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e0d407564b
Unfortunately, I never committed the fix to a nasty oops which can occur as a result of that commit: ------------[ cut here ]------------ kernel BUG at /home/olof/work/batch/include/linux/mm.h:414! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 490 Comm: killall5 Not tainted 3.11.0-rc3-00288-gabe0308 #53 task: e90acac0 ti: e9be8000 task.ti: e9be8000 PC is at special_mapping_fault+0xa4/0xc4 LR is at __do_fault+0x68/0x48c This doesn't show up unless you do quite a bit of testing; a simple boot test does not do this, so all my nightly tests were passing fine. The reason for this is that install_special_mapping() expects the page array to stick around, and as this was only inserting one page which was stored on the kernel stack, that's why this was blowing up. Reported-by: Olof Johansson <olof@lixom.net> Tested-by: Olof Johansson <olof@lixom.net> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
646 lines
17 KiB
C
646 lines
17 KiB
C
/*
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* linux/arch/arm/kernel/signal.c
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*
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* Copyright (C) 1995-2009 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/errno.h>
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#include <linux/random.h>
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#include <linux/signal.h>
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#include <linux/personality.h>
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#include <linux/uaccess.h>
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#include <linux/tracehook.h>
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#include <asm/elf.h>
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#include <asm/cacheflush.h>
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#include <asm/traps.h>
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#include <asm/ucontext.h>
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#include <asm/unistd.h>
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#include <asm/vfp.h>
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/*
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* For ARM syscalls, we encode the syscall number into the instruction.
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*/
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#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
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#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
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/*
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* With EABI, the syscall number has to be loaded into r7.
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*/
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#define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
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#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
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/*
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* For Thumb syscalls, we pass the syscall number via r7. We therefore
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* need two 16-bit instructions.
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*/
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#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
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#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
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static const unsigned long sigreturn_codes[7] = {
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MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
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MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
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};
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static unsigned long signal_return_offset;
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#ifdef CONFIG_CRUNCH
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static int preserve_crunch_context(struct crunch_sigframe __user *frame)
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{
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char kbuf[sizeof(*frame) + 8];
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struct crunch_sigframe *kframe;
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/* the crunch context must be 64 bit aligned */
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kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
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kframe->magic = CRUNCH_MAGIC;
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kframe->size = CRUNCH_STORAGE_SIZE;
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crunch_task_copy(current_thread_info(), &kframe->storage);
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return __copy_to_user(frame, kframe, sizeof(*frame));
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}
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static int restore_crunch_context(struct crunch_sigframe __user *frame)
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{
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char kbuf[sizeof(*frame) + 8];
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struct crunch_sigframe *kframe;
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/* the crunch context must be 64 bit aligned */
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kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
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if (__copy_from_user(kframe, frame, sizeof(*frame)))
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return -1;
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if (kframe->magic != CRUNCH_MAGIC ||
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kframe->size != CRUNCH_STORAGE_SIZE)
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return -1;
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crunch_task_restore(current_thread_info(), &kframe->storage);
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return 0;
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}
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#endif
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#ifdef CONFIG_IWMMXT
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static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
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{
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char kbuf[sizeof(*frame) + 8];
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struct iwmmxt_sigframe *kframe;
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/* the iWMMXt context must be 64 bit aligned */
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kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
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kframe->magic = IWMMXT_MAGIC;
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kframe->size = IWMMXT_STORAGE_SIZE;
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iwmmxt_task_copy(current_thread_info(), &kframe->storage);
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return __copy_to_user(frame, kframe, sizeof(*frame));
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}
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static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
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{
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char kbuf[sizeof(*frame) + 8];
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struct iwmmxt_sigframe *kframe;
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/* the iWMMXt context must be 64 bit aligned */
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kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
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if (__copy_from_user(kframe, frame, sizeof(*frame)))
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return -1;
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if (kframe->magic != IWMMXT_MAGIC ||
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kframe->size != IWMMXT_STORAGE_SIZE)
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return -1;
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iwmmxt_task_restore(current_thread_info(), &kframe->storage);
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return 0;
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}
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#endif
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#ifdef CONFIG_VFP
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static int preserve_vfp_context(struct vfp_sigframe __user *frame)
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{
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const unsigned long magic = VFP_MAGIC;
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const unsigned long size = VFP_STORAGE_SIZE;
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int err = 0;
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__put_user_error(magic, &frame->magic, err);
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__put_user_error(size, &frame->size, err);
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if (err)
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return -EFAULT;
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return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
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}
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static int restore_vfp_context(struct vfp_sigframe __user *frame)
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{
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unsigned long magic;
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unsigned long size;
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int err = 0;
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__get_user_error(magic, &frame->magic, err);
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__get_user_error(size, &frame->size, err);
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if (err)
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return -EFAULT;
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if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
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return -EINVAL;
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return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
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}
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#endif
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/*
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* Do a signal return; undo the signal stack. These are aligned to 64-bit.
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*/
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struct sigframe {
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struct ucontext uc;
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unsigned long retcode[2];
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};
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struct rt_sigframe {
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struct siginfo info;
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struct sigframe sig;
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};
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static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
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{
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struct aux_sigframe __user *aux;
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sigset_t set;
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int err;
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err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
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if (err == 0)
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set_current_blocked(&set);
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__get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
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__get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
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__get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
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__get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
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__get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
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__get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
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__get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
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__get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
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__get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
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__get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
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__get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
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__get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
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__get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
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__get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
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__get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
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__get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
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__get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
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err |= !valid_user_regs(regs);
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aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
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#ifdef CONFIG_CRUNCH
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if (err == 0)
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err |= restore_crunch_context(&aux->crunch);
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#endif
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#ifdef CONFIG_IWMMXT
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if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
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err |= restore_iwmmxt_context(&aux->iwmmxt);
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#endif
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#ifdef CONFIG_VFP
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if (err == 0)
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err |= restore_vfp_context(&aux->vfp);
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#endif
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return err;
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}
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asmlinkage int sys_sigreturn(struct pt_regs *regs)
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{
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struct sigframe __user *frame;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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/*
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* Since we stacked the signal on a 64-bit boundary,
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* then 'sp' should be word aligned here. If it's
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* not, then the user is trying to mess with us.
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*/
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if (regs->ARM_sp & 7)
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goto badframe;
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frame = (struct sigframe __user *)regs->ARM_sp;
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if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
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goto badframe;
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if (restore_sigframe(regs, frame))
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goto badframe;
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return regs->ARM_r0;
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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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asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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/*
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* Since we stacked the signal on a 64-bit boundary,
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* then 'sp' should be word aligned here. If it's
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* not, then the user is trying to mess with us.
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*/
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if (regs->ARM_sp & 7)
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goto badframe;
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frame = (struct rt_sigframe __user *)regs->ARM_sp;
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if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
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goto badframe;
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if (restore_sigframe(regs, &frame->sig))
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goto badframe;
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if (restore_altstack(&frame->sig.uc.uc_stack))
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goto badframe;
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return regs->ARM_r0;
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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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static int
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setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
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{
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struct aux_sigframe __user *aux;
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int err = 0;
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__put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
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__put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
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__put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
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__put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
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__put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
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__put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
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__put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
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__put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
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__put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
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__put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
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__put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
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__put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
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__put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
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__put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
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__put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
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__put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
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__put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
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__put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
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__put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
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__put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
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__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
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err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
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aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
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#ifdef CONFIG_CRUNCH
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if (err == 0)
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err |= preserve_crunch_context(&aux->crunch);
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#endif
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#ifdef CONFIG_IWMMXT
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if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
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err |= preserve_iwmmxt_context(&aux->iwmmxt);
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#endif
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#ifdef CONFIG_VFP
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if (err == 0)
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err |= preserve_vfp_context(&aux->vfp);
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#endif
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__put_user_error(0, &aux->end_magic, err);
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return err;
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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, int framesize)
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{
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unsigned long sp = sigsp(regs->ARM_sp, ksig);
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void __user *frame;
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/*
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* ATPCS B01 mandates 8-byte alignment
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*/
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frame = (void __user *)((sp - framesize) & ~7);
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/*
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* Check that we can actually write to the signal frame.
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*/
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if (!access_ok(VERIFY_WRITE, frame, framesize))
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frame = NULL;
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return frame;
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}
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/*
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* translate the signal
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*/
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static inline int map_sig(int sig)
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{
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struct thread_info *thread = current_thread_info();
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if (sig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
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sig = thread->exec_domain->signal_invmap[sig];
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return sig;
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}
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static int
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setup_return(struct pt_regs *regs, struct ksignal *ksig,
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unsigned long __user *rc, void __user *frame)
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{
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unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
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unsigned long retcode;
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int thumb = 0;
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unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
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cpsr |= PSR_ENDSTATE;
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/*
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* Maybe we need to deliver a 32-bit signal to a 26-bit task.
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*/
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if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
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cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
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#ifdef CONFIG_ARM_THUMB
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if (elf_hwcap & HWCAP_THUMB) {
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/*
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* The LSB of the handler determines if we're going to
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* be using THUMB or ARM mode for this signal handler.
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*/
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thumb = handler & 1;
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if (thumb) {
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cpsr |= PSR_T_BIT;
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#if __LINUX_ARM_ARCH__ >= 7
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/* clear the If-Then Thumb-2 execution state */
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cpsr &= ~PSR_IT_MASK;
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#endif
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} else
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cpsr &= ~PSR_T_BIT;
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}
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#endif
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if (ksig->ka.sa.sa_flags & SA_RESTORER) {
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retcode = (unsigned long)ksig->ka.sa.sa_restorer;
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} else {
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unsigned int idx = thumb << 1;
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if (ksig->ka.sa.sa_flags & SA_SIGINFO)
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idx += 3;
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/*
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* Put the sigreturn code on the stack no matter which return
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* mechanism we use in order to remain ABI compliant
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*/
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if (__put_user(sigreturn_codes[idx], rc) ||
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__put_user(sigreturn_codes[idx+1], rc+1))
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return 1;
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if ((cpsr & MODE32_BIT) && !IS_ENABLED(CONFIG_ARM_MPU)) {
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struct mm_struct *mm = current->mm;
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/*
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* 32-bit code can use the signal return page
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* except when the MPU has protected the vectors
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* page from PL0
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*/
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retcode = mm->context.sigpage + signal_return_offset +
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(idx << 2) + thumb;
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} else {
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/*
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* Ensure that the instruction cache sees
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* the return code written onto the stack.
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*/
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flush_icache_range((unsigned long)rc,
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(unsigned long)(rc + 2));
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retcode = ((unsigned long)rc) + thumb;
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}
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}
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regs->ARM_r0 = map_sig(ksig->sig);
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regs->ARM_sp = (unsigned long)frame;
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regs->ARM_lr = retcode;
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regs->ARM_pc = handler;
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regs->ARM_cpsr = cpsr;
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return 0;
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}
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static int
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setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
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{
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struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
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int err = 0;
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if (!frame)
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return 1;
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/*
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|
* Set uc.uc_flags to a value which sc.trap_no would never have.
|
|
*/
|
|
__put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
|
|
|
|
err |= setup_sigframe(frame, regs, set);
|
|
if (err == 0)
|
|
err = setup_return(regs, ksig, frame->retcode, frame);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int
|
|
setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
|
|
{
|
|
struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
|
|
int err = 0;
|
|
|
|
if (!frame)
|
|
return 1;
|
|
|
|
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
|
|
|
|
__put_user_error(0, &frame->sig.uc.uc_flags, err);
|
|
__put_user_error(NULL, &frame->sig.uc.uc_link, err);
|
|
|
|
err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
|
|
err |= setup_sigframe(&frame->sig, regs, set);
|
|
if (err == 0)
|
|
err = setup_return(regs, ksig, frame->sig.retcode, frame);
|
|
|
|
if (err == 0) {
|
|
/*
|
|
* For realtime signals we must also set the second and third
|
|
* arguments for the signal handler.
|
|
* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
|
|
*/
|
|
regs->ARM_r1 = (unsigned long)&frame->info;
|
|
regs->ARM_r2 = (unsigned long)&frame->sig.uc;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* OK, we're invoking a handler
|
|
*/
|
|
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
|
|
{
|
|
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);
|
|
|
|
/*
|
|
* Check that the resulting registers are actually sane.
|
|
*/
|
|
ret |= !valid_user_regs(regs);
|
|
|
|
signal_setup_done(ret, ksig, 0);
|
|
}
|
|
|
|
/*
|
|
* 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 int do_signal(struct pt_regs *regs, int syscall)
|
|
{
|
|
unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
|
|
struct ksignal ksig;
|
|
int restart = 0;
|
|
|
|
/*
|
|
* If we were from a system call, check for system call restarting...
|
|
*/
|
|
if (syscall) {
|
|
continue_addr = regs->ARM_pc;
|
|
restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
|
|
retval = regs->ARM_r0;
|
|
|
|
/*
|
|
* Prepare for system call restart. We do this here so that a
|
|
* debugger will see the already changed PSW.
|
|
*/
|
|
switch (retval) {
|
|
case -ERESTART_RESTARTBLOCK:
|
|
restart -= 2;
|
|
case -ERESTARTNOHAND:
|
|
case -ERESTARTSYS:
|
|
case -ERESTARTNOINTR:
|
|
restart++;
|
|
regs->ARM_r0 = regs->ARM_ORIG_r0;
|
|
regs->ARM_pc = restart_addr;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get the signal to deliver. When running under ptrace, at this
|
|
* point the debugger may change all our registers ...
|
|
*/
|
|
/*
|
|
* Depending on the signal settings we may need to revert the
|
|
* decision to restart the system call. But skip this if a
|
|
* debugger has chosen to restart at a different PC.
|
|
*/
|
|
if (get_signal(&ksig)) {
|
|
/* handler */
|
|
if (unlikely(restart) && regs->ARM_pc == restart_addr) {
|
|
if (retval == -ERESTARTNOHAND ||
|
|
retval == -ERESTART_RESTARTBLOCK
|
|
|| (retval == -ERESTARTSYS
|
|
&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
|
|
regs->ARM_r0 = -EINTR;
|
|
regs->ARM_pc = continue_addr;
|
|
}
|
|
}
|
|
handle_signal(&ksig, regs);
|
|
} else {
|
|
/* no handler */
|
|
restore_saved_sigmask();
|
|
if (unlikely(restart) && regs->ARM_pc == restart_addr) {
|
|
regs->ARM_pc = continue_addr;
|
|
return restart;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
asmlinkage int
|
|
do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
|
|
{
|
|
do {
|
|
if (likely(thread_flags & _TIF_NEED_RESCHED)) {
|
|
schedule();
|
|
} else {
|
|
if (unlikely(!user_mode(regs)))
|
|
return 0;
|
|
local_irq_enable();
|
|
if (thread_flags & _TIF_SIGPENDING) {
|
|
int restart = do_signal(regs, syscall);
|
|
if (unlikely(restart)) {
|
|
/*
|
|
* Restart without handlers.
|
|
* Deal with it without leaving
|
|
* the kernel space.
|
|
*/
|
|
return restart;
|
|
}
|
|
syscall = 0;
|
|
} else {
|
|
clear_thread_flag(TIF_NOTIFY_RESUME);
|
|
tracehook_notify_resume(regs);
|
|
}
|
|
}
|
|
local_irq_disable();
|
|
thread_flags = current_thread_info()->flags;
|
|
} while (thread_flags & _TIF_WORK_MASK);
|
|
return 0;
|
|
}
|
|
|
|
struct page *get_signal_page(void)
|
|
{
|
|
unsigned long ptr;
|
|
unsigned offset;
|
|
struct page *page;
|
|
void *addr;
|
|
|
|
page = alloc_pages(GFP_KERNEL, 0);
|
|
|
|
if (!page)
|
|
return NULL;
|
|
|
|
addr = page_address(page);
|
|
|
|
/* Give the signal return code some randomness */
|
|
offset = 0x200 + (get_random_int() & 0x7fc);
|
|
signal_return_offset = offset;
|
|
|
|
/*
|
|
* Copy signal return handlers into the vector page, and
|
|
* set sigreturn to be a pointer to these.
|
|
*/
|
|
memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
|
|
|
|
ptr = (unsigned long)addr + offset;
|
|
flush_icache_range(ptr, ptr + sizeof(sigreturn_codes));
|
|
|
|
return page;
|
|
}
|