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- /*
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
- * Copyright (C) 2005, 2006 by Ralf Baechle ([email protected])
- * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
- * Copyright (C) 2004 Thiemo Seufer
- * Copyright (C) 2013 Imagination Technologies Ltd.
- */
- #include <linux/cpu.h>
- #include <linux/errno.h>
- #include <linux/init.h>
- #include <linux/kallsyms.h>
- #include <linux/kernel.h>
- #include <linux/nmi.h>
- #include <linux/personality.h>
- #include <linux/prctl.h>
- #include <linux/random.h>
- #include <linux/sched.h>
- #include <linux/sched/debug.h>
- #include <linux/sched/task_stack.h>
- #include <asm/abi.h>
- #include <asm/asm.h>
- #include <asm/dsemul.h>
- #include <asm/dsp.h>
- #include <asm/exec.h>
- #include <asm/fpu.h>
- #include <asm/inst.h>
- #include <asm/irq.h>
- #include <asm/irq_regs.h>
- #include <asm/isadep.h>
- #include <asm/msa.h>
- #include <asm/mips-cps.h>
- #include <asm/mipsregs.h>
- #include <asm/processor.h>
- #include <asm/reg.h>
- #include <asm/stacktrace.h>
- #ifdef CONFIG_HOTPLUG_CPU
- void arch_cpu_idle_dead(void)
- {
- play_dead();
- }
- #endif
- asmlinkage void ret_from_fork(void);
- asmlinkage void ret_from_kernel_thread(void);
- void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
- {
- unsigned long status;
- /* New thread loses kernel privileges. */
- status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_CU2|ST0_FR|KU_MASK);
- status |= KU_USER;
- regs->cp0_status = status;
- lose_fpu(0);
- clear_thread_flag(TIF_MSA_CTX_LIVE);
- clear_used_math();
- #ifdef CONFIG_MIPS_FP_SUPPORT
- atomic_set(¤t->thread.bd_emu_frame, BD_EMUFRAME_NONE);
- #endif
- init_dsp();
- regs->cp0_epc = pc;
- regs->regs[29] = sp;
- }
- void exit_thread(struct task_struct *tsk)
- {
- /*
- * User threads may have allocated a delay slot emulation frame.
- * If so, clean up that allocation.
- */
- if (!(current->flags & PF_KTHREAD))
- dsemul_thread_cleanup(tsk);
- }
- int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
- {
- /*
- * Save any process state which is live in hardware registers to the
- * parent context prior to duplication. This prevents the new child
- * state becoming stale if the parent is preempted before copy_thread()
- * gets a chance to save the parent's live hardware registers to the
- * child context.
- */
- preempt_disable();
- if (is_msa_enabled())
- save_msa(current);
- else if (is_fpu_owner())
- _save_fp(current);
- save_dsp(current);
- preempt_enable();
- *dst = *src;
- return 0;
- }
- /*
- * Copy architecture-specific thread state
- */
- int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
- {
- unsigned long clone_flags = args->flags;
- unsigned long usp = args->stack;
- unsigned long tls = args->tls;
- struct thread_info *ti = task_thread_info(p);
- struct pt_regs *childregs, *regs = current_pt_regs();
- unsigned long childksp;
- childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
- /* set up new TSS. */
- childregs = (struct pt_regs *) childksp - 1;
- /* Put the stack after the struct pt_regs. */
- childksp = (unsigned long) childregs;
- p->thread.cp0_status = (read_c0_status() & ~(ST0_CU2|ST0_CU1)) | ST0_KERNEL_CUMASK;
- /*
- * New tasks lose permission to use the fpu. This accelerates context
- * switching for most programs since they don't use the fpu.
- */
- clear_tsk_thread_flag(p, TIF_USEDFPU);
- clear_tsk_thread_flag(p, TIF_USEDMSA);
- clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
- #ifdef CONFIG_MIPS_MT_FPAFF
- clear_tsk_thread_flag(p, TIF_FPUBOUND);
- #endif /* CONFIG_MIPS_MT_FPAFF */
- if (unlikely(args->fn)) {
- /* kernel thread */
- unsigned long status = p->thread.cp0_status;
- memset(childregs, 0, sizeof(struct pt_regs));
- p->thread.reg16 = (unsigned long)args->fn;
- p->thread.reg17 = (unsigned long)args->fn_arg;
- p->thread.reg29 = childksp;
- p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
- #if defined(CONFIG_CPU_R3000)
- status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
- ((status & (ST0_KUC | ST0_IEC)) << 2);
- #else
- status |= ST0_EXL;
- #endif
- childregs->cp0_status = status;
- return 0;
- }
- /* user thread */
- *childregs = *regs;
- childregs->regs[7] = 0; /* Clear error flag */
- childregs->regs[2] = 0; /* Child gets zero as return value */
- if (usp)
- childregs->regs[29] = usp;
- p->thread.reg29 = (unsigned long) childregs;
- p->thread.reg31 = (unsigned long) ret_from_fork;
- childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
- #ifdef CONFIG_MIPS_FP_SUPPORT
- atomic_set(&p->thread.bd_emu_frame, BD_EMUFRAME_NONE);
- #endif
- if (clone_flags & CLONE_SETTLS)
- ti->tp_value = tls;
- return 0;
- }
- #ifdef CONFIG_STACKPROTECTOR
- #include <linux/stackprotector.h>
- unsigned long __stack_chk_guard __read_mostly;
- EXPORT_SYMBOL(__stack_chk_guard);
- #endif
- struct mips_frame_info {
- void *func;
- unsigned long func_size;
- int frame_size;
- int pc_offset;
- };
- #define J_TARGET(pc,target) \
- (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
- static inline int is_jr_ra_ins(union mips_instruction *ip)
- {
- #ifdef CONFIG_CPU_MICROMIPS
- /*
- * jr16 ra
- * jr ra
- */
- if (mm_insn_16bit(ip->word >> 16)) {
- if (ip->mm16_r5_format.opcode == mm_pool16c_op &&
- ip->mm16_r5_format.rt == mm_jr16_op &&
- ip->mm16_r5_format.imm == 31)
- return 1;
- return 0;
- }
- if (ip->r_format.opcode == mm_pool32a_op &&
- ip->r_format.func == mm_pool32axf_op &&
- ((ip->u_format.uimmediate >> 6) & GENMASK(9, 0)) == mm_jalr_op &&
- ip->r_format.rt == 31)
- return 1;
- return 0;
- #else
- if (ip->r_format.opcode == spec_op &&
- ip->r_format.func == jr_op &&
- ip->r_format.rs == 31)
- return 1;
- return 0;
- #endif
- }
- static inline int is_ra_save_ins(union mips_instruction *ip, int *poff)
- {
- #ifdef CONFIG_CPU_MICROMIPS
- /*
- * swsp ra,offset
- * swm16 reglist,offset(sp)
- * swm32 reglist,offset(sp)
- * sw32 ra,offset(sp)
- * jradiussp - NOT SUPPORTED
- *
- * microMIPS is way more fun...
- */
- if (mm_insn_16bit(ip->word >> 16)) {
- switch (ip->mm16_r5_format.opcode) {
- case mm_swsp16_op:
- if (ip->mm16_r5_format.rt != 31)
- return 0;
- *poff = ip->mm16_r5_format.imm;
- *poff = (*poff << 2) / sizeof(ulong);
- return 1;
- case mm_pool16c_op:
- switch (ip->mm16_m_format.func) {
- case mm_swm16_op:
- *poff = ip->mm16_m_format.imm;
- *poff += 1 + ip->mm16_m_format.rlist;
- *poff = (*poff << 2) / sizeof(ulong);
- return 1;
- default:
- return 0;
- }
- default:
- return 0;
- }
- }
- switch (ip->i_format.opcode) {
- case mm_sw32_op:
- if (ip->i_format.rs != 29)
- return 0;
- if (ip->i_format.rt != 31)
- return 0;
- *poff = ip->i_format.simmediate / sizeof(ulong);
- return 1;
- case mm_pool32b_op:
- switch (ip->mm_m_format.func) {
- case mm_swm32_func:
- if (ip->mm_m_format.rd < 0x10)
- return 0;
- if (ip->mm_m_format.base != 29)
- return 0;
- *poff = ip->mm_m_format.simmediate;
- *poff += (ip->mm_m_format.rd & 0xf) * sizeof(u32);
- *poff /= sizeof(ulong);
- return 1;
- default:
- return 0;
- }
- default:
- return 0;
- }
- #else
- /* sw / sd $ra, offset($sp) */
- if ((ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
- ip->i_format.rs == 29 && ip->i_format.rt == 31) {
- *poff = ip->i_format.simmediate / sizeof(ulong);
- return 1;
- }
- #ifdef CONFIG_CPU_LOONGSON64
- if ((ip->loongson3_lswc2_format.opcode == swc2_op) &&
- (ip->loongson3_lswc2_format.ls == 1) &&
- (ip->loongson3_lswc2_format.fr == 0) &&
- (ip->loongson3_lswc2_format.base == 29)) {
- if (ip->loongson3_lswc2_format.rt == 31) {
- *poff = ip->loongson3_lswc2_format.offset << 1;
- return 1;
- }
- if (ip->loongson3_lswc2_format.rq == 31) {
- *poff = (ip->loongson3_lswc2_format.offset << 1) + 1;
- return 1;
- }
- }
- #endif
- return 0;
- #endif
- }
- static inline int is_jump_ins(union mips_instruction *ip)
- {
- #ifdef CONFIG_CPU_MICROMIPS
- /*
- * jr16,jrc,jalr16,jalr16
- * jal
- * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
- * jraddiusp - NOT SUPPORTED
- *
- * microMIPS is kind of more fun...
- */
- if (mm_insn_16bit(ip->word >> 16)) {
- if ((ip->mm16_r5_format.opcode == mm_pool16c_op &&
- (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op))
- return 1;
- return 0;
- }
- if (ip->j_format.opcode == mm_j32_op)
- return 1;
- if (ip->j_format.opcode == mm_jal32_op)
- return 1;
- if (ip->r_format.opcode != mm_pool32a_op ||
- ip->r_format.func != mm_pool32axf_op)
- return 0;
- return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
- #else
- if (ip->j_format.opcode == j_op)
- return 1;
- if (ip->j_format.opcode == jal_op)
- return 1;
- if (ip->r_format.opcode != spec_op)
- return 0;
- return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
- #endif
- }
- static inline int is_sp_move_ins(union mips_instruction *ip, int *frame_size)
- {
- #ifdef CONFIG_CPU_MICROMIPS
- unsigned short tmp;
- /*
- * addiusp -imm
- * addius5 sp,-imm
- * addiu32 sp,sp,-imm
- * jradiussp - NOT SUPPORTED
- *
- * microMIPS is not more fun...
- */
- if (mm_insn_16bit(ip->word >> 16)) {
- if (ip->mm16_r3_format.opcode == mm_pool16d_op &&
- ip->mm16_r3_format.simmediate & mm_addiusp_func) {
- tmp = ip->mm_b0_format.simmediate >> 1;
- tmp = ((tmp & 0x1ff) ^ 0x100) - 0x100;
- if ((tmp + 2) < 4) /* 0x0,0x1,0x1fe,0x1ff are special */
- tmp ^= 0x100;
- *frame_size = -(signed short)(tmp << 2);
- return 1;
- }
- if (ip->mm16_r5_format.opcode == mm_pool16d_op &&
- ip->mm16_r5_format.rt == 29) {
- tmp = ip->mm16_r5_format.imm >> 1;
- *frame_size = -(signed short)(tmp & 0xf);
- return 1;
- }
- return 0;
- }
- if (ip->mm_i_format.opcode == mm_addiu32_op &&
- ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29) {
- *frame_size = -ip->i_format.simmediate;
- return 1;
- }
- #else
- /* addiu/daddiu sp,sp,-imm */
- if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
- return 0;
- if (ip->i_format.opcode == addiu_op ||
- ip->i_format.opcode == daddiu_op) {
- *frame_size = -ip->i_format.simmediate;
- return 1;
- }
- #endif
- return 0;
- }
- static int get_frame_info(struct mips_frame_info *info)
- {
- bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS);
- union mips_instruction insn, *ip, *ip_end;
- unsigned int last_insn_size = 0;
- bool saw_jump = false;
- info->pc_offset = -1;
- info->frame_size = 0;
- ip = (void *)msk_isa16_mode((ulong)info->func);
- if (!ip)
- goto err;
- ip_end = (void *)ip + (info->func_size ? info->func_size : 512);
- while (ip < ip_end) {
- ip = (void *)ip + last_insn_size;
- if (is_mmips && mm_insn_16bit(ip->halfword[0])) {
- insn.word = ip->halfword[0] << 16;
- last_insn_size = 2;
- } else if (is_mmips) {
- insn.word = ip->halfword[0] << 16 | ip->halfword[1];
- last_insn_size = 4;
- } else {
- insn.word = ip->word;
- last_insn_size = 4;
- }
- if (is_jr_ra_ins(ip)) {
- break;
- } else if (!info->frame_size) {
- is_sp_move_ins(&insn, &info->frame_size);
- continue;
- } else if (!saw_jump && is_jump_ins(ip)) {
- /*
- * If we see a jump instruction, we are finished
- * with the frame save.
- *
- * Some functions can have a shortcut return at
- * the beginning of the function, so don't start
- * looking for jump instruction until we see the
- * frame setup.
- *
- * The RA save instruction can get put into the
- * delay slot of the jump instruction, so look
- * at the next instruction, too.
- */
- saw_jump = true;
- continue;
- }
- if (info->pc_offset == -1 &&
- is_ra_save_ins(&insn, &info->pc_offset))
- break;
- if (saw_jump)
- break;
- }
- if (info->frame_size && info->pc_offset >= 0) /* nested */
- return 0;
- if (info->pc_offset < 0) /* leaf */
- return 1;
- /* prologue seems bogus... */
- err:
- return -1;
- }
- static struct mips_frame_info schedule_mfi __read_mostly;
- #ifdef CONFIG_KALLSYMS
- static unsigned long get___schedule_addr(void)
- {
- return kallsyms_lookup_name("__schedule");
- }
- #else
- static unsigned long get___schedule_addr(void)
- {
- union mips_instruction *ip = (void *)schedule;
- int max_insns = 8;
- int i;
- for (i = 0; i < max_insns; i++, ip++) {
- if (ip->j_format.opcode == j_op)
- return J_TARGET(ip, ip->j_format.target);
- }
- return 0;
- }
- #endif
- static int __init frame_info_init(void)
- {
- unsigned long size = 0;
- #ifdef CONFIG_KALLSYMS
- unsigned long ofs;
- #endif
- unsigned long addr;
- addr = get___schedule_addr();
- if (!addr)
- addr = (unsigned long)schedule;
- #ifdef CONFIG_KALLSYMS
- kallsyms_lookup_size_offset(addr, &size, &ofs);
- #endif
- schedule_mfi.func = (void *)addr;
- schedule_mfi.func_size = size;
- get_frame_info(&schedule_mfi);
- /*
- * Without schedule() frame info, result given by
- * thread_saved_pc() and __get_wchan() are not reliable.
- */
- if (schedule_mfi.pc_offset < 0)
- printk("Can't analyze schedule() prologue at %p\n", schedule);
- return 0;
- }
- arch_initcall(frame_info_init);
- /*
- * Return saved PC of a blocked thread.
- */
- static unsigned long thread_saved_pc(struct task_struct *tsk)
- {
- struct thread_struct *t = &tsk->thread;
- /* New born processes are a special case */
- if (t->reg31 == (unsigned long) ret_from_fork)
- return t->reg31;
- if (schedule_mfi.pc_offset < 0)
- return 0;
- return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
- }
- #ifdef CONFIG_KALLSYMS
- /* generic stack unwinding function */
- unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
- unsigned long *sp,
- unsigned long pc,
- unsigned long *ra)
- {
- unsigned long low, high, irq_stack_high;
- struct mips_frame_info info;
- unsigned long size, ofs;
- struct pt_regs *regs;
- int leaf;
- if (!stack_page)
- return 0;
- /*
- * IRQ stacks start at IRQ_STACK_START
- * task stacks at THREAD_SIZE - 32
- */
- low = stack_page;
- if (!preemptible() && on_irq_stack(raw_smp_processor_id(), *sp)) {
- high = stack_page + IRQ_STACK_START;
- irq_stack_high = high;
- } else {
- high = stack_page + THREAD_SIZE - 32;
- irq_stack_high = 0;
- }
- /*
- * If we reached the top of the interrupt stack, start unwinding
- * the interrupted task stack.
- */
- if (unlikely(*sp == irq_stack_high)) {
- unsigned long task_sp = *(unsigned long *)*sp;
- /*
- * Check that the pointer saved in the IRQ stack head points to
- * something within the stack of the current task
- */
- if (!object_is_on_stack((void *)task_sp))
- return 0;
- /*
- * Follow pointer to tasks kernel stack frame where interrupted
- * state was saved.
- */
- regs = (struct pt_regs *)task_sp;
- pc = regs->cp0_epc;
- if (!user_mode(regs) && __kernel_text_address(pc)) {
- *sp = regs->regs[29];
- *ra = regs->regs[31];
- return pc;
- }
- return 0;
- }
- if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
- return 0;
- /*
- * Return ra if an exception occurred at the first instruction
- */
- if (unlikely(ofs == 0)) {
- pc = *ra;
- *ra = 0;
- return pc;
- }
- info.func = (void *)(pc - ofs);
- info.func_size = ofs; /* analyze from start to ofs */
- leaf = get_frame_info(&info);
- if (leaf < 0)
- return 0;
- if (*sp < low || *sp + info.frame_size > high)
- return 0;
- if (leaf)
- /*
- * For some extreme cases, get_frame_info() can
- * consider wrongly a nested function as a leaf
- * one. In that cases avoid to return always the
- * same value.
- */
- pc = pc != *ra ? *ra : 0;
- else
- pc = ((unsigned long *)(*sp))[info.pc_offset];
- *sp += info.frame_size;
- *ra = 0;
- return __kernel_text_address(pc) ? pc : 0;
- }
- EXPORT_SYMBOL(unwind_stack_by_address);
- /* used by show_backtrace() */
- unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
- unsigned long pc, unsigned long *ra)
- {
- unsigned long stack_page = 0;
- int cpu;
- for_each_possible_cpu(cpu) {
- if (on_irq_stack(cpu, *sp)) {
- stack_page = (unsigned long)irq_stack[cpu];
- break;
- }
- }
- if (!stack_page)
- stack_page = (unsigned long)task_stack_page(task);
- return unwind_stack_by_address(stack_page, sp, pc, ra);
- }
- #endif
- /*
- * __get_wchan - a maintenance nightmare^W^Wpain in the ass ...
- */
- unsigned long __get_wchan(struct task_struct *task)
- {
- unsigned long pc = 0;
- #ifdef CONFIG_KALLSYMS
- unsigned long sp;
- unsigned long ra = 0;
- #endif
- if (!task_stack_page(task))
- goto out;
- pc = thread_saved_pc(task);
- #ifdef CONFIG_KALLSYMS
- sp = task->thread.reg29 + schedule_mfi.frame_size;
- while (in_sched_functions(pc))
- pc = unwind_stack(task, &sp, pc, &ra);
- #endif
- out:
- return pc;
- }
- unsigned long mips_stack_top(void)
- {
- unsigned long top = TASK_SIZE & PAGE_MASK;
- if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
- /* One page for branch delay slot "emulation" */
- top -= PAGE_SIZE;
- }
- /* Space for the VDSO, data page & GIC user page */
- top -= PAGE_ALIGN(current->thread.abi->vdso->size);
- top -= PAGE_SIZE;
- top -= mips_gic_present() ? PAGE_SIZE : 0;
- /* Space for cache colour alignment */
- if (cpu_has_dc_aliases)
- top -= shm_align_mask + 1;
- /* Space to randomize the VDSO base */
- if (current->flags & PF_RANDOMIZE)
- top -= VDSO_RANDOMIZE_SIZE;
- return top;
- }
- /*
- * Don't forget that the stack pointer must be aligned on a 8 bytes
- * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
- */
- unsigned long arch_align_stack(unsigned long sp)
- {
- if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
- sp -= prandom_u32_max(PAGE_SIZE);
- return sp & ALMASK;
- }
- static struct cpumask backtrace_csd_busy;
- static void handle_backtrace(void *info)
- {
- nmi_cpu_backtrace(get_irq_regs());
- cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy);
- }
- static DEFINE_PER_CPU(call_single_data_t, backtrace_csd) =
- CSD_INIT(handle_backtrace, NULL);
- static void raise_backtrace(cpumask_t *mask)
- {
- call_single_data_t *csd;
- int cpu;
- for_each_cpu(cpu, mask) {
- /*
- * If we previously sent an IPI to the target CPU & it hasn't
- * cleared its bit in the busy cpumask then it didn't handle
- * our previous IPI & it's not safe for us to reuse the
- * call_single_data_t.
- */
- if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) {
- pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",
- cpu);
- continue;
- }
- csd = &per_cpu(backtrace_csd, cpu);
- smp_call_function_single_async(cpu, csd);
- }
- }
- void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
- {
- nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace);
- }
- int mips_get_process_fp_mode(struct task_struct *task)
- {
- int value = 0;
- if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS))
- value |= PR_FP_MODE_FR;
- if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS))
- value |= PR_FP_MODE_FRE;
- return value;
- }
- static long prepare_for_fp_mode_switch(void *unused)
- {
- /*
- * This is icky, but we use this to simply ensure that all CPUs have
- * context switched, regardless of whether they were previously running
- * kernel or user code. This ensures that no CPU that a mode-switching
- * program may execute on keeps its FPU enabled (& in the old mode)
- * throughout the mode switch.
- */
- return 0;
- }
- int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
- {
- const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
- struct task_struct *t;
- struct cpumask process_cpus;
- int cpu;
- /* If nothing to change, return right away, successfully. */
- if (value == mips_get_process_fp_mode(task))
- return 0;
- /* Only accept a mode change if 64-bit FP enabled for o32. */
- if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT))
- return -EOPNOTSUPP;
- /* And only for o32 tasks. */
- if (IS_ENABLED(CONFIG_64BIT) && !test_thread_flag(TIF_32BIT_REGS))
- return -EOPNOTSUPP;
- /* Check the value is valid */
- if (value & ~known_bits)
- return -EOPNOTSUPP;
- /* Setting FRE without FR is not supported. */
- if ((value & (PR_FP_MODE_FR | PR_FP_MODE_FRE)) == PR_FP_MODE_FRE)
- return -EOPNOTSUPP;
- /* Avoid inadvertently triggering emulation */
- if ((value & PR_FP_MODE_FR) && raw_cpu_has_fpu &&
- !(raw_current_cpu_data.fpu_id & MIPS_FPIR_F64))
- return -EOPNOTSUPP;
- if ((value & PR_FP_MODE_FRE) && raw_cpu_has_fpu && !cpu_has_fre)
- return -EOPNOTSUPP;
- /* FR = 0 not supported in MIPS R6 */
- if (!(value & PR_FP_MODE_FR) && raw_cpu_has_fpu && cpu_has_mips_r6)
- return -EOPNOTSUPP;
- /* Indicate the new FP mode in each thread */
- for_each_thread(task, t) {
- /* Update desired FP register width */
- if (value & PR_FP_MODE_FR) {
- clear_tsk_thread_flag(t, TIF_32BIT_FPREGS);
- } else {
- set_tsk_thread_flag(t, TIF_32BIT_FPREGS);
- clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE);
- }
- /* Update desired FP single layout */
- if (value & PR_FP_MODE_FRE)
- set_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
- else
- clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
- }
- /*
- * We need to ensure that all threads in the process have switched mode
- * before returning, in order to allow userland to not worry about
- * races. We can do this by forcing all CPUs that any thread in the
- * process may be running on to schedule something else - in this case
- * prepare_for_fp_mode_switch().
- *
- * We begin by generating a mask of all CPUs that any thread in the
- * process may be running on.
- */
- cpumask_clear(&process_cpus);
- for_each_thread(task, t)
- cpumask_set_cpu(task_cpu(t), &process_cpus);
- /*
- * Now we schedule prepare_for_fp_mode_switch() on each of those CPUs.
- *
- * The CPUs may have rescheduled already since we switched mode or
- * generated the cpumask, but that doesn't matter. If the task in this
- * process is scheduled out then our scheduling
- * prepare_for_fp_mode_switch() will simply be redundant. If it's
- * scheduled in then it will already have picked up the new FP mode
- * whilst doing so.
- */
- cpus_read_lock();
- for_each_cpu_and(cpu, &process_cpus, cpu_online_mask)
- work_on_cpu(cpu, prepare_for_fp_mode_switch, NULL);
- cpus_read_unlock();
- return 0;
- }
- #if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32)
- void mips_dump_regs32(u32 *uregs, const struct pt_regs *regs)
- {
- unsigned int i;
- for (i = MIPS32_EF_R1; i <= MIPS32_EF_R31; i++) {
- /* k0/k1 are copied as zero. */
- if (i == MIPS32_EF_R26 || i == MIPS32_EF_R27)
- uregs[i] = 0;
- else
- uregs[i] = regs->regs[i - MIPS32_EF_R0];
- }
- uregs[MIPS32_EF_LO] = regs->lo;
- uregs[MIPS32_EF_HI] = regs->hi;
- uregs[MIPS32_EF_CP0_EPC] = regs->cp0_epc;
- uregs[MIPS32_EF_CP0_BADVADDR] = regs->cp0_badvaddr;
- uregs[MIPS32_EF_CP0_STATUS] = regs->cp0_status;
- uregs[MIPS32_EF_CP0_CAUSE] = regs->cp0_cause;
- }
- #endif /* CONFIG_32BIT || CONFIG_MIPS32_O32 */
- #ifdef CONFIG_64BIT
- void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs)
- {
- unsigned int i;
- for (i = MIPS64_EF_R1; i <= MIPS64_EF_R31; i++) {
- /* k0/k1 are copied as zero. */
- if (i == MIPS64_EF_R26 || i == MIPS64_EF_R27)
- uregs[i] = 0;
- else
- uregs[i] = regs->regs[i - MIPS64_EF_R0];
- }
- uregs[MIPS64_EF_LO] = regs->lo;
- uregs[MIPS64_EF_HI] = regs->hi;
- uregs[MIPS64_EF_CP0_EPC] = regs->cp0_epc;
- uregs[MIPS64_EF_CP0_BADVADDR] = regs->cp0_badvaddr;
- uregs[MIPS64_EF_CP0_STATUS] = regs->cp0_status;
- uregs[MIPS64_EF_CP0_CAUSE] = regs->cp0_cause;
- }
- #endif /* CONFIG_64BIT */
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