1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/linkage.h> 4 #include <linux/types.h> 5 6 #include <asm/desc.h> 7 #include <asm/init.h> 8 #include <asm/setup.h> 9 #include <asm/sev.h> 10 #include <asm/trapnr.h> 11 12 /* 13 * Data structures and code used for IDT setup in head_64.S. The bringup-IDT is 14 * used until the idt_table takes over. On the boot CPU this happens in 15 * x86_64_start_kernel(), on secondary CPUs in start_secondary(). In both cases 16 * this happens in the functions called from head_64.S. 17 * 18 * The idt_table can't be used that early because all the code modifying it is 19 * in idt.c and can be instrumented by tracing or KASAN, which both don't work 20 * during early CPU bringup. Also the idt_table has the runtime vectors 21 * configured which require certain CPU state to be setup already (like TSS), 22 * which also hasn't happened yet in early CPU bringup. 23 */ 24 static gate_desc bringup_idt_table[NUM_EXCEPTION_VECTORS] __page_aligned_data; 25 26 /* This may run while still in the direct mapping */ 27 void __head startup_64_load_idt(void *vc_handler) 28 { 29 struct desc_ptr desc = { 30 .address = (unsigned long)rip_rel_ptr(bringup_idt_table), 31 .size = sizeof(bringup_idt_table) - 1, 32 }; 33 struct idt_data data; 34 gate_desc idt_desc; 35 36 /* @vc_handler is set only for a VMM Communication Exception */ 37 if (vc_handler) { 38 init_idt_data(&data, X86_TRAP_VC, vc_handler); 39 idt_init_desc(&idt_desc, &data); 40 native_write_idt_entry((gate_desc *)desc.address, X86_TRAP_VC, &idt_desc); 41 } 42 43 native_load_idt(&desc); 44 } 45 46 /* 47 * Setup boot CPU state needed before kernel switches to virtual addresses. 48 */ 49 void __head startup_64_setup_gdt_idt(void) 50 { 51 struct gdt_page *gp = rip_rel_ptr((void *)(__force unsigned long)&gdt_page); 52 void *handler = NULL; 53 54 struct desc_ptr startup_gdt_descr = { 55 .address = (unsigned long)gp->gdt, 56 .size = GDT_SIZE - 1, 57 }; 58 59 /* Load GDT */ 60 native_load_gdt(&startup_gdt_descr); 61 62 /* New GDT is live - reload data segment registers */ 63 asm volatile("movl %%eax, %%ds\n" 64 "movl %%eax, %%ss\n" 65 "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory"); 66 67 if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) 68 handler = rip_rel_ptr(vc_no_ghcb); 69 70 startup_64_load_idt(handler); 71 } 72