* [PATCH 1/3] powerpc/tm: Remove msr_tm_active()
@ 2018-06-15 17:37 Breno Leitao
2018-06-15 17:42 ` [PATCH 2/3] powerpc/tm: Fix HTM documentation Breno Leitao
2018-06-15 20:06 ` [PATCH 1/3] powerpc/tm: Remove msr_tm_active() kbuild test robot
0 siblings, 2 replies; 19+ messages in thread
From: Breno Leitao @ 2018-06-15 17:37 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Breno Leitao
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
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 2/3] powerpc/tm: Fix HTM documentation
2018-06-15 17:37 [PATCH 1/3] powerpc/tm: Remove msr_tm_active() Breno Leitao
@ 2018-06-15 17:42 ` Breno Leitao
2018-06-15 17:42 ` [PATCH 3/3] powerpc/tm: Remove struct thread_info param from tm_reclaim_thread() Breno Leitao
2018-06-15 20:06 ` [PATCH 1/3] powerpc/tm: Remove msr_tm_active() kbuild test robot
1 sibling, 1 reply; 19+ messages in thread
From: Breno Leitao @ 2018-06-15 17:42 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Breno Leitao
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(¤t->thread);
}
--
2.16.3
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 3/3] powerpc/tm: Remove struct thread_info param from tm_reclaim_thread()
2018-06-15 17:42 ` [PATCH 2/3] powerpc/tm: Fix HTM documentation Breno Leitao
@ 2018-06-15 17:42 ` Breno Leitao
0 siblings, 0 replies; 19+ messages in thread
From: Breno Leitao @ 2018-06-15 17:42 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Cyril Bur, Breno Leitao
From: Cyril Bur <cyrilbur@gmail.com>
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 <cyrilbur@gmail.com>
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(¤t->thread, current_thread_info(), cause);
+ tm_reclaim_thread(¤t->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
^ permalink raw reply related [flat|nested] 19+ messages in thread
* Re: [PATCH 1/3] powerpc/tm: Remove msr_tm_active()
2018-06-15 17:37 [PATCH 1/3] powerpc/tm: Remove msr_tm_active() Breno Leitao
2018-06-15 17:42 ` [PATCH 2/3] powerpc/tm: Fix HTM documentation Breno Leitao
@ 2018-06-15 20:06 ` kbuild test robot
2018-06-18 22:59 ` [PATCH v2 1/4] " Breno Leitao
1 sibling, 1 reply; 19+ messages in thread
From: kbuild test robot @ 2018-06-15 20:06 UTC (permalink / raw)
To: Breno Leitao; +Cc: kbuild-all, linuxppc-dev, Breno Leitao
[-- Attachment #1: Type: text/plain, Size: 7752 bytes --]
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':
>> 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:117:18: note: in expansion of macro '__MASK'
#define MSR_TS_T __MASK(MSR_TS_T_LG) /* Transaction Transactional */
^~~~~~
>> 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 */
^~~~~~~~
>> 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:244:7: note: in expansion of macro 'MSR_TM_ACTIVE'
if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
^~~~~~~~~~~~~
>> 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 */
^~~~~~
>> 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 */
^~~~~~~~
>> 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:244:7: note: in expansion of macro 'MSR_TM_ACTIVE'
if(!MSR_TM_ACTIVE(cpumsr) && MSR_TM_ACTIVE(current->thread.regs->msr))
^~~~~~~~~~~~~
>> 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:117:18: note: in expansion of macro '__MASK'
#define MSR_TS_T __MASK(MSR_TS_T_LG) /* Transaction Transactional */
^~~~~~
>> 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 */
^~~~~~~~
>> 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/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 */
^~~~~~
>> 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 */
^~~~~~~~
>> 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':
>> 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:117:18: note: in expansion of macro '__MASK'
#define MSR_TS_T __MASK(MSR_TS_T_LG) /* Transaction Transactional */
^~~~~~
>> 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 */
^~~~~~~~
>> 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
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 12632 bytes --]
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active()
2018-06-15 20:06 ` [PATCH 1/3] powerpc/tm: Remove msr_tm_active() kbuild test robot
@ 2018-06-18 22:59 ` Breno Leitao
2018-06-18 22:59 ` [PATCH v2 2/4] powerpc/tm: Fix HTM documentation Breno Leitao
` (3 more replies)
0 siblings, 4 replies; 19+ messages in thread
From: Breno Leitao @ 2018-06-18 22:59 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Breno Leitao
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
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH v2 2/4] powerpc/tm: Fix HTM documentation
2018-06-18 22:59 ` [PATCH v2 1/4] " Breno Leitao
@ 2018-06-18 22:59 ` Breno Leitao
2018-08-15 23:46 ` Michael Neuling
2018-09-20 4:20 ` [v2,2/4] " Michael Ellerman
2018-06-18 22:59 ` [PATCH v2 3/4] powerpc/tm: Adjust tm_reclaim_thread() parameters Breno Leitao
` (2 subsequent siblings)
3 siblings, 2 replies; 19+ messages in thread
From: Breno Leitao @ 2018-06-18 22:59 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Breno Leitao
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(¤t->thread);
}
--
2.16.3
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH v2 3/4] powerpc/tm: Adjust tm_reclaim_thread() parameters
2018-06-18 22:59 ` [PATCH v2 1/4] " Breno Leitao
2018-06-18 22:59 ` [PATCH v2 2/4] powerpc/tm: Fix HTM documentation Breno Leitao
@ 2018-06-18 22:59 ` Breno Leitao
2018-08-15 23:48 ` Michael Neuling
2018-06-18 22:59 ` [PATCH v2 4/4] powerpc/tm: Do not recheckpoint non-tm task Breno Leitao
2018-08-15 23:46 ` [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active() Michael Neuling
3 siblings, 1 reply; 19+ messages in thread
From: Breno Leitao @ 2018-06-18 22:59 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Cyril Bur, Breno Leitao
From: Cyril Bur <cyrilbur@gmail.com>
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 <cyrilbur@gmail.com>
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(¤t->thread, current_thread_info(), cause);
+ tm_reclaim_thread(¤t->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
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH v2 4/4] powerpc/tm: Do not recheckpoint non-tm task
2018-06-18 22:59 ` [PATCH v2 1/4] " Breno Leitao
2018-06-18 22:59 ` [PATCH v2 2/4] powerpc/tm: Fix HTM documentation Breno Leitao
2018-06-18 22:59 ` [PATCH v2 3/4] powerpc/tm: Adjust tm_reclaim_thread() parameters Breno Leitao
@ 2018-06-18 22:59 ` Breno Leitao
2018-08-15 23:50 ` Michael Neuling
2018-08-15 23:46 ` [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active() Michael Neuling
3 siblings, 1 reply; 19+ messages in thread
From: Breno Leitao @ 2018-06-18 22:59 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Breno Leitao
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
^ permalink raw reply related [flat|nested] 19+ messages in thread
* Re: [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active()
2018-06-18 22:59 ` [PATCH v2 1/4] " Breno Leitao
` (2 preceding siblings ...)
2018-06-18 22:59 ` [PATCH v2 4/4] powerpc/tm: Do not recheckpoint non-tm task Breno Leitao
@ 2018-08-15 23:46 ` Michael Neuling
2018-08-16 17:21 ` [PATCH v3] " Breno Leitao
2018-08-17 0:49 ` [PATCH v2 1/4] " Michael Ellerman
3 siblings, 2 replies; 19+ messages in thread
From: Michael Neuling @ 2018-08-15 23:46 UTC (permalink / raw)
To: Breno Leitao, linuxppc-dev
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);
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH v2 2/4] powerpc/tm: Fix HTM documentation
2018-06-18 22:59 ` [PATCH v2 2/4] powerpc/tm: Fix HTM documentation Breno Leitao
@ 2018-08-15 23:46 ` Michael Neuling
2018-09-20 4:20 ` [v2,2/4] " Michael Ellerman
1 sibling, 0 replies; 19+ messages in thread
From: Michael Neuling @ 2018-08-15 23:46 UTC (permalink / raw)
To: Breno Leitao, linuxppc-dev
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 <mikey@neuling.org>
Thanks
> ---
> arch/powerpc/kernel/tm.S | 10 +++++-----
> arch/powerpc/kernel/traps.c | 15 +++++++++------
> 2 files changed, 14 insertions(+), 11 deletions(-)
>=20
> 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)
> =20
> /* 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)
> =20
> /* 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)
> =20
> 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.
> + */
> =20
> /* Enable FP for the task: */
> current->thread.load_fp =3D 1;
> =20
> - /* 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(¤t->thread);
> }
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH v2 3/4] powerpc/tm: Adjust tm_reclaim_thread() parameters
2018-06-18 22:59 ` [PATCH v2 3/4] powerpc/tm: Adjust tm_reclaim_thread() parameters Breno Leitao
@ 2018-08-15 23:48 ` Michael Neuling
0 siblings, 0 replies; 19+ messages in thread
From: Michael Neuling @ 2018-08-15 23:48 UTC (permalink / raw)
To: Breno Leitao, linuxppc-dev; +Cc: Cyril Bur
On Mon, 2018-06-18 at 19:59 -0300, Breno Leitao wrote:
> From: Cyril Bur <cyrilbur@gmail.com>
>=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 <cyrilbur@gmail.com>
> Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Michael Neuling <mikey@neuling.org.>
> ---
> arch/powerpc/kernel/process.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>=20
> 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);
> }
> =20
> -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 *t=
hr,
> void tm_reclaim_current(uint8_t cause)
> {
> tm_enable();
> - tm_reclaim_thread(¤t->thread, current_thread_info(), cause);
> + tm_reclaim_thread(¤t->thread, cause);
> }
> =20
> 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);
> =20
> - tm_reclaim_thread(thr, task_thread_info(tsk), TM_CAUSE_RESCHED);
> + tm_reclaim_thread(thr, TM_CAUSE_RESCHED);
> =20
> TM_DEBUG("--- tm_reclaim on pid %d complete\n",
> tsk->pid);
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH v2 4/4] powerpc/tm: Do not recheckpoint non-tm task
2018-06-18 22:59 ` [PATCH v2 4/4] powerpc/tm: Do not recheckpoint non-tm task Breno Leitao
@ 2018-08-15 23:50 ` Michael Neuling
2018-08-16 14:19 ` Breno Leitao
0 siblings, 1 reply; 19+ messages in thread
From: Michael Neuling @ 2018-08-15 23:50 UTC (permalink / raw)
To: Breno Leitao, linuxppc-dev
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
> is clearly wrong since task B might not be an active TM user.
>=20
> 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.
>=20
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
> arch/powerpc/kernel/process.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>=20
> 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_struc=
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
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH v2 4/4] powerpc/tm: Do not recheckpoint non-tm task
2018-08-15 23:50 ` Michael Neuling
@ 2018-08-16 14:19 ` Breno Leitao
0 siblings, 0 replies; 19+ messages in thread
From: Breno Leitao @ 2018-08-16 14:19 UTC (permalink / raw)
To: Michael Neuling, linuxppc-dev
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:
>> 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.
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH v3] powerpc/tm: Remove msr_tm_active()
2018-08-15 23:46 ` [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active() Michael Neuling
@ 2018-08-16 17:21 ` Breno Leitao
2018-10-04 6:14 ` [v3] " Michael Ellerman
2018-08-17 0:49 ` [PATCH v2 1/4] " Michael Ellerman
1 sibling, 1 reply; 19+ messages in thread
From: Breno Leitao @ 2018-08-16 17:21 UTC (permalink / raw)
To: linuxppc-dev; +Cc: mikey, Breno Leitao
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
^ permalink raw reply related [flat|nested] 19+ messages in thread
* Re: [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active()
2018-08-15 23:46 ` [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active() Michael Neuling
2018-08-16 17:21 ` [PATCH v3] " Breno Leitao
@ 2018-08-17 0:49 ` Michael Ellerman
2018-08-17 12:26 ` Breno Leitao
1 sibling, 1 reply; 19+ messages in thread
From: Michael Ellerman @ 2018-08-17 0:49 UTC (permalink / raw)
To: Michael Neuling, Breno Leitao, linuxppc-dev
Michael Neuling <mikey@neuling.org> writes:
> 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.
>>
>> 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...
>
>>
>> - 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
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active()
2018-08-17 0:49 ` [PATCH v2 1/4] " Michael Ellerman
@ 2018-08-17 12:26 ` Breno Leitao
2018-08-21 6:33 ` Michael Ellerman
0 siblings, 1 reply; 19+ messages in thread
From: Breno Leitao @ 2018-08-17 12:26 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: Michael Neuling
Hi Michael,
On 08/16/2018 09:49 PM, Michael Ellerman wrote:
> Michael Neuling <mikey@neuling.org> writes:
>
>> 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.
>>>
>>> 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...
>>
>>>
>>> - 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!
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active()
2018-08-17 12:26 ` Breno Leitao
@ 2018-08-21 6:33 ` Michael Ellerman
0 siblings, 0 replies; 19+ messages in thread
From: Michael Ellerman @ 2018-08-21 6:33 UTC (permalink / raw)
To: Breno Leitao, linuxppc-dev; +Cc: Michael Neuling
Breno Leitao <leitao@debian.org> writes:
> On 08/16/2018 09:49 PM, Michael Ellerman wrote:
>> Michael Neuling <mikey@neuling.org> writes:
>>
>>> 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.
>>>>
>>>> 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...
>>>
>>>>
>>>> - 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
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [v2,2/4] powerpc/tm: Fix HTM documentation
2018-06-18 22:59 ` [PATCH v2 2/4] powerpc/tm: Fix HTM documentation Breno Leitao
2018-08-15 23:46 ` Michael Neuling
@ 2018-09-20 4:20 ` Michael Ellerman
1 sibling, 0 replies; 19+ messages in thread
From: Michael Ellerman @ 2018-09-20 4:20 UTC (permalink / raw)
To: Breno Leitao, linuxppc-dev; +Cc: Breno Leitao
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 <mikey@neuling.org>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/96695563cebfb810b09479a9951ebb
cheers
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [v3] powerpc/tm: Remove msr_tm_active()
2018-08-16 17:21 ` [PATCH v3] " Breno Leitao
@ 2018-10-04 6:14 ` Michael Ellerman
0 siblings, 0 replies; 19+ messages in thread
From: Michael Ellerman @ 2018-10-04 6:14 UTC (permalink / raw)
To: Breno Leitao, linuxppc-dev; +Cc: Breno Leitao, mikey
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
^ permalink raw reply [flat|nested] 19+ messages in thread
end of thread, other threads:[~2018-10-04 6:24 UTC | newest]
Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-06-15 17:37 [PATCH 1/3] powerpc/tm: Remove msr_tm_active() Breno Leitao
2018-06-15 17:42 ` [PATCH 2/3] powerpc/tm: Fix HTM documentation Breno Leitao
2018-06-15 17:42 ` [PATCH 3/3] powerpc/tm: Remove struct thread_info param from tm_reclaim_thread() Breno Leitao
2018-06-15 20:06 ` [PATCH 1/3] powerpc/tm: Remove msr_tm_active() kbuild test robot
2018-06-18 22:59 ` [PATCH v2 1/4] " Breno Leitao
2018-06-18 22:59 ` [PATCH v2 2/4] powerpc/tm: Fix HTM documentation Breno Leitao
2018-08-15 23:46 ` Michael Neuling
2018-09-20 4:20 ` [v2,2/4] " Michael Ellerman
2018-06-18 22:59 ` [PATCH v2 3/4] powerpc/tm: Adjust tm_reclaim_thread() parameters Breno Leitao
2018-08-15 23:48 ` Michael Neuling
2018-06-18 22:59 ` [PATCH v2 4/4] powerpc/tm: Do not recheckpoint non-tm task Breno Leitao
2018-08-15 23:50 ` Michael Neuling
2018-08-16 14:19 ` Breno Leitao
2018-08-15 23:46 ` [PATCH v2 1/4] powerpc/tm: Remove msr_tm_active() Michael Neuling
2018-08-16 17:21 ` [PATCH v3] " Breno Leitao
2018-10-04 6:14 ` [v3] " Michael Ellerman
2018-08-17 0:49 ` [PATCH v2 1/4] " Michael Ellerman
2018-08-17 12:26 ` Breno Leitao
2018-08-21 6:33 ` Michael Ellerman
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