// SPDX-License-Identifier: GPL-2.0
/*
 * Stack dumping functions
 *
 *  Copyright IBM Corp. 1999, 2013
 */

#include <linux/kallsyms.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <linux/utsname.h>
#include <linux/export.h>
#include <linux/kdebug.h>
#include <linux/ptrace.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <asm/asm-offsets.h>
#include <asm/processor.h>
#include <asm/debug.h>
#include <asm/dis.h>
#include <asm/ipl.h>
#include <asm/unwind.h>

const char *stack_type_name(enum stack_type type)
{
        switch (type) {
        case STACK_TYPE_TASK:
                return "task";
        case STACK_TYPE_IRQ:
                return "irq";
        case STACK_TYPE_NODAT:
                return "nodat";
        case STACK_TYPE_RESTART:
                return "restart";
        default:
                return "unknown";
        }
}
EXPORT_SYMBOL_GPL(stack_type_name);

static inline bool in_stack(unsigned long sp, struct stack_info *info,
                            enum stack_type type, unsigned long stack)
{
        if (sp < stack || sp >= stack + THREAD_SIZE)
                return false;
        info->type = type;
        info->begin = stack;
        info->end = stack + THREAD_SIZE;
        return true;
}

static bool in_task_stack(unsigned long sp, struct task_struct *task,
                          struct stack_info *info)
{
        unsigned long stack = (unsigned long)task_stack_page(task);

        return in_stack(sp, info, STACK_TYPE_TASK, stack);
}

static bool in_irq_stack(unsigned long sp, struct stack_info *info)
{
        unsigned long stack = get_lowcore()->async_stack - STACK_INIT_OFFSET;

        return in_stack(sp, info, STACK_TYPE_IRQ, stack);
}

static bool in_nodat_stack(unsigned long sp, struct stack_info *info)
{
        unsigned long stack = get_lowcore()->nodat_stack - STACK_INIT_OFFSET;

        return in_stack(sp, info, STACK_TYPE_NODAT, stack);
}

static bool in_mcck_stack(unsigned long sp, struct stack_info *info)
{
        unsigned long stack = get_lowcore()->mcck_stack - STACK_INIT_OFFSET;

        return in_stack(sp, info, STACK_TYPE_MCCK, stack);
}

static bool in_restart_stack(unsigned long sp, struct stack_info *info)
{
        unsigned long stack = get_lowcore()->restart_stack - STACK_INIT_OFFSET;

        return in_stack(sp, info, STACK_TYPE_RESTART, stack);
}

int get_stack_info(unsigned long sp, struct task_struct *task,
                   struct stack_info *info, unsigned long *visit_mask)
{
        if (!sp)
                goto unknown;

        /* Sanity check: ABI requires SP to be aligned 8 bytes. */
        if (sp & 0x7)
                goto unknown;

        /* Check per-task stack */
        if (in_task_stack(sp, task, info))
                goto recursion_check;

        if (task != current)
                goto unknown;

        /* Check per-cpu stacks */
        if (!in_irq_stack(sp, info) &&
            !in_nodat_stack(sp, info) &&
            !in_restart_stack(sp, info) &&
            !in_mcck_stack(sp, info))
                goto unknown;

recursion_check:
        /*
         * Make sure we don't iterate through any given stack more than once.
         * If it comes up a second time then there's something wrong going on:
         * just break out and report an unknown stack type.
         */
        if (*visit_mask & (1UL << info->type))
                goto unknown;
        *visit_mask |= 1UL << info->type;
        return 0;
unknown:
        info->type = STACK_TYPE_UNKNOWN;
        return -EINVAL;
}

void show_stack(struct task_struct *task, unsigned long *stack,
                       const char *loglvl)
{
        struct unwind_state state;

        printk("%sCall Trace:\n", loglvl);
        unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
                printk(state.reliable ? "%s [<%016lx>] %pSR \n" :
                                        "%s([<%016lx>] %pSR)\n",
                       loglvl, state.ip, (void *) state.ip);
        debug_show_held_locks(task ? : current);
}

static void show_last_breaking_event(struct pt_regs *regs)
{
        printk("Last Breaking-Event-Address:\n");
        printk(" [<%016lx>] ", regs->last_break);
        if (user_mode(regs)) {
                print_vma_addr(KERN_CONT, regs->last_break);
                pr_cont("\n");
        } else {
                pr_cont("%pSR\n", (void *)regs->last_break);
        }
}

void show_registers(struct pt_regs *regs)
{
        struct psw_bits *psw = &psw_bits(regs->psw);
        unsigned long pswaddr;
        char *mode;

        pswaddr = regs->psw.addr;
        if (test_pt_regs_flag(regs, PIF_PSW_ADDR_ADJUSTED))
                pswaddr = __forward_psw(regs->psw, regs->int_code >> 16);
        mode = user_mode(regs) ? "User" : "Krnl";
        printk("%s PSW : %px %px", mode, (void *)regs->psw.mask, (void *)pswaddr);
        if (!user_mode(regs))
                pr_cont(" (%pSR)", (void *)pswaddr);
        pr_cont("\n");
        printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
               "P:%x AS:%x CC:%x PM:%x", psw->per, psw->dat, psw->io, psw->ext,
               psw->key, psw->mcheck, psw->wait, psw->pstate, psw->as, psw->cc, psw->pm);
        pr_cont(" RI:%x EA:%x\n", psw->ri, psw->eaba);
        printk("%s GPRS: %016lx %016lx %016lx %016lx\n", mode,
               regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
        printk("           %016lx %016lx %016lx %016lx\n",
               regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
        printk("           %016lx %016lx %016lx %016lx\n",
               regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
        printk("           %016lx %016lx %016lx %016lx\n",
               regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
        show_code(regs);
}

void show_regs(struct pt_regs *regs)
{
        show_regs_print_info(KERN_DEFAULT);
        show_registers(regs);
        /* Show stack backtrace if pt_regs is from kernel mode */
        if (!user_mode(regs))
                show_stack(NULL, (unsigned long *) regs->gprs[15], KERN_DEFAULT);
        show_last_breaking_event(regs);
}

static DEFINE_SPINLOCK(die_lock);

void __noreturn die(struct pt_regs *regs, const char *str)
{
        static int die_counter;

        oops_enter();
        lgr_info_log();
        debug_stop_all();
        console_verbose();
        spin_lock_irq(&die_lock);
        bust_spinlocks(1);
        printk("%s: %04x ilc:%d [#%d]", str, regs->int_code & 0xffff,
               regs->int_code >> 17, ++die_counter);
        pr_cont("SMP ");
        if (debug_pagealloc_enabled())
                pr_cont("DEBUG_PAGEALLOC");
        pr_cont("\n");
        notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
        print_modules();
        show_regs(regs);
        bust_spinlocks(0);
        add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
        spin_unlock_irq(&die_lock);
        if (in_interrupt())
                panic("Fatal exception in interrupt");
        if (panic_on_oops)
                panic("Fatal exception: panic_on_oops");
        oops_exit();
        make_task_dead(SIGSEGV);
}