// SPDX-License-Identifier: GPL-2.0-or-later /* * PowerPC version * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) * * Derived from "arch/i386/kernel/signal.c" * Copyright (C) 1991, 1992 Linus Torvalds * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "signal.h" #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs)) #define FP_REGS_SIZE sizeof(elf_fpregset_t) #define TRAMP_TRACEBACK 4 #define TRAMP_SIZE 7 /* * When we have signals to deliver, we set up on the user stack, * going down from the original stack pointer: * 1) a rt_sigframe struct which contains the ucontext * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller * frame for the signal handler. */ struct rt_sigframe { /* sys_rt_sigreturn requires the ucontext be the first field */ struct ucontext uc; #ifdef CONFIG_PPC_TRANSACTIONAL_MEM struct ucontext uc_transact; #endif unsigned long _unused[2]; unsigned int tramp[TRAMP_SIZE]; struct siginfo __user *pinfo; void __user *puc; struct siginfo info; /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */ char abigap[USER_REDZONE_SIZE]; } __attribute__ ((aligned (16))); /* * This computes a quad word aligned pointer inside the vmx_reserve array * element. For historical reasons sigcontext might not be quad word aligned, * but the location we write the VMX regs to must be. See the comment in * sigcontext for more detail. */ #ifdef CONFIG_ALTIVEC static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc) { return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful); } #endif static void prepare_setup_sigcontext(struct task_struct *tsk) { #ifdef CONFIG_ALTIVEC /* save altivec registers */ if (tsk->thread.used_vr) flush_altivec_to_thread(tsk); if (cpu_has_feature(CPU_FTR_ALTIVEC)) tsk->thread.vrsave = mfspr(SPRN_VRSAVE); #endif /* CONFIG_ALTIVEC */ flush_fp_to_thread(tsk); #ifdef CONFIG_VSX if (tsk->thread.used_vsr) flush_vsx_to_thread(tsk); #endif /* CONFIG_VSX */ } /* * Set up the sigcontext for the signal frame. */ #define unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region, label)\ do { \ if (__unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region))\ goto label; \ } while (0) static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc, struct task_struct *tsk, int signr, sigset_t *set, unsigned long handler, int ctx_has_vsx_region) { /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the * process never used altivec yet (MSR_VEC is zero in pt_regs of * the context). This is very important because we must ensure we * don't lose the VRSAVE content that may have been set prior to * the process doing its first vector operation * Userland shall check AT_HWCAP to know whether it can rely on the * v_regs pointer or not */ #ifdef CONFIG_ALTIVEC elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); #endif struct pt_regs *regs = tsk->thread.regs; unsigned long msr = regs->msr; /* Force usr to alway see softe as 1 (interrupts enabled) */ unsigned long softe = 0x1; BUG_ON(tsk != current); #ifdef CONFIG_ALTIVEC unsafe_put_user(v_regs, &sc->v_regs, efault_out); /* save altivec registers */ if (tsk->thread.used_vr) { /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ unsafe_copy_to_user(v_regs, &tsk->thread.vr_state, 33 * sizeof(vector128), efault_out); /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg) * contains valid data. */ msr |= MSR_VEC; } /* We always copy to/from vrsave, it's 0 if we don't have or don't * use altivec. */ unsafe_put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); #else /* CONFIG_ALTIVEC */ unsafe_put_user(0, &sc->v_regs, efault_out); #endif /* CONFIG_ALTIVEC */ /* copy fpr regs and fpscr */ unsafe_copy_fpr_to_user(&sc->fp_regs, tsk, efault_out); /* * Clear the MSR VSX bit to indicate there is no valid state attached * to this context, except in the specific case below where we set it. */ msr &= ~MSR_VSX; #ifdef CONFIG_VSX /* * Copy VSX low doubleword to local buffer for formatting, * then out to userspace. Update v_regs to point after the * VMX data. */ if (tsk->thread.used_vsr && ctx_has_vsx_region) { v_regs += ELF_NVRREG; unsafe_copy_vsx_to_user(v_regs, tsk, efault_out); /* set MSR_VSX in the MSR value in the frame to * indicate that sc->vs_reg) contains valid data. */ msr |= MSR_VSX; } #endif /* CONFIG_VSX */ unsafe_put_user(&sc->gp_regs, &sc->regs, efault_out); WARN_ON(!FULL_REGS(regs)); unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out); unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out); unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out); unsafe_put_user(signr, &sc->signal, efault_out); unsafe_put_user(handler, &sc->handler, efault_out); if (set != NULL) unsafe_put_user(set->sig[0], &sc->oldmask, efault_out); return 0; efault_out: return -EFAULT; } #ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* * As above, but Transactional Memory is in use, so deliver sigcontexts * containing checkpointed and transactional register states. * * To do this, we treclaim (done before entering here) to gather both sets of * registers and set up the 'normal' sigcontext registers with rolled-back * register values such that a simple signal handler sees a correct * checkpointed register state. If interested, a TM-aware sighandler can * examine the transactional registers in the 2nd sigcontext to determine the * real origin of the signal. */ static long setup_tm_sigcontexts(struct sigcontext __user *sc, struct sigcontext __user *tm_sc, struct task_struct *tsk, int signr, sigset_t *set, unsigned long handler, unsigned long msr) { /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the * process never used altivec yet (MSR_VEC is zero in pt_regs of * the context). This is very important because we must ensure we * don't lose the VRSAVE content that may have been set prior to * the process doing its first vector operation * Userland shall check AT_HWCAP to know wether it can rely on the * v_regs pointer or not. */ #ifdef CONFIG_ALTIVEC elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc); #endif struct pt_regs *regs = tsk->thread.regs; long err = 0; BUG_ON(tsk != current); BUG_ON(!MSR_TM_ACTIVE(msr)); WARN_ON(tm_suspend_disabled); /* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as * it contains the correct FP, VEC, VSX state after we treclaimed * the transaction and giveup_all() was called on reclaiming. */ msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX); #ifdef CONFIG_ALTIVEC err |= __put_user(v_regs, &sc->v_regs); err |= __put_user(tm_v_regs, &tm_sc->v_regs); /* save altivec registers */ if (tsk->thread.used_vr) { /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state, 33 * sizeof(vector128)); /* If VEC was enabled there are transactional VRs valid too, * else they're a copy of the checkpointed VRs. */ if (msr & MSR_VEC) err |= __copy_to_user(tm_v_regs, &tsk->thread.vr_state, 33 * sizeof(vector128)); else err |= __copy_to_user(tm_v_regs, &tsk->thread.ckvr_state, 33 * sizeof(vector128)); /* set MSR_VEC in the MSR value in the frame to indicate * that sc->v_reg contains valid data. */ msr |= MSR_VEC; } /* We always copy to/from vrsave, it's 0 if we don't have or don't * use altivec. */ if (cpu_has_feature(CPU_FTR_ALTIVEC)) tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE); err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]); if (msr & MSR_VEC) err |= __put_user(tsk->thread.vrsave, (u32 __user *)&tm_v_regs[33]); else err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&tm_v_regs[33]); #else /* CONFIG_ALTIVEC */ err |= __put_user(0, &sc->v_regs); err |= __put_user(0, &tm_sc->v_regs); #endif /* CONFIG_ALTIVEC */ /* copy fpr regs and fpscr */ err |= copy_ckfpr_to_user(&sc->fp_regs, tsk); if (msr & MSR_FP) err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk); else err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk); #ifdef CONFIG_VSX /* * Copy VSX low doubleword to local buffer for formatting, * then out to userspace. Update v_regs to point after the * VMX data. */ if (tsk->thread.used_vsr) { v_regs += ELF_NVRREG; tm_v_regs += ELF_NVRREG; err |= copy_ckvsx_to_user(v_regs, tsk); if (msr & MSR_VSX) err |= copy_vsx_to_user(tm_v_regs, tsk); else err |= copy_ckvsx_to_user(tm_v_regs, tsk); /* set MSR_VSX in the MSR value in the frame to * indicate that sc->vs_reg) contains valid data. */ msr |= MSR_VSX; } #endif /* CONFIG_VSX */ err |= __put_user(&sc->gp_regs, &sc->regs); err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs); WARN_ON(!FULL_REGS(regs)); err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE); err |= __copy_to_user(&sc->gp_regs, &tsk->thread.ckpt_regs, GP_REGS_SIZE); err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]); err |= __put_user(msr, &sc->gp_regs[PT_MSR]); err |= __put_user(signr, &sc->signal); err |= __put_user(handler, &sc->handler); if (set != NULL) err |= __put_user(set->sig[0], &sc->oldmask); return err; } #endif /* * Restore the sigcontext from the signal frame. */ #define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do { \ if (__unsafe_restore_sigcontext(tsk, set, sig, sc)) \ goto label; \ } while (0) static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig, struct sigcontext __user *sc) { #ifdef CONFIG_ALTIVEC elf_vrreg_t __user *v_regs; #endif unsigned long save_r13 = 0; unsigned long msr; struct pt_regs *regs = tsk->thread.regs; #ifdef CONFIG_VSX int i; #endif BUG_ON(tsk != current); /* If this is not a signal return, we preserve the TLS in r13 */ if (!sig) save_r13 = regs->gpr[13]; /* copy the GPRs */ unsafe_copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr), efault_out); unsafe_get_user(regs->nip, &sc->gp_regs[PT_NIP], efault_out); /* get MSR separately, transfer the LE bit if doing signal return */ unsafe_get_user(msr, &sc->gp_regs[PT_MSR], efault_out); if (sig) regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); unsafe_get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3], efault_out); unsafe_get_user(regs->ctr, &sc->gp_regs[PT_CTR], efault_out); unsafe_get_user(regs->link, &sc->gp_regs[PT_LNK], efault_out); unsafe_get_user(regs->xer, &sc->gp_regs[PT_XER], efault_out); unsafe_get_user(regs->ccr, &sc->gp_regs[PT_CCR], efault_out); /* Don't allow userspace to set SOFTE */ set_trap_norestart(regs); unsafe_get_user(regs->dar, &sc->gp_regs[PT_DAR], efault_out); unsafe_get_user(regs->dsisr, &sc->gp_regs[PT_DSISR], efault_out); unsafe_get_user(regs->result, &sc->gp_regs[PT_RESULT], efault_out); if (!sig) regs->gpr[13] = save_r13; if (set != NULL) unsafe_get_user(set->sig[0], &sc->oldmask, efault_out); /* * 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->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX); #ifdef CONFIG_ALTIVEC unsafe_get_user(v_regs, &sc->v_regs, efault_out); if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) return -EFAULT; /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ if (v_regs != NULL && (msr & MSR_VEC) != 0) { unsafe_copy_from_user(&tsk->thread.vr_state, v_regs, 33 * sizeof(vector128), efault_out); tsk->thread.used_vr = true; } else if (tsk->thread.used_vr) { memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); } /* Always get VRSAVE back */ if (v_regs != NULL) unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); else tsk->thread.vrsave = 0; if (cpu_has_feature(CPU_FTR_ALTIVEC)) mtspr(SPRN_VRSAVE, tsk->thread.vrsave); #endif /* CONFIG_ALTIVEC */ /* restore floating point */ unsafe_copy_fpr_from_user(tsk, &sc->fp_regs, efault_out); #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. */ v_regs += ELF_NVRREG; if ((msr & MSR_VSX) != 0) { unsafe_copy_vsx_from_user(tsk, v_regs, efault_out); tsk->thread.used_vsr = true; } else { for (i = 0; i < 32 ; i++) tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; } #endif return 0; efault_out: return -EFAULT; } #ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* * Restore the two sigcontexts from the frame of a transactional processes. */ static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc, struct sigcontext __user *tm_sc) { #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->msr = (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->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->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->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->msr |= (MSR_FP | tsk->thread.fpexc_mode); } if (msr & MSR_VEC) { load_vr_state(&tsk->thread.vr_state); 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; /* bctrl # call the handler */ err |= __put_user(PPC_INST_BCTRL, &tramp[0]); /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */ err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[1]); /* li r0, __NR_[rt_]sigreturn| */ err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[2]); /* sc */ err |= __put_user(PPC_INST_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_pages_readable((u8 __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)) do_exit(SIGSEGV); 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(); do_exit(SIGSEGV); } 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->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. */ 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(); /* 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->nip = VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64); } else { err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); if (err) goto badframe; regs->nip = (unsigned long) &frame->tramp[0]; } /* Save the siginfo outside of the unsafe block. */ if (copy_siginfo_to_user(&frame->info, &ksig->info)) goto badframe; /* 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. */ func_descr_t __user *funct_desc_ptr = (func_descr_t __user *) ksig->ka.sa.sa_handler; err |= get_user(regs->ctr, &funct_desc_ptr->entry); err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); } /* enter the signal handler in native-endian mode */ regs->msr &= ~MSR_LE; regs->msr |= (MSR_KERNEL & MSR_LE); regs->gpr[1] = newsp; regs->gpr[3] = ksig->sig; regs->result = 0; if (ksig->ka.sa.sa_flags & SA_SIGINFO) { err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo); 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 0; badframe_block: user_write_access_end(); badframe: signal_fault(current, regs, "handle_rt_signal64", frame); return 1; }