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/linkage.h> 8#include <asm/msr-index.h> 9#include <asm/unwind_hints.h> 10#include <asm/segment.h> 11#include <asm/cache.h> 12#include <asm/cpufeatures.h> 13#include <asm/nospec-branch.h> 14 15#include "calling.h" 16 17.pushsection .noinstr.text, "ax" 18 19SYM_FUNC_START(entry_ibpb) 20 movl $MSR_IA32_PRED_CMD, %ecx 21 movl $PRED_CMD_IBPB, %eax 22 xorl %edx, %edx 23 wrmsr 24 25 /* Make sure IBPB clears return stack preductions too. */ 26 FILL_RETURN_BUFFER %rax, RSB_CLEAR_LOOPS, X86_BUG_IBPB_NO_RET 27 RET 28SYM_FUNC_END(entry_ibpb) 29/* For KVM */ 30EXPORT_SYMBOL_GPL(entry_ibpb); 31 32.popsection 33 34/* 35 * Define the VERW operand that is disguised as entry code so that 36 * it can be referenced with KPTI enabled. This ensure VERW can be 37 * used late in exit-to-user path after page tables are switched. 38 */ 39.pushsection .entry.text, "ax" 40 41.align L1_CACHE_BYTES, 0xcc 42SYM_CODE_START_NOALIGN(mds_verw_sel) 43 UNWIND_HINT_UNDEFINED 44 ANNOTATE_NOENDBR 45 .word __KERNEL_DS 46.align L1_CACHE_BYTES, 0xcc 47SYM_CODE_END(mds_verw_sel); 48/* For KVM */ 49EXPORT_SYMBOL_GPL(mds_verw_sel); 50 51.popsection 52 53THUNK warn_thunk_thunk, __warn_thunk 54 55#ifndef CONFIG_X86_64 56/* 57 * Clang's implementation of TLS stack cookies requires the variable in 58 * question to be a TLS variable. If the variable happens to be defined as an 59 * ordinary variable with external linkage in the same compilation unit (which 60 * amounts to the whole of vmlinux with LTO enabled), Clang will drop the 61 * segment register prefix from the references, resulting in broken code. Work 62 * around this by avoiding the symbol used in -mstack-protector-guard-symbol= 63 * entirely in the C code, and use an alias emitted by the linker script 64 * instead. 65 */ 66#ifdef CONFIG_STACKPROTECTOR 67EXPORT_SYMBOL(__ref_stack_chk_guard); 68#endif 69#endif 70