[PATCH 3.16 013/131] x86/speculation: Create spec-ctrl.h to avoid include hell

[Ben Hutchings]

3.16.59-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

commit 28a2775217b17208811fa43a9e96bd1fdf417b86 upstream.

Having everything in nospec-branch.h creates a hell of dependencies when
adding the prctl based switching mechanism. Move everything which is not
required in nospec-branch.h to spec-ctrl.h and fix up the includes in the
relevant files.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/nospec-branch.h | 14 --------------
 arch/x86/include/asm/spec-ctrl.h     | 21 +++++++++++++++++++++
 arch/x86/kernel/cpu/amd.c            |  2 +-
 arch/x86/kernel/cpu/bugs.c           |  2 +-
 arch/x86/kvm/svm.c                   |  2 +-
 arch/x86/kvm/vmx.c                   |  2 +-
 6 files changed, 25 insertions(+), 18 deletions(-)
 create mode 100644 arch/x86/include/asm/spec-ctrl.h

--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -183,26 +183,12 @@ enum spectre_v2_mitigation {
 extern void x86_spec_ctrl_set(u64);
 extern u64 x86_spec_ctrl_get_default(void);
 
-/*
- * On VMENTER we must preserve whatever view of the SPEC_CTRL MSR
- * the guest has, while on VMEXIT we restore the host view. This
- * would be easier if SPEC_CTRL were architecturally maskable or
- * shadowable for guests but this is not (currently) the case.
- * Takes the guest view of SPEC_CTRL MSR as a parameter.
- */
-extern void x86_spec_ctrl_set_guest(u64);
-extern void x86_spec_ctrl_restore_host(u64);
-
 /* The Speculative Store Bypass disable variants */
 enum ssb_mitigation {
 	SPEC_STORE_BYPASS_NONE,
 	SPEC_STORE_BYPASS_DISABLE,
 };
 
-/* AMD specific Speculative Store Bypass MSR data */
-extern u64 x86_amd_ls_cfg_base;
-extern u64 x86_amd_ls_cfg_rds_mask;
-
 extern char __indirect_thunk_start[];
 extern char __indirect_thunk_end[];
 
--- /dev/null
+++ b/arch/x86/include/asm/spec-ctrl.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_SPECCTRL_H_
+#define _ASM_X86_SPECCTRL_H_
+
+#include <asm/nospec-branch.h>
+
+/*
+ * On VMENTER we must preserve whatever view of the SPEC_CTRL MSR
+ * the guest has, while on VMEXIT we restore the host view. This
+ * would be easier if SPEC_CTRL were architecturally maskable or
+ * shadowable for guests but this is not (currently) the case.
+ * Takes the guest view of SPEC_CTRL MSR as a parameter.
+ */
+extern void x86_spec_ctrl_set_guest(u64);
+extern void x86_spec_ctrl_restore_host(u64);
+
+/* AMD specific Speculative Store Bypass MSR data */
+extern u64 x86_amd_ls_cfg_base;
+extern u64 x86_amd_ls_cfg_rds_mask;
+
+#endif
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -8,7 +8,7 @@
 #include <asm/processor.h>
 #include <asm/apic.h>
 #include <asm/cpu.h>
-#include <asm/nospec-branch.h>
+#include <asm/spec-ctrl.h>
 #include <asm/pci-direct.h>
 
 #ifdef CONFIG_X86_64
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -12,7 +12,7 @@
 #include <linux/cpu.h>
 #include <linux/module.h>
 
-#include <asm/nospec-branch.h>
+#include <asm/spec-ctrl.h>
 #include <asm/cmdline.h>
 #include <asm/bugs.h>
 #include <asm/processor.h>
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -37,7 +37,7 @@
 #include <asm/debugreg.h>
 #include <asm/kvm_para.h>
 #include <asm/microcode.h>
-#include <asm/nospec-branch.h>
+#include <asm/spec-ctrl.h>
 
 #include <asm/virtext.h>
 #include "trace.h"
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -47,7 +47,7 @@
 #include <asm/debugreg.h>
 #include <asm/kexec.h>
 #include <asm/microcode.h>
-#include <asm/nospec-branch.h>
+#include <asm/spec-ctrl.h>
 
 #include "trace.h"