The following commit has been merged into the x86/splitlock branch of tip: Commit-ID: ef79970d7ccdc4e8855aa6079fc2f4797a6807fb Gitweb: https://git.kernel.org/tip/ef79970d7ccdc4e8855aa6079fc2f4797a6807fb Author: Tony Luck <tony.luck@xxxxxxxxx> AuthorDate: Thu, 10 Mar 2022 12:48:54 -08:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Wed, 27 Apr 2022 15:43:39 +02:00 x86/split-lock: Remove unused TIF_SLD bit Changes to the "warn" mode of split lock handling mean that TIF_SLD is never set. Remove the bit, and the functions that use it. Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220310204854.31752-3-tony.luck@xxxxxxxxx --- arch/x86/include/asm/cpu.h | 2 -- arch/x86/include/asm/thread_info.h | 4 +--- arch/x86/kernel/cpu/intel.c | 12 ------------ arch/x86/kernel/process.c | 3 --- 4 files changed, 1 insertion(+), 20 deletions(-) diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h index 86e5e4e..d1c86b2 100644 --- a/arch/x86/include/asm/cpu.h +++ b/arch/x86/include/asm/cpu.h @@ -43,14 +43,12 @@ unsigned int x86_model(unsigned int sig); unsigned int x86_stepping(unsigned int sig); #ifdef CONFIG_CPU_SUP_INTEL extern void __init sld_setup(struct cpuinfo_x86 *c); -extern void switch_to_sld(unsigned long tifn); 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); #else static inline void __init sld_setup(struct cpuinfo_x86 *c) {} -static inline void switch_to_sld(unsigned long tifn) {} static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code) { return false; diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index ebec69c..f0cb881 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -92,7 +92,6 @@ struct thread_info { #define TIF_NOCPUID 15 /* CPUID is not accessible in userland */ #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_NOTIFY_SIGNAL 17 /* signal notifications exist */ -#define TIF_SLD 18 /* Restore split lock detection on context switch */ #define TIF_MEMDIE 20 /* is terminating due to OOM killer */ #define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */ #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ @@ -116,7 +115,6 @@ struct thread_info { #define _TIF_NOCPUID (1 << TIF_NOCPUID) #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) -#define _TIF_SLD (1 << TIF_SLD) #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) #define _TIF_SPEC_FORCE_UPDATE (1 << TIF_SPEC_FORCE_UPDATE) @@ -128,7 +126,7 @@ struct thread_info { /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW_BASE \ (_TIF_NOCPUID | _TIF_NOTSC | _TIF_BLOCKSTEP | \ - _TIF_SSBD | _TIF_SPEC_FORCE_UPDATE | _TIF_SLD) + _TIF_SSBD | _TIF_SPEC_FORCE_UPDATE) /* * Avoid calls to __switch_to_xtra() on UP as STIBP is not evaluated. diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index be2a0bd..672e253 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -1233,18 +1233,6 @@ void handle_bus_lock(struct pt_regs *regs) } /* - * This function is called only when switching between tasks with - * different split-lock detection modes. It sets the MSR for the - * mode of the new task. This is right most of the time, but since - * the MSR is shared by hyperthreads on a physical core there can - * be glitches when the two threads need different modes. - */ -void switch_to_sld(unsigned long tifn) -{ - sld_update_msr(!(tifn & _TIF_SLD)); -} - -/* * Bits in the IA32_CORE_CAPABILITIES are not architectural, so they should * only be trusted if it is confirmed that a CPU model implements a * specific feature at a particular bit position. diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index b370767..bcc76c1 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -686,9 +686,6 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p) /* Enforce MSR update to ensure consistent state */ __speculation_ctrl_update(~tifn, tifn); } - - if ((tifp ^ tifn) & _TIF_SLD) - switch_to_sld(tifn); } /*
![]() |