// SPDX-License-Identifier: GPL-2.0

#include <linux/linkage.h>
#include <linux/types.h>

#include <asm/desc.h>
#include <asm/init.h>
#include <asm/setup.h>
#include <asm/sev.h>
#include <asm/trapnr.h>

/*
 * Data structures and code used for IDT setup in head_64.S. The bringup-IDT is
 * used until the idt_table takes over. On the boot CPU this happens in
 * x86_64_start_kernel(), on secondary CPUs in start_secondary(). In both cases
 * this happens in the functions called from head_64.S.
 *
 * The idt_table can't be used that early because all the code modifying it is
 * in idt.c and can be instrumented by tracing or KASAN, which both don't work
 * during early CPU bringup. Also the idt_table has the runtime vectors
 * configured which require certain CPU state to be setup already (like TSS),
 * which also hasn't happened yet in early CPU bringup.
 */
static gate_desc bringup_idt_table[NUM_EXCEPTION_VECTORS] __page_aligned_data;

/* This may run while still in the direct mapping */
void startup_64_load_idt(void *vc_handler)
{
        struct desc_ptr desc = {
                .address = (unsigned long)rip_rel_ptr(bringup_idt_table),
                .size    = sizeof(bringup_idt_table) - 1,
        };
        struct idt_data data;
        gate_desc idt_desc;

        /* @vc_handler is set only for a VMM Communication Exception */
        if (vc_handler) {
                init_idt_data(&data, X86_TRAP_VC, vc_handler);
                idt_init_desc(&idt_desc, &data);
                native_write_idt_entry((gate_desc *)desc.address, X86_TRAP_VC, &idt_desc);
        }

        native_load_idt(&desc);
}

/*
 * Setup boot CPU state needed before kernel switches to virtual addresses.
 */
void __init startup_64_setup_gdt_idt(void)
{
        struct gdt_page *gp = rip_rel_ptr((void *)(__force unsigned long)&gdt_page);
        void *handler = NULL;

        struct desc_ptr startup_gdt_descr = {
                .address = (unsigned long)gp->gdt,
                .size    = GDT_SIZE - 1,
        };

        /* Load GDT */
        native_load_gdt(&startup_gdt_descr);

        /* New GDT is live - reload data segment registers */
        asm volatile("movl %%eax, %%ds\n"
                     "movl %%eax, %%ss\n"
                     "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory");

        if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
                handler = rip_rel_ptr(vc_no_ghcb);

        startup_64_load_idt(handler);
}