479 lines
14 KiB
C
479 lines
14 KiB
C
/*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Derived from "arch/i386/kernel/signal.c"
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* Copyright (C) 1991, 1992 Linus Torvalds
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* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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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/unistd.h>
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#include <linux/stddef.h>
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#include <linux/elf.h>
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#include <linux/ptrace.h>
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#include <linux/module.h>
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#include <asm/sigcontext.h>
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#include <asm/ucontext.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/unistd.h>
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#include <asm/cacheflush.h>
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#include <asm/syscalls.h>
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#include <asm/vdso.h>
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#include "signal.h"
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#define DEBUG_SIG 0
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#define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
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#define FP_REGS_SIZE sizeof(elf_fpregset_t)
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#define TRAMP_TRACEBACK 3
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#define TRAMP_SIZE 6
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/*
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* When we have signals to deliver, we set up on the user stack,
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* going down from the original stack pointer:
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* 1) a rt_sigframe struct which contains the ucontext
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* 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
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* frame for the signal handler.
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*/
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struct rt_sigframe {
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/* sys_rt_sigreturn requires the ucontext be the first field */
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struct ucontext uc;
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unsigned long _unused[2];
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unsigned int tramp[TRAMP_SIZE];
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struct siginfo __user *pinfo;
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void __user *puc;
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struct siginfo info;
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/* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
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char abigap[288];
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} __attribute__ ((aligned (16)));
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static const char fmt32[] = KERN_INFO \
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"%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n";
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static const char fmt64[] = KERN_INFO \
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"%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n";
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/*
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* Set up the sigcontext for the signal frame.
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*/
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static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
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int signr, sigset_t *set, unsigned long handler,
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int ctx_has_vsx_region)
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{
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/* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
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* process never used altivec yet (MSR_VEC is zero in pt_regs of
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* the context). This is very important because we must ensure we
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* don't lose the VRSAVE content that may have been set prior to
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* the process doing its first vector operation
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* Userland shall check AT_HWCAP to know wether it can rely on the
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* v_regs pointer or not
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*/
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#ifdef CONFIG_ALTIVEC
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elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
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#endif
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unsigned long msr = regs->msr;
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long err = 0;
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flush_fp_to_thread(current);
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#ifdef CONFIG_ALTIVEC
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err |= __put_user(v_regs, &sc->v_regs);
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/* save altivec registers */
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if (current->thread.used_vr) {
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flush_altivec_to_thread(current);
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/* Copy 33 vec registers (vr0..31 and vscr) to the stack */
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err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128));
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/* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
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* contains valid data.
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*/
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msr |= MSR_VEC;
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}
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/* We always copy to/from vrsave, it's 0 if we don't have or don't
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* use altivec.
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*/
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err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
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#else /* CONFIG_ALTIVEC */
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err |= __put_user(0, &sc->v_regs);
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#endif /* CONFIG_ALTIVEC */
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flush_fp_to_thread(current);
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/* copy fpr regs and fpscr */
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err |= copy_fpr_to_user(&sc->fp_regs, current);
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#ifdef CONFIG_VSX
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/*
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* Copy VSX low doubleword to local buffer for formatting,
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* then out to userspace. Update v_regs to point after the
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* VMX data.
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*/
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if (current->thread.used_vsr && ctx_has_vsx_region) {
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__giveup_vsx(current);
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v_regs += ELF_NVRREG;
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err |= copy_vsx_to_user(v_regs, current);
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/* set MSR_VSX in the MSR value in the frame to
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* indicate that sc->vs_reg) contains valid data.
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*/
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msr |= MSR_VSX;
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}
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#endif /* CONFIG_VSX */
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err |= __put_user(&sc->gp_regs, &sc->regs);
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WARN_ON(!FULL_REGS(regs));
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err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
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err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
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err |= __put_user(signr, &sc->signal);
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err |= __put_user(handler, &sc->handler);
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if (set != NULL)
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err |= __put_user(set->sig[0], &sc->oldmask);
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return err;
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}
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/*
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* Restore the sigcontext from the signal frame.
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*/
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static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
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struct sigcontext __user *sc)
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{
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#ifdef CONFIG_ALTIVEC
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elf_vrreg_t __user *v_regs;
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#endif
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unsigned long err = 0;
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unsigned long save_r13 = 0;
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unsigned long msr;
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#ifdef CONFIG_VSX
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int i;
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#endif
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/* If this is not a signal return, we preserve the TLS in r13 */
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if (!sig)
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save_r13 = regs->gpr[13];
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/* copy the GPRs */
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err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
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err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]);
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/* get MSR separately, transfer the LE bit if doing signal return */
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err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
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if (sig)
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regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
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err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
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err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
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err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
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err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
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err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
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/* skip SOFTE */
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err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
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err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
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err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
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err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
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if (!sig)
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regs->gpr[13] = save_r13;
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if (set != NULL)
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err |= __get_user(set->sig[0], &sc->oldmask);
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/*
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* Do this before updating the thread state in
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* current->thread.fpr/vr. That way, if we get preempted
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* and another task grabs the FPU/Altivec, it won't be
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* tempted to save the current CPU state into the thread_struct
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* and corrupt what we are writing there.
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*/
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discard_lazy_cpu_state();
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/*
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* Force reload of FP/VEC.
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* This has to be done before copying stuff into current->thread.fpr/vr
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* for the reasons explained in the previous comment.
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*/
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regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
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#ifdef CONFIG_ALTIVEC
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err |= __get_user(v_regs, &sc->v_regs);
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if (err)
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return err;
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if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
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return -EFAULT;
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/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
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if (v_regs != 0 && (msr & MSR_VEC) != 0)
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err |= __copy_from_user(current->thread.vr, v_regs,
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33 * sizeof(vector128));
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else if (current->thread.used_vr)
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memset(current->thread.vr, 0, 33 * sizeof(vector128));
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/* Always get VRSAVE back */
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if (v_regs != 0)
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err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
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else
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current->thread.vrsave = 0;
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#endif /* CONFIG_ALTIVEC */
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/* restore floating point */
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err |= copy_fpr_from_user(current, &sc->fp_regs);
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#ifdef CONFIG_VSX
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/*
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* Get additional VSX data. Update v_regs to point after the
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* VMX data. Copy VSX low doubleword from userspace to local
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* buffer for formatting, then into the taskstruct.
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*/
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v_regs += ELF_NVRREG;
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if ((msr & MSR_VSX) != 0)
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err |= copy_vsx_from_user(current, v_regs);
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else
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for (i = 0; i < 32 ; i++)
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current->thread.fpr[i][TS_VSRLOWOFFSET] = 0;
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#endif
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return err;
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}
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/*
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* Setup the trampoline code on the stack
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*/
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static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
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{
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int i;
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long err = 0;
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/* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */
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err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
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/* li r0, __NR_[rt_]sigreturn| */
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err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
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/* sc */
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err |= __put_user(0x44000002UL, &tramp[2]);
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/* Minimal traceback info */
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for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
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err |= __put_user(0, &tramp[i]);
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if (!err)
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flush_icache_range((unsigned long) &tramp[0],
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(unsigned long) &tramp[TRAMP_SIZE]);
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return err;
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}
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/*
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* Userspace code may pass a ucontext which doesn't include VSX added
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* at the end. We need to check for this case.
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*/
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#define UCONTEXTSIZEWITHOUTVSX \
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(sizeof(struct ucontext) - 32*sizeof(long))
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/*
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* Handle {get,set,swap}_context operations
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*/
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int sys_swapcontext(struct ucontext __user *old_ctx,
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struct ucontext __user *new_ctx,
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long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
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{
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unsigned char tmp;
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sigset_t set;
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unsigned long new_msr = 0;
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int ctx_has_vsx_region = 0;
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if (new_ctx &&
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get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
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return -EFAULT;
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/*
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* Check that the context is not smaller than the original
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* size (with VMX but without VSX)
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*/
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if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
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return -EINVAL;
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/*
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* If the new context state sets the MSR VSX bits but
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* it doesn't provide VSX state.
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*/
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if ((ctx_size < sizeof(struct ucontext)) &&
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(new_msr & MSR_VSX))
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return -EINVAL;
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/* Does the context have enough room to store VSX data? */
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if (ctx_size >= sizeof(struct ucontext))
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ctx_has_vsx_region = 1;
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if (old_ctx != NULL) {
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if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
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|| setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0,
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ctx_has_vsx_region)
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|| __copy_to_user(&old_ctx->uc_sigmask,
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¤t->blocked, sizeof(sigset_t)))
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return -EFAULT;
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}
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if (new_ctx == NULL)
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return 0;
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if (!access_ok(VERIFY_READ, new_ctx, ctx_size)
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|| __get_user(tmp, (u8 __user *) new_ctx)
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|| __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
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return -EFAULT;
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/*
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* If we get a fault copying the context into the kernel's
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* image of the user's registers, we can't just return -EFAULT
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* because the user's registers will be corrupted. For instance
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* the NIP value may have been updated but not some of the
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* other registers. Given that we have done the access_ok
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* and successfully read the first and last bytes of the region
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* above, this should only happen in an out-of-memory situation
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* or if another thread unmaps the region containing the context.
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* We kill the task with a SIGSEGV in this situation.
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*/
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if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
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do_exit(SIGSEGV);
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restore_sigmask(&set);
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if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
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do_exit(SIGSEGV);
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/* This returns like rt_sigreturn */
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set_thread_flag(TIF_RESTOREALL);
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return 0;
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}
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/*
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* Do a signal return; undo the signal stack.
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*/
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int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
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unsigned long r6, unsigned long r7, unsigned long r8,
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struct pt_regs *regs)
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{
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struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
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sigset_t set;
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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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if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
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goto badframe;
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if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
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goto badframe;
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restore_sigmask(&set);
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if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
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goto badframe;
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/* do_sigaltstack expects a __user pointer and won't modify
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* what's in there anyway
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*/
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do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);
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set_thread_flag(TIF_RESTOREALL);
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return 0;
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badframe:
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#if DEBUG_SIG
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printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
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regs, uc, &uc->uc_mcontext);
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#endif
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if (show_unhandled_signals && printk_ratelimit())
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printk(regs->msr & MSR_SF ? fmt64 : fmt32,
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current->comm, current->pid, "rt_sigreturn",
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(long)uc, regs->nip, regs->link);
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force_sig(SIGSEGV, current);
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return 0;
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}
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int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info,
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sigset_t *set, struct pt_regs *regs)
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{
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/* Handler is *really* a pointer to the function descriptor for
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* the signal routine. The first entry in the function
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* descriptor is the entry address of signal and the second
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* entry is the TOC value we need to use.
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*/
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func_descr_t __user *funct_desc_ptr;
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struct rt_sigframe __user *frame;
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unsigned long newsp = 0;
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long err = 0;
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frame = get_sigframe(ka, regs, sizeof(*frame), 0);
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if (unlikely(frame == NULL))
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goto badframe;
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err |= __put_user(&frame->info, &frame->pinfo);
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err |= __put_user(&frame->uc, &frame->puc);
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err |= copy_siginfo_to_user(&frame->info, info);
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if (err)
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goto badframe;
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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 |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
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err |= __put_user(sas_ss_flags(regs->gpr[1]),
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&frame->uc.uc_stack.ss_flags);
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err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
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err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL,
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(unsigned long)ka->sa.sa_handler, 1);
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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 badframe;
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/* Make sure signal handler doesn't get spurious FP exceptions */
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current->thread.fpscr.val = 0;
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/* Set up to return from userspace. */
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if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
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regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp;
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} else {
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err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
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if (err)
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goto badframe;
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regs->link = (unsigned long) &frame->tramp[0];
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}
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funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;
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/* Allocate a dummy caller frame for the signal handler. */
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newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
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err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
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/* Set up "regs" so we "return" to the signal handler. */
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err |= get_user(regs->nip, &funct_desc_ptr->entry);
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/* enter the signal handler in big-endian mode */
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regs->msr &= ~MSR_LE;
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regs->gpr[1] = newsp;
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err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
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regs->gpr[3] = signr;
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regs->result = 0;
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if (ka->sa.sa_flags & SA_SIGINFO) {
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err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
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err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
|
|
regs->gpr[6] = (unsigned long) frame;
|
|
} else {
|
|
regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
|
|
}
|
|
if (err)
|
|
goto badframe;
|
|
|
|
return 1;
|
|
|
|
badframe:
|
|
#if DEBUG_SIG
|
|
printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
|
|
regs, frame, newsp);
|
|
#endif
|
|
if (show_unhandled_signals && printk_ratelimit())
|
|
printk(regs->msr & MSR_SF ? fmt64 : fmt32,
|
|
current->comm, current->pid, "setup_rt_frame",
|
|
(long)frame, regs->nip, regs->link);
|
|
|
|
force_sigsegv(signr, current);
|
|
return 0;
|
|
}
|