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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/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)
/* For KVM */
EXPORT_SYMBOL_GPL(write_ibpb);
.popsection
/*
* Define the VERW operand that is disguised as entry code so that
* it can be referenced with KPTI enabled. This ensure 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(mds_verw_sel)
UNWIND_HINT_UNDEFINED
ANNOTATE_NOENDBR
.word __KERNEL_DS
.align L1_CACHE_BYTES, 0xcc
SYM_CODE_END(mds_verw_sel);
/* For KVM */
EXPORT_SYMBOL_GPL(mds_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
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