diff options
Diffstat (limited to 'arch/x86/entry/entry.S')
| -rw-r--r-- | arch/x86/entry/entry.S | 67 |
1 files changed, 61 insertions, 6 deletions
diff --git a/arch/x86/entry/entry.S b/arch/x86/entry/entry.S index bfb7bcb362bc..6ba2b3adcef0 100644 --- a/arch/x86/entry/entry.S +++ b/arch/x86/entry/entry.S @@ -3,20 +3,75 @@ * Common place for both 32- and 64-bit entry routines. */ +#include <linux/export.h> +#include <linux/kvm_types.h> #include <linux/linkage.h> -#include <asm/export.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" -SYM_FUNC_START(entry_ibpb) +/* Clobbers AX, CX, DX */ +SYM_FUNC_START(write_ibpb) + ANNOTATE_NOENDBR movl $MSR_IA32_PRED_CMD, %ecx - movl $PRED_CMD_IBPB, %eax + 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(entry_ibpb) -/* For KVM */ -EXPORT_SYMBOL_GPL(entry_ibpb); +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 |