// SPDX-License-Identifier: GPL-2.0-only

#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/memory.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>

#define NOP32_HI        0xc400
#define NOP32_LO        0x4820
#define BSR_LINK        0xe000

void arch_jump_label_transform(struct jump_entry *entry,
                               enum jump_label_type type)
{
        unsigned long addr = jump_entry_code(entry);
        u16 insn[2];
        int ret = 0;

        if (type == JUMP_LABEL_JMP) {
                long offset = jump_entry_target(entry) - jump_entry_code(entry);

                if (WARN_ON(offset & 1 || offset < -67108864 || offset >= 67108864))
                        return;

                offset = offset >> 1;

                insn[0] = BSR_LINK |
                        ((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
                insn[1] = (uint16_t)((unsigned long) offset & 0xffff);
        } else {
                insn[0] = NOP32_HI;
                insn[1] = NOP32_LO;
        }

        ret = copy_to_kernel_nofault((void *)addr, insn, 4);
        WARN_ON(ret);

        flush_icache_range(addr, addr + 4);
}

void arch_jump_label_transform_static(struct jump_entry *entry,
                                      enum jump_label_type type)
{
        /*
         * We use the same instructions in the arch_static_branch and
         * arch_static_branch_jump inline functions, so there's no
         * need to patch them up here.
         * The core will call arch_jump_label_transform  when those
         * instructions need to be replaced.
         */
        arch_jump_label_transform(entry, type);
}