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linux/arch/nios2/kernel/process.c
Peter Zijlstra 89b3098703 arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled 
Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.

However, the very first thing the generic code does after calling
arch_cpu_idle() is raw_local_irq_disable(). This means that
architectures that can idle with IRQs disabled end up doing a
pointless 'enable-disable' dance.

Therefore, push this IRQ disabling into the idle function, meaning
that those architectures can avoid the pointless IRQ state flipping.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org
2023-01-13 11:48:15 +01:00

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/*
* Architecture-dependent parts of process handling.
*
* Copyright (C) 2013 Altera Corporation
* Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2009 Wind River Systems Inc
* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
* Copyright (C) 2004 Microtronix Datacom Ltd
*
* 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.
*/
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/mm_types.h>
#include <linux/tick.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/traps.h>
#include <asm/cpuinfo.h>
asmlinkage void ret_from_fork(void);
asmlinkage void ret_from_kernel_thread(void);
void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);
void arch_cpu_idle(void)
{
}
/*
* The development boards have no way to pull a board reset. Just jump to the
* cpu reset address and let the boot loader or the code in head.S take care of
* resetting peripherals.
*/
void machine_restart(char *__unused)
{
pr_notice("Machine restart (%08x)...\n", cpuinfo.reset_addr);
local_irq_disable();
__asm__ __volatile__ (
"jmp %0\n\t"
:
: "r" (cpuinfo.reset_addr)
: "r4");
}
void machine_halt(void)
{
pr_notice("Machine halt...\n");
local_irq_disable();
for (;;)
;
}
/*
* There is no way to power off the development boards. So just spin for now. If
* we ever have a way of resetting a board using a GPIO we should add that here.
*/
void machine_power_off(void)
{
pr_notice("Machine power off...\n");
local_irq_disable();
for (;;)
;
}
void show_regs(struct pt_regs *regs)
{
pr_notice("\n");
show_regs_print_info(KERN_DEFAULT);
pr_notice("r1: %08lx r2: %08lx r3: %08lx r4: %08lx\n",
regs->r1, regs->r2, regs->r3, regs->r4);
pr_notice("r5: %08lx r6: %08lx r7: %08lx r8: %08lx\n",
regs->r5, regs->r6, regs->r7, regs->r8);
pr_notice("r9: %08lx r10: %08lx r11: %08lx r12: %08lx\n",
regs->r9, regs->r10, regs->r11, regs->r12);
pr_notice("r13: %08lx r14: %08lx r15: %08lx\n",
regs->r13, regs->r14, regs->r15);
pr_notice("ra: %08lx fp: %08lx sp: %08lx gp: %08lx\n",
regs->ra, regs->fp, regs->sp, regs->gp);
pr_notice("ea: %08lx estatus: %08lx\n",
regs->ea, regs->estatus);
}
void flush_thread(void)
{
}
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 pt_regs *childregs = task_pt_regs(p);
struct pt_regs *regs;
struct switch_stack *stack;
struct switch_stack *childstack =
((struct switch_stack *)childregs) - 1;
if (unlikely(args->fn)) {
memset(childstack, 0,
sizeof(struct switch_stack) + sizeof(struct pt_regs));
childstack->r16 = (unsigned long) args->fn;
childstack->r17 = (unsigned long) args->fn_arg;
childstack->ra = (unsigned long) ret_from_kernel_thread;
childregs->estatus = STATUS_PIE;
childregs->sp = (unsigned long) childstack;
p->thread.ksp = (unsigned long) childstack;
p->thread.kregs = childregs;
return 0;
}
regs = current_pt_regs();
*childregs = *regs;
childregs->r2 = 0; /* Set the return value for the child. */
childregs->r7 = 0;
stack = ((struct switch_stack *) regs) - 1;
*childstack = *stack;
childstack->ra = (unsigned long)ret_from_fork;
p->thread.kregs = childregs;
p->thread.ksp = (unsigned long) childstack;
if (usp)
childregs->sp = usp;
/* Initialize tls register. */
if (clone_flags & CLONE_SETTLS)
childstack->r23 = tls;
return 0;
}
/*
* Generic dumping code. Used for panic and debug.
*/
void dump(struct pt_regs *fp)
{
unsigned long *sp;
unsigned char *tp;
int i;
pr_emerg("\nCURRENT PROCESS:\n\n");
pr_emerg("COMM=%s PID=%d\n", current->comm, current->pid);
if (current->mm) {
pr_emerg("TEXT=%08x-%08x DATA=%08x-%08x BSS=%08x-%08x\n",
(int) current->mm->start_code,
(int) current->mm->end_code,
(int) current->mm->start_data,
(int) current->mm->end_data,
(int) current->mm->end_data,
(int) current->mm->brk);
pr_emerg("USER-STACK=%08x KERNEL-STACK=%08x\n\n",
(int) current->mm->start_stack,
(int)(((unsigned long) current) + THREAD_SIZE));
}
pr_emerg("PC: %08lx\n", fp->ea);
pr_emerg("SR: %08lx SP: %08lx\n",
(long) fp->estatus, (long) fp);
pr_emerg("r1: %08lx r2: %08lx r3: %08lx\n",
fp->r1, fp->r2, fp->r3);
pr_emerg("r4: %08lx r5: %08lx r6: %08lx r7: %08lx\n",
fp->r4, fp->r5, fp->r6, fp->r7);
pr_emerg("r8: %08lx r9: %08lx r10: %08lx r11: %08lx\n",
fp->r8, fp->r9, fp->r10, fp->r11);
pr_emerg("r12: %08lx r13: %08lx r14: %08lx r15: %08lx\n",
fp->r12, fp->r13, fp->r14, fp->r15);
pr_emerg("or2: %08lx ra: %08lx fp: %08lx sp: %08lx\n",
fp->orig_r2, fp->ra, fp->fp, fp->sp);
pr_emerg("\nUSP: %08x TRAPFRAME: %08x\n",
(unsigned int) fp->sp, (unsigned int) fp);
pr_emerg("\nCODE:");
tp = ((unsigned char *) fp->ea) - 0x20;
for (sp = (unsigned long *) tp, i = 0; (i < 0x40); i += 4) {
if ((i % 0x10) == 0)
pr_emerg("\n%08x: ", (int) (tp + i));
pr_emerg("%08x ", (int) *sp++);
}
pr_emerg("\n");
pr_emerg("\nKERNEL STACK:");
tp = ((unsigned char *) fp) - 0x40;
for (sp = (unsigned long *) tp, i = 0; (i < 0xc0); i += 4) {
if ((i % 0x10) == 0)
pr_emerg("\n%08x: ", (int) (tp + i));
pr_emerg("%08x ", (int) *sp++);
}
pr_emerg("\n");
pr_emerg("\n");
pr_emerg("\nUSER STACK:");
tp = (unsigned char *) (fp->sp - 0x10);
for (sp = (unsigned long *) tp, i = 0; (i < 0x80); i += 4) {
if ((i % 0x10) == 0)
pr_emerg("\n%08x: ", (int) (tp + i));
pr_emerg("%08x ", (int) *sp++);
}
pr_emerg("\n\n");
}
unsigned long __get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
stack_page = (unsigned long)p;
fp = ((struct switch_stack *)p->thread.ksp)->fp; /* ;dgt2 */
do {
if (fp < stack_page+sizeof(struct task_struct) ||
fp >= 8184+stack_page) /* ;dgt2;tmp */
return 0;
pc = ((unsigned long *)fp)[1];
if (!in_sched_functions(pc))
return pc;
fp = *(unsigned long *) fp;
} while (count++ < 16); /* ;dgt2;tmp */
return 0;
}
/*
* Do necessary setup to start up a newly executed thread.
* Will startup in user mode (status_extension = 0).
*/
void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
{
memset((void *) regs, 0, sizeof(struct pt_regs));
regs->estatus = ESTATUS_EPIE | ESTATUS_EU;
regs->ea = pc;
regs->sp = sp;
}
asmlinkage int nios2_clone(unsigned long clone_flags, unsigned long newsp,
int __user *parent_tidptr, int __user *child_tidptr,
unsigned long tls)
{
struct kernel_clone_args args = {
.flags = (lower_32_bits(clone_flags) & ~CSIGNAL),
.pidfd = parent_tidptr,
.child_tid = child_tidptr,
.parent_tid = parent_tidptr,
.exit_signal = (lower_32_bits(clone_flags) & CSIGNAL),
.stack = newsp,
.tls = tls,
};
return kernel_clone(&args);
}
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