linux-kernel - [PATCH v9 1/8] x86/split_lock: Rename TIF_SLD to TIF_SLD

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Date:   Sat,  9 May 2020 19:05:35 +0800
From:   Xiaoyao Li <xiaoyao.li@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>, peterz@...radead.org,
        Arvind Sankar <nivedita@...m.mit.edu>,
        Tony Luck <tony.luck@...el.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Xiaoyao Li <xiaoyao.li@...el.com>
Subject: [PATCH v9 1/8] x86/split_lock: Rename TIF_SLD to TIF_SLD_DISABLED

TIF_SLD can only be set if a user space thread hits split lock and
sld_state == sld_warn. This flag is set to indicate SLD (split lock
detection) is turned off for the thread, so rename it to
TIF_SLD_DISABLED, which is pretty self explaining.

Suggested-by: Sean Christopherson <sean.j.christopherson@...el.com>
Suggested-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
---
 arch/x86/include/asm/thread_info.h | 6 +++---
 arch/x86/kernel/cpu/intel.c        | 6 +++---
 arch/x86/kernel/process.c          | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 8de8ceccb8bc..451a930de1c0 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -92,7 +92,7 @@ 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_IA32		17	/* IA32 compatibility process */
-#define TIF_SLD			18	/* Restore split lock detection on context switch */
+#define TIF_SLD_DISABLED	18	/* split lock detection is turned off */
 #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 */
@@ -122,7 +122,7 @@ struct thread_info {
 #define _TIF_NOCPUID		(1 << TIF_NOCPUID)
 #define _TIF_NOTSC		(1 << TIF_NOTSC)
 #define _TIF_IA32		(1 << TIF_IA32)
-#define _TIF_SLD		(1 << TIF_SLD)
+#define _TIF_SLD_DISABLED	(1 << TIF_SLD_DISABLED)
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 #define _TIF_IO_BITMAP		(1 << TIF_IO_BITMAP)
 #define _TIF_FORCED_TF		(1 << TIF_FORCED_TF)
@@ -141,7 +141,7 @@ 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 | _TIF_SLD_DISABLED)
 
 /*
  * 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 a19a680542ce..0e6aee6ef1e8 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1074,11 +1074,11 @@ static void split_lock_warn(unsigned long ip)
 
 	/*
 	 * Disable the split lock detection for this task so it can make
-	 * progress and set TIF_SLD so the detection is re-enabled via
+	 * progress and set TIF_SLD_DISABLED so the detection is re-enabled via
 	 * switch_to_sld() when the task is scheduled out.
 	 */
 	sld_update_msr(false);
-	set_tsk_thread_flag(current, TIF_SLD);
+	set_tsk_thread_flag(current, TIF_SLD_DISABLED);
 }
 
 bool handle_guest_split_lock(unsigned long ip)
@@ -1116,7 +1116,7 @@ bool handle_user_split_lock(struct pt_regs *regs, long error_code)
  */
 void switch_to_sld(unsigned long tifn)
 {
-	sld_update_msr(!(tifn & _TIF_SLD));
+	sld_update_msr(!(tifn & _TIF_SLD_DISABLED));
 }
 
 /*
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 9da70b279dad..e7693a283489 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -650,7 +650,7 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p)
 		__speculation_ctrl_update(~tifn, tifn);
 	}
 
-	if ((tifp ^ tifn) & _TIF_SLD)
+	if ((tifp ^ tifn) & _TIF_SLD_DISABLED)
 		switch_to_sld(tifn);
 }
 
-- 
2.18.2