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 20/* Clobbers AX, CX, DX */ 21SYM_FUNC_START(write_ibpb) 22 ANNOTATE_NOENDBR 23 movl $MSR_IA32_PRED_CMD, %ecx 24 movl _ASM_RIP(x86_pred_cmd), %eax 25 xorl %edx, %edx 26 wrmsr 27 28 /* Make sure IBPB clears return stack preductions too. */ 29 FILL_RETURN_BUFFER %rax, RSB_CLEAR_LOOPS, X86_BUG_IBPB_NO_RET 30 RET 31SYM_FUNC_END(write_ibpb) 32/* For KVM */ 33EXPORT_SYMBOL_GPL(write_ibpb); 34 35.popsection 36 37/* 38 * Define the VERW operand that is disguised as entry code so that 39 * it can be referenced with KPTI enabled. This ensure VERW can be 40 * used late in exit-to-user path after page tables are switched. 41 */ 42.pushsection .entry.text, "ax" 43 44.align L1_CACHE_BYTES, 0xcc 45SYM_CODE_START_NOALIGN(mds_verw_sel) 46 UNWIND_HINT_UNDEFINED 47 ANNOTATE_NOENDBR 48 .word __KERNEL_DS 49.align L1_CACHE_BYTES, 0xcc 50SYM_CODE_END(mds_verw_sel); 51/* For KVM */ 52EXPORT_SYMBOL_GPL(mds_verw_sel); 53 54.popsection 55 56THUNK warn_thunk_thunk, __warn_thunk 57 58/* 59 * Clang's implementation of TLS stack cookies requires the variable in 60 * question to be a TLS variable. If the variable happens to be defined as an 61 * ordinary variable with external linkage in the same compilation unit (which 62 * amounts to the whole of vmlinux with LTO enabled), Clang will drop the 63 * segment register prefix from the references, resulting in broken code. Work 64 * around this by avoiding the symbol used in -mstack-protector-guard-symbol= 65 * entirely in the C code, and use an alias emitted by the linker script 66 * instead. 67 */ 68#if defined(CONFIG_STACKPROTECTOR) && defined(CONFIG_SMP) 69EXPORT_SYMBOL(__ref_stack_chk_guard); 70#endif 71