1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * Common place for both 32- and 64-bit entry routines. 4 */ 5 6#include <linux/export.h> 7#include <linux/kvm_types.h> 8#include <linux/linkage.h> 9#include <linux/objtool.h> 10#include <asm/msr-index.h> 11#include <asm/unwind_hints.h> 12#include <asm/segment.h> 13#include <asm/cache.h> 14#include <asm/cpufeatures.h> 15#include <asm/nospec-branch.h> 16 17#include "calling.h" 18 19.pushsection .noinstr.text, "ax" 20 21/* Clobbers AX, CX, DX */ 22SYM_FUNC_START(write_ibpb) 23 ANNOTATE_NOENDBR 24 movl $MSR_IA32_PRED_CMD, %ecx 25 movl _ASM_RIP(x86_pred_cmd), %eax 26 xorl %edx, %edx 27 wrmsr 28 29 /* Make sure IBPB clears return stack preductions too. */ 30 FILL_RETURN_BUFFER %rax, RSB_CLEAR_LOOPS, X86_BUG_IBPB_NO_RET 31 RET 32SYM_FUNC_END(write_ibpb) 33EXPORT_SYMBOL_FOR_KVM(write_ibpb); 34 35SYM_FUNC_START(__WARN_trap) 36 ANNOTATE_NOENDBR 37 ANNOTATE_REACHABLE 38 ud1 (%edx), %_ASM_ARG1 39 RET 40SYM_FUNC_END(__WARN_trap) 41EXPORT_SYMBOL(__WARN_trap) 42 43.popsection 44 45/* 46 * Define the VERW operand that is disguised as entry code so that 47 * it can be referenced with KPTI enabled. This ensures VERW can be 48 * used late in exit-to-user path after page tables are switched. 49 */ 50.pushsection .entry.text, "ax" 51 52.align L1_CACHE_BYTES, 0xcc 53SYM_CODE_START_NOALIGN(x86_verw_sel) 54 UNWIND_HINT_UNDEFINED 55 ANNOTATE_NOENDBR 56 .word __KERNEL_DS 57.align L1_CACHE_BYTES, 0xcc 58SYM_CODE_END(x86_verw_sel); 59EXPORT_SYMBOL_FOR_KVM(x86_verw_sel); 60 61.popsection 62 63THUNK warn_thunk_thunk, __warn_thunk 64 65/* 66 * Clang's implementation of TLS stack cookies requires the variable in 67 * question to be a TLS variable. If the variable happens to be defined as an 68 * ordinary variable with external linkage in the same compilation unit (which 69 * amounts to the whole of vmlinux with LTO enabled), Clang will drop the 70 * segment register prefix from the references, resulting in broken code. Work 71 * around this by avoiding the symbol used in -mstack-protector-guard-symbol= 72 * entirely in the C code, and use an alias emitted by the linker script 73 * instead. 74 */ 75#if defined(CONFIG_STACKPROTECTOR) && defined(CONFIG_SMP) 76EXPORT_SYMBOL(__ref_stack_chk_guard); 77#endif 78 79#if IS_ENABLED(CONFIG_KVM_INTEL) 80.macro IDT_DO_EVENT_IRQOFF call_insn call_target 81 /* 82 * Unconditionally create a stack frame, getting the correct RSP on the 83 * stack (for x86-64) would take two instructions anyways, and RBP can 84 * be used to restore RSP to make objtool happy (see below). 85 */ 86 push %_ASM_BP 87 mov %_ASM_SP, %_ASM_BP 88 89#ifdef CONFIG_X86_64 90 /* 91 * Align RSP to a 16-byte boundary (to emulate CPU behavior) before 92 * creating the synthetic interrupt stack frame for the IRQ/NMI. 93 */ 94 and $-16, %rsp 95 push $__KERNEL_DS 96 push %rbp 97#endif 98 pushf 99 push $__KERNEL_CS 100 \call_insn \call_target 101 102 /* 103 * "Restore" RSP from RBP, even though IRET has already unwound RSP to 104 * the correct value. objtool doesn't know the callee will IRET and, 105 * without the explicit restore, thinks the stack is getting walloped. 106 * Using an unwind hint is problematic due to x86-64's dynamic alignment. 107 */ 108 leave 109 RET 110.endm 111 112#ifndef CONFIG_X86_64 113.pushsection .text, "ax" 114SYM_FUNC_START(idt_do_interrupt_irqoff) 115 IDT_DO_EVENT_IRQOFF CALL_NOSPEC _ASM_ARG1 116SYM_FUNC_END(idt_do_interrupt_irqoff) 117.popsection 118#endif 119 120.pushsection .noinstr.text, "ax" 121SYM_FUNC_START(idt_do_nmi_irqoff) 122 IDT_DO_EVENT_IRQOFF call asm_exc_nmi_kvm_vmx 123SYM_FUNC_END(idt_do_nmi_irqoff) 124.popsection 125#endif 126