/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _KSTACK_H
#define _KSTACK_H

#include <linux/thread_info.h>
#include <linux/sched.h>
#include <asm/ptrace.h>
#include <asm/irq.h>

/* SP must be STACK_BIAS adjusted already.  */
static inline bool kstack_valid(struct thread_info *tp, unsigned long sp)
{
        unsigned long base = (unsigned long) tp;

        /* Stack pointer must be 16-byte aligned.  */
        if (sp & (16UL - 1))
                return false;

        if (sp >= (base + sizeof(struct thread_info)) &&
            sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
                return true;

        if (hardirq_stack[tp->cpu]) {
                base = (unsigned long) hardirq_stack[tp->cpu];
                if (sp >= base &&
                    sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
                        return true;
                base = (unsigned long) softirq_stack[tp->cpu];
                if (sp >= base &&
                    sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
                        return true;
        }
        return false;
}

/* Does "regs" point to a valid pt_regs trap frame?  */
static inline bool kstack_is_trap_frame(struct thread_info *tp, struct pt_regs *regs)
{
        unsigned long base = (unsigned long) tp;
        unsigned long addr = (unsigned long) regs;

        if (addr >= base &&
            addr <= (base + THREAD_SIZE - sizeof(*regs)))
                goto check_magic;

        if (hardirq_stack[tp->cpu]) {
                base = (unsigned long) hardirq_stack[tp->cpu];
                if (addr >= base &&
                    addr <= (base + THREAD_SIZE - sizeof(*regs)))
                        goto check_magic;
                base = (unsigned long) softirq_stack[tp->cpu];
                if (addr >= base &&
                    addr <= (base + THREAD_SIZE - sizeof(*regs)))
                        goto check_magic;
        }
        return false;

check_magic:
        if ((regs->magic & ~0x1ff) == PT_REGS_MAGIC)
                return true;
        return false;

}

static inline __attribute__((always_inline)) void *set_hardirq_stack(void)
{
        void *orig_sp, *sp = hardirq_stack[smp_processor_id()];

        __asm__ __volatile__("mov %%sp, %0" : "=r" (orig_sp));
        if (orig_sp < sp ||
            orig_sp > (sp + THREAD_SIZE)) {
                sp += THREAD_SIZE - 192 - STACK_BIAS;
                __asm__ __volatile__("mov %0, %%sp" : : "r" (sp));
        }

        return orig_sp;
}

static inline __attribute__((always_inline)) void restore_hardirq_stack(void *orig_sp)
{
        __asm__ __volatile__("mov %0, %%sp" : : "r" (orig_sp));
}

#endif /* _KSTACK_H */