/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_UNWIND_H
#define _ASM_X86_UNWIND_H

#include <linux/sched.h>
#include <linux/ftrace.h>
#include <linux/rethook.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>

#define IRET_FRAME_OFFSET (offsetof(struct pt_regs, ip))
#define IRET_FRAME_SIZE   (sizeof(struct pt_regs) - IRET_FRAME_OFFSET)

struct unwind_state {
        struct stack_info stack_info;
        unsigned long stack_mask;
        struct task_struct *task;
        int graph_idx;
#if defined(CONFIG_RETHOOK)
        struct llist_node *kr_cur;
#endif
        bool error;
#if defined(CONFIG_UNWINDER_ORC)
        bool signal, full_regs;
        unsigned long sp, bp, ip;
        struct pt_regs *regs, *prev_regs;
#elif defined(CONFIG_UNWINDER_FRAME_POINTER)
        bool got_irq;
        unsigned long *bp, *orig_sp, ip;
        /*
         * If non-NULL: The current frame is incomplete and doesn't contain a
         * valid BP. When looking for the next frame, use this instead of the
         * non-existent saved BP.
         */
        unsigned long *next_bp;
        struct pt_regs *regs;
#else
        unsigned long *sp;
#endif
};

void __unwind_start(struct unwind_state *state, struct task_struct *task,
                    struct pt_regs *regs, unsigned long *first_frame);
bool unwind_next_frame(struct unwind_state *state);
unsigned long unwind_get_return_address(struct unwind_state *state);
unsigned long *unwind_get_return_address_ptr(struct unwind_state *state);

static inline bool unwind_done(struct unwind_state *state)
{
        return state->stack_info.type == STACK_TYPE_UNKNOWN;
}

static inline bool unwind_error(struct unwind_state *state)
{
        return state->error;
}

static inline
void unwind_start(struct unwind_state *state, struct task_struct *task,
                  struct pt_regs *regs, unsigned long *first_frame)
{
        first_frame = first_frame ? : get_stack_pointer(task, regs);

        __unwind_start(state, task, regs, first_frame);
}

#if defined(CONFIG_UNWINDER_ORC) || defined(CONFIG_UNWINDER_FRAME_POINTER)
/*
 * If 'partial' returns true, only the iret frame registers are valid.
 */
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state,
                                                    bool *partial)
{
        if (unwind_done(state))
                return NULL;

        if (partial) {
#ifdef CONFIG_UNWINDER_ORC
                *partial = !state->full_regs;
#else
                *partial = false;
#endif
        }

        return state->regs;
}
#else
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state,
                                                    bool *partial)
{
        return NULL;
}
#endif

#ifdef CONFIG_UNWINDER_ORC
void unwind_init(void);
void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
                        void *orc, size_t orc_size);
#else
static inline void unwind_init(void) {}
static inline
void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
                        void *orc, size_t orc_size) {}
#endif

static inline
unsigned long unwind_recover_rethook(struct unwind_state *state,
                                     unsigned long addr, unsigned long *addr_p)
{
#ifdef CONFIG_RETHOOK
        if (is_rethook_trampoline(addr))
                return rethook_find_ret_addr(state->task, (unsigned long)addr_p,
                                             &state->kr_cur);
#endif
        return addr;
}

/* Recover the return address modified by rethook and ftrace_graph. */
static inline
unsigned long unwind_recover_ret_addr(struct unwind_state *state,
                                     unsigned long addr, unsigned long *addr_p)
{
        unsigned long ret;

        ret = ftrace_graph_ret_addr(state->task, &state->graph_idx,
                                    addr, addr_p);
        return unwind_recover_rethook(state, ret, addr_p);
}

/*
 * This disables KASAN checking when reading a value from another task's stack,
 * since the other task could be running on another CPU and could have poisoned
 * the stack in the meantime.
 */
#define READ_ONCE_TASK_STACK(task, x)                   \
({                                                      \
        unsigned long val;                              \
        if (task == current)                            \
                val = READ_ONCE(x);                     \
        else                                            \
                val = READ_ONCE_NOCHECK(x);             \
        val;                                            \
})

static inline bool task_on_another_cpu(struct task_struct *task)
{
#ifdef CONFIG_SMP
        return task != current && task->on_cpu;
#else
        return false;
#endif
}

#endif /* _ASM_X86_UNWIND_H */