[PATCH 1/3] powerpc/tm: Remove msr_tm_active()

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.

This function is not necessary, since MSR_TM_ACTIVE() just do the same,
checking for the TS bits and does not require any TM facility.

This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE();

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/kernel/process.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9ef4aea9fffe..6b73d74793c2 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -102,24 +102,18 @@ static void check_if_tm_restore_required(struct task_struct *tsk)
 	}
 }
 
-static inline bool msr_tm_active(unsigned long msr)
-{
-	return MSR_TM_ACTIVE(msr);
-}
-
 static bool tm_active_with_fp(struct task_struct *tsk)
 {
-	return msr_tm_active(tsk->thread.regs->msr) &&
+	return MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
 		(tsk->thread.ckpt_regs.msr & MSR_FP);
 }
 
 static bool tm_active_with_altivec(struct task_struct *tsk)
 {
-	return msr_tm_active(tsk->thread.regs->msr) &&
+	return MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
 		(tsk->thread.ckpt_regs.msr & MSR_VEC);
 }
 #else
-static inline bool msr_tm_active(unsigned long msr) { return false; }
 static inline void check_if_tm_restore_required(struct task_struct *tsk) { }
 static inline bool tm_active_with_fp(struct task_struct *tsk) { return false; }
 static inline bool tm_active_with_altivec(struct task_struct *tsk) { return false; }

@@ -247,7 +241,7 @@ void enable_kernel_fp(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
 		__giveup_fpu(current);
 	}

@@ -311,7 +305,7 @@ void enable_kernel_altivec(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
 		__giveup_altivec(current);
 	}

@@ -397,7 +391,7 @@ void enable_kernel_vsx(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
 		__giveup_vsx(current);
 	}

@@ -530,7 +524,7 @@ void restore_math(struct pt_regs *regs)
 {
 	unsigned long msr;
 
-	if (!msr_tm_active(regs->msr) &&
+	if (!MSR_TM_ACTIVE(regs->msr) &&
 		!current->thread.load_fp && !loadvec(current->thread))
 		return;
 

-- 
2.16.3

This patch simply fix part of the documentation on the HTM code.

This fixes reference to old fields that were renamed in commit
000ec280e3dd ("powerpc: tm: Rename transct_(*) to ck(\1)_state").

It also documents better the flow after commit eb5c3f1c8647 ("powerpc:
Always save/restore checkpointed regs during treclaim/trecheckpoint"),
where tm_recheckpoint can recheckpoint what is in ck{fp,vr}_state blindly.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/kernel/tm.S    | 10 +++++-----
 arch/powerpc/kernel/traps.c | 15 +++++++++------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
index ff12f47a96b6..019d73053cd3 100644
--- a/arch/powerpc/kernel/tm.S
+++ b/arch/powerpc/kernel/tm.S

@@ -95,9 +95,9 @@ EXPORT_SYMBOL_GPL(tm_abort);
  *		   uint8_t cause)
  *
  *	- Performs a full reclaim.  This destroys outstanding
- *	  transactions and updates thread->regs.tm_ckpt_* with the
- *	  original checkpointed state.  Note that thread->regs is
- *	  unchanged.
+ *	  transactions and updates thread.ckpt_regs, thread.ckfp_state and
+ *	  thread.ckvr_state with the original checkpointed state.  Note that
+ *	  thread->regs is unchanged.
  *
  * Purpose is to both abort transactions of, and preserve the state of,
  * a transactions at a context switch. We preserve/restore both sets of process

@@ -260,7 +260,7 @@ _GLOBAL(tm_reclaim)
 
 	/* Altivec (VEC/VMX/VR)*/
 	addi	r7, r3, THREAD_CKVRSTATE
-	SAVE_32VRS(0, r6, r7)	/* r6 scratch, r7 transact vr state */
+	SAVE_32VRS(0, r6, r7)	/* r6 scratch, r7 ckvr_state */
 	mfvscr	v0
 	li	r6, VRSTATE_VSCR
 	stvx	v0, r7, r6

@@ -271,7 +271,7 @@ _GLOBAL(tm_reclaim)
 
 	/* Floating Point (FP) */
 	addi	r7, r3, THREAD_CKFPSTATE
-	SAVE_32FPRS_VSRS(0, R6, R7)	/* r6 scratch, r7 transact fp state */
+	SAVE_32FPRS_VSRS(0, R6, R7)	/* r6 scratch, r7 ckfp_state */
 	mffs    fr0
 	stfd    fr0,FPSTATE_FPSCR(r7)
 

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 0e17dcb48720..6742b6b3eb37 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c

@@ -1719,16 +1719,19 @@ void fp_unavailable_tm(struct pt_regs *regs)
          * checkpointed FP registers need to be loaded.
 	 */
 	tm_reclaim_current(TM_CAUSE_FAC_UNAV);
-	/* Reclaim didn't save out any FPRs to transact_fprs. */
+
+	/* Reclaim initially saved out bogus (lazy) FPRs to ckfp_state, and
+	 * then it was overwrite by the thr->fp_state by tm_reclaim_thread().
+	 *
+	 * At this point, ck{fp,vr}_state contains the exact values we want to
+	 * recheckpoint.
+	 */
 
 	/* Enable FP for the task: */
 	current->thread.load_fp = 1;
 
-	/* This loads and recheckpoints the FP registers from
-	 * thread.fpr[].  They will remain in registers after the
-	 * checkpoint so we don't need to reload them after.
-	 * If VMX is in use, the VRs now hold checkpointed values,
-	 * so we don't want to load the VRs from the thread_struct.
+	/*
+	 * Recheckpoint all the checkpointed ckpt, ck{fp, vr}_state registers.
 	 */
 	tm_recheckpoint(&current->thread);
 }

-- 
2.16.3

From: Cyril Bur <redacted>

tm_reclaim_thread() doesn't use the parameter anymore, both callers have
to bother getting it as they have no need for a struct thread_info
either.

It was previously used but became unused in dc3106690b20 ("powerpc: tm:
Always use fp_state and vr_state to store live registers")

Just remove it and adjust the callers.

Signed-off-by: Cyril Bur <redacted>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/kernel/process.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 6b73d74793c2..061a1c4cb3a8 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -860,8 +860,7 @@ static inline bool tm_enabled(struct task_struct *tsk)
 	return tsk && tsk->thread.regs && (tsk->thread.regs->msr & MSR_TM);
 }
 
-static void tm_reclaim_thread(struct thread_struct *thr,
-			      struct thread_info *ti, uint8_t cause)
+static void tm_reclaim_thread(struct thread_struct *thr, uint8_t cause)
 {
 	/*
 	 * Use the current MSR TM suspended bit to track if we have

@@ -908,7 +907,7 @@ static void tm_reclaim_thread(struct thread_struct *thr,
 void tm_reclaim_current(uint8_t cause)
 {
 	tm_enable();
-	tm_reclaim_thread(&current->thread, current_thread_info(), cause);
+	tm_reclaim_thread(&current->thread, cause);
 }
 
 static inline void tm_reclaim_task(struct task_struct *tsk)

@@ -939,7 +938,7 @@ static inline void tm_reclaim_task(struct task_struct *tsk)
 		 thr->regs->ccr, thr->regs->msr,
 		 thr->regs->trap);
 
-	tm_reclaim_thread(thr, task_thread_info(tsk), TM_CAUSE_RESCHED);
+	tm_reclaim_thread(thr, TM_CAUSE_RESCHED);
 
 	TM_DEBUG("--- tm_reclaim on pid %d complete\n",
 		 tsk->pid);

-- 
2.16.3

Hi Breno,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on powerpc/next]
[also build test ERROR on v4.17 next-20180615]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Breno-Leitao/powerpc-tm-Remove-msr_tm_active/20180616-015124
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-mpc8272_ads_defconfig (attached as .config)
compiler: powerpc-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=powerpc 

All error/warnings (new ones prefixed by >>):

   In file included from arch/powerpc/include/asm/processor.h:13:0,
                    from arch/powerpc/include/asm/thread_info.h:26,
                    from include/linux/thread_info.h:38,
                    from arch/powerpc/include/asm/ptrace.h:158,
                    from arch/powerpc/include/asm/hw_irq.h:12,
                    from arch/powerpc/include/asm/irqflags.h:12,
                    from include/linux/irqflags.h:16,
                    from include/asm-generic/cmpxchg-local.h:6,
                    from arch/powerpc/include/asm/cmpxchg.h:537,
                    from arch/powerpc/include/asm/atomic.h:11,
                    from include/linux/atomic.h:5,
                    from include/linux/rcupdate.h:38,
                    from include/linux/rculist.h:11,
                    from include/linux/pid.h:5,
                    from include/linux/sched.h:14,
                    from arch/powerpc/kernel/process.c:18:
   arch/powerpc/kernel/process.c: In function 'enable_kernel_fp':

quoted

arch/powerpc/include/asm/reg.h:65:23: error: left shift count >= width of type [-Werror=shift-count-overflow]

    #define __MASK(X) (1UL<<(X))
                          ^

quoted

arch/powerpc/include/asm/reg.h:117:18: note: in expansion of macro '__MASK'

    #define MSR_TS_T __MASK(MSR_TS_T_LG) /*  Transaction Transactional */
                     ^~~~~~

quoted

arch/powerpc/include/asm/reg.h:118:22: note: in expansion of macro 'MSR_TS_T'

    #define MSR_TS_MASK (MSR_TS_T | MSR_TS_S)   /* Transaction State bits */
                         ^~~~~~~~

quoted

arch/powerpc/include/asm/reg.h:119:34: note: in expansion of macro 'MSR_TS_MASK'

    #define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
                                     ^~~~~~~~~~~

quoted

arch/powerpc/kernel/process.c:244:7: note: in expansion of macro 'MSR_TM_ACTIVE'

      if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
          ^~~~~~~~~~~~~

quoted

arch/powerpc/include/asm/reg.h:65:23: error: left shift count >= width of type [-Werror=shift-count-overflow]

    #define __MASK(X) (1UL<<(X))
                          ^
   arch/powerpc/include/asm/reg.h:116:18: note: in expansion of macro '__MASK'
    #define MSR_TS_S __MASK(MSR_TS_S_LG) /*  Transaction Suspended */
                     ^~~~~~

quoted

arch/powerpc/include/asm/reg.h:118:33: note: in expansion of macro 'MSR_TS_S'

    #define MSR_TS_MASK (MSR_TS_T | MSR_TS_S)   /* Transaction State bits */
                                    ^~~~~~~~

quoted

arch/powerpc/include/asm/reg.h:119:34: note: in expansion of macro 'MSR_TS_MASK'

    #define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
                                     ^~~~~~~~~~~

quoted

arch/powerpc/kernel/process.c:244:7: note: in expansion of macro 'MSR_TM_ACTIVE'

      if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
          ^~~~~~~~~~~~~

quoted

arch/powerpc/include/asm/reg.h:65:23: error: left shift count >= width of type [-Werror=shift-count-overflow]

    #define __MASK(X) (1UL<<(X))
                          ^

quoted

arch/powerpc/include/asm/reg.h:117:18: note: in expansion of macro '__MASK'

    #define MSR_TS_T __MASK(MSR_TS_T_LG) /*  Transaction Transactional */
                     ^~~~~~

quoted

arch/powerpc/include/asm/reg.h:118:22: note: in expansion of macro 'MSR_TS_T'

    #define MSR_TS_MASK (MSR_TS_T | MSR_TS_S)   /* Transaction State bits */
                         ^~~~~~~~

quoted

arch/powerpc/include/asm/reg.h:119:34: note: in expansion of macro 'MSR_TS_MASK'

    #define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
                                     ^~~~~~~~~~~
   arch/powerpc/kernel/process.c:244:32: note: in expansion of macro 'MSR_TM_ACTIVE'
      if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
                                   ^~~~~~~~~~~~~

quoted

arch/powerpc/include/asm/reg.h:65:23: error: left shift count >= width of type [-Werror=shift-count-overflow]

    #define __MASK(X) (1UL<<(X))
                          ^
   arch/powerpc/include/asm/reg.h:116:18: note: in expansion of macro '__MASK'
    #define MSR_TS_S __MASK(MSR_TS_S_LG) /*  Transaction Suspended */
                     ^~~~~~

quoted

arch/powerpc/include/asm/reg.h:118:33: note: in expansion of macro 'MSR_TS_S'

    #define MSR_TS_MASK (MSR_TS_T | MSR_TS_S)   /* Transaction State bits */
                                    ^~~~~~~~

quoted

arch/powerpc/include/asm/reg.h:119:34: note: in expansion of macro 'MSR_TS_MASK'

    #define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
                                     ^~~~~~~~~~~
   arch/powerpc/kernel/process.c:244:32: note: in expansion of macro 'MSR_TM_ACTIVE'
      if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
                                   ^~~~~~~~~~~~~
   arch/powerpc/kernel/process.c: In function 'restore_math':

quoted

arch/powerpc/include/asm/reg.h:65:23: error: left shift count >= width of type [-Werror=shift-count-overflow]

    #define __MASK(X) (1UL<<(X))
                          ^

quoted

arch/powerpc/include/asm/reg.h:117:18: note: in expansion of macro '__MASK'

    #define MSR_TS_T __MASK(MSR_TS_T_LG) /*  Transaction Transactional */
                     ^~~~~~

quoted

arch/powerpc/include/asm/reg.h:118:22: note: in expansion of macro 'MSR_TS_T'

    #define MSR_TS_MASK (MSR_TS_T | MSR_TS_S)   /* Transaction State bits */
                         ^~~~~~~~

quoted

arch/powerpc/include/asm/reg.h:119:34: note: in expansion of macro 'MSR_TS_MASK'

    #define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
                                     ^~~~~~~~~~~
   arch/powerpc/kernel/process.c:527:7: note: in expansion of macro 'MSR_TM_ACTIVE'
     if (!MSR_TM_ACTIVE(regs->msr) &&
          ^~~~~~~~~~~~~

vim +/MSR_TM_ACTIVE +244 arch/powerpc/kernel/process.c

   226	
   227	void enable_kernel_fp(void)
   228	{
   229		unsigned long cpumsr;
   230	
   231		WARN_ON(preemptible());
   232	
   233		cpumsr = msr_check_and_set(MSR_FP);
   234	
   235		if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) {
   236			check_if_tm_restore_required(current);
   237			/*
   238			 * If a thread has already been reclaimed then the
   239			 * checkpointed registers are on the CPU but have definitely
   240			 * been saved by the reclaim code. Don't need to and *cannot*
   241			 * giveup as this would save  to the 'live' structure not the
   242			 * checkpointed structure.
   243			 */
 > 244			if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
   245				return;
   246			__giveup_fpu(current);
   247		}
   248	}
   249	EXPORT_SYMBOL(enable_kernel_fp);
   250	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.

This function is not necessary, since MSR_TM_ACTIVE() just do the same,
checking for the TS bits and does not require any TM facility.

This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/kernel/process.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index d26a150766ef..661e4ed5f628 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -102,24 +102,18 @@ static void check_if_tm_restore_required(struct task_struct *tsk)
 	}
 }
 
-static inline bool msr_tm_active(unsigned long msr)
-{
-	return MSR_TM_ACTIVE(msr);
-}
-
 static bool tm_active_with_fp(struct task_struct *tsk)
 {
-	return msr_tm_active(tsk->thread.regs->msr) &&
+	return MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
 		(tsk->thread.ckpt_regs.msr & MSR_FP);
 }
 
 static bool tm_active_with_altivec(struct task_struct *tsk)
 {
-	return msr_tm_active(tsk->thread.regs->msr) &&
+	return MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
 		(tsk->thread.ckpt_regs.msr & MSR_VEC);
 }
 #else
-static inline bool msr_tm_active(unsigned long msr) { return false; }
 static inline void check_if_tm_restore_required(struct task_struct *tsk) { }
 static inline bool tm_active_with_fp(struct task_struct *tsk) { return false; }
 static inline bool tm_active_with_altivec(struct task_struct *tsk) { return false; }

@@ -239,6 +233,7 @@ void enable_kernel_fp(void)
 	cpumsr = msr_check_and_set(MSR_FP);
 
 	if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 		check_if_tm_restore_required(current);
 		/*
 		 * If a thread has already been reclaimed then the

@@ -247,8 +242,10 @@ void enable_kernel_fp(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if (!MSR_TM_ACTIVE(cpumsr) &&
+		     MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
+#endif
 		__giveup_fpu(current);
 	}
 }

@@ -303,6 +300,7 @@ void enable_kernel_altivec(void)
 	cpumsr = msr_check_and_set(MSR_VEC);
 
 	if (current->thread.regs && (current->thread.regs->msr & MSR_VEC)) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 		check_if_tm_restore_required(current);
 		/*
 		 * If a thread has already been reclaimed then the

@@ -311,8 +309,10 @@ void enable_kernel_altivec(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if (!MSR_TM_ACTIVE(cpumsr) &&
+		     MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
+#endif
 		__giveup_altivec(current);
 	}
 }

@@ -389,6 +389,7 @@ void enable_kernel_vsx(void)
 
 	if (current->thread.regs &&
 	    (current->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP))) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 		check_if_tm_restore_required(current);
 		/*
 		 * If a thread has already been reclaimed then the

@@ -397,8 +398,10 @@ void enable_kernel_vsx(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if (!MSR_TM_ACTIVE(cpumsr) &&
+		     MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
+#endif
 		__giveup_vsx(current);
 	}
 }

@@ -530,9 +533,14 @@ void restore_math(struct pt_regs *regs)
 {
 	unsigned long msr;
 
-	if (!msr_tm_active(regs->msr) &&
-		!current->thread.load_fp && !loadvec(current->thread))
+	if (!current->thread.load_fp && !loadvec(current->thread)) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+		if (!MSR_TM_ACTIVE(regs->msr))
+			return;
+#else
 		return;
+#endif
+	}
 
 	msr = regs->msr;
 	msr_check_and_set(msr_all_available);

-- 
2.16.3

This patch simply fix part of the documentation on the HTM code.

This fixes reference to old fields that were renamed in commit
000ec280e3dd ("powerpc: tm: Rename transct_(*) to ck(\1)_state")

It also documents better the flow after commit eb5c3f1c8647 ("powerpc:
Always save/restore checkpointed regs during treclaim/trecheckpoint"),
where tm_recheckpoint can recheckpoint what is in ck{fp,vr}_state blindly.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/kernel/tm.S    | 10 +++++-----
 arch/powerpc/kernel/traps.c | 15 +++++++++------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
index ff12f47a96b6..019d73053cd3 100644
--- a/arch/powerpc/kernel/tm.S
+++ b/arch/powerpc/kernel/tm.S

@@ -95,9 +95,9 @@ EXPORT_SYMBOL_GPL(tm_abort);
  *		   uint8_t cause)
  *
  *	- Performs a full reclaim.  This destroys outstanding
- *	  transactions and updates thread->regs.tm_ckpt_* with the
- *	  original checkpointed state.  Note that thread->regs is
- *	  unchanged.
+ *	  transactions and updates thread.ckpt_regs, thread.ckfp_state and
+ *	  thread.ckvr_state with the original checkpointed state.  Note that
+ *	  thread->regs is unchanged.
  *
  * Purpose is to both abort transactions of, and preserve the state of,
  * a transactions at a context switch. We preserve/restore both sets of process

@@ -260,7 +260,7 @@ _GLOBAL(tm_reclaim)
 
 	/* Altivec (VEC/VMX/VR)*/
 	addi	r7, r3, THREAD_CKVRSTATE
-	SAVE_32VRS(0, r6, r7)	/* r6 scratch, r7 transact vr state */
+	SAVE_32VRS(0, r6, r7)	/* r6 scratch, r7 ckvr_state */
 	mfvscr	v0
 	li	r6, VRSTATE_VSCR
 	stvx	v0, r7, r6

@@ -271,7 +271,7 @@ _GLOBAL(tm_reclaim)
 
 	/* Floating Point (FP) */
 	addi	r7, r3, THREAD_CKFPSTATE
-	SAVE_32FPRS_VSRS(0, R6, R7)	/* r6 scratch, r7 transact fp state */
+	SAVE_32FPRS_VSRS(0, R6, R7)	/* r6 scratch, r7 ckfp_state */
 	mffs    fr0
 	stfd    fr0,FPSTATE_FPSCR(r7)
 

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 0e17dcb48720..6742b6b3eb37 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c

@@ -1719,16 +1719,19 @@ void fp_unavailable_tm(struct pt_regs *regs)
          * checkpointed FP registers need to be loaded.
 	 */
 	tm_reclaim_current(TM_CAUSE_FAC_UNAV);
-	/* Reclaim didn't save out any FPRs to transact_fprs. */
+
+	/* Reclaim initially saved out bogus (lazy) FPRs to ckfp_state, and
+	 * then it was overwrite by the thr->fp_state by tm_reclaim_thread().
+	 *
+	 * At this point, ck{fp,vr}_state contains the exact values we want to
+	 * recheckpoint.
+	 */
 
 	/* Enable FP for the task: */
 	current->thread.load_fp = 1;
 
-	/* This loads and recheckpoints the FP registers from
-	 * thread.fpr[].  They will remain in registers after the
-	 * checkpoint so we don't need to reload them after.
-	 * If VMX is in use, the VRs now hold checkpointed values,
-	 * so we don't want to load the VRs from the thread_struct.
+	/*
+	 * Recheckpoint all the checkpointed ckpt, ck{fp, vr}_state registers.
 	 */
 	tm_recheckpoint(&current->thread);
 }

-- 
2.16.3

From: Cyril Bur <redacted>

tm_reclaim_thread() doesn't use the parameter anymore, both callers have
to bother getting it as they have no need for a struct thread_info
either.

It was previously used but became unused in commit
dc3106690b20 ("powerpc: tm: Always use fp_state and vr_state to store live
registers")

Just remove it and adjust the callers.

Signed-off-by: Cyril Bur <redacted>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/kernel/process.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9ef4aea9fffe..f8beee03f00a 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -866,8 +866,7 @@ static inline bool tm_enabled(struct task_struct *tsk)
 	return tsk && tsk->thread.regs && (tsk->thread.regs->msr & MSR_TM);
 }
 
-static void tm_reclaim_thread(struct thread_struct *thr,
-			      struct thread_info *ti, uint8_t cause)
+static void tm_reclaim_thread(struct thread_struct *thr, uint8_t cause)
 {
 	/*
 	 * Use the current MSR TM suspended bit to track if we have

@@ -914,7 +913,7 @@ static void tm_reclaim_thread(struct thread_struct *thr,
 void tm_reclaim_current(uint8_t cause)
 {
 	tm_enable();
-	tm_reclaim_thread(&current->thread, current_thread_info(), cause);
+	tm_reclaim_thread(&current->thread, cause);
 }
 
 static inline void tm_reclaim_task(struct task_struct *tsk)

@@ -945,7 +944,7 @@ static inline void tm_reclaim_task(struct task_struct *tsk)
 		 thr->regs->ccr, thr->regs->msr,
 		 thr->regs->trap);
 
-	tm_reclaim_thread(thr, task_thread_info(tsk), TM_CAUSE_RESCHED);
+	tm_reclaim_thread(thr, TM_CAUSE_RESCHED);
 
 	TM_DEBUG("--- tm_reclaim on pid %d complete\n",
 		 tsk->pid);

-- 
2.16.3

If __switch_to() tries to context switch from task A to task B, and task A
 had task->thread->regs->msr[TM] enabled, then __switch_to_tm() will call
tm_recheckpoint_new_task(), which will call trecheckpoint, for task B, which
 is clearly wrong since task B might not be an active TM user.

This does not cause a lot of damage because tm_recheckpoint() will abort
the call since it realize that the current task does not have msr[TM] bit
set.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/kernel/process.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index f8beee03f00a..d26a150766ef 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -1036,7 +1036,8 @@ static inline void __switch_to_tm(struct task_struct *prev,
 				prev->thread.regs->msr &= ~MSR_TM;
 		}
 
-		tm_recheckpoint_new_task(new);
+		if (tm_enabled(new))
+			tm_recheckpoint_new_task(new);
 	}
 }
 

-- 
2.16.3

On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.
=20
This function is not necessary, since MSR_TM_ACTIVE() just do the same,
checking for the TS bits and does not require any TM facility.
=20
This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().
=20
Signed-off-by: Breno Leitao <leitao@debian.org>
=20

Patch looks good... one minor nit below...

=20
-	if (!msr_tm_active(regs->msr) &&
-		!current->thread.load_fp && !loadvec(current->thread))
+	if (!current->thread.load_fp && !loadvec(current->thread)) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+		if (!MSR_TM_ACTIVE(regs->msr))
+			return;

Can you make a MSR_TM_ACTIVE() that returns false when
!CONFIG_PPC_TRANSACTIONAL_MEM. Then you don't need this inline #ifdef.

Mikey

+#else
 		return;
+#endif
+	}
=20
 	msr =3D regs->msr;
 	msr_check_and_set(msr_all_available);

On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:

From: Cyril Bur <redacted>
=20
tm_reclaim_thread() doesn't use the parameter anymore, both callers have
to bother getting it as they have no need for a struct thread_info
either.
=20
It was previously used but became unused in commit
dc3106690b20 ("powerpc: tm: Always use fp_state and vr_state to store liv=

e

registers")
=20
Just remove it and adjust the callers.
=20
Signed-off-by: Cyril Bur <redacted>
Signed-off-by: Breno Leitao <leitao@debian.org>

Acked-by: Michael Neuling <redacted>

c

)

hr,

On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:

If __switch_to() tries to context switch from task A to task B, and task =

A

 had task->thread->regs->msr[TM] enabled, then __switch_to_tm() will call
tm_recheckpoint_new_task(), which will call trecheckpoint, for task B, wh=

ich

c

t

*prev,
 				prev->thread.regs->msr &=3D ~MSR_TM;
 		}
=20
-		tm_recheckpoint_new_task(new);
+		if (tm_enabled(new))
+			tm_recheckpoint_new_task(new);

I'm not sure we need this patch as tm_recheckpoint_new_task() does this its=
elf.

---
static inline void tm_recheckpoint_new_task(struct task_struct *new)
{
	if (!cpu_has_feature(CPU_FTR_TM))
		return;

	/* Recheckpoint the registers of the thread we're about to switch to.
	 *
	 * If the task was using FP, we non-lazily reload both the original and
	 * the speculative FP register states.  This is because the kernel
	 * doesn't see if/when a TM rollback occurs, so if we take an FP
	 * unavailable later, we are unable to determine which set of FP regs
	 * need to be restored.
	 */
	if (!tm_enabled(new))
		return;


---
Mikey

On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:

This patch simply fix part of the documentation on the HTM code.
=20
This fixes reference to old fields that were renamed in commit
000ec280e3dd ("powerpc: tm: Rename transct_(*) to ck(\1)_state")
=20
It also documents better the flow after commit eb5c3f1c8647 ("powerpc:
Always save/restore checkpointed regs during treclaim/trecheckpoint"),
where tm_recheckpoint can recheckpoint what is in ck{fp,vr}_state blindly=

.

=20
Signed-off-by: Breno Leitao <leitao@debian.org>

Acked-By: Michael Neuling <redacted>

Thanks

Hey Mikey,

Thanks for the review.

On 08/15/2018 08:50 PM, Michael Neuling wrote:

On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:

quoted

If __switch_to() tries to context switch from task A to task B, and task A
 had task->thread->regs->msr[TM] enabled, then __switch_to_tm() will call
tm_recheckpoint_new_task(), which will call trecheckpoint, for task B, which
 is clearly wrong since task B might not be an active TM user.

This does not cause a lot of damage because tm_recheckpoint() will abort
the call since it realize that the current task does not have msr[TM] bit
set.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/kernel/process.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index f8beee03f00a..d26a150766ef 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -1036,7 +1036,8 @@ static inline void __switch_to_tm(struct task_struct

*prev,
 				prev->thread.regs->msr &= ~MSR_TM;
 		}
 
-		tm_recheckpoint_new_task(new);
+		if (tm_enabled(new))
+			tm_recheckpoint_new_task(new);

I'm not sure we need this patch as tm_recheckpoint_new_task() does this itself.

My plan is to move this check prior to calling these TM functions, doing
early checking and avoiding calling tm_recheckpoint on a non-tm enabled task.
It is very weird when you see, during a tracing, a kernel thread (PF_KTHREAD)
being tm_recheckpointed. :-/

That said, the TM function would do the operation other than "check and do
it" mode.

Ideally I would like to check the thread before calling any TM functions,
and warning (WARN_ON) if we detect, later in the game, that a thread is not
TM enabled.

This helps on two different fronts, in my opinion:

 * Code readability
 * Understanding tracing (ftrace) outputs.

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.

This function is not necessary, since MSR_TM_ACTIVE() just do the same and
could be used, removing the dualism and simplifying the code.

This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/include/asm/reg.h |  7 ++++++-
 arch/powerpc/kernel/process.c  | 21 +++++++++------------
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 562568414cf4..58393bc6c964 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h

@@ -116,11 +116,16 @@
 #define MSR_TS_S	__MASK(MSR_TS_S_LG)	/*  Transaction Suspended */
 #define MSR_TS_T	__MASK(MSR_TS_T_LG)	/*  Transaction Transactional */
 #define MSR_TS_MASK	(MSR_TS_T | MSR_TS_S)   /* Transaction State bits */
-#define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
 #define MSR_TM_RESV(x) (((x) & MSR_TS_MASK) == MSR_TS_MASK) /* Reserved */
 #define MSR_TM_TRANSACTIONAL(x)	(((x) & MSR_TS_MASK) == MSR_TS_T)
 #define MSR_TM_SUSPENDED(x)	(((x) & MSR_TS_MASK) == MSR_TS_S)
 
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+#define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
+#else
+#define MSR_TM_ACTIVE(x) 0
+#endif
+
 #if defined(CONFIG_PPC_BOOK3S_64)
 #define MSR_64BIT	MSR_SF
 

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9ef4aea9fffe..f18dba07ea16 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c

@@ -102,24 +102,18 @@ static void check_if_tm_restore_required(struct task_struct *tsk)
 	}
 }
 
-static inline bool msr_tm_active(unsigned long msr)
-{
-	return MSR_TM_ACTIVE(msr);
-}
-
 static bool tm_active_with_fp(struct task_struct *tsk)
 {
-	return msr_tm_active(tsk->thread.regs->msr) &&
+	return MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
 		(tsk->thread.ckpt_regs.msr & MSR_FP);
 }
 
 static bool tm_active_with_altivec(struct task_struct *tsk)
 {
-	return msr_tm_active(tsk->thread.regs->msr) &&
+	return MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
 		(tsk->thread.ckpt_regs.msr & MSR_VEC);
 }
 #else
-static inline bool msr_tm_active(unsigned long msr) { return false; }
 static inline void check_if_tm_restore_required(struct task_struct *tsk) { }
 static inline bool tm_active_with_fp(struct task_struct *tsk) { return false; }
 static inline bool tm_active_with_altivec(struct task_struct *tsk) { return false; }

@@ -247,7 +241,8 @@ void enable_kernel_fp(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if (!MSR_TM_ACTIVE(cpumsr) &&
+		     MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
 		__giveup_fpu(current);
 	}

@@ -311,7 +306,8 @@ void enable_kernel_altivec(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if (!MSR_TM_ACTIVE(cpumsr) &&
+		     MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
 		__giveup_altivec(current);
 	}

@@ -397,7 +393,8 @@ void enable_kernel_vsx(void)
 		 * giveup as this would save  to the 'live' structure not the
 		 * checkpointed structure.
 		 */
-		if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr))
+		if (!MSR_TM_ACTIVE(cpumsr) &&
+		     MSR_TM_ACTIVE(current->thread.regs->msr))
 			return;
 		__giveup_vsx(current);
 	}

@@ -530,7 +527,7 @@ void restore_math(struct pt_regs *regs)
 {
 	unsigned long msr;
 
-	if (!msr_tm_active(regs->msr) &&
+	if (!MSR_TM_ACTIVE(regs->msr) &&
 		!current->thread.load_fp && !loadvec(current->thread))
 		return;
 

-- 
2.16.3

Michael Neuling [off-list ref] writes:

On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:

quoted

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.

This function is not necessary, since MSR_TM_ACTIVE() just do the same,
checking for the TS bits and does not require any TM facility.

This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().

Signed-off-by: Breno Leitao <leitao@debian.org>

Patch looks good... one minor nit below...

quoted

 
-	if (!msr_tm_active(regs->msr) &&
-		!current->thread.load_fp && !loadvec(current->thread))
+	if (!current->thread.load_fp && !loadvec(current->thread)) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+		if (!MSR_TM_ACTIVE(regs->msr))
+			return;

Can you make a MSR_TM_ACTIVE() that returns false when
!CONFIG_PPC_TRANSACTIONAL_MEM. Then you don't need this inline #ifdef.

Is that safe?

I see ~50 callers of MSR_TM_ACTIVE(), are they all inside #ifdef TM ?

cheers

Hi Michael,

On 08/16/2018 09:49 PM, Michael Ellerman wrote:

Michael Neuling [off-list ref] writes:

quoted

On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:

quoted

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.

This function is not necessary, since MSR_TM_ACTIVE() just do the same,
checking for the TS bits and does not require any TM facility.

This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().

Signed-off-by: Breno Leitao <leitao@debian.org>

Patch looks good... one minor nit below...

quoted

 
-	if (!msr_tm_active(regs->msr) &&
-		!current->thread.load_fp && !loadvec(current->thread))
+	if (!current->thread.load_fp && !loadvec(current->thread)) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+		if (!MSR_TM_ACTIVE(regs->msr))
+			return;

Can you make a MSR_TM_ACTIVE() that returns false when
!CONFIG_PPC_TRANSACTIONAL_MEM. Then you don't need this inline #ifdef.

Is that safe?

I see ~50 callers of MSR_TM_ACTIVE(), are they all inside #ifdef TM ?

I checked all of them, and the only two that are not called inside a #ifdef
are at kvm/book3s_hv_tm.c. They are:

  kvm/book3s_hv_tm.c:		if (!MSR_TM_ACTIVE(msr)) {
  kvm/book3s_hv_tm.c:		if (MSR_TM_ACTIVE(msr) || !(vcpu->arch.texasr & TEXASR_FS)) {

All the others are being called inside the #ifdef

Other than that, I do not see why it would be a problem in the way I
implemented it, since it will return false for the two cases above, which
seems correct. Take a look on how the definition became:

  #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
  #define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
  #else
  #define MSR_TM_ACTIVE(x) 0
  #endif

I also tested it with different config files, and I didn't see any complain.
These are the platforms I built for.

* powernv_defconfig
* pseries_le_defconfig
* pseries_defconfig
* ppc64_defconfig
* ppc64e_defconfig
* pmac32_defconfig
* ppc44x_defconfig
* mpc85xx_smp_defconfig
* mpc85xx_defconfig
* ps3_defconfig

Anyway, if you have any other suggestion I can follow in order to guarantee
that I am not causing any regression, I would be happy. Touching these core
kernel macros is scary!

Thanks!

Breno Leitao [off-list ref] writes:

On 08/16/2018 09:49 PM, Michael Ellerman wrote:

quoted

Michael Neuling [off-list ref] writes:

quoted

On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:

quoted

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.

This function is not necessary, since MSR_TM_ACTIVE() just do the same,
checking for the TS bits and does not require any TM facility.

This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().

Signed-off-by: Breno Leitao <leitao@debian.org>

Patch looks good... one minor nit below...

quoted

 
-	if (!msr_tm_active(regs->msr) &&
-		!current->thread.load_fp && !loadvec(current->thread))
+	if (!current->thread.load_fp && !loadvec(current->thread)) {
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+		if (!MSR_TM_ACTIVE(regs->msr))
+			return;

Can you make a MSR_TM_ACTIVE() that returns false when
!CONFIG_PPC_TRANSACTIONAL_MEM. Then you don't need this inline #ifdef.

Is that safe?

I see ~50 callers of MSR_TM_ACTIVE(), are they all inside #ifdef TM ?

I checked all of them, and the only two that are not called inside a #ifdef
are at kvm/book3s_hv_tm.c. They are:

  kvm/book3s_hv_tm.c:		if (!MSR_TM_ACTIVE(msr)) {
  kvm/book3s_hv_tm.c:		if (MSR_TM_ACTIVE(msr) || !(vcpu->arch.texasr & TEXASR_FS)) {

That whole file is only built if TM=y:

kvm-hv-$(CONFIG_PPC_TRANSACTIONAL_MEM) += \
	book3s_hv_tm.o

All the others are being called inside the #ifdef

Other than that, I do not see why it would be a problem in the way I
implemented it, since it will return false for the two cases above, which
seems correct. Take a look on how the definition became:

  #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
  #define MSR_TM_ACTIVE(x) (((x) & MSR_TS_MASK) != 0) /* Transaction active? */
  #else
  #define MSR_TM_ACTIVE(x) 0
  #endif

Imagine we had some code somewhere that checked for TM being active in a
non-TM aware kernel, that would break with this change, because now the
MSR check does nothing when TM=n.

eg. we might check at boot time that we're not transactional, eg. in
case we came from a kdump kernel that was in a transaction.

So if all the call-sites are already inside an #ifdef I'd be inclined to
not add the #ifdef around the MSR_TM_ACTIVE macro.

That way the macro can always be used to check the MSR value, whether TM
is compiled in or out.

cheers

On Mon, 2018-06-18 at 22:59:42 UTC, Breno Leitao wrote:

This patch simply fix part of the documentation on the HTM code.

This fixes reference to old fields that were renamed in commit
000ec280e3dd ("powerpc: tm: Rename transct_(*) to ck(\1)_state")

It also documents better the flow after commit eb5c3f1c8647 ("powerpc:
Always save/restore checkpointed regs during treclaim/trecheckpoint"),
where tm_recheckpoint can recheckpoint what is in ck{fp,vr}_state blindly.

Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-By: Michael Neuling <redacted>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/96695563cebfb810b09479a9951ebb

cheers

On Thu, 2018-08-16 at 17:21:07 UTC, Breno Leitao wrote:

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.

This function is not necessary, since MSR_TM_ACTIVE() just do the same and
could be used, removing the dualism and simplifying the code.

This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().

Signed-off-by: Breno Leitao <leitao@debian.org>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/5c784c8414fba11b62e12439f11e10

cheers