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// SPDX-License-Identifier: GPL-2.0
/*
* arch/sh/kernel/process.c
*
* This file handles the architecture-dependent parts of process handling..
*
* Copyright (C) 1995 Linus Torvalds
*
* SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
* Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
* Copyright (C) 2002 - 2008 Paul Mundt
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/elfcore.h>
#include <linux/fs.h>
#include <linux/ftrace.h>
#include <linux/hw_breakpoint.h>
#include <linux/prefetch.h>
#include <linux/stackprotector.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/fpu.h>
#include <asm/syscalls.h>
#include <asm/switch_to.h>
void show_regs(struct pt_regs * regs)
{
printk("\n");
show_regs_print_info(KERN_DEFAULT);
printk("PC is at %pS\n", (void *)instruction_pointer(regs));
printk("PR is at %pS\n", (void *)regs->pr);
printk("PC : %08lx SP : %08lx SR : %08lx ",
regs->pc, regs->regs[15], regs->sr);
#ifdef CONFIG_MMU
printk("TEA : %08x\n", __raw_readl(MMU_TEA));
#else
printk("\n");
#endif
printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
regs->regs[0],regs->regs[1],
regs->regs[2],regs->regs[3]);
printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
regs->regs[4],regs->regs[5],
regs->regs[6],regs->regs[7]);
printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
regs->regs[8],regs->regs[9],
regs->regs[10],regs->regs[11]);
printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
regs->regs[12],regs->regs[13],
regs->regs[14]);
printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
regs->mach, regs->macl, regs->gbr, regs->pr);
show_trace(NULL, (unsigned long *)regs->regs[15], regs, KERN_DEFAULT);
show_code(regs);
}
void start_thread(struct pt_regs *regs, unsigned long new_pc,
unsigned long new_sp)
{
regs->pr = 0;
regs->sr = SR_FD;
regs->pc = new_pc;
regs->regs[15] = new_sp;
free_thread_xstate(current);
}
EXPORT_SYMBOL(start_thread);
void flush_thread(void)
{
struct task_struct *tsk = current;
flush_ptrace_hw_breakpoint(tsk);
#if defined(CONFIG_SH_FPU)
/* Forget lazy FPU state */
clear_fpu(tsk, task_pt_regs(tsk));
clear_used_math();
#endif
}
void release_thread(struct task_struct *dead_task)
{
/* do nothing */
}
/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
int fpvalid = 0;
#if defined(CONFIG_SH_FPU)
struct task_struct *tsk = current;
fpvalid = !!tsk_used_math(tsk);
if (fpvalid)
fpvalid = !fpregs_get(tsk, NULL,
(struct membuf){fpu, sizeof(*fpu)});
#endif
return fpvalid;
}
EXPORT_SYMBOL(dump_fpu);
asmlinkage void ret_from_fork(void);
asmlinkage void ret_from_kernel_thread(void);
int copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long arg, struct task_struct *p)
{
struct thread_info *ti = task_thread_info(p);
struct pt_regs *childregs;
#if defined(CONFIG_SH_DSP)
struct task_struct *tsk = current;
if (is_dsp_enabled(tsk)) {
/* We can use the __save_dsp or just copy the struct:
* __save_dsp(p);
* p->thread.dsp_status.status |= SR_DSP
*/
p->thread.dsp_status = tsk->thread.dsp_status;
}
#endif
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
childregs = task_pt_regs(p);
p->thread.sp = (unsigned long) childregs;
if (unlikely(p->flags & PF_KTHREAD)) {
memset(childregs, 0, sizeof(struct pt_regs));
p->thread.pc = (unsigned long) ret_from_kernel_thread;
childregs->regs[4] = arg;
childregs->regs[5] = usp;
childregs->sr = SR_MD;
#if defined(CONFIG_SH_FPU)
childregs->sr |= SR_FD;
#endif
ti->addr_limit = KERNEL_DS;
ti->status &= ~TS_USEDFPU;
p->thread.fpu_counter = 0;
return 0;
}
*childregs = *current_pt_regs();
if (usp)
childregs->regs[15] = usp;
ti->addr_limit = USER_DS;
if (clone_flags & CLONE_SETTLS)
childregs->gbr = childregs->regs[0];
childregs->regs[0] = 0; /* Set return value for child */
p->thread.pc = (unsigned long) ret_from_fork;
return 0;
}
/*
* switch_to(x,y) should switch tasks from x to y.
*
*/
__notrace_funcgraph struct task_struct *
__switch_to(struct task_struct *prev, struct task_struct *next)
{
struct thread_struct *next_t = &next->thread;
#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP)
__stack_chk_guard = next->stack_canary;
#endif
unlazy_fpu(prev, task_pt_regs(prev));
/* we're going to use this soon, after a few expensive things */
if (next->thread.fpu_counter > 5)
prefetch(next_t->xstate);
#ifdef CONFIG_MMU
/*
* Restore the kernel mode register
* k7 (r7_bank1)
*/
asm volatile("ldc %0, r7_bank"
: /* no output */
: "r" (task_thread_info(next)));
#endif
/*
* If the task has used fpu the last 5 timeslices, just do a full
* restore of the math state immediately to avoid the trap; the
* chances of needing FPU soon are obviously high now
*/
if (next->thread.fpu_counter > 5)
__fpu_state_restore();
return prev;
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long pc;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
/*
* The same comment as on the Alpha applies here, too ...
*/
pc = thread_saved_pc(p);
#ifdef CONFIG_FRAME_POINTER
if (in_sched_functions(pc)) {
unsigned long schedule_frame = (unsigned long)p->thread.sp;
return ((unsigned long *)schedule_frame)[21];
}
#endif
return pc;
}
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