long tramp[2]; /* signal trampoline */
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};
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static int restore_sigcontext(struct pt_regs *regs,
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struct sigcontext __user *sc, int *rval_p)
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{
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unsigned int err = 0;
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#define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); }
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COPY(r0);
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COPY(r1);
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COPY(r2); COPY(r3); COPY(r4); COPY(r5);
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COPY(r6); COPY(r7); COPY(r8); COPY(r9);
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COPY(r10); COPY(r11); COPY(r12); COPY(r13);
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COPY(r14); COPY(r15); COPY(r16); COPY(r17);
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COPY(r18); COPY(r19); COPY(r20); COPY(r21);
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COPY(r22); COPY(r23); COPY(r24); COPY(r25);
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COPY(r26); COPY(r27); COPY(r28); COPY(r29);
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COPY(r30); COPY(r31);
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COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
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#undef COPY
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*rval_p = regs->r3;
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return err;
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}
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asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame =
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(struct rt_sigframe __user *)(regs->r1);
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sigset_t set;
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int rval;
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/* Always make any pending restarted system calls return -EINTR */
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current->restart_block.fn = do_no_restart_syscall;
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
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goto badframe;
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
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goto badframe;
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set_current_blocked(&set);
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if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
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goto badframe;
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if (restore_altstack(&frame->uc.uc_stack))
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goto badframe;
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return rval;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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/*
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* Set up a signal frame.
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*/
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static int
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setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
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unsigned long mask)
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{
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int err = 0;
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#define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); }
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COPY(r0);
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COPY(r1);
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COPY(r2); COPY(r3); COPY(r4); COPY(r5);
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COPY(r6); COPY(r7); COPY(r8); COPY(r9);
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COPY(r10); COPY(r11); COPY(r12); COPY(r13);
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COPY(r14); COPY(r15); COPY(r16); COPY(r17);
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COPY(r18); COPY(r19); COPY(r20); COPY(r21);
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COPY(r22); COPY(r23); COPY(r24); COPY(r25);
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COPY(r26); COPY(r27); COPY(r28); COPY(r29);
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COPY(r30); COPY(r31);
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COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
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#undef COPY
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err |= __put_user(mask, &sc->oldmask);
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return err;
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}
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/*
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* Determine which stack to use..
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*/
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static inline void __user *
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get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
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{
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/* Default to using normal stack */
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unsigned long sp = sigsp(regs->r1, ksig);
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return (void __user *)((sp - frame_size) & -8UL);
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}
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static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
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struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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int err = 0, sig = ksig->sig;
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unsigned long address = 0;
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#ifdef CONFIG_MMU
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pmd_t *pmdp;
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pte_t *ptep;
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#endif
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frame = get_sigframe(ksig, regs, sizeof(*frame));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return -EFAULT;
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if (ksig->ka.sa.sa_flags & SA_SIGINFO)
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err |= copy_siginfo_to_user(&frame->info, &ksig->info);
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/* Create the ucontext. */
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err |= __put_user(0, &frame->uc.uc_flags);
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err |= __put_user(NULL, &frame->uc.uc_link);
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err |= __save_altstack(&frame->uc.uc_stack, regs->r1);
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err |= setup_sigcontext(&frame->uc.uc_mcontext,
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regs, set->sig[0]);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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/* minus 8 is offset to cater for "rtsd r15,8" */
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/* addi r12, r0, __NR_sigreturn */
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err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
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frame->tramp + 0);
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/* brki r14, 0x8 */
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err |= __put_user(0xb9cc0008, frame->tramp + 1);
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/* Return from sighandler will jump to the tramp.
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Negative 8 offset because return is rtsd r15, 8 */
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regs->r15 = ((unsigned long)frame->tramp)-8;
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address = ((unsigned long)frame->tramp);
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#ifdef CONFIG_MMU
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pmdp = pmd_offset(pud_offset(
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pgd_offset(current->mm, address),
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address), address);
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preempt_disable();
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ptep = pte_offset_map(pmdp, address);
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if (pte_present(*ptep)) {
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address = (unsigned long) page_address(pte_page(*ptep));
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/* MS: I need add offset in page */
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address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
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/* MS address is virtual */
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address = __virt_to_phys(address);
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invalidate_icache_range(address, address + 8);
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flush_dcache_range(address, address + 8);
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}
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pte_unmap(ptep);
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preempt_enable();
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#else
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flush_icache_range(address, address + 8);
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flush_dcache_range(address, address + 8);
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#endif
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if (err)
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return -EFAULT;
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/* Set up registers for signal handler */
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regs->r1 = (unsigned long) frame;
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/* Signal handler args: */
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regs->r5 = sig; /* arg 0: signum */
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regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
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regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
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/* Offset to handle microblaze rtid r14, 0 */
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regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
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#ifdef DEBUG_SIG
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pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n",
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current->comm, current->pid, frame, regs->pc);
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#endif
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return 0;
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}
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/* Handle restarting system calls */
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static inline void
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handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
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{
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switch (regs->r3) {
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case -ERESTART_RESTARTBLOCK:
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case -ERESTARTNOHAND:
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if (!has_handler)
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goto do_restart;
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regs->r3 = -EINTR;
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break;
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case -ERESTARTSYS:
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if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
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regs->r3 = -EINTR;
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break;
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}
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/* fallthrough */
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case -ERESTARTNOINTR:
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do_restart:
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/* offset of 4 bytes to re-execute trap (brki) instruction */
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regs->pc -= 4;
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break;
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}
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}
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/*
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* OK, we're invoking a handler
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*/
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static void
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handle_signal(struct ksignal *ksig, struct pt_regs *regs)
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{
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sigset_t *oldset = sigmask_to_save();
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int ret;
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/* Set up the stack frame */
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ret = setup_rt_frame(ksig, oldset, regs);
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signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
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}
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/*
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* Note that 'init' is a special process: it doesn't get signals it doesn't
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* want to handle. Thus you cannot kill init even with a SIGKILL even by
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* mistake.
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*
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* Note that we go through the signals twice: once to check the signals that
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* the kernel can handle, and then we build all the user-level signal handling
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* stack-frames in one go after that.
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*/
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static void do_signal(struct pt_regs *regs, int in_syscall)
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{
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struct ksignal ksig;
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#ifdef DEBUG_SIG
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pr_info("do signal: %p %d\n", regs, in_syscall);
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pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
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regs->r12, current_thread_info()->flags);
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#endif
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if (get_signal(&ksig)) {
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/* Whee! Actually deliver the signal. */
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if (in_syscall)
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handle_restart(regs, &ksig.ka, 1);
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handle_signal(&ksig, regs);
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return;
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}
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if (in_syscall)
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handle_restart(regs, NULL, 0);
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/*
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* If there's no signal to deliver, we just put the saved sigmask
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* back.
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*/
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restore_saved_sigmask();
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}
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asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall)
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{
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if (test_thread_flag(TIF_SIGPENDING))
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do_signal(regs, in_syscall);
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if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
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tracehook_notify_resume(regs);
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}
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