Merge tag 'x86-splitlock-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 splitlock updates from Ingo Molnar:

 - Move Split and Bus lock code to a dedicated file (Ravi Bangoria)

 - Add split/bus lock support for AMD (Ravi Bangoria)

* tag 'x86-splitlock-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/bus_lock: Add support for AMD
  x86/split_lock: Move Split and Bus lock code to a dedicated file

Author: torvalds

Documentation/arch/x86/buslock.rst

@@ -26,7 +26,8 @@ Detection
 =========
 
 Intel processors may support either or both of the following hardware
-mechanisms to detect split locks and bus locks.
+mechanisms to detect split locks and bus locks. Some AMD processors also
+support bus lock detect.
 
 #AC exception for split lock detection
 --------------------------------------

arch/x86/Kconfig

@@ -2429,6 +2429,14 @@ config CFI_AUTO_DEFAULT
 
 source "kernel/livepatch/Kconfig"
 
+config X86_BUS_LOCK_DETECT
+	bool "Split Lock Detect and Bus Lock Detect support"
+	depends on CPU_SUP_INTEL || CPU_SUP_AMD
+	default y
+	help
+	  Enable Split Lock Detect and Bus Lock Detect functionalities.
+	  See <file:Documentation/arch/x86/buslock.rst> for more information.
+
 endmenu
 
 config CC_HAS_NAMED_AS

arch/x86/include/asm/cpu.h

@@ -26,13 +26,13 @@ int mwait_usable(const struct cpuinfo_x86 *);
 unsigned int x86_family(unsigned int sig);
 unsigned int x86_model(unsigned int sig);
 unsigned int x86_stepping(unsigned int sig);
-#ifdef CONFIG_CPU_SUP_INTEL
+#ifdef CONFIG_X86_BUS_LOCK_DETECT
 extern void __init sld_setup(struct cpuinfo_x86 *c);
 extern bool handle_user_split_lock(struct pt_regs *regs, long error_code);
 extern bool handle_guest_split_lock(unsigned long ip);
 extern void handle_bus_lock(struct pt_regs *regs);
-u8 get_this_hybrid_cpu_type(void);
-u32 get_this_hybrid_cpu_native_id(void);
+void split_lock_init(void);
+void bus_lock_init(void);
 #else
 static inline void __init sld_setup(struct cpuinfo_x86 *c) {}
 static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code)
@@ -46,7 +46,14 @@ static inline bool handle_guest_split_lock(unsigned long ip)
 }
 
 static inline void handle_bus_lock(struct pt_regs *regs) {}
+static inline void split_lock_init(void) {}
+static inline void bus_lock_init(void) {}
+#endif
 
+#ifdef CONFIG_CPU_SUP_INTEL
+u8 get_this_hybrid_cpu_type(void);
+u32 get_this_hybrid_cpu_native_id(void);
+#else
 static inline u8 get_this_hybrid_cpu_type(void)
 {
 	return 0;

arch/x86/kernel/cpu/Makefile

@@ -59,6 +59,8 @@ obj-$(CONFIG_ACRN_GUEST)		+= acrn.o
 
 obj-$(CONFIG_DEBUG_FS)			+= debugfs.o
 
+obj-$(CONFIG_X86_BUS_LOCK_DETECT)	+= bus_lock.o
+
 quiet_cmd_mkcapflags = MKCAP   $@
       cmd_mkcapflags = $(CONFIG_SHELL) $(src)/mkcapflags.sh $@ $^