// SPDX-License-Identifier: GPL-2.0-or-later /* * Derived from "arch/i386/kernel/process.c" * Copyright (C) 1995 Linus Torvalds * * Updated and modified by Cort Dougan (cort@cs.nmt.edu) and * Paul Mackerras (paulus@cs.anu.edu.au) * * PowerPC version * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) */ #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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_PPC64 #include #include #endif #include #include #include #include #include #include #include #include #include /* Transactional Memory debug */ #ifdef TM_DEBUG_SW #define TM_DEBUG(x...) printk(KERN_INFO x) #else #define TM_DEBUG(x...) do { } while(0) #endif extern unsigned long _get_SP(void); #ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* * Are we running in "Suspend disabled" mode? If so we have to block any * sigreturn that would get us into suspended state, and we also warn in some * other paths that we should never reach with suspend disabled. */ bool tm_suspend_disabled __ro_after_init = false; static void check_if_tm_restore_required(struct task_struct *tsk) { /* * If we are saving the current thread's registers, and the * thread is in a transactional state, set the TIF_RESTORE_TM * bit so that we know to restore the registers before * returning to userspace. */ if (tsk == current && tsk->thread.regs && MSR_TM_ACTIVE(tsk->thread.regs->msr) && !test_thread_flag(TIF_RESTORE_TM)) { tsk->thread.ckpt_regs.msr = tsk->thread.regs->msr; set_thread_flag(TIF_RESTORE_TM); } } #else static inline void check_if_tm_restore_required(struct task_struct *tsk) { } #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ bool strict_msr_control; EXPORT_SYMBOL(strict_msr_control); static int __init enable_strict_msr_control(char *str) { strict_msr_control = true; pr_info("Enabling strict facility control\n"); return 0; } early_param("ppc_strict_facility_enable", enable_strict_msr_control); /* notrace because it's called by restore_math */ unsigned long notrace msr_check_and_set(unsigned long bits) { unsigned long oldmsr = mfmsr(); unsigned long newmsr; newmsr = oldmsr | bits; if (cpu_has_feature(CPU_FTR_VSX) && (bits & MSR_FP)) newmsr |= MSR_VSX; if (oldmsr != newmsr) mtmsr_isync(newmsr); return newmsr; } EXPORT_SYMBOL_GPL(msr_check_and_set); /* notrace because it's called by restore_math */ void notrace __msr_check_and_clear(unsigned long bits) { unsigned long oldmsr = mfmsr(); unsigned long newmsr; newmsr = oldmsr & ~bits; if (cpu_has_feature(CPU_FTR_VSX) && (bits & MSR_FP)) newmsr &= ~MSR_VSX; if (oldmsr != newmsr) mtmsr_isync(newmsr); } EXPORT_SYMBOL(__msr_check_and_clear); #ifdef CONFIG_PPC_FPU static void __giveup_fpu(struct task_struct *tsk) { unsigned long msr; save_fpu(tsk); msr = tsk->thread.regs->msr; msr &= ~(MSR_FP|MSR_FE0|MSR_FE1); if (cpu_has_feature(CPU_FTR_VSX)) msr &= ~MSR_VSX; tsk->thread.regs->msr = msr; } void giveup_fpu(struct task_struct *tsk) { check_if_tm_restore_required(tsk); msr_check_and_set(MSR_FP); __giveup_fpu(tsk); msr_check_and_clear(MSR_FP); } EXPORT_SYMBOL(giveup_fpu); /* * Make sure the floating-point register state in the * the thread_struct is up to date for task tsk. */ void flush_fp_to_thread(struct task_struct *tsk) { if (tsk->thread.regs) { /* * We need to disable preemption here because if we didn't, * another process could get scheduled after the regs->msr * test but before we have finished saving the FP registers * to the thread_struct. That process could take over the * FPU, and then when we get scheduled again we would store * bogus values for the remaining FP registers. */ preempt_disable(); if (tsk->thread.regs->msr & MSR_FP) { /* * This should only ever be called for current or * for a stopped child process. Since we save away * the FP register state on context switch, * there is something wrong if a stopped child appears * to still have its FP state in the CPU registers. */ BUG_ON(tsk != current); giveup_fpu(tsk); } preempt_enable(); } } EXPORT_SYMBOL_GPL(flush_fp_to_thread); void enable_kernel_fp(void) { unsigned long cpumsr; WARN_ON(preemptible()); cpumsr = msr_check_and_set(MSR_FP); if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) { check_if_tm_restore_required(current); /* * If a thread has already been reclaimed then the * checkpointed registers are on the CPU but have definitely * been saved by the reclaim code. Don't need to and *cannot* * giveup as this would save to the 'live' structure not the * checkpointed structure. */ if (!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr)) return; __giveup_fpu(current); } } EXPORT_SYMBOL(enable_kernel_fp); #else static inline void __giveup_fpu(struct task_struct *tsk) { } #endif /* CONFIG_PPC_FPU */ #ifdef CONFIG_ALTIVEC static void __giveup_altivec(struct task_struct *tsk) { unsigned long msr; save_altivec(tsk); msr = tsk->thread.regs->msr; msr &= ~MSR_VEC; if (cpu_has_feature(CPU_FTR_VSX)) msr &= ~MSR_VSX; tsk->thread.regs->msr = msr; } void giveup_altivec(struct task_struct *tsk) { check_if_tm_restore_required(tsk); msr_check_and_set(MSR_VEC); __giveup_altivec(tsk); msr_check_and_clear(MSR_VEC); } EXPORT_SYMBOL(giveup_altivec); void enable_kernel_altivec(void) { unsigned long cpumsr; WARN_ON(preemptible()); cpumsr = msr_check_and_set(MSR_VEC); if (current->thread.regs && (current->thread.regs->msr & MSR_VEC)) { check_if_tm_restore_required(current); /* * If a thread has already been reclaimed then the * checkpointed registers are on the CPU but have definitely * been saved by the reclaim code. Don't need to and *cannot* * giveup as this would save to the 'live' structure not the * checkpointed structure. */ if (!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr)) return; __giveup_altivec(current); } } EXPORT_SYMBOL(enable_kernel_altivec); /* * Make sure the VMX/Altivec register state in the * the thread_struct is up to date for task tsk. */ void flush_altivec_to_thread(struct task_struct *tsk) { if (tsk->thread.regs) { preempt_disable(); if (tsk->thread.regs->msr & MSR_VEC) { BUG_ON(tsk != current); giveup_altivec(tsk); } preempt_enable(); } } EXPORT_SYMBOL_GPL(flush_altivec_to_thread); #endif /* CONFIG_ALTIVEC */ #ifdef CONFIG_VSX static void __giveup_vsx(struct task_struct *tsk) { unsigned long msr = tsk->thread.regs->msr; /* * We should never be ssetting MSR_VSX without also setting * MSR_FP and MSR_VEC */ WARN_ON((msr & MSR_VSX) && !((msr & MSR_FP) && (msr & MSR_VEC))); /* __giveup_fpu will clear MSR_VSX */ if (msr & MSR_FP) __giveup_fpu(tsk); if (msr & MSR_VEC) __giveup_altivec(tsk); } static void giveup_vsx(struct task_struct *tsk) { check_if_tm_restore_required(tsk); msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX); __giveup_vsx(tsk); msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX); } void enable_kernel_vsx(void) { unsigned long cpumsr; WARN_ON(preemptible()); cpumsr = msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX); if (current->thread.regs && (current->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP))) { check_if_tm_restore_required(current); /* * If a thread has already been reclaimed then the * checkpointed registers are on the CPU but have definitely * been saved by the reclaim code. Don't need to and *cannot* * giveup as this would save to the 'live' structure not the * checkpointed structure. */ if (!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr)) return; __giveup_vsx(current); } } EXPORT_SYMBOL(enable_kernel_vsx); void flush_vsx_to_thread(struct task_struct *tsk) { if (tsk->thread.regs) { preempt_disable(); if (tsk->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP)) { BUG_ON(tsk != current); giveup_vsx(tsk); } preempt_enable(); } } EXPORT_SYMBOL_GPL(flush_vsx_to_thread); #endif /* CONFIG_VSX */ #ifdef CONFIG_SPE void giveup_spe(struct task_struct *tsk) { check_if_tm_restore_required(tsk); msr_check_and_set(MSR_SPE); __giveup_spe(tsk); msr_check_and_clear(MSR_SPE); } EXPORT_SYMBOL(giveup_spe); void enable_kernel_spe(void) { WARN_ON(preemptible()); msr_check_and_set(MSR_SPE); if (current->thread.regs && (current->thread.regs->msr & MSR_SPE)) { check_if_tm_restore_required(current); __giveup_spe(current); } } EXPORT_SYMBOL(enable_kernel_spe); void flush_spe_to_thread(struct task_struct *tsk) { if (tsk->thread.regs) { preempt_disable(); if (tsk->thread.regs->msr & MSR_SPE) { BUG_ON(tsk != current); tsk->thread.spefscr = mfspr(SPRN_SPEFSCR); giveup_spe(tsk); } preempt_enable(); } } #endif /* CONFIG_SPE */ static unsigned long msr_all_available; static int __init init_msr_all_available(void) { if (IS_ENABLED(CONFIG_PPC_FPU)) msr_all_available |= MSR_FP; if (cpu_has_feature(CPU_FTR_ALTIVEC)) msr_all_available |= MSR_VEC; if (cpu_has_feature(CPU_FTR_VSX)) msr_all_available |= MSR_VSX; if (cpu_has_feature(CPU_FTR_SPE)) msr_all_available |= MSR_SPE; return 0; } early_initcall(init_msr_all_available); void giveup_all(struct task_struct *tsk) { unsigned long usermsr; if (!tsk->thread.regs) return; check_if_tm_restore_required(tsk); usermsr = tsk->thread.regs->msr; if ((usermsr & msr_all_available) == 0) return; msr_check_and_set(msr_all_available); WARN_ON((usermsr & MSR_VSX) && !((usermsr & MSR_FP) && (usermsr & MSR_VEC))); if (usermsr & MSR_FP) __giveup_fpu(tsk); if (usermsr & MSR_VEC) __giveup_altivec(tsk); if (usermsr & MSR_SPE) __giveup_spe(tsk); msr_check_and_clear(msr_all_available); } EXPORT_SYMBOL(giveup_all); #ifdef CONFIG_PPC_BOOK3S_64 #ifdef CONFIG_PPC_FPU static bool should_restore_fp(void) { if (current->thread.load_fp) { current->thread.load_fp++; return true; } return false; } static void do_restore_fp(void) { load_fp_state(¤t->thread.fp_state); } #else static bool should_restore_fp(void) { return false; } static void do_restore_fp(void) { } #endif /* CONFIG_PPC_FPU */ #ifdef CONFIG_ALTIVEC static bool should_restore_altivec(void) { if (cpu_has_feature(CPU_FTR_ALTIVEC) && (current->thread.load_vec)) { current->thread.load_vec++; return true; } return false; } static void do_restore_altivec(void) { load_vr_state(¤t->thread.vr_state); current->thread.used_vr = 1; } #else static bool should_restore_altivec(void) { return false; } static void do_restore_altivec(void) { } #endif /* CONFIG_ALTIVEC */ static bool should_restore_vsx(void) { if (cpu_has_feature(CPU_FTR_VSX)) return true; return false; } #ifdef CONFIG_VSX static void do_restore_vsx(void) { current->thread.used_vsr = 1; } #else static void do_restore_vsx(void) { } #endif /* CONFIG_VSX */ /* * The exception exit path calls restore_math() with interrupts hard disabled * but the soft irq state not "reconciled". ftrace code that calls * local_irq_save/restore causes warnings. * * Rather than complicate the exit path, just don't trace restore_math. This * could be done by having ftrace entry code check for this un-reconciled * condition where MSR[EE]=0 and PACA_IRQ_HARD_DIS is not set, and * temporarily fix it up for the duration of the ftrace call. */ void notrace restore_math(struct pt_regs *regs) { unsigned long msr; unsigned long new_msr = 0; msr = regs->msr; /* * new_msr tracks the facilities that are to be restored. Only reload * if the bit is not set in the user MSR (if it is set, the registers * are live for the user thread). */ if ((!(msr & MSR_FP)) && should_restore_fp()) new_msr |= MSR_FP; if ((!(msr & MSR_VEC)) && should_restore_altivec()) new_msr |= MSR_VEC; if ((!(msr & MSR_VSX)) && should_restore_vsx()) { if (((msr | new_msr) & (MSR_FP | MSR_VEC)) == (MSR_FP | MSR_VEC)) new_msr |= MSR_VSX; } if (new_msr) { unsigned long fpexc_mode = 0; msr_check_and_set(new_msr); if (new_msr & MSR_FP) { do_restore_fp(); // This also covers VSX, because VSX implies FP fpexc_mode = current->thread.fpexc_mode; } if (new_msr & MSR_VEC) do_restore_altivec(); if (new_msr & MSR_VSX) do_restore_vsx(); msr_check_and_clear(new_msr); regs->msr |= new_msr | fpexc_mode; } } #endif /* CONFIG_PPC_BOOK3S_64 */ static void save_all(struct task_struct *tsk) { unsigned long usermsr; if (!tsk->thread.regs) return; usermsr = tsk->thread.regs->msr; if ((usermsr & msr_all_available) == 0) return; msr_check_and_set(msr_all_available); WARN_ON((usermsr & MSR_VSX) && !((usermsr & MSR_FP) && (usermsr & MSR_VEC))); if (usermsr & MSR_FP) save_fpu(tsk); if (usermsr & MSR_VEC) save_altivec(tsk); if (usermsr & MSR_SPE) __giveup_spe(tsk); msr_check_and_clear(msr_all_available); thread_pkey_regs_save(&tsk->thread); } void flush_all_to_thread(struct task_struct *tsk) { if (tsk->thread.regs) { preempt_disable(); BUG_ON(tsk != current); #ifdef CONFIG_SPE if (tsk->thread.regs->msr & MSR_SPE) tsk->thread.spefscr = mfspr(SPRN_SPEFSCR); #endif save_all(tsk); preempt_enable(); } } EXPORT_SYMBOL(flush_all_to_thread); #ifdef CONFIG_PPC_ADV_DEBUG_REGS void do_send_trap(struct pt_regs *regs, unsigned long address, unsigned long error_code, int breakpt) { current->thread.trap_nr = TRAP_HWBKPT; if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code, 11, SIGSEGV) == NOTIFY_STOP) return; /* Deliver the signal to userspace */ force_sig_ptrace_errno_trap(breakpt, /* breakpoint or watchpoint id */ (void __user *)address); } #else /* !CONFIG_PPC_ADV_DEBUG_REGS */ static void do_break_handler(struct pt_regs *regs) { struct arch_hw_breakpoint null_brk = {0}; struct arch_hw_breakpoint *info; struct ppc_inst instr = ppc_inst(0); int type = 0; int size = 0; unsigned long ea; int i; /* * If underneath hw supports only one watchpoint, we know it * caused exception. 8xx also falls into this category. */ if (nr_wp_slots() == 1) { __set_breakpoint(0, &null_brk); current->thread.hw_brk[0] = null_brk; current->thread.hw_brk[0].flags |= HW_BRK_FLAG_DISABLED; return; } /* Otherwise findout which DAWR caused exception and disable it. */ wp_get_instr_detail(regs, &instr, &type, &size, &ea); for (i = 0; i < nr_wp_slots(); i++) { info = ¤t->thread.hw_brk[i]; if (!info->address) continue; if (wp_check_constraints(regs, instr, ea, type, size, info)) { __set_breakpoint(i, &null_brk); current->thread.hw_brk[i] = null_brk; current->thread.hw_brk[i].flags |= HW_BRK_FLAG_DISABLED; } } } void do_break (struct pt_regs *regs, unsigned long address, unsigned long error_code) { current->thread.trap_nr = TRAP_HWBKPT; if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code, 11, SIGSEGV) == NOTIFY_STOP) return; if (debugger_break_match(regs)) return; /* * We reach here only when watchpoint exception is generated by ptrace * event (or hw is buggy!). Now if CONFIG_HAVE_HW_BREAKPOINT is set, * watchpoint is already handled by hw_breakpoint_handler() so we don't * have to do anything. But when CONFIG_HAVE_HW_BREAKPOINT is not set, * we need to manually handle the watchpoint here. */ if (!IS_ENABLED(CONFIG_HAVE_HW_BREAKPOINT)) do_break_handler(regs); /* Deliver the signal to userspace */ force_sig_fault(SIGTRAP, TRAP_HWBKPT, (void __user *)address); } #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk[HBP_NUM_MAX]); #ifdef CONFIG_PPC_ADV_DEBUG_REGS /* * Set the debug registers back to their default "safe" values. */ static void set_debug_reg_defaults(struct thread_struct *thread) { thread->debug.iac1 = thread->debug.iac2 = 0; #if CONFIG_PPC_ADV_DEBUG_IACS > 2 thread->debug.iac3 = thread->debug.iac4 = 0; #endif thread->debug.dac1 = thread->debug.dac2 = 0; #if CONFIG_PPC_ADV_DEBUG_DVCS > 0 thread->debug.dvc1 = thread->debug.dvc2 = 0; #endif thread->debug.dbcr0 = 0; #ifdef CONFIG_BOOKE /* * Force User/Supervisor bits to b11 (user-only MSR[PR]=1) */ thread->debug.dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US | DBCR1_IAC3US | DBCR1_IAC4US; /* * Force Data Address Compare User/Supervisor bits to be User-only * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0. */ thread->debug.dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; #else thread->debug.dbcr1 = 0; #endif } static void prime_debug_regs(struct debug_reg *debug) { /* * We could have inherited MSR_DE from userspace, since * it doesn't get cleared on exception entry. Make sure * MSR_DE is clear before we enable any debug events. */ mtmsr(mfmsr() & ~MSR_DE); mtspr(SPRN_IAC1, debug->iac1); mtspr(SPRN_IAC2, debug->iac2); #if CONFIG_PPC_ADV_DEBUG_IACS > 2 mtspr(SPRN_IAC3, debug->iac3); mtspr(SPRN_IAC4, debug->iac4); #endif mtspr(SPRN_DAC1, debug->dac1); mtspr(SPRN_DAC2, debug->dac2); #if CONFIG_PPC_ADV_DEBUG_DVCS > 0 mtspr(SPRN_DVC1, debug->dvc1); mtspr(SPRN_DVC2, debug->dvc2); #endif mtspr(SPRN_DBCR0, debug->dbcr0); mtspr(SPRN_DBCR1, debug->dbcr1); #ifdef CONFIG_BOOKE mtspr(SPRN_DBCR2, debug->dbcr2); #endif } /* * Unless neither the old or new thread are making use of the * debug registers, set the debug registers from the values * stored in the new thread. */ void switch_booke_debug_regs(struct debug_reg *new_debug) { if ((current->thread.debug.dbcr0 & DBCR0_IDM) || (new_debug->dbcr0 & DBCR0_IDM)) prime_debug_regs(new_debug); } EXPORT_SYMBOL_GPL(switch_booke_debug_regs); #else /* !CONFIG_PPC_ADV_DEBUG_REGS */ #ifndef CONFIG_HAVE_HW_BREAKPOINT static void set_breakpoint(int i, struct arch_hw_breakpoint *brk) { preempt_disable(); __set_breakpoint(i, brk); preempt_enable(); } static void set_debug_reg_defaults(struct thread_struct *thread) { int i; struct arch_hw_breakpoint null_brk = {0}; for (i = 0; i < nr_wp_slots(); i++) { thread->hw_brk[i] = null_brk; if (ppc_breakpoint_available()) set_breakpoint(i, &thread->hw_brk[i]); } } static inline bool hw_brk_match(struct arch_hw_breakpoint *a, struct arch_hw_breakpoint *b) { if (a->address != b->address) return false; if (a->type != b->type) return false; if (a->len != b->len) return false; /* no need to check hw_len. it's calculated from address and len */ return true; } static void switch_hw_breakpoint(struct task_struct *new) { int i; for (i = 0; i < nr_wp_slots(); i++) { if (likely(hw_brk_match(this_cpu_ptr(¤t_brk[i]), &new->thread.hw_brk[i]))) continue; __set_breakpoint(i, &new->thread.hw_brk[i]); } } #endif /* !CONFIG_HAVE_HW_BREAKPOINT */ #endif /* CONFIG_PPC_ADV_DEBUG_REGS */ #ifdef CONFIG_PPC_ADV_DEBUG_REGS static inline int __set_dabr(unsigned long dabr, unsigned long dabrx) { mtspr(SPRN_DAC1, dabr); if (IS_ENABLED(CONFIG_PPC_47x)) isync(); return 0; } #elif defined(CONFIG_PPC_BOOK3S) static inline int __set_dabr(unsigned long dabr, unsigned long dabrx) { mtspr(SPRN_DABR, dabr); if (cpu_has_feature(CPU_FTR_DABRX)) mtspr(SPRN_DABRX, dabrx); return 0; } #else static inline int __set_dabr(unsigned long dabr, unsigned long dabrx) { return -EINVAL; } #endif static inline int set_dabr(struct arch_hw_breakpoint *brk) { unsigned long dabr, dabrx; dabr = brk->address | (brk->type & HW_BRK_TYPE_DABR); dabrx = ((brk->type >> 3) & 0x7); if (ppc_md.set_dabr) return ppc_md.set_dabr(dabr, dabrx); return __set_dabr(dabr, dabrx); } static inline int set_breakpoint_8xx(struct arch_hw_breakpoint *brk) { unsigned long lctrl1 = LCTRL1_CTE_GT | LCTRL1_CTF_LT | LCTRL1_CRWE_RW | LCTRL1_CRWF_RW; unsigned long lctrl2 = LCTRL2_LW0EN | LCTRL2_LW0LADC | LCTRL2_SLW0EN; unsigned long start_addr = ALIGN_DOWN(brk->address, HW_BREAKPOINT_SIZE); unsigned long end_addr = ALIGN(brk->address + brk->len, HW_BREAKPOINT_SIZE); if (start_addr == 0) lctrl2 |= LCTRL2_LW0LA_F; else if (end_addr == 0) lctrl2 |= LCTRL2_LW0LA_E; else lctrl2 |= LCTRL2_LW0LA_EandF; mtspr(SPRN_LCTRL2, 0); if ((brk->type & HW_BRK_TYPE_RDWR) == 0) return 0; if ((brk->type & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_READ) lctrl1 |= LCTRL1_CRWE_RO | LCTRL1_CRWF_RO; if ((brk->type & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_WRITE) lctrl1 |= LCTRL1_CRWE_WO | LCTRL1_CRWF_WO; mtspr(SPRN_CMPE, start_addr - 1); mtspr(SPRN_CMPF, end_addr); mtspr(SPRN_LCTRL1, lctrl1); mtspr(SPRN_LCTRL2, lctrl2); return 0; } void __set_breakpoint(int nr, struct arch_hw_breakpoint *brk) { memcpy(this_cpu_ptr(¤t_brk[nr]), brk, sizeof(*brk)); if (dawr_enabled()) // Power8 or later set_dawr(nr, brk); else if (IS_ENABLED(CONFIG_PPC_8xx)) set_breakpoint_8xx(brk); else if (!cpu_has_feature(CPU_FTR_ARCH_207S)) // Power7 or earlier set_dabr(brk); else // Shouldn't happen due to higher level checks WARN_ON_ONCE(1); } /* Check if we have DAWR or DABR hardware */ bool ppc_breakpoint_available(void) { if (dawr_enabled()) return true; /* POWER8 DAWR or POWER9 forced DAWR */ if (cpu_has_feature(CPU_FTR_ARCH_207S)) return false; /* POWER9 with DAWR disabled */ /* DABR: Everything but POWER8 and POWER9 */ return true; } EXPORT_SYMBOL_GPL(ppc_breakpoint_available); #ifdef CONFIG_PPC_TRANSACTIONAL_MEM static inline bool tm_enabled(struct task_struct *tsk) { return tsk && tsk->thread.regs && (tsk->thread.regs->msr & MSR_TM); } static void tm_reclaim_thread(struct thread_struct *thr, uint8_t cause) { /* * Use the current MSR TM suspended bit to track if we have * checkpointed state outstanding. * On signal delivery, we'd normally reclaim the checkpointed * state to obtain stack pointer (see:get_tm_stackpointer()). * This will then directly return to userspace without going * through __switch_to(). However, if the stack frame is bad, * we need to exit this thread which calls __switch_to() which * will again attempt to reclaim the already saved tm state. * Hence we need to check that we've not already reclaimed * this state. * We do this using the current MSR, rather tracking it in * some specific thread_struct bit, as it has the additional * benefit of checking for a potential TM bad thing exception. */ if (!MSR_TM_SUSPENDED(mfmsr())) return; giveup_all(container_of(thr, struct task_struct, thread)); tm_reclaim(thr, cause); /* * If we are in a transaction and FP is off then we can't have * used FP inside that transaction. Hence the checkpointed * state is the same as the live state. We need to copy the * live state to the checkpointed state so that when the * transaction is restored, the checkpointed state is correct * and the aborted transaction sees the correct state. We use * ckpt_regs.msr here as that's what tm_reclaim will use to * determine if it's going to write the checkpointed state or * not. So either this will write the checkpointed registers, * or reclaim will. Similarly for VMX. */ if ((thr->ckpt_regs.msr & MSR_FP) == 0) memcpy(&thr->ckfp_state, &thr->fp_state, sizeof(struct thread_fp_state)); if ((thr->ckpt_regs.msr & MSR_VEC) == 0) memcpy(&thr->ckvr_state, &thr->vr_state, sizeof(struct thread_vr_state)); } void tm_reclaim_current(uint8_t cause) { tm_enable(); tm_reclaim_thread(¤t->thread, cause); } static inline void tm_reclaim_task(struct task_struct *tsk) { /* We have to work out if we're switching from/to a task that's in the * middle of a transaction. * * In switching we need to maintain a 2nd register state as * oldtask->thread.ckpt_regs. We tm_reclaim(oldproc); this saves the * checkpointed (tbegin) state in ckpt_regs, ckfp_state and * ckvr_state * * We also context switch (save) TFHAR/TEXASR/TFIAR in here. */ struct thread_struct *thr = &tsk->thread; if (!thr->regs) return; if (!MSR_TM_ACTIVE(thr->regs->msr)) goto out_and_saveregs; WARN_ON(tm_suspend_disabled); TM_DEBUG("--- tm_reclaim on pid %d (NIP=%lx, " "ccr=%lx, msr=%lx, trap=%lx)\n", tsk->pid, thr->regs->nip, thr->regs->ccr, thr->regs->msr, thr->regs->trap); tm_reclaim_thread(thr, TM_CAUSE_RESCHED); TM_DEBUG("--- tm_reclaim on pid %d complete\n", tsk->pid); out_and_saveregs: /* Always save the regs here, even if a transaction's not active. * This context-switches a thread's TM info SPRs. We do it here to * be consistent with the restore path (in recheckpoint) which * cannot happen later in _switch(). */ tm_save_sprs(thr); } extern void __tm_recheckpoint(struct thread_struct *thread); void tm_recheckpoint(struct thread_struct *thread) { unsigned long flags; if (!(thread->regs->msr & MSR_TM)) return; /* We really can't be interrupted here as the TEXASR registers can't * change and later in the trecheckpoint code, we have a userspace R1. * So let's hard disable over this region. */ local_irq_save(flags); hard_irq_disable(); /* The TM SPRs are restored here, so that TEXASR.FS can be set * before the trecheckpoint and no explosion occurs. */ tm_restore_sprs(thread); __tm_recheckpoint(thread); local_irq_restore(flags); } static inline void tm_recheckpoint_new_task(struct task_struct *new) { if (!cpu_has_feature(CPU_FTR_TM)) return; /* Recheckpoint the registers of the thread we're about to switch to. * * If the task was using FP, we non-lazily reload both the original and * the speculative FP register states. This is because the kernel * doesn't see if/when a TM rollback occurs, so if we take an FP * unavailable later, we are unable to determine which set of FP regs * need to be restored. */ if (!tm_enabled(new)) return; if (!MSR_TM_ACTIVE(new->thread.regs->msr)){ tm_restore_sprs(&new->thread); return; } /* Recheckpoint to restore original checkpointed register state. */ TM_DEBUG("*** tm_recheckpoint of pid %d (new->msr 0x%lx)\n", new->pid, new->thread.regs->msr); tm_recheckpoint(&new->thread); /* * The checkpointed state has been restored but the live state has * not, ensure all the math functionality is turned off to trigger * restore_math() to reload. */ new->thread.regs->msr &= ~(MSR_FP | MSR_VEC | MSR_VSX); TM_DEBUG("*** tm_recheckpoint of pid %d complete " "(kernel msr 0x%lx)\n", new->pid, mfmsr()); } static inline void __switch_to_tm(struct task_struct *prev, struct task_struct *new) { if (cpu_has_feature(CPU_FTR_TM)) { if (tm_enabled(prev) || tm_enabled(new)) tm_enable(); if (tm_enabled(prev)) { prev->thread.load_tm++; tm_reclaim_task(prev); if (!MSR_TM_ACTIVE(prev->thread.regs->msr) && prev->thread.load_tm == 0) prev->thread.regs->msr &= ~MSR_TM; } tm_recheckpoint_new_task(new); } } /* * This is called if we are on the way out to userspace and the * TIF_RESTORE_TM flag is set. It checks if we need to reload * FP and/or vector state and does so if necessary. * If userspace is inside a transaction (whether active or * suspended) and FP/VMX/VSX instructions have ever been enabled * inside that transaction, then we have to keep them enabled * and keep the FP/VMX/VSX state loaded while ever the transaction * continues. The reason is that if we didn't, and subsequently * got a FP/VMX/VSX unavailable interrupt inside a transaction, * we don't know whether it's the same transaction, and thus we * don't know which of the checkpointed state and the transactional * state to use. */ void restore_tm_state(struct pt_regs *regs) { unsigned long msr_diff; /* * This is the only moment we should clear TIF_RESTORE_TM as * it is here that ckpt_regs.msr and pt_regs.msr become the same * again, anything else could lead to an incorrect ckpt_msr being * saved and therefore incorrect signal contexts. */ clear_thread_flag(TIF_RESTORE_TM); if (!MSR_TM_ACTIVE(regs->msr)) return; msr_diff = current->thread.ckpt_regs.msr & ~regs->msr; msr_diff &= MSR_FP | MSR_VEC | MSR_VSX; /* Ensure that restore_math() will restore */ if (msr_diff & MSR_FP) current->thread.load_fp = 1; #ifdef CONFIG_ALTIVEC if (cpu_has_feature(CPU_FTR_ALTIVEC) && msr_diff & MSR_VEC) current->thread.load_vec = 1; #endif restore_math(regs); regs->msr |= msr_diff; } #else #define tm_recheckpoint_new_task(new) #define __switch_to_tm(prev, new) #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ static inline void save_sprs(struct thread_struct *t) { #ifdef CONFIG_ALTIVEC if (cpu_has_feature(CPU_FTR_ALTIVEC)) t->vrsave = mfspr(SPRN_VRSAVE); #endif #ifdef CONFIG_PPC_BOOK3S_64 if (cpu_has_feature(CPU_FTR_DSCR)) t->dscr = mfspr(SPRN_DSCR); if (cpu_has_feature(CPU_FTR_ARCH_207S)) { t->bescr = mfspr(SPRN_BESCR); t->ebbhr = mfspr(SPRN_EBBHR); t->ebbrr = mfspr(SPRN_EBBRR); t->fscr = mfspr(SPRN_FSCR); /* * Note that the TAR is not available for use in the kernel. * (To provide this, the TAR should be backed up/restored on * exception entry/exit instead, and be in pt_regs. FIXME, * this should be in pt_regs anyway (for debug).) */ t->tar = mfspr(SPRN_TAR); } #endif thread_pkey_regs_save(t); } static inline void restore_sprs(struct thread_struct *old_thread, struct thread_struct *new_thread) { #ifdef CONFIG_ALTIVEC if (cpu_has_feature(CPU_FTR_ALTIVEC) && old_thread->vrsave != new_thread->vrsave) mtspr(SPRN_VRSAVE, new_thread->vrsave); #endif #ifdef CONFIG_PPC_BOOK3S_64 if (cpu_has_feature(CPU_FTR_DSCR)) { u64 dscr = get_paca()->dscr_default; if (new_thread->dscr_inherit) dscr = new_thread->dscr; if (old_thread->dscr != dscr) mtspr(SPRN_DSCR, dscr); } if (cpu_has_feature(CPU_FTR_ARCH_207S)) { if (old_thread->bescr != new_thread->bescr) mtspr(SPRN_BESCR, new_thread->bescr); if (old_thread->ebbhr != new_thread->ebbhr) mtspr(SPRN_EBBHR, new_thread->ebbhr); if (old_thread->ebbrr != new_thread->ebbrr) mtspr(SPRN_EBBRR, new_thread->ebbrr); if (old_thread->fscr != new_thread->fscr) mtspr(SPRN_FSCR, new_thread->fscr); if (old_thread->tar != new_thread->tar) mtspr(SPRN_TAR, new_thread->tar); } if (cpu_has_feature(CPU_FTR_P9_TIDR) && old_thread->tidr != new_thread->tidr) mtspr(SPRN_TIDR, new_thread->tidr); #endif thread_pkey_regs_restore(new_thread, old_thread); } struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *new) { struct thread_struct *new_thread, *old_thread; struct task_struct *last; #ifdef CONFIG_PPC_BOOK3S_64 struct ppc64_tlb_batch *batch; #endif new_thread = &new->thread; old_thread = ¤t->thread; WARN_ON(!irqs_disabled()); #ifdef CONFIG_PPC_BOOK3S_64 batch = this_cpu_ptr(&ppc64_tlb_batch); if (batch->active) { current_thread_info()->local_flags |= _TLF_LAZY_MMU; if (batch->index) __flush_tlb_pending(batch); batch->active = 0; } /* * On POWER9 the copy-paste buffer can only paste into * foreign real addresses, so unprivileged processes can not * see the data or use it in any way unless they have * foreign real mappings. If the new process has the foreign * real address mappings, we must issue a cp_abort to clear * any state and prevent snooping, corruption or a covert * channel. ISA v3.1 supports paste into local memory. */ if (new->mm && (cpu_has_feature(CPU_FTR_ARCH_31) || atomic_read(&new->mm->context.vas_windows))) asm volatile(PPC_CP_ABORT); #endif /* CONFIG_PPC_BOOK3S_64 */ #ifdef CONFIG_PPC_ADV_DEBUG_REGS switch_booke_debug_regs(&new->thread.debug); #else /* * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would * schedule DABR */ #ifndef CONFIG_HAVE_HW_BREAKPOINT switch_hw_breakpoint(new); #endif /* CONFIG_HAVE_HW_BREAKPOINT */ #endif /* * We need to save SPRs before treclaim/trecheckpoint as these will * change a number of them. */ save_sprs(&prev->thread); /* Save FPU, Altivec, VSX and SPE state */ giveup_all(prev); __switch_to_tm(prev, new); if (!radix_enabled()) { /* * We can't take a PMU exception inside _switch() since there * is a window where the kernel stack SLB and the kernel stack * are out of sync. Hard disable here. */ hard_irq_disable(); } /* * Call restore_sprs() before calling _switch(). If we move it after * _switch() then we miss out on calling it for new tasks. The reason * for this is we manually create a stack frame for new tasks that * directly returns through ret_from_fork() or * ret_from_kernel_thread(). See copy_thread() for details. */ restore_sprs(old_thread, new_thread); last = _switch(old_thread, new_thread); /* * Nothing after _switch will be run for newly created tasks, * because they switch directly to ret_from_fork/ret_from_kernel_thread * etc. Code added here should have a comment explaining why that is * okay. */ #ifdef CONFIG_PPC_BOOK3S_64 /* * This applies to a process that was context switched while inside * arch_enter_lazy_mmu_mode(), to re-activate the batch that was * deactivated above, before _switch(). This will never be the case * for new tasks. */ if (current_thread_info()->local_flags & _TLF_LAZY_MMU) { current_thread_info()->local_flags &= ~_TLF_LAZY_MMU; batch = this_cpu_ptr(&ppc64_tlb_batch); batch->active = 1; } /* * Math facilities are masked out of the child MSR in copy_thread. * A new task does not need to restore_math because it will * demand fault them. */ if (current->thread.regs) restore_math(current->thread.regs); #endif /* CONFIG_PPC_BOOK3S_64 */ return last; } #define NR_INSN_TO_PRINT 16 static void show_instructions(struct pt_regs *regs) { int i; unsigned long nip = regs->nip; unsigned long pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int)); printk("Instruction dump:"); /* * If we were executing with the MMU off for instructions, adjust pc * rather than printing XXXXXXXX. */ if (!IS_ENABLED(CONFIG_BOOKE) && !(regs->msr & MSR_IR)) { pc = (unsigned long)phys_to_virt(pc); nip = (unsigned long)phys_to_virt(regs->nip); } for (i = 0; i < NR_INSN_TO_PRINT; i++) { int instr; if (!(i % 8)) pr_cont("\n"); if (!__kernel_text_address(pc) || get_kernel_nofault(instr, (const void *)pc)) { pr_cont("XXXXXXXX "); } else { if (nip == pc) pr_cont("<%08x> ", instr); else pr_cont("%08x ", instr); } pc += sizeof(int); } pr_cont("\n"); } void show_user_instructions(struct pt_regs *regs) { unsigned long pc; int n = NR_INSN_TO_PRINT; struct seq_buf s; char buf[96]; /* enough for 8 times 9 + 2 chars */ pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int)); seq_buf_init(&s, buf, sizeof(buf)); while (n) { int i; seq_buf_clear(&s); for (i = 0; i < 8 && n; i++, n--, pc += sizeof(int)) { int instr; if (copy_from_user_nofault(&instr, (void __user *)pc, sizeof(instr))) { seq_buf_printf(&s, "XXXXXXXX "); continue; } seq_buf_printf(&s, regs->nip == pc ? "<%08x> " : "%08x ", instr); } if (!seq_buf_has_overflowed(&s)) pr_info("%s[%d]: code: %s\n", current->comm, current->pid, s.buffer); } } struct regbit { unsigned long bit; const char *name; }; static struct regbit msr_bits[] = { #if defined(CONFIG_PPC64) && !defined(CONFIG_BOOKE) {MSR_SF, "SF"}, {MSR_HV, "HV"}, #endif {MSR_VEC, "VEC"}, {MSR_VSX, "VSX"}, #ifdef CONFIG_BOOKE {MSR_CE, "CE"}, #endif {MSR_EE, "EE"}, {MSR_PR, "PR"}, {MSR_FP, "FP"}, {MSR_ME, "ME"}, #ifdef CONFIG_BOOKE {MSR_DE, "DE"}, #else {MSR_SE, "SE"}, {MSR_BE, "BE"}, #endif {MSR_IR, "IR"}, {MSR_DR, "DR"}, {MSR_PMM, "PMM"}, #ifndef CONFIG_BOOKE {MSR_RI, "RI"}, {MSR_LE, "LE"}, #endif {0, NULL} }; static void print_bits(unsigned long val, struct regbit *bits, const char *sep) { const char *s = ""; for (; bits->bit; ++bits) if (val & bits->bit) { pr_cont("%s%s", s, bits->name); s = sep; } } #ifdef CONFIG_PPC_TRANSACTIONAL_MEM static struct regbit msr_tm_bits[] = { {MSR_TS_T, "T"}, {MSR_TS_S, "S"}, {MSR_TM, "E"}, {0, NULL} }; static void print_tm_bits(unsigned long val) { /* * This only prints something if at least one of the TM bit is set. * Inside the TM[], the output means: * E: Enabled (bit 32) * S: Suspended (bit 33) * T: Transactional (bit 34) */ if (val & (MSR_TM | MSR_TS_S | MSR_TS_T)) { pr_cont(",TM["); print_bits(val, msr_tm_bits, ""); pr_cont("]"); } } #else static void print_tm_bits(unsigned long val) {} #endif static void print_msr_bits(unsigned long val) { pr_cont("<"); print_bits(val, msr_bits, ","); print_tm_bits(val); pr_cont(">"); } #ifdef CONFIG_PPC64 #define REG "%016lx" #define REGS_PER_LINE 4 #define LAST_VOLATILE 13 #else #define REG "%08lx" #define REGS_PER_LINE 8 #define LAST_VOLATILE 12 #endif void show_regs(struct pt_regs * regs) { int i, trap; show_regs_print_info(KERN_DEFAULT); printk("NIP: "REG" LR: "REG" CTR: "REG"\n", regs->nip, regs->link, regs->ctr); printk("REGS: %px TRAP: %04lx %s (%s)\n", regs, regs->trap, print_tainted(), init_utsname()->release); printk("MSR: "REG" ", regs->msr); print_msr_bits(regs->msr); pr_cont(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer); trap = TRAP(regs); if (!trap_is_syscall(regs) && cpu_has_feature(CPU_FTR_CFAR)) pr_cont("CFAR: "REG" ", regs->orig_gpr3); if (trap == 0x200 || trap == 0x300 || trap == 0x600) { if (IS_ENABLED(CONFIG_4xx) || IS_ENABLED(CONFIG_BOOKE)) pr_cont("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr); else pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr); } #ifdef CONFIG_PPC64 pr_cont("IRQMASK: %lx ", regs->softe); #endif #ifdef CONFIG_PPC_TRANSACTIONAL_MEM if (MSR_TM_ACTIVE(regs->msr)) pr_cont("\nPACATMSCRATCH: %016llx ", get_paca()->tm_scratch); #endif for (i = 0; i < 32; i++) { if ((i % REGS_PER_LINE) == 0) pr_cont("\nGPR%02d: ", i); pr_cont(REG " ", regs->gpr[i]); if (i == LAST_VOLATILE && !FULL_REGS(regs)) break; } pr_cont("\n"); /* * Lookup NIP late so we have the best change of getting the * above info out without failing */ if (IS_ENABLED(CONFIG_KALLSYMS)) { printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip); printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link); } show_stack(current, (unsigned long *) regs->gpr[1], KERN_DEFAULT); if (!user_mode(regs)) show_instructions(regs); } void flush_thread(void) { #ifdef CONFIG_HAVE_HW_BREAKPOINT flush_ptrace_hw_breakpoint(current); #else /* CONFIG_HAVE_HW_BREAKPOINT */ set_debug_reg_defaults(¤t->thread); #endif /* CONFIG_HAVE_HW_BREAKPOINT */ } #ifdef CONFIG_PPC_BOOK3S_64 void arch_setup_new_exec(void) { if (radix_enabled()) return; hash__setup_new_exec(); } #endif #ifdef CONFIG_PPC64 /** * Assign a TIDR (thread ID) for task @t and set it in the thread * structure. For now, we only support setting TIDR for 'current' task. * * Since the TID value is a truncated form of it PID, it is possible * (but unlikely) for 2 threads to have the same TID. In the unlikely event * that 2 threads share the same TID and are waiting, one of the following * cases will happen: * * 1. The correct thread is running, the wrong thread is not * In this situation, the correct thread is woken and proceeds to pass it's * condition check. * * 2. Neither threads are running * In this situation, neither thread will be woken. When scheduled, the waiting * threads will execute either a wait, which will return immediately, followed * by a condition check, which will pass for the correct thread and fail * for the wrong thread, or they will execute the condition check immediately. * * 3. The wrong thread is running, the correct thread is not * The wrong thread will be woken, but will fail it's condition check and * re-execute wait. The correct thread, when scheduled, will execute either * it's condition check (which will pass), or wait, which returns immediately * when called the first time after the thread is scheduled, followed by it's * condition check (which will pass). * * 4. Both threads are running * Both threads will be woken. The wrong thread will fail it's condition check * and execute another wait, while the correct thread will pass it's condition * check. * * @t: the task to set the thread ID for */ int set_thread_tidr(struct task_struct *t) { if (!cpu_has_feature(CPU_FTR_P9_TIDR)) return -EINVAL; if (t != current) return -EINVAL; if (t->thread.tidr) return 0; t->thread.tidr = (u16)task_pid_nr(t); mtspr(SPRN_TIDR, t->thread.tidr); return 0; } EXPORT_SYMBOL_GPL(set_thread_tidr); #endif /* CONFIG_PPC64 */ void release_thread(struct task_struct *t) { } /* * this gets called so that we can store coprocessor state into memory and * copy the current task into the new thread. */ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { flush_all_to_thread(src); /* * Flush TM state out so we can copy it. __switch_to_tm() does this * flush but it removes the checkpointed state from the current CPU and * transitions the CPU out of TM mode. Hence we need to call * tm_recheckpoint_new_task() (on the same task) to restore the * checkpointed state back and the TM mode. * * Can't pass dst because it isn't ready. Doesn't matter, passing * dst is only important for __switch_to() */ __switch_to_tm(src, src); *dst = *src; clear_task_ebb(dst); return 0; } static void setup_ksp_vsid(struct task_struct *p, unsigned long sp) { #ifdef CONFIG_PPC_BOOK3S_64 unsigned long sp_vsid; unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp; if (radix_enabled()) return; if (mmu_has_feature(MMU_FTR_1T_SEGMENT)) sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T) << SLB_VSID_SHIFT_1T; else sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M) << SLB_VSID_SHIFT; sp_vsid |= SLB_VSID_KERNEL | llp; p->thread.ksp_vsid = sp_vsid; #endif } /* * Copy a thread.. */ /* * Copy architecture-specific thread state */ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long kthread_arg, struct task_struct *p, unsigned long tls) { struct pt_regs *childregs, *kregs; extern void ret_from_fork(void); extern void ret_from_fork_scv(void); extern void ret_from_kernel_thread(void); void (*f)(void); unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; struct thread_info *ti = task_thread_info(p); #ifdef CONFIG_HAVE_HW_BREAKPOINT int i; #endif klp_init_thread_info(p); /* Copy registers */ sp -= sizeof(struct pt_regs); childregs = (struct pt_regs *) sp; if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { /* kernel thread */ memset(childregs, 0, sizeof(struct pt_regs)); childregs->gpr[1] = sp + sizeof(struct pt_regs); /* function */ if (usp) childregs->gpr[14] = ppc_function_entry((void *)usp); #ifdef CONFIG_PPC64 clear_tsk_thread_flag(p, TIF_32BIT); childregs->softe = IRQS_ENABLED; #endif childregs->gpr[15] = kthread_arg; p->thread.regs = NULL; /* no user register state */ ti->flags |= _TIF_RESTOREALL; f = ret_from_kernel_thread; } else { /* user thread */ struct pt_regs *regs = current_pt_regs(); CHECK_FULL_REGS(regs); *childregs = *regs; if (usp) childregs->gpr[1] = usp; p->thread.regs = childregs; /* 64s sets this in ret_from_fork */ if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64)) childregs->gpr[3] = 0; /* Result from fork() */ if (clone_flags & CLONE_SETTLS) { if (!is_32bit_task()) childregs->gpr[13] = tls; else childregs->gpr[2] = tls; } if (trap_is_scv(regs)) f = ret_from_fork_scv; else f = ret_from_fork; } childregs->msr &= ~(MSR_FP|MSR_VEC|MSR_VSX); sp -= STACK_FRAME_OVERHEAD; /* * The way this works is that at some point in the future * some task will call _switch to switch to the new task. * That will pop off the stack frame created below and start * the new task running at ret_from_fork. The new task will * do some house keeping and then return from the fork or clone * system call, using the stack frame created above. */ ((unsigned long *)sp)[0] = 0; sp -= sizeof(struct pt_regs); kregs = (struct pt_regs *) sp; sp -= STACK_FRAME_OVERHEAD; p->thread.ksp = sp; #ifdef CONFIG_PPC32 p->thread.ksp_limit = (unsigned long)end_of_stack(p); #endif #ifdef CONFIG_HAVE_HW_BREAKPOINT for (i = 0; i < nr_wp_slots(); i++) p->thread.ptrace_bps[i] = NULL; #endif p->thread.fp_save_area = NULL; #ifdef CONFIG_ALTIVEC p->thread.vr_save_area = NULL; #endif setup_ksp_vsid(p, sp); #ifdef CONFIG_PPC64 if (cpu_has_feature(CPU_FTR_DSCR)) { p->thread.dscr_inherit = current->thread.dscr_inherit; p->thread.dscr = mfspr(SPRN_DSCR); } if (cpu_has_feature(CPU_FTR_HAS_PPR)) childregs->ppr = DEFAULT_PPR; p->thread.tidr = 0; #endif kregs->nip = ppc_function_entry(f); return 0; } void preload_new_slb_context(unsigned long start, unsigned long sp); /* * Set up a thread for executing a new program */ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) { #ifdef CONFIG_PPC64 unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */ if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled()) preload_new_slb_context(start, sp); #endif /* * If we exec out of a kernel thread then thread.regs will not be * set. Do it now. */ if (!current->thread.regs) { struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE; current->thread.regs = regs - 1; } #ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* * Clear any transactional state, we're exec()ing. 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); #endif memset(®s->gpr[1], 0, sizeof(regs->gpr) - sizeof(regs->gpr[0])); regs->ctr = 0; regs->link = 0; regs->xer = 0; regs->ccr = 0; regs->gpr[1] = sp; /* * We have just cleared all the nonvolatile GPRs, so make * FULL_REGS(regs) return true. This is necessary to allow * ptrace to examine the thread immediately after exec. */ SET_FULL_REGS(regs); #ifdef CONFIG_PPC32 regs->mq = 0; regs->nip = start; regs->msr = MSR_USER; #else if (!is_32bit_task()) { unsigned long entry; if (is_elf2_task()) { /* Look ma, no function descriptors! */ entry = start; /* * Ulrich says: * The latest iteration of the ABI requires that when * calling a function (at its global entry point), * the caller must ensure r12 holds the entry point * address (so that the function can quickly * establish addressability). */ regs->gpr[12] = start; /* Make sure that's restored on entry to userspace. */ set_thread_flag(TIF_RESTOREALL); } else { unsigned long toc; /* start is a relocated pointer to the function * descriptor for the elf _start routine. The first * entry in the function descriptor is the entry * address of _start and the second entry is the TOC * value we need to use. */ __get_user(entry, (unsigned long __user *)start); __get_user(toc, (unsigned long __user *)start+1); /* Check whether the e_entry function descriptor entries * need to be relocated before we can use them. */ if (load_addr != 0) { entry += load_addr; toc += load_addr; } regs->gpr[2] = toc; } regs->nip = entry; regs->msr = MSR_USER64; } else { regs->nip = start; regs->gpr[2] = 0; regs->msr = MSR_USER32; } #endif #ifdef CONFIG_VSX current->thread.used_vsr = 0; #endif current->thread.load_slb = 0; current->thread.load_fp = 0; memset(¤t->thread.fp_state, 0, sizeof(current->thread.fp_state)); current->thread.fp_save_area = NULL; #ifdef CONFIG_ALTIVEC memset(¤t->thread.vr_state, 0, sizeof(current->thread.vr_state)); current->thread.vr_state.vscr.u[3] = 0x00010000; /* Java mode disabled */ current->thread.vr_save_area = NULL; current->thread.vrsave = 0; current->thread.used_vr = 0; current->thread.load_vec = 0; #endif /* CONFIG_ALTIVEC */ #ifdef CONFIG_SPE memset(current->thread.evr, 0, sizeof(current->thread.evr)); current->thread.acc = 0; current->thread.spefscr = 0; current->thread.used_spe = 0; #endif /* CONFIG_SPE */ #ifdef CONFIG_PPC_TRANSACTIONAL_MEM current->thread.tm_tfhar = 0; current->thread.tm_texasr = 0; current->thread.tm_tfiar = 0; current->thread.load_tm = 0; #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ thread_pkey_regs_init(¤t->thread); } EXPORT_SYMBOL(start_thread); #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \ | PR_FP_EXC_RES | PR_FP_EXC_INV) int set_fpexc_mode(struct task_struct *tsk, unsigned int val) { struct pt_regs *regs = tsk->thread.regs; /* This is a bit hairy. If we are an SPE enabled processor * (have embedded fp) we store the IEEE exception enable flags in * fpexc_mode. fpexc_mode is also used for setting FP exception * mode (asyn, precise, disabled) for 'Classic' FP. */ if (val & PR_FP_EXC_SW_ENABLE) { if (cpu_has_feature(CPU_FTR_SPE)) { /* * When the sticky exception bits are set * directly by userspace, it must call prctl * with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE * in the existing prctl settings) or * PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in * the bits being set). functions * saving and restoring the whole * floating-point environment need to do so * anyway to restore the prctl settings from * the saved environment. */ #ifdef CONFIG_SPE tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR); tsk->thread.fpexc_mode = val & (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT); #endif return 0; } else { return -EINVAL; } } /* on a CONFIG_SPE this does not hurt us. The bits that * __pack_fe01 use do not overlap with bits used for * PR_FP_EXC_SW_ENABLE. Additionally, the MSR[FE0,FE1] bits * on CONFIG_SPE implementations are reserved so writing to * them does not change anything */ if (val > PR_FP_EXC_PRECISE) return -EINVAL; tsk->thread.fpexc_mode = __pack_fe01(val); if (regs != NULL && (regs->msr & MSR_FP) != 0) regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1)) | tsk->thread.fpexc_mode; return 0; } int get_fpexc_mode(struct task_struct *tsk, unsigned long adr) { unsigned int val = 0; if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE) { if (cpu_has_feature(CPU_FTR_SPE)) { /* * When the sticky exception bits are set * directly by userspace, it must call prctl * with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE * in the existing prctl settings) or * PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in * the bits being set). functions * saving and restoring the whole * floating-point environment need to do so * anyway to restore the prctl settings from * the saved environment. */ #ifdef CONFIG_SPE tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR); val = tsk->thread.fpexc_mode; #endif } else return -EINVAL; } else { val = __unpack_fe01(tsk->thread.fpexc_mode); } return put_user(val, (unsigned int __user *) adr); } int set_endian(struct task_struct *tsk, unsigned int val) { struct pt_regs *regs = tsk->thread.regs; if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) || (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE))) return -EINVAL; if (regs == NULL) return -EINVAL; if (val == PR_ENDIAN_BIG) regs->msr &= ~MSR_LE; else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE) regs->msr |= MSR_LE; else return -EINVAL; return 0; } int get_endian(struct task_struct *tsk, unsigned long adr) { struct pt_regs *regs = tsk->thread.regs; unsigned int val; if (!cpu_has_feature(CPU_FTR_PPC_LE) && !cpu_has_feature(CPU_FTR_REAL_LE)) return -EINVAL; if (regs == NULL) return -EINVAL; if (regs->msr & MSR_LE) { if (cpu_has_feature(CPU_FTR_REAL_LE)) val = PR_ENDIAN_LITTLE; else val = PR_ENDIAN_PPC_LITTLE; } else val = PR_ENDIAN_BIG; return put_user(val, (unsigned int __user *)adr); } int set_unalign_ctl(struct task_struct *tsk, unsigned int val) { tsk->thread.align_ctl = val; return 0; } int get_unalign_ctl(struct task_struct *tsk, unsigned long adr) { return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr); } static inline int valid_irq_stack(unsigned long sp, struct task_struct *p, unsigned long nbytes) { unsigned long stack_page; unsigned long cpu = task_cpu(p); stack_page = (unsigned long)hardirq_ctx[cpu]; if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; stack_page = (unsigned long)softirq_ctx[cpu]; if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; return 0; } static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p, unsigned long nbytes) { #ifdef CONFIG_PPC64 unsigned long stack_page; unsigned long cpu = task_cpu(p); stack_page = (unsigned long)paca_ptrs[cpu]->emergency_sp - THREAD_SIZE; if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; # ifdef CONFIG_PPC_BOOK3S_64 stack_page = (unsigned long)paca_ptrs[cpu]->nmi_emergency_sp - THREAD_SIZE; if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; stack_page = (unsigned long)paca_ptrs[cpu]->mc_emergency_sp - THREAD_SIZE; if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; # endif #endif return 0; } int validate_sp(unsigned long sp, struct task_struct *p, unsigned long nbytes) { unsigned long stack_page = (unsigned long)task_stack_page(p); if (sp < THREAD_SIZE) return 0; if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; if (valid_irq_stack(sp, p, nbytes)) return 1; return valid_emergency_stack(sp, p, nbytes); } EXPORT_SYMBOL(validate_sp); static unsigned long __get_wchan(struct task_struct *p) { unsigned long ip, sp; int count = 0; if (!p || p == current || p->state == TASK_RUNNING) return 0; sp = p->thread.ksp; if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) return 0; do { sp = READ_ONCE_NOCHECK(*(unsigned long *)sp); if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD) || p->state == TASK_RUNNING) return 0; if (count > 0) { ip = READ_ONCE_NOCHECK(((unsigned long *)sp)[STACK_FRAME_LR_SAVE]); if (!in_sched_functions(ip)) return ip; } } while (count++ < 16); return 0; } unsigned long get_wchan(struct task_struct *p) { unsigned long ret; if (!try_get_task_stack(p)) return 0; ret = __get_wchan(p); put_task_stack(p); return ret; } static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; void show_stack(struct task_struct *tsk, unsigned long *stack, const char *loglvl) { unsigned long sp, ip, lr, newsp; int count = 0; int firstframe = 1; unsigned long ret_addr; int ftrace_idx = 0; if (tsk == NULL) tsk = current; if (!try_get_task_stack(tsk)) return; sp = (unsigned long) stack; if (sp == 0) { if (tsk == current) sp = current_stack_frame(); else sp = tsk->thread.ksp; } lr = 0; printk("%sCall Trace:\n", loglvl); do { if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) break; stack = (unsigned long *) sp; newsp = stack[0]; ip = stack[STACK_FRAME_LR_SAVE]; if (!firstframe || ip != lr) { printk("%s["REG"] ["REG"] %pS", loglvl, sp, ip, (void *)ip); ret_addr = ftrace_graph_ret_addr(current, &ftrace_idx, ip, stack); if (ret_addr != ip) pr_cont(" (%pS)", (void *)ret_addr); if (firstframe) pr_cont(" (unreliable)"); pr_cont("\n"); } firstframe = 0; /* * See if this is an exception frame. * We look for the "regshere" marker in the current frame. */ if (validate_sp(sp, tsk, STACK_FRAME_WITH_PT_REGS) && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { struct pt_regs *regs = (struct pt_regs *) (sp + STACK_FRAME_OVERHEAD); lr = regs->link; printk("%s--- interrupt: %lx at %pS\n LR = %pS\n", loglvl, regs->trap, (void *)regs->nip, (void *)lr); firstframe = 1; } sp = newsp; } while (count++ < kstack_depth_to_print); put_task_stack(tsk); } #ifdef CONFIG_PPC64 /* Called with hard IRQs off */ void notrace __ppc64_runlatch_on(void) { struct thread_info *ti = current_thread_info(); if (cpu_has_feature(CPU_FTR_ARCH_206)) { /* * Least significant bit (RUN) is the only writable bit of * the CTRL register, so we can avoid mfspr. 2.06 is not the * earliest ISA where this is the case, but it's convenient. */ mtspr(SPRN_CTRLT, CTRL_RUNLATCH); } else { unsigned long ctrl; /* * Some architectures (e.g., Cell) have writable fields other * than RUN, so do the read-modify-write. */ ctrl = mfspr(SPRN_CTRLF); ctrl |= CTRL_RUNLATCH; mtspr(SPRN_CTRLT, ctrl); } ti->local_flags |= _TLF_RUNLATCH; } /* Called with hard IRQs off */ void notrace __ppc64_runlatch_off(void) { struct thread_info *ti = current_thread_info(); ti->local_flags &= ~_TLF_RUNLATCH; if (cpu_has_feature(CPU_FTR_ARCH_206)) { mtspr(SPRN_CTRLT, 0); } else { unsigned long ctrl; ctrl = mfspr(SPRN_CTRLF); ctrl &= ~CTRL_RUNLATCH; mtspr(SPRN_CTRLT, ctrl); } } #endif /* CONFIG_PPC64 */ unsigned long arch_align_stack(unsigned long sp) { if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) sp -= get_random_int() & ~PAGE_MASK; return sp & ~0xf; } static inline unsigned long brk_rnd(void) { unsigned long rnd = 0; /* 8MB for 32bit, 1GB for 64bit */ if (is_32bit_task()) rnd = (get_random_long() % (1UL<<(23-PAGE_SHIFT))); else rnd = (get_random_long() % (1UL<<(30-PAGE_SHIFT))); return rnd << PAGE_SHIFT; } unsigned long arch_randomize_brk(struct mm_struct *mm) { unsigned long base = mm->brk; unsigned long ret; #ifdef CONFIG_PPC_BOOK3S_64 /* * If we are using 1TB segments and we are allowed to randomise * the heap, we can put it above 1TB so it is backed by a 1TB * segment. Otherwise the heap will be in the bottom 1TB * which always uses 256MB segments and this may result in a * performance penalty. We don't need to worry about radix. For * radix, mmu_highuser_ssize remains unchanged from 256MB. */ if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T)) base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T); #endif ret = PAGE_ALIGN(base + brk_rnd()); if (ret < mm->brk) return mm->brk; return ret; }