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325 lines
8.4 KiB
325 lines
8.4 KiB
/* |
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* Copyright (C) 2013-2014 Altera Corporation |
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* Copyright (C) 2011-2012 Tobias Klauser <[email protected]> |
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* Copyright (C) 2004 Microtronix Datacom Ltd |
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* Copyright (C) 1991, 1992 Linus Torvalds |
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* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file COPYING in the main directory of this archive |
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* for more details. |
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*/ |
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#include <linux/signal.h> |
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#include <linux/errno.h> |
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#include <linux/ptrace.h> |
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#include <linux/uaccess.h> |
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#include <linux/unistd.h> |
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#include <linux/personality.h> |
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#include <linux/tracehook.h> |
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#include <asm/ucontext.h> |
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#include <asm/cacheflush.h> |
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#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) |
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/* |
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* Do a signal return; undo the signal stack. |
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* |
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* Keep the return code on the stack quadword aligned! |
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* That makes the cache flush below easier. |
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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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}; |
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static inline int rt_restore_ucontext(struct pt_regs *regs, |
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struct switch_stack *sw, |
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struct ucontext *uc, int *pr2) |
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{ |
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int temp; |
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unsigned long *gregs = uc->uc_mcontext.gregs; |
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int err; |
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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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err = __get_user(temp, &uc->uc_mcontext.version); |
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if (temp != MCONTEXT_VERSION) |
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goto badframe; |
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/* restore passed registers */ |
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err |= __get_user(regs->r1, &gregs[0]); |
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err |= __get_user(regs->r2, &gregs[1]); |
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err |= __get_user(regs->r3, &gregs[2]); |
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err |= __get_user(regs->r4, &gregs[3]); |
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err |= __get_user(regs->r5, &gregs[4]); |
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err |= __get_user(regs->r6, &gregs[5]); |
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err |= __get_user(regs->r7, &gregs[6]); |
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err |= __get_user(regs->r8, &gregs[7]); |
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err |= __get_user(regs->r9, &gregs[8]); |
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err |= __get_user(regs->r10, &gregs[9]); |
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err |= __get_user(regs->r11, &gregs[10]); |
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err |= __get_user(regs->r12, &gregs[11]); |
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err |= __get_user(regs->r13, &gregs[12]); |
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err |= __get_user(regs->r14, &gregs[13]); |
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err |= __get_user(regs->r15, &gregs[14]); |
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err |= __get_user(sw->r16, &gregs[15]); |
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err |= __get_user(sw->r17, &gregs[16]); |
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err |= __get_user(sw->r18, &gregs[17]); |
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err |= __get_user(sw->r19, &gregs[18]); |
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err |= __get_user(sw->r20, &gregs[19]); |
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err |= __get_user(sw->r21, &gregs[20]); |
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err |= __get_user(sw->r22, &gregs[21]); |
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err |= __get_user(sw->r23, &gregs[22]); |
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/* gregs[23] is handled below */ |
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err |= __get_user(sw->fp, &gregs[24]); /* Verify, should this be |
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settable */ |
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err |= __get_user(sw->gp, &gregs[25]); /* Verify, should this be |
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settable */ |
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err |= __get_user(temp, &gregs[26]); /* Not really necessary no user |
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settable bits */ |
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err |= __get_user(regs->ea, &gregs[27]); |
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err |= __get_user(regs->ra, &gregs[23]); |
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err |= __get_user(regs->sp, &gregs[28]); |
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regs->orig_r2 = -1; /* disable syscall checks */ |
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err |= restore_altstack(&uc->uc_stack); |
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if (err) |
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goto badframe; |
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*pr2 = regs->r2; |
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return err; |
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badframe: |
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return 1; |
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} |
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asmlinkage int do_rt_sigreturn(struct switch_stack *sw) |
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{ |
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struct pt_regs *regs = (struct pt_regs *)(sw + 1); |
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/* Verify, can we follow the stack back */ |
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struct rt_sigframe *frame = (struct rt_sigframe *) regs->sp; |
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sigset_t set; |
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int rval; |
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if (!access_ok(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 (rt_restore_ucontext(regs, sw, &frame->uc, &rval)) |
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goto badframe; |
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return rval; |
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badframe: |
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force_sig(SIGSEGV); |
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return 0; |
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} |
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static inline int rt_setup_ucontext(struct ucontext *uc, struct pt_regs *regs) |
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{ |
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struct switch_stack *sw = (struct switch_stack *)regs - 1; |
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unsigned long *gregs = uc->uc_mcontext.gregs; |
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int err = 0; |
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err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version); |
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err |= __put_user(regs->r1, &gregs[0]); |
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err |= __put_user(regs->r2, &gregs[1]); |
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err |= __put_user(regs->r3, &gregs[2]); |
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err |= __put_user(regs->r4, &gregs[3]); |
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err |= __put_user(regs->r5, &gregs[4]); |
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err |= __put_user(regs->r6, &gregs[5]); |
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err |= __put_user(regs->r7, &gregs[6]); |
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err |= __put_user(regs->r8, &gregs[7]); |
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err |= __put_user(regs->r9, &gregs[8]); |
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err |= __put_user(regs->r10, &gregs[9]); |
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err |= __put_user(regs->r11, &gregs[10]); |
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err |= __put_user(regs->r12, &gregs[11]); |
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err |= __put_user(regs->r13, &gregs[12]); |
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err |= __put_user(regs->r14, &gregs[13]); |
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err |= __put_user(regs->r15, &gregs[14]); |
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err |= __put_user(sw->r16, &gregs[15]); |
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err |= __put_user(sw->r17, &gregs[16]); |
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err |= __put_user(sw->r18, &gregs[17]); |
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err |= __put_user(sw->r19, &gregs[18]); |
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err |= __put_user(sw->r20, &gregs[19]); |
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err |= __put_user(sw->r21, &gregs[20]); |
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err |= __put_user(sw->r22, &gregs[21]); |
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err |= __put_user(sw->r23, &gregs[22]); |
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err |= __put_user(regs->ra, &gregs[23]); |
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err |= __put_user(sw->fp, &gregs[24]); |
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err |= __put_user(sw->gp, &gregs[25]); |
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err |= __put_user(regs->ea, &gregs[27]); |
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err |= __put_user(regs->sp, &gregs[28]); |
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return err; |
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} |
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static inline void *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, |
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size_t frame_size) |
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{ |
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unsigned long usp; |
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/* Default to using normal stack. */ |
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usp = regs->sp; |
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/* This is the X/Open sanctioned signal stack switching. */ |
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usp = sigsp(usp, ksig); |
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/* Verify, is it 32 or 64 bit aligned */ |
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return (void *)((usp - 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 *frame; |
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int err = 0; |
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frame = get_sigframe(ksig, regs, sizeof(*frame)); |
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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(0, &frame->uc.uc_link); |
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err |= __save_altstack(&frame->uc.uc_stack, regs->sp); |
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err |= rt_setup_ucontext(&frame->uc, regs); |
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err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
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if (err) |
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goto give_sigsegv; |
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/* Set up to return from userspace; jump to fixed address sigreturn |
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trampoline on kuser page. */ |
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regs->ra = (unsigned long) (0x1044); |
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/* Set up registers for signal handler */ |
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regs->sp = (unsigned long) frame; |
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regs->r4 = (unsigned long) ksig->sig; |
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regs->r5 = (unsigned long) &frame->info; |
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regs->r6 = (unsigned long) &frame->uc; |
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regs->ea = (unsigned long) ksig->ka.sa.sa_handler; |
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return 0; |
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give_sigsegv: |
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force_sigsegv(ksig->sig); |
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return -EFAULT; |
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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 handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
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{ |
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int ret; |
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sigset_t *oldset = sigmask_to_save(); |
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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, 0); |
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} |
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static int do_signal(struct pt_regs *regs) |
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{ |
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unsigned int retval = 0, continue_addr = 0, restart_addr = 0; |
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int restart = 0; |
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struct ksignal ksig; |
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current->thread.kregs = regs; |
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/* |
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* If we were from a system call, check for system call restarting... |
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*/ |
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if (regs->orig_r2 >= 0) { |
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continue_addr = regs->ea; |
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restart_addr = continue_addr - 4; |
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retval = regs->r2; |
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/* |
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* Prepare for system call restart. We do this here so that a |
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* debugger will see the already changed PC. |
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*/ |
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switch (retval) { |
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case ERESTART_RESTARTBLOCK: |
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restart = -2; |
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fallthrough; |
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case ERESTARTNOHAND: |
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case ERESTARTSYS: |
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case ERESTARTNOINTR: |
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restart++; |
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regs->r2 = regs->orig_r2; |
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regs->r7 = regs->orig_r7; |
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regs->ea = restart_addr; |
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break; |
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} |
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} |
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if (get_signal(&ksig)) { |
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/* handler */ |
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if (unlikely(restart && regs->ea == restart_addr)) { |
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if (retval == ERESTARTNOHAND || |
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retval == ERESTART_RESTARTBLOCK || |
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(retval == ERESTARTSYS |
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&& !(ksig.ka.sa.sa_flags & SA_RESTART))) { |
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regs->r2 = EINTR; |
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regs->r7 = 1; |
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regs->ea = continue_addr; |
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} |
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} |
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handle_signal(&ksig, regs); |
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return 0; |
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} |
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/* |
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* No handler present |
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*/ |
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if (unlikely(restart) && regs->ea == restart_addr) { |
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regs->ea = continue_addr; |
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regs->r2 = __NR_restart_syscall; |
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} |
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/* |
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* If there's no signal to deliver, we just put the saved sigmask back. |
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*/ |
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restore_saved_sigmask(); |
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return restart; |
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} |
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asmlinkage int do_notify_resume(struct pt_regs *regs) |
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{ |
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/* |
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* We want the common case to go fast, which is why we may in certain |
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* cases get here from kernel mode. Just return without doing anything |
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* if so. |
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*/ |
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if (!user_mode(regs)) |
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return 0; |
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if (test_thread_flag(TIF_SIGPENDING) || |
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test_thread_flag(TIF_NOTIFY_SIGNAL)) { |
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int restart = do_signal(regs); |
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if (unlikely(restart)) { |
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/* |
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* Restart without handlers. |
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* Deal with it without leaving |
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* the kernel space. |
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*/ |
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return restart; |
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} |
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} else if (test_thread_flag(TIF_NOTIFY_RESUME)) |
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tracehook_notify_resume(regs); |
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return 0; |
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}
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