From: Michael Neuling <mikey@neuling.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org,
Michael Neuling <mikey@neuling.org>,
Paul Mackerras <paulus@samba.org>
Subject: [PATCH 3/3] powerpc/tm: Add checking to treclaim/trechkpt
Date: Fri, 28 Mar 2014 16:40:34 +1100 [thread overview]
Message-ID: <1395985234-27281-3-git-send-email-mikey@neuling.org> (raw)
In-Reply-To: <1395985234-27281-1-git-send-email-mikey@neuling.org>
If we do a treclaim and we are not in TM suspend mode, it results in a TM bad
thing (ie. a 0x700 program check). Similarly if we do a trechkpt and we have
an active transaction or TEXASR Failure Summary (FS) is not set, we also take a
TM bad thing.
This should never happen, but if it does (ie. a kernel bug), the cause is
almost impossible to debug as the GPR state is mostly userspace and hence we
don't get a call chain.
This adds some checks in these cases case a BUG_ON() (in asm) in case we ever
hit these cases. It moves the register saving around to preserve r1 till later
also.
Signed-off-by: Michael Neuling <mikey@neuling.org>
---
arch/powerpc/include/asm/reg.h | 1 +
arch/powerpc/kernel/tm.S | 38 +++++++++++++++++++++++++++++++++++---
2 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 1a36b8e..c09627d 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -214,6 +214,7 @@
#define SPRN_TFIAR 0x81 /* Transaction Failure Inst Addr */
#define SPRN_TEXASR 0x82 /* Transaction EXception & Summary */
#define SPRN_TEXASRU 0x83 /* '' '' '' Upper 32 */
+#define TEXASR_FS __MASK(63-36) /* TEXASR Failure Summary */
#define SPRN_TFHAR 0x80 /* Transaction Failure Handler Addr */
#define SPRN_CTRLF 0x088
#define SPRN_CTRLT 0x098
diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
index 0535c7f..508c54b 100644
--- a/arch/powerpc/kernel/tm.S
+++ b/arch/powerpc/kernel/tm.S
@@ -10,6 +10,7 @@
#include <asm/ppc-opcode.h>
#include <asm/ptrace.h>
#include <asm/reg.h>
+#include <asm/bug.h>
#ifdef CONFIG_VSX
/* See fpu.S, this is borrowed from there */
@@ -175,6 +176,13 @@ dont_backup_vec:
stfd fr0,FPSTATE_FPSCR(r7)
dont_backup_fp:
+ /* Do sanity check on MSR to make sure we are suspended */
+ li r7, (MSR_TS_S)@higher
+ srdi r6, r14, 32
+ and r6, r6, r7
+1: tdeqi r6, 0
+ EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0
+
/* The moment we treclaim, ALL of our GPRs will switch
* to user register state. (FPRs, CCR etc. also!)
* Use an sprg and a tm_scratch in the PACA to shuffle.
@@ -383,12 +391,10 @@ restore_gprs:
/* ******************** CR,LR,CCR,MSR ********** */
ld r4, _CTR(r7)
ld r5, _LINK(r7)
- ld r6, _CCR(r7)
ld r8, _XER(r7)
mtctr r4
mtlr r5
- mtcr r6
mtxer r8
/* ******************** TAR ******************** */
@@ -404,7 +410,8 @@ restore_gprs:
li r4, 0
mtmsrd r4, 1
- REST_4GPRS(0, r7) /* GPR0-3 */
+ REST_GPR(0, r7) /* GPR0 */
+ REST_2GPRS(2, r7) /* GPR2-3 */
REST_GPR(4, r7) /* GPR4 */
REST_4GPRS(8, r7) /* GPR8-11 */
REST_2GPRS(12, r7) /* GPR12-13 */
@@ -416,6 +423,31 @@ restore_gprs:
mtspr SPRN_DSCR, r5
mtspr SPRN_PPR, r6
+ /* Do final sanity check on TEXASR to make sure FS is set. Do this
+ * here before we load up the userspace r1 so any bugs we hit will get
+ * a call chain */
+ mfspr r5, SPRN_TEXASR
+ srdi r5, r5, 16
+ li r6, (TEXASR_FS)@h
+ and r6, r6, r5
+1: tdeqi r6, 0
+ EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0
+
+ /* Do final sanity check on MSR to make sure we are not transactional
+ * or suspended
+ */
+ mfmsr r6
+ li r5, (MSR_TS_MASK)@higher
+ srdi r6, r6, 32
+ and r6, r6, r5
+1: tdnei r6, 0
+ EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0
+
+ /* Restore CR */
+ ld r6, _CCR(r7)
+ mtcr r6
+
+ REST_GPR(1, r7) /* GPR1 */
REST_GPR(5, r7) /* GPR5-7 */
REST_GPR(6, r7)
ld r7, GPR7(r7)
--
1.8.3.2
next prev parent reply other threads:[~2014-03-28 5:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-28 5:40 [PATCH 1/3] powerpc/tm: Disable IRQ in tm_recheckpoint Michael Neuling
2014-03-28 5:40 ` [PATCH 2/3] powerpc/tm: Remove unnecessary r1 save Michael Neuling
2014-03-28 5:40 ` Michael Neuling [this message]
2014-04-04 9:19 ` [PATCH v2] powerpc/tm: Disable IRQ in tm_recheckpoint Michael Neuling
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