[PATCH v9 1/8] x86/split_lock: Rename TIF_SLD to TIF_SLD_DISABLED

From: Xiaoyao Li
Date: Fri May 08 2020 - 23:03:48 EST


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@xxxxxxxxx>
Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
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