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