978 lines
30 KiB
C
978 lines
30 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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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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#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/ratelimit.h>
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#include <linux/syscalls.h>
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#include <linux/pagemap.h>
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#include <asm/sigcontext.h>
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#include <asm/ucontext.h>
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#include <linux/uaccess.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 <asm/switch_to.h>
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#include <asm/tm.h>
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#include <asm/asm-prototypes.h>
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#include "signal.h"
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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 4
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#define TRAMP_SIZE 7
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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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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
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struct ucontext uc_transact;
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#endif
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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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/* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
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char abigap[USER_REDZONE_SIZE];
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} __attribute__ ((aligned (16)));
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unsigned long get_min_sigframe_size_64(void)
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{
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return sizeof(struct rt_sigframe) + __SIGNAL_FRAMESIZE;
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}
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/*
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* This computes a quad word aligned pointer inside the vmx_reserve array
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* element. For historical reasons sigcontext might not be quad word aligned,
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* but the location we write the VMX regs to must be. See the comment in
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* sigcontext for more detail.
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*/
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#ifdef CONFIG_ALTIVEC
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static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
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{
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return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
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}
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#endif
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static void prepare_setup_sigcontext(struct task_struct *tsk)
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{
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#ifdef CONFIG_ALTIVEC
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/* save altivec registers */
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if (tsk->thread.used_vr)
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flush_altivec_to_thread(tsk);
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if (cpu_has_feature(CPU_FTR_ALTIVEC))
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tsk->thread.vrsave = mfspr(SPRN_VRSAVE);
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#endif /* CONFIG_ALTIVEC */
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flush_fp_to_thread(tsk);
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#ifdef CONFIG_VSX
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if (tsk->thread.used_vsr)
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flush_vsx_to_thread(tsk);
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#endif /* CONFIG_VSX */
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}
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/*
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* Set up the sigcontext for the signal frame.
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*/
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#define unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region, label)\
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do { \
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if (__unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region))\
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goto label; \
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} while (0)
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static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc,
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struct task_struct *tsk, int signr, sigset_t *set,
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unsigned long handler, 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 whether 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 = sigcontext_vmx_regs(sc);
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#endif
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struct pt_regs *regs = tsk->thread.regs;
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unsigned long msr = regs->msr;
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/* Force usr to always see softe as 1 (interrupts enabled) */
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unsigned long softe = 0x1;
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BUG_ON(tsk != current);
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#ifdef CONFIG_ALTIVEC
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unsafe_put_user(v_regs, &sc->v_regs, efault_out);
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/* save altivec registers */
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if (tsk->thread.used_vr) {
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/* Copy 33 vec registers (vr0..31 and vscr) to the stack */
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unsafe_copy_to_user(v_regs, &tsk->thread.vr_state,
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33 * sizeof(vector128), efault_out);
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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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unsafe_put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out);
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#else /* CONFIG_ALTIVEC */
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unsafe_put_user(0, &sc->v_regs, efault_out);
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#endif /* CONFIG_ALTIVEC */
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/* copy fpr regs and fpscr */
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unsafe_copy_fpr_to_user(&sc->fp_regs, tsk, efault_out);
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/*
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* Clear the MSR VSX bit to indicate there is no valid state attached
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* to this context, except in the specific case below where we set it.
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*/
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msr &= ~MSR_VSX;
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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 (tsk->thread.used_vsr && ctx_has_vsx_region) {
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v_regs += ELF_NVRREG;
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unsafe_copy_vsx_to_user(v_regs, tsk, efault_out);
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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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unsafe_put_user(&sc->gp_regs, &sc->regs, efault_out);
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unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out);
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unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out);
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unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out);
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unsafe_put_user(signr, &sc->signal, efault_out);
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unsafe_put_user(handler, &sc->handler, efault_out);
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if (set != NULL)
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unsafe_put_user(set->sig[0], &sc->oldmask, efault_out);
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return 0;
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efault_out:
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return -EFAULT;
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}
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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
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/*
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* As above, but Transactional Memory is in use, so deliver sigcontexts
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* containing checkpointed and transactional register states.
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*
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* To do this, we treclaim (done before entering here) to gather both sets of
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* registers and set up the 'normal' sigcontext registers with rolled-back
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* register values such that a simple signal handler sees a correct
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* checkpointed register state. If interested, a TM-aware sighandler can
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* examine the transactional registers in the 2nd sigcontext to determine the
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* real origin of the signal.
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*/
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static long setup_tm_sigcontexts(struct sigcontext __user *sc,
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struct sigcontext __user *tm_sc,
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struct task_struct *tsk,
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int signr, sigset_t *set, unsigned long handler,
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unsigned long msr)
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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 = sigcontext_vmx_regs(sc);
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elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
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#endif
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struct pt_regs *regs = tsk->thread.regs;
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long err = 0;
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BUG_ON(tsk != current);
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BUG_ON(!MSR_TM_ACTIVE(msr));
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WARN_ON(tm_suspend_disabled);
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/* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as
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* it contains the correct FP, VEC, VSX state after we treclaimed
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* the transaction and giveup_all() was called on reclaiming.
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*/
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msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX);
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#ifdef CONFIG_ALTIVEC
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err |= __put_user(v_regs, &sc->v_regs);
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err |= __put_user(tm_v_regs, &tm_sc->v_regs);
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/* save altivec registers */
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if (tsk->thread.used_vr) {
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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, &tsk->thread.ckvr_state,
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33 * sizeof(vector128));
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/* If VEC was enabled there are transactional VRs valid too,
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* else they're a copy of the checkpointed VRs.
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*/
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if (msr & MSR_VEC)
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err |= __copy_to_user(tm_v_regs,
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&tsk->thread.vr_state,
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33 * sizeof(vector128));
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else
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err |= __copy_to_user(tm_v_regs,
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&tsk->thread.ckvr_state,
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33 * sizeof(vector128));
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/* set MSR_VEC in the MSR value in the frame to indicate
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* that sc->v_reg 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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if (cpu_has_feature(CPU_FTR_ALTIVEC))
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tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE);
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err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]);
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if (msr & MSR_VEC)
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err |= __put_user(tsk->thread.vrsave,
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(u32 __user *)&tm_v_regs[33]);
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else
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err |= __put_user(tsk->thread.ckvrsave,
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(u32 __user *)&tm_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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err |= __put_user(0, &tm_sc->v_regs);
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#endif /* CONFIG_ALTIVEC */
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/* copy fpr regs and fpscr */
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err |= copy_ckfpr_to_user(&sc->fp_regs, tsk);
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if (msr & MSR_FP)
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err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk);
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else
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err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk);
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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 (tsk->thread.used_vsr) {
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v_regs += ELF_NVRREG;
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tm_v_regs += ELF_NVRREG;
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err |= copy_ckvsx_to_user(v_regs, tsk);
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if (msr & MSR_VSX)
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err |= copy_vsx_to_user(tm_v_regs, tsk);
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else
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err |= copy_ckvsx_to_user(tm_v_regs, tsk);
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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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err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
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err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
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err |= __copy_to_user(&sc->gp_regs,
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&tsk->thread.ckpt_regs, GP_REGS_SIZE);
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err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
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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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#endif
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/*
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* Restore the sigcontext from the signal frame.
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*/
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#define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do { \
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if (__unsafe_restore_sigcontext(tsk, set, sig, sc)) \
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goto label; \
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} while (0)
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static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set,
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int sig, 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 save_r13 = 0;
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unsigned long msr;
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struct pt_regs *regs = tsk->thread.regs;
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#ifdef CONFIG_VSX
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int i;
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#endif
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BUG_ON(tsk != current);
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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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unsafe_copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr), efault_out);
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unsafe_get_user(regs->nip, &sc->gp_regs[PT_NIP], efault_out);
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/* get MSR separately, transfer the LE bit if doing signal return */
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unsafe_get_user(msr, &sc->gp_regs[PT_MSR], efault_out);
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if (sig)
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regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE));
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unsafe_get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3], efault_out);
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unsafe_get_user(regs->ctr, &sc->gp_regs[PT_CTR], efault_out);
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unsafe_get_user(regs->link, &sc->gp_regs[PT_LNK], efault_out);
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unsafe_get_user(regs->xer, &sc->gp_regs[PT_XER], efault_out);
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unsafe_get_user(regs->ccr, &sc->gp_regs[PT_CCR], efault_out);
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/* Don't allow userspace to set SOFTE */
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set_trap_norestart(regs);
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unsafe_get_user(regs->dar, &sc->gp_regs[PT_DAR], efault_out);
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unsafe_get_user(regs->dsisr, &sc->gp_regs[PT_DSISR], efault_out);
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unsafe_get_user(regs->result, &sc->gp_regs[PT_RESULT], efault_out);
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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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unsafe_get_user(set->sig[0], &sc->oldmask, efault_out);
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/*
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* Force reload of FP/VEC/VSX so userspace sees any changes.
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* Clear these bits from the user process' MSR before copying into the
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* thread struct. If we are rescheduled or preempted and another task
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* uses FP/VEC/VSX, and this process has the MSR bits set, then the
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* context switch code will save the current CPU state into the
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* thread_struct - possibly overwriting the data we are updating here.
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*/
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regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX));
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#ifdef CONFIG_ALTIVEC
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unsafe_get_user(v_regs, &sc->v_regs, efault_out);
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if (v_regs && !access_ok(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 != NULL && (msr & MSR_VEC) != 0) {
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unsafe_copy_from_user(&tsk->thread.vr_state, v_regs,
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33 * sizeof(vector128), efault_out);
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tsk->thread.used_vr = true;
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} else if (tsk->thread.used_vr) {
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memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
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}
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/* Always get VRSAVE back */
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if (v_regs != NULL)
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unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out);
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else
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tsk->thread.vrsave = 0;
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if (cpu_has_feature(CPU_FTR_ALTIVEC))
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mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
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#endif /* CONFIG_ALTIVEC */
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/* restore floating point */
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unsafe_copy_fpr_from_user(tsk, &sc->fp_regs, efault_out);
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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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unsafe_copy_vsx_from_user(tsk, v_regs, efault_out);
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tsk->thread.used_vsr = true;
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} else {
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for (i = 0; i < 32 ; i++)
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tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
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}
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#endif
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return 0;
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efault_out:
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return -EFAULT;
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}
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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
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/*
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* Restore the two sigcontexts from the frame of a transactional processes.
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*/
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static long restore_tm_sigcontexts(struct task_struct *tsk,
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struct sigcontext __user *sc,
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struct sigcontext __user *tm_sc)
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{
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#ifdef CONFIG_ALTIVEC
|
|
elf_vrreg_t __user *v_regs, *tm_v_regs;
|
|
#endif
|
|
unsigned long err = 0;
|
|
unsigned long msr;
|
|
struct pt_regs *regs = tsk->thread.regs;
|
|
#ifdef CONFIG_VSX
|
|
int i;
|
|
#endif
|
|
|
|
BUG_ON(tsk != current);
|
|
|
|
if (tm_suspend_disabled)
|
|
return -EINVAL;
|
|
|
|
/* copy the GPRs */
|
|
err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
|
|
err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs,
|
|
sizeof(regs->gpr));
|
|
|
|
/*
|
|
* TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
|
|
* TEXASR was set by the signal delivery reclaim, as was TFIAR.
|
|
* Users doing anything abhorrent like thread-switching w/ signals for
|
|
* TM-Suspended code will have to back TEXASR/TFIAR up themselves.
|
|
* For the case of getting a signal and simply returning from it,
|
|
* we don't need to re-copy them here.
|
|
*/
|
|
err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
|
|
err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
|
|
|
|
/* get MSR separately, transfer the LE bit if doing signal return */
|
|
err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
|
|
/* Don't allow reserved mode. */
|
|
if (MSR_TM_RESV(msr))
|
|
return -EINVAL;
|
|
|
|
/* pull in MSR LE from user context */
|
|
regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE));
|
|
|
|
/* The following non-GPR non-FPR non-VR state is also checkpointed: */
|
|
err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
|
|
err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
|
|
err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
|
|
err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
|
|
err |= __get_user(tsk->thread.ckpt_regs.ctr,
|
|
&sc->gp_regs[PT_CTR]);
|
|
err |= __get_user(tsk->thread.ckpt_regs.link,
|
|
&sc->gp_regs[PT_LNK]);
|
|
err |= __get_user(tsk->thread.ckpt_regs.xer,
|
|
&sc->gp_regs[PT_XER]);
|
|
err |= __get_user(tsk->thread.ckpt_regs.ccr,
|
|
&sc->gp_regs[PT_CCR]);
|
|
/* Don't allow userspace to set SOFTE */
|
|
set_trap_norestart(regs);
|
|
/* These regs are not checkpointed; they can go in 'regs'. */
|
|
err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
|
|
err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
|
|
err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
|
|
|
|
/*
|
|
* Force reload of FP/VEC.
|
|
* This has to be done before copying stuff into tsk->thread.fpr/vr
|
|
* for the reasons explained in the previous comment.
|
|
*/
|
|
regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX));
|
|
|
|
#ifdef CONFIG_ALTIVEC
|
|
err |= __get_user(v_regs, &sc->v_regs);
|
|
err |= __get_user(tm_v_regs, &tm_sc->v_regs);
|
|
if (err)
|
|
return err;
|
|
if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
|
|
return -EFAULT;
|
|
if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128)))
|
|
return -EFAULT;
|
|
/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
|
|
if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
|
|
err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs,
|
|
33 * sizeof(vector128));
|
|
err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs,
|
|
33 * sizeof(vector128));
|
|
current->thread.used_vr = true;
|
|
}
|
|
else if (tsk->thread.used_vr) {
|
|
memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
|
|
memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128));
|
|
}
|
|
/* Always get VRSAVE back */
|
|
if (v_regs != NULL && tm_v_regs != NULL) {
|
|
err |= __get_user(tsk->thread.ckvrsave,
|
|
(u32 __user *)&v_regs[33]);
|
|
err |= __get_user(tsk->thread.vrsave,
|
|
(u32 __user *)&tm_v_regs[33]);
|
|
}
|
|
else {
|
|
tsk->thread.vrsave = 0;
|
|
tsk->thread.ckvrsave = 0;
|
|
}
|
|
if (cpu_has_feature(CPU_FTR_ALTIVEC))
|
|
mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
|
|
#endif /* CONFIG_ALTIVEC */
|
|
/* restore floating point */
|
|
err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs);
|
|
err |= copy_ckfpr_from_user(tsk, &sc->fp_regs);
|
|
#ifdef CONFIG_VSX
|
|
/*
|
|
* Get additional VSX data. Update v_regs to point after the
|
|
* VMX data. Copy VSX low doubleword from userspace to local
|
|
* buffer for formatting, then into the taskstruct.
|
|
*/
|
|
if (v_regs && ((msr & MSR_VSX) != 0)) {
|
|
v_regs += ELF_NVRREG;
|
|
tm_v_regs += ELF_NVRREG;
|
|
err |= copy_vsx_from_user(tsk, tm_v_regs);
|
|
err |= copy_ckvsx_from_user(tsk, v_regs);
|
|
tsk->thread.used_vsr = true;
|
|
} else {
|
|
for (i = 0; i < 32 ; i++) {
|
|
tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
|
|
tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
|
|
}
|
|
}
|
|
#endif
|
|
tm_enable();
|
|
/* Make sure the transaction is marked as failed */
|
|
tsk->thread.tm_texasr |= TEXASR_FS;
|
|
|
|
/*
|
|
* Disabling preemption, since it is unsafe to be preempted
|
|
* with MSR[TS] set without recheckpointing.
|
|
*/
|
|
preempt_disable();
|
|
|
|
/* pull in MSR TS bits from user context */
|
|
regs_set_return_msr(regs, regs->msr | (msr & MSR_TS_MASK));
|
|
|
|
/*
|
|
* Ensure that TM is enabled in regs->msr before we leave the signal
|
|
* handler. It could be the case that (a) user disabled the TM bit
|
|
* through the manipulation of the MSR bits in uc_mcontext or (b) the
|
|
* TM bit was disabled because a sufficient number of context switches
|
|
* happened whilst in the signal handler and load_tm overflowed,
|
|
* disabling the TM bit. In either case we can end up with an illegal
|
|
* TM state leading to a TM Bad Thing when we return to userspace.
|
|
*
|
|
* CAUTION:
|
|
* After regs->MSR[TS] being updated, make sure that get_user(),
|
|
* put_user() or similar functions are *not* called. These
|
|
* functions can generate page faults which will cause the process
|
|
* to be de-scheduled with MSR[TS] set but without calling
|
|
* tm_recheckpoint(). This can cause a bug.
|
|
*/
|
|
regs_set_return_msr(regs, regs->msr | MSR_TM);
|
|
|
|
/* This loads the checkpointed FP/VEC state, if used */
|
|
tm_recheckpoint(&tsk->thread);
|
|
|
|
msr_check_and_set(msr & (MSR_FP | MSR_VEC));
|
|
if (msr & MSR_FP) {
|
|
load_fp_state(&tsk->thread.fp_state);
|
|
regs_set_return_msr(regs, regs->msr | (MSR_FP | tsk->thread.fpexc_mode));
|
|
}
|
|
if (msr & MSR_VEC) {
|
|
load_vr_state(&tsk->thread.vr_state);
|
|
regs_set_return_msr(regs, regs->msr | MSR_VEC);
|
|
}
|
|
|
|
preempt_enable();
|
|
|
|
return err;
|
|
}
|
|
#else /* !CONFIG_PPC_TRANSACTIONAL_MEM */
|
|
static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc,
|
|
struct sigcontext __user *tm_sc)
|
|
{
|
|
return -EINVAL;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Setup the trampoline code on the stack
|
|
*/
|
|
static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
|
|
{
|
|
int i;
|
|
long err = 0;
|
|
|
|
/* Call the handler and pop the dummy stackframe*/
|
|
err |= __put_user(PPC_RAW_BCTRL(), &tramp[0]);
|
|
err |= __put_user(PPC_RAW_ADDI(_R1, _R1, __SIGNAL_FRAMESIZE), &tramp[1]);
|
|
|
|
err |= __put_user(PPC_RAW_LI(_R0, syscall), &tramp[2]);
|
|
err |= __put_user(PPC_RAW_SC(), &tramp[3]);
|
|
|
|
/* Minimal traceback info */
|
|
for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
|
|
err |= __put_user(0, &tramp[i]);
|
|
|
|
if (!err)
|
|
flush_icache_range((unsigned long) &tramp[0],
|
|
(unsigned long) &tramp[TRAMP_SIZE]);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Userspace code may pass a ucontext which doesn't include VSX added
|
|
* at the end. We need to check for this case.
|
|
*/
|
|
#define UCONTEXTSIZEWITHOUTVSX \
|
|
(sizeof(struct ucontext) - 32*sizeof(long))
|
|
|
|
/*
|
|
* Handle {get,set,swap}_context operations
|
|
*/
|
|
SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
|
|
struct ucontext __user *, new_ctx, long, ctx_size)
|
|
{
|
|
sigset_t set;
|
|
unsigned long new_msr = 0;
|
|
int ctx_has_vsx_region = 0;
|
|
|
|
if (new_ctx &&
|
|
get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
|
|
return -EFAULT;
|
|
/*
|
|
* Check that the context is not smaller than the original
|
|
* size (with VMX but without VSX)
|
|
*/
|
|
if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
|
|
return -EINVAL;
|
|
/*
|
|
* If the new context state sets the MSR VSX bits but
|
|
* it doesn't provide VSX state.
|
|
*/
|
|
if ((ctx_size < sizeof(struct ucontext)) &&
|
|
(new_msr & MSR_VSX))
|
|
return -EINVAL;
|
|
/* Does the context have enough room to store VSX data? */
|
|
if (ctx_size >= sizeof(struct ucontext))
|
|
ctx_has_vsx_region = 1;
|
|
|
|
if (old_ctx != NULL) {
|
|
prepare_setup_sigcontext(current);
|
|
if (!user_write_access_begin(old_ctx, ctx_size))
|
|
return -EFAULT;
|
|
|
|
unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL,
|
|
0, ctx_has_vsx_region, efault_out);
|
|
unsafe_copy_to_user(&old_ctx->uc_sigmask, ¤t->blocked,
|
|
sizeof(sigset_t), efault_out);
|
|
|
|
user_write_access_end();
|
|
}
|
|
if (new_ctx == NULL)
|
|
return 0;
|
|
if (!access_ok(new_ctx, ctx_size) ||
|
|
fault_in_readable((char __user *)new_ctx, ctx_size))
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* If we get a fault copying the context into the kernel's
|
|
* image of the user's registers, we can't just return -EFAULT
|
|
* because the user's registers will be corrupted. For instance
|
|
* the NIP value may have been updated but not some of the
|
|
* other registers. Given that we have done the access_ok
|
|
* and successfully read the first and last bytes of the region
|
|
* above, this should only happen in an out-of-memory situation
|
|
* or if another thread unmaps the region containing the context.
|
|
* We kill the task with a SIGSEGV in this situation.
|
|
*/
|
|
|
|
if (__get_user_sigset(&set, &new_ctx->uc_sigmask)) {
|
|
force_exit_sig(SIGSEGV);
|
|
return -EFAULT;
|
|
}
|
|
set_current_blocked(&set);
|
|
|
|
if (!user_read_access_begin(new_ctx, ctx_size))
|
|
return -EFAULT;
|
|
if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) {
|
|
user_read_access_end();
|
|
force_exit_sig(SIGSEGV);
|
|
return -EFAULT;
|
|
}
|
|
user_read_access_end();
|
|
|
|
/* This returns like rt_sigreturn */
|
|
set_thread_flag(TIF_RESTOREALL);
|
|
|
|
return 0;
|
|
|
|
efault_out:
|
|
user_write_access_end();
|
|
return -EFAULT;
|
|
}
|
|
|
|
|
|
/*
|
|
* Do a signal return; undo the signal stack.
|
|
*/
|
|
|
|
SYSCALL_DEFINE0(rt_sigreturn)
|
|
{
|
|
struct pt_regs *regs = current_pt_regs();
|
|
struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
|
|
sigset_t set;
|
|
unsigned long msr;
|
|
|
|
/* Always make any pending restarted system calls return -EINTR */
|
|
current->restart_block.fn = do_no_restart_syscall;
|
|
|
|
if (!access_ok(uc, sizeof(*uc)))
|
|
goto badframe;
|
|
|
|
if (__get_user_sigset(&set, &uc->uc_sigmask))
|
|
goto badframe;
|
|
set_current_blocked(&set);
|
|
|
|
if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) {
|
|
/*
|
|
* If there is a transactional state then throw it away.
|
|
* The purpose of a sigreturn is to destroy all traces of the
|
|
* signal frame, this includes any transactional state created
|
|
* within in. We only check for suspended as we can never be
|
|
* active in the kernel, we are active, there is nothing better to
|
|
* do than go ahead and Bad Thing later.
|
|
* The cause is not important as there will never be a
|
|
* recheckpoint so it's not user visible.
|
|
*/
|
|
if (MSR_TM_SUSPENDED(mfmsr()))
|
|
tm_reclaim_current(0);
|
|
|
|
/*
|
|
* Disable MSR[TS] bit also, so, if there is an exception in the
|
|
* code below (as a page fault in copy_ckvsx_to_user()), it does
|
|
* not recheckpoint this task if there was a context switch inside
|
|
* the exception.
|
|
*
|
|
* A major page fault can indirectly call schedule(). A reschedule
|
|
* process in the middle of an exception can have a side effect
|
|
* (Changing the CPU MSR[TS] state), since schedule() is called
|
|
* with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
|
|
* (switch_to() calls tm_recheckpoint() for the 'new' process). In
|
|
* this case, the process continues to be the same in the CPU, but
|
|
* the CPU state just changed.
|
|
*
|
|
* This can cause a TM Bad Thing, since the MSR in the stack will
|
|
* have the MSR[TS]=0, and this is what will be used to RFID.
|
|
*
|
|
* Clearing MSR[TS] state here will avoid a recheckpoint if there
|
|
* is any process reschedule in kernel space. The MSR[TS] state
|
|
* does not need to be saved also, since it will be replaced with
|
|
* the MSR[TS] that came from user context later, at
|
|
* restore_tm_sigcontexts.
|
|
*/
|
|
regs_set_return_msr(regs, regs->msr & ~MSR_TS_MASK);
|
|
|
|
if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
|
|
goto badframe;
|
|
}
|
|
|
|
if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) {
|
|
/* We recheckpoint on return. */
|
|
struct ucontext __user *uc_transact;
|
|
|
|
/* Trying to start TM on non TM system */
|
|
if (!cpu_has_feature(CPU_FTR_TM))
|
|
goto badframe;
|
|
|
|
if (__get_user(uc_transact, &uc->uc_link))
|
|
goto badframe;
|
|
if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
|
|
&uc_transact->uc_mcontext))
|
|
goto badframe;
|
|
} else {
|
|
/*
|
|
* Fall through, for non-TM restore
|
|
*
|
|
* Unset MSR[TS] on the thread regs since MSR from user
|
|
* context does not have MSR active, and recheckpoint was
|
|
* not called since restore_tm_sigcontexts() was not called
|
|
* also.
|
|
*
|
|
* If not unsetting it, the code can RFID to userspace with
|
|
* MSR[TS] set, but without CPU in the proper state,
|
|
* causing a TM bad thing.
|
|
*/
|
|
regs_set_return_msr(current->thread.regs,
|
|
current->thread.regs->msr & ~MSR_TS_MASK);
|
|
if (!user_read_access_begin(&uc->uc_mcontext, sizeof(uc->uc_mcontext)))
|
|
goto badframe;
|
|
|
|
unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext,
|
|
badframe_block);
|
|
|
|
user_read_access_end();
|
|
}
|
|
|
|
if (restore_altstack(&uc->uc_stack))
|
|
goto badframe;
|
|
|
|
set_thread_flag(TIF_RESTOREALL);
|
|
|
|
return 0;
|
|
|
|
badframe_block:
|
|
user_read_access_end();
|
|
badframe:
|
|
signal_fault(current, regs, "rt_sigreturn", uc);
|
|
|
|
force_sig(SIGSEGV);
|
|
return 0;
|
|
}
|
|
|
|
int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
|
|
struct task_struct *tsk)
|
|
{
|
|
struct rt_sigframe __user *frame;
|
|
unsigned long newsp = 0;
|
|
long err = 0;
|
|
struct pt_regs *regs = tsk->thread.regs;
|
|
/* Save the thread's msr before get_tm_stackpointer() changes it */
|
|
unsigned long msr = regs->msr;
|
|
|
|
frame = get_sigframe(ksig, tsk, sizeof(*frame), 0);
|
|
|
|
/*
|
|
* This only applies when calling unsafe_setup_sigcontext() and must be
|
|
* called before opening the uaccess window.
|
|
*/
|
|
if (!MSR_TM_ACTIVE(msr))
|
|
prepare_setup_sigcontext(tsk);
|
|
|
|
if (!user_write_access_begin(frame, sizeof(*frame)))
|
|
goto badframe;
|
|
|
|
unsafe_put_user(&frame->info, &frame->pinfo, badframe_block);
|
|
unsafe_put_user(&frame->uc, &frame->puc, badframe_block);
|
|
|
|
/* Create the ucontext. */
|
|
unsafe_put_user(0, &frame->uc.uc_flags, badframe_block);
|
|
unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], badframe_block);
|
|
|
|
if (MSR_TM_ACTIVE(msr)) {
|
|
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
|
|
/* The ucontext_t passed to userland points to the second
|
|
* ucontext_t (for transactional state) with its uc_link ptr.
|
|
*/
|
|
unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block);
|
|
|
|
user_write_access_end();
|
|
|
|
err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
|
|
&frame->uc_transact.uc_mcontext,
|
|
tsk, ksig->sig, NULL,
|
|
(unsigned long)ksig->ka.sa.sa_handler,
|
|
msr);
|
|
|
|
if (!user_write_access_begin(&frame->uc.uc_sigmask,
|
|
sizeof(frame->uc.uc_sigmask)))
|
|
goto badframe;
|
|
|
|
#endif
|
|
} else {
|
|
unsafe_put_user(0, &frame->uc.uc_link, badframe_block);
|
|
unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
|
|
NULL, (unsigned long)ksig->ka.sa.sa_handler,
|
|
1, badframe_block);
|
|
}
|
|
|
|
unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block);
|
|
user_write_access_end();
|
|
|
|
/* Save the siginfo outside of the unsafe block. */
|
|
if (copy_siginfo_to_user(&frame->info, &ksig->info))
|
|
goto badframe;
|
|
|
|
/* Make sure signal handler doesn't get spurious FP exceptions */
|
|
tsk->thread.fp_state.fpscr = 0;
|
|
|
|
/* Set up to return from userspace. */
|
|
if (tsk->mm->context.vdso) {
|
|
regs_set_return_ip(regs, VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64));
|
|
} else {
|
|
err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
|
|
if (err)
|
|
goto badframe;
|
|
regs_set_return_ip(regs, (unsigned long) &frame->tramp[0]);
|
|
}
|
|
|
|
/* Allocate a dummy caller frame for the signal handler. */
|
|
newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
|
|
err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
|
|
|
|
/* Set up "regs" so we "return" to the signal handler. */
|
|
if (is_elf2_task()) {
|
|
regs->ctr = (unsigned long) ksig->ka.sa.sa_handler;
|
|
regs->gpr[12] = regs->ctr;
|
|
} else {
|
|
/* Handler is *really* a pointer to the function descriptor for
|
|
* the signal routine. The first entry in the function
|
|
* descriptor is the entry address of signal and the second
|
|
* entry is the TOC value we need to use.
|
|
*/
|
|
struct func_desc __user *ptr =
|
|
(struct func_desc __user *)ksig->ka.sa.sa_handler;
|
|
|
|
err |= get_user(regs->ctr, &ptr->addr);
|
|
err |= get_user(regs->gpr[2], &ptr->toc);
|
|
}
|
|
|
|
/* enter the signal handler in native-endian mode */
|
|
regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (MSR_KERNEL & MSR_LE));
|
|
regs->gpr[1] = newsp;
|
|
regs->gpr[3] = ksig->sig;
|
|
regs->result = 0;
|
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
|
|
regs->gpr[4] = (unsigned long)&frame->info;
|
|
regs->gpr[5] = (unsigned long)&frame->uc;
|
|
regs->gpr[6] = (unsigned long) frame;
|
|
} else {
|
|
regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
|
|
}
|
|
if (err)
|
|
goto badframe;
|
|
|
|
return 0;
|
|
|
|
badframe_block:
|
|
user_write_access_end();
|
|
badframe:
|
|
signal_fault(current, regs, "handle_rt_signal64", frame);
|
|
|
|
return 1;
|
|
}
|