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From: Cyril Bur <cyrilbur@gmail.com>
To: mikey@neuling.org, benh@kernel.crashing.org,
	linuxppc-dev@lists.ozlabs.org
Subject: [RFC PATCH 07/12] [WIP] powerpc/tm: Add TM_KERNEL_ENTRY in more delicate exception pathes
Date: Tue, 20 Feb 2018 11:22:36 +1100	[thread overview]
Message-ID: <20180220002241.29648-8-cyrilbur@gmail.com> (raw)
In-Reply-To: <20180220002241.29648-1-cyrilbur@gmail.com>

---
 arch/powerpc/kernel/entry_64.S       | 15 ++++++++++++++-
 arch/powerpc/kernel/exceptions-64s.S | 31 ++++++++++++++++++++++++++++---
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 107c15c6f48b..32e8d8f7e091 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -967,7 +967,20 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	bl	__check_irq_replay
 	cmpwi	cr0,r3,0
 	beq	.Lrestore_no_replay
- 
+
+	/*
+	 * We decide VERY late if we need to replay interrupts, theres
+	 * not much which can be done about that so this will have to
+	 * do
+	 */
+	TM_KERNEL_ENTRY
+	/*
+	 * This will restore r3 that TM_KERNEL_ENTRY clobbered.
+	 * Clearly not ideal! I wonder if we could change the trap
+	 * value beforehand...
+	 */
+	bl	__check_irq_replay
+
 	/*
 	 * We need to re-emit an interrupt. We do so by re-using our
 	 * existing exception frame. We first change the trap value,
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 3ac87e53b3da..c8899bf77fb0 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -504,6 +504,11 @@ EXC_COMMON_BEGIN(data_access_common)
 	li	r5,0x300
 	std	r3,_DAR(r1)
 	std	r4,_DSISR(r1)
+	/*
+	 * Can't do TM_KERNEL_ENTRY here as do_hash_page might jump to
+	 * very late in the expection exit code, well after any
+	 * possiblity of doing a recheckpoint
+	 */
 BEGIN_MMU_FTR_SECTION
 	b	do_hash_page		/* Try to handle as hpte fault */
 MMU_FTR_SECTION_ELSE
@@ -548,6 +553,11 @@ EXC_COMMON_BEGIN(instruction_access_common)
 	li	r5,0x400
 	std	r3,_DAR(r1)
 	std	r4,_DSISR(r1)
+	/*
+	 * Can't do TM_KERNEL_ENTRY here as do_hash_page might jump to
+	 * very late in the expection exit code, well after any
+	 * possiblity of doing a recheckpoint
+	 */
 BEGIN_MMU_FTR_SECTION
 	b	do_hash_page		/* Try to handle as hpte fault */
 MMU_FTR_SECTION_ELSE
@@ -761,6 +771,7 @@ EXC_COMMON_BEGIN(alignment_common)
 	std	r4,_DSISR(r1)
 	bl	save_nvgprs
 	RECONCILE_IRQ_STATE(r10, r11)
+	TM_KERNEL_ENTRY
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	alignment_exception
 	b	ret_from_except
@@ -1668,7 +1679,9 @@ do_hash_page:
 
 /* Here we have a page fault that hash_page can't handle. */
 handle_page_fault:
-11:	andis.  r0,r4,DSISR_DABRMATCH@h
+11:	TM_KERNEL_ENTRY
+	ld      r4,_DSISR(r1)
+	andis.  r0,r4,DSISR_DABRMATCH@h
 	bne-    handle_dabr_fault
 	ld	r4,_DAR(r1)
 	ld	r5,_DSISR(r1)
@@ -1685,6 +1698,10 @@ handle_page_fault:
 
 /* We have a data breakpoint exception - handle it */
 handle_dabr_fault:
+	/*
+	 * Don't need to do TM_KERNEL_ENTRY here as we'll
+	 * come from handle_page_fault: which has done it already
+	 */
 	bl	save_nvgprs
 	ld      r4,_DAR(r1)
 	ld      r5,_DSISR(r1)
@@ -1698,7 +1715,14 @@ handle_dabr_fault:
  * the PTE insertion
  */
 13:	bl	save_nvgprs
-	mr	r5,r3
+	/*
+	 * Use a non-volatile as the TM code will call, r3 is the
+	 * return value from __hash_page() so not exactly easy to get
+	 * again.
+	 */
+	mr	r31,r3
+	TM_KERNEL_ENTRY
+	mr	r5, r31
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	ld	r4,_DAR(r1)
 	bl	low_hash_fault
@@ -1713,7 +1737,8 @@ handle_dabr_fault:
  * the access, or panic if there isn't a handler.
  */
 77:	bl	save_nvgprs
-	mr	r4,r3
+	TM_KERNEL_ENTRY
+	ld	r4,_DAR(r1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	li	r5,SIGSEGV
 	bl	bad_page_fault
-- 
2.16.2

  parent reply	other threads:[~2018-02-20  0:23 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-20  0:22 [RFC PATCH 00/12] Deal with TM on kernel entry and exit Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 01/12] powerpc/tm: Remove struct thread_info param from tm_reclaim_thread() Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 02/12] selftests/powerpc: Fix tm.h helpers Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 03/12] selftests/powerpc: Add tm-signal-drop-transaction TM test Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 04/12] selftests/powerpc: Use less common thread names Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 05/12] [WIP] powerpc/tm: Reclaim/recheckpoint on entry/exit Cyril Bur
2018-02-20  2:50   ` Michael Neuling
2018-02-20  3:54     ` Cyril Bur
2018-02-20  5:25       ` Michael Neuling
2018-02-20  6:32         ` Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 06/12] [WIP] powerpc/tm: Remove dead code from __switch_to_tm() Cyril Bur
2018-02-20  2:52   ` Michael Neuling
2018-02-20  3:43     ` Cyril Bur
2018-02-20  0:22 ` Cyril Bur [this message]
2018-02-20  0:22 ` [RFC PATCH 08/12] [WIP] powerpc/tm: Fix *unavailable_tm exceptions Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 09/12] [WIP] powerpc/tm: Tweak signal code to handle new reclaim/recheckpoint times Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 10/12] [WIP] powerpc/tm: Correctly save/restore checkpointed sprs Cyril Bur
2018-02-20  3:00   ` Michael Neuling
2018-02-20  3:59     ` Cyril Bur
2018-02-20  5:27       ` Michael Neuling
2018-02-20  0:22 ` [RFC PATCH 11/12] [WIP] powerpc/tm: Afterthoughts Cyril Bur
2018-02-20  0:22 ` [RFC PATCH 12/12] [WIP] selftests/powerpc: Remove incorrect tm-syscall selftest Cyril Bur
2018-02-20  3:04   ` Michael Neuling
2018-02-20  3:42     ` Cyril Bur
2018-06-13 22:38 ` [RFC,00/12] Deal with TM on kernel entry and exit Breno Leitao

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