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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Common place for both 32- and 64-bit entry routines.
*/
#include <linux/export.h>
#include <linux/kvm_types.h>
#include <linux/linkage.h>
#include <linux/objtool.h>
#include <asm/msr-index.h>
#include <asm/unwind_hints.h>
#include <asm/segment.h>
#include <asm/cache.h>
#include <asm/cpufeatures.h>
#include <asm/nospec-branch.h>
#include "calling.h"
.pushsection .noinstr.text, "ax"
/* Clobbers AX, CX, DX */
SYM_FUNC_START(write_ibpb)
ANNOTATE_NOENDBR
movl $MSR_IA32_PRED_CMD, %ecx
movl _ASM_RIP(x86_pred_cmd), %eax
xorl %edx, %edx
wrmsr
/* Make sure IBPB clears return stack preductions too. */
FILL_RETURN_BUFFER %rax, RSB_CLEAR_LOOPS, X86_BUG_IBPB_NO_RET
RET
SYM_FUNC_END(write_ibpb)
EXPORT_SYMBOL_FOR_KVM(write_ibpb);
SYM_FUNC_START(__WARN_trap)
ANNOTATE_NOENDBR
ANNOTATE_REACHABLE
ud1 (%edx), %_ASM_ARG1
RET
SYM_FUNC_END(__WARN_trap)
EXPORT_SYMBOL(__WARN_trap)
.popsection
/*
* Define the VERW operand that is disguised as entry code so that
* it can be referenced with KPTI enabled. This ensures VERW can be
* used late in exit-to-user path after page tables are switched.
*/
.pushsection .entry.text, "ax"
.align L1_CACHE_BYTES, 0xcc
SYM_CODE_START_NOALIGN(x86_verw_sel)
UNWIND_HINT_UNDEFINED
ANNOTATE_NOENDBR
.word __KERNEL_DS
.align L1_CACHE_BYTES, 0xcc
SYM_CODE_END(x86_verw_sel);
EXPORT_SYMBOL_FOR_KVM(x86_verw_sel);
.popsection
THUNK warn_thunk_thunk, __warn_thunk
/*
* Clang's implementation of TLS stack cookies requires the variable in
* question to be a TLS variable. If the variable happens to be defined as an
* ordinary variable with external linkage in the same compilation unit (which
* amounts to the whole of vmlinux with LTO enabled), Clang will drop the
* segment register prefix from the references, resulting in broken code. Work
* around this by avoiding the symbol used in -mstack-protector-guard-symbol=
* entirely in the C code, and use an alias emitted by the linker script
* instead.
*/
#if defined(CONFIG_STACKPROTECTOR) && defined(CONFIG_SMP)
EXPORT_SYMBOL(__ref_stack_chk_guard);
#endif
#if IS_ENABLED(CONFIG_KVM_INTEL)
.macro IDT_DO_EVENT_IRQOFF call_insn call_target
/*
* Unconditionally create a stack frame, getting the correct RSP on the
* stack (for x86-64) would take two instructions anyways, and RBP can
* be used to restore RSP to make objtool happy (see below).
*/
push %_ASM_BP
mov %_ASM_SP, %_ASM_BP
#ifdef CONFIG_X86_64
/*
* Align RSP to a 16-byte boundary (to emulate CPU behavior) before
* creating the synthetic interrupt stack frame for the IRQ/NMI.
*/
and $-16, %rsp
push $__KERNEL_DS
push %rbp
#endif
pushf
push $__KERNEL_CS
\call_insn \call_target
/*
* "Restore" RSP from RBP, even though IRET has already unwound RSP to
* the correct value. objtool doesn't know the callee will IRET and,
* without the explicit restore, thinks the stack is getting walloped.
* Using an unwind hint is problematic due to x86-64's dynamic alignment.
*/
leave
RET
.endm
#ifndef CONFIG_X86_64
.pushsection .text, "ax"
SYM_FUNC_START(idt_do_interrupt_irqoff)
IDT_DO_EVENT_IRQOFF CALL_NOSPEC _ASM_ARG1
SYM_FUNC_END(idt_do_interrupt_irqoff)
.popsection
#endif
.pushsection .noinstr.text, "ax"
SYM_FUNC_START(idt_do_nmi_irqoff)
IDT_DO_EVENT_IRQOFF call asm_exc_nmi_kvm_vmx
SYM_FUNC_END(idt_do_nmi_irqoff)
.popsection
#endif
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