From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/openrisc/kernel/process.c | 284 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 284 insertions(+) create mode 100644 arch/openrisc/kernel/process.c (limited to 'arch/openrisc/kernel/process.c') diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c new file mode 100644 index 000000000..f94b5ec06 --- /dev/null +++ b/arch/openrisc/kernel/process.c @@ -0,0 +1,284 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * OpenRISC process.c + * + * Linux architectural port borrowing liberally from similar works of + * others. All original copyrights apply as per the original source + * declaration. + * + * Modifications for the OpenRISC architecture: + * Copyright (C) 2003 Matjaz Breskvar + * Copyright (C) 2010-2011 Jonas Bonn + * + * This file handles the architecture-dependent parts of process handling... + */ + +#define __KERNEL_SYSCALLS__ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +#include + +/* + * Pointer to Current thread info structure. + * + * Used at user space -> kernel transitions. + */ +struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, }; + +void machine_restart(char *cmd) +{ + do_kernel_restart(cmd); + + __asm__("l.nop 13"); + + /* Give a grace period for failure to restart of 1s */ + mdelay(1000); + + /* Whoops - the platform was unable to reboot. Tell the user! */ + pr_emerg("Reboot failed -- System halted\n"); + while (1); +} + +/* + * This is used if pm_power_off has not been set by a power management + * driver, in this case we can assume we are on a simulator. On + * OpenRISC simulators l.nop 1 will trigger the simulator exit. + */ +static void default_power_off(void) +{ + __asm__("l.nop 1"); +} + +/* + * Similar to machine_power_off, but don't shut off power. Add code + * here to freeze the system for e.g. post-mortem debug purpose when + * possible. This halt has nothing to do with the idle halt. + */ +void machine_halt(void) +{ + printk(KERN_INFO "*** MACHINE HALT ***\n"); + __asm__("l.nop 1"); +} + +/* If or when software power-off is implemented, add code here. */ +void machine_power_off(void) +{ + printk(KERN_INFO "*** MACHINE POWER OFF ***\n"); + if (pm_power_off != NULL) + pm_power_off(); + else + default_power_off(); +} + +/* + * Send the doze signal to the cpu if available. + * Make sure, that all interrupts are enabled + */ +void arch_cpu_idle(void) +{ + raw_local_irq_enable(); + if (mfspr(SPR_UPR) & SPR_UPR_PMP) + mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME); +} + +void (*pm_power_off)(void) = NULL; +EXPORT_SYMBOL(pm_power_off); + +/* + * When a process does an "exec", machine state like FPU and debug + * registers need to be reset. This is a hook function for that. + * Currently we don't have any such state to reset, so this is empty. + */ +void flush_thread(void) +{ +} + +void show_regs(struct pt_regs *regs) +{ + extern void show_registers(struct pt_regs *regs); + + show_regs_print_info(KERN_DEFAULT); + /* __PHX__ cleanup this mess */ + show_registers(regs); +} + +/* + * Copy the thread-specific (arch specific) info from the current + * process to the new one p + */ +extern asmlinkage void ret_from_fork(void); + +/* + * copy_thread + * @clone_flags: flags + * @usp: user stack pointer or fn for kernel thread + * @arg: arg to fn for kernel thread; always NULL for userspace thread + * @p: the newly created task + * @tls: the Thread Local Storage pointer for the new process + * + * At the top of a newly initialized kernel stack are two stacked pt_reg + * structures. The first (topmost) is the userspace context of the thread. + * The second is the kernelspace context of the thread. + * + * A kernel thread will not be returning to userspace, so the topmost pt_regs + * struct can be uninitialized; it _does_ need to exist, though, because + * a kernel thread can become a userspace thread by doing a kernel_execve, in + * which case the topmost context will be initialized and used for 'returning' + * to userspace. + * + * The second pt_reg struct needs to be initialized to 'return' to + * ret_from_fork. A kernel thread will need to set r20 to the address of + * a function to call into (with arg in r22); userspace threads need to set + * r20 to NULL in which case ret_from_fork will just continue a return to + * userspace. + * + * A kernel thread 'fn' may return; this is effectively what happens when + * kernel_execve is called. In that case, the userspace pt_regs must have + * been initialized (which kernel_execve takes care of, see start_thread + * below); ret_from_fork will then continue its execution causing the + * 'kernel thread' to return to userspace as a userspace thread. + */ + +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 *userregs; + struct pt_regs *kregs; + unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; + unsigned long top_of_kernel_stack; + + top_of_kernel_stack = sp; + + /* Locate userspace context on stack... */ + sp -= STACK_FRAME_OVERHEAD; /* redzone */ + sp -= sizeof(struct pt_regs); + userregs = (struct pt_regs *) sp; + + /* ...and kernel context */ + sp -= STACK_FRAME_OVERHEAD; /* redzone */ + sp -= sizeof(struct pt_regs); + kregs = (struct pt_regs *)sp; + + if (unlikely(args->fn)) { + memset(kregs, 0, sizeof(struct pt_regs)); + kregs->gpr[20] = (unsigned long)args->fn; + kregs->gpr[22] = (unsigned long)args->fn_arg; + } else { + *userregs = *current_pt_regs(); + + if (usp) + userregs->sp = usp; + + /* + * For CLONE_SETTLS set "tp" (r10) to the TLS pointer. + */ + if (clone_flags & CLONE_SETTLS) + userregs->gpr[10] = tls; + + userregs->gpr[11] = 0; /* Result from fork() */ + + kregs->gpr[20] = 0; /* Userspace thread */ + } + + /* + * _switch wants the kernel stack page in pt_regs->sp so that it + * can restore it to thread_info->ksp... see _switch for details. + */ + kregs->sp = top_of_kernel_stack; + kregs->gpr[9] = (unsigned long)ret_from_fork; + + task_thread_info(p)->ksp = (unsigned long)kregs; + + return 0; +} + +/* + * Set up a thread for executing a new program + */ +void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) +{ + unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM; + + memset(regs, 0, sizeof(struct pt_regs)); + + regs->pc = pc; + regs->sr = sr; + regs->sp = sp; +} + +extern struct thread_info *_switch(struct thread_info *old_ti, + struct thread_info *new_ti); +extern int lwa_flag; + +struct task_struct *__switch_to(struct task_struct *old, + struct task_struct *new) +{ + struct task_struct *last; + struct thread_info *new_ti, *old_ti; + unsigned long flags; + + local_irq_save(flags); + + /* current_set is an array of saved current pointers + * (one for each cpu). we need them at user->kernel transition, + * while we save them at kernel->user transition + */ + new_ti = new->stack; + old_ti = old->stack; + + lwa_flag = 0; + + current_thread_info_set[smp_processor_id()] = new_ti; + last = (_switch(old_ti, new_ti))->task; + + local_irq_restore(flags); + + return last; +} + +/* + * Write out registers in core dump format, as defined by the + * struct user_regs_struct + */ +void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs) +{ + dest[0] = 0; /* r0 */ + memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long)); + dest[32] = regs->pc; + dest[33] = regs->sr; + dest[34] = 0; + dest[35] = 0; +} + +unsigned long __get_wchan(struct task_struct *p) +{ + /* TODO */ + + return 0; +} -- cgit v1.2.3