[PATCH 11/12] powerpc: Replace mfmsr instructions with load from PACA kernel_msr field

All of lore.kernel.org
 help / color / mirror / Atom feed

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: linuxppc-dev@ozlabs.org
Subject: [PATCH 11/12] powerpc: Replace mfmsr instructions with load from PACA kernel_msr field
Date: Fri,  2 Mar 2012 20:35:21 +1100	[thread overview]
Message-ID: <1330680922-6894-12-git-send-email-benh@kernel.crashing.org> (raw)
In-Reply-To: <1330680922-6894-1-git-send-email-benh@kernel.crashing.org>

On 64-bit, the mfmsr instruction can be quite slow, slower
than loading a field from the cache-hot PACA, which happens
to already contain the value we want in most cases.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 arch/powerpc/include/asm/exception-64s.h |    2 +-
 arch/powerpc/include/asm/hw_irq.h        |    4 ++--
 arch/powerpc/kernel/entry_64.S           |   14 +++++---------
 arch/powerpc/kernel/exceptions-64s.S     |    5 ++---
 4 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 7f4718c..70354af 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -298,7 +298,7 @@ label##_hv:								\
 
 /* Exception addition: Keep interrupt state */
 #define ENABLE_INTS				\
-	mfmsr	r11;				\
+	ld	r11,PACAKMSR(r13);		\
 	ld	r12,_MSR(r1);			\
 	rlwimi	r11,r12,0,MSR_EE;		\
 	mtmsrd	r11,1
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 531ba00..6c6fa95 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -68,8 +68,8 @@ static inline bool arch_irqs_disabled(void)
 #define __hard_irq_enable()	asm volatile("wrteei 1" : : : "memory");
 #define __hard_irq_disable()	asm volatile("wrteei 0" : : : "memory");
 #else
-#define __hard_irq_enable()	__mtmsrd(mfmsr() | MSR_EE, 1)
-#define __hard_irq_disable()	__mtmsrd(mfmsr() & ~MSR_EE, 1)
+#define __hard_irq_enable()	__mtmsrd(local_paca->kernel_msr | MSR_EE, 1)
+#define __hard_irq_disable()	__mtmsrd(local_paca->kernel_msr, 1)
 #endif
 
 #define  hard_irq_disable()			\
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index cc030b7..c513beb 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -557,10 +557,8 @@ _GLOBAL(ret_from_except_lite)
 #ifdef CONFIG_PPC_BOOK3E
 	wrteei	0
 #else
-	mfmsr	r10		/* Get current interrupt state */
-	rldicl	r9,r10,48,1	/* clear MSR_EE */
-	rotldi	r9,r9,16
-	mtmsrd	r9,1		/* Update machine state */
+	ld	r10,PACAKMSR(r13) /* Get kernel MSR without EE */
+	mtmsrd	r10,1		  /* Update machine state */
 #endif /* CONFIG_PPC_BOOK3E */
 
 #ifdef CONFIG_PREEMPT
@@ -625,8 +623,8 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
 	 * userspace and we take an exception after restoring r13,
 	 * we end up corrupting the userspace r13 value.
 	 */
-	mfmsr	r4
-	andc	r4,r4,r0	/* r0 contains MSR_RI here */
+	ld	r4,PACAKMSR(r13) /* Get kernel MSR without EE */
+	andc	r4,r4,r0	 /* r0 contains MSR_RI here */
 	mtmsrd	r4,1
 
 	/*
@@ -686,9 +684,7 @@ do_work:
 #ifdef CONFIG_PPC_BOOK3E
 	wrteei	0
 #else
-	mfmsr	r10
-	rldicl	r10,r10,48,1
-	rotldi	r10,r10,16
+	ld	r10,PACAKMSR(r13) /* Get kernel MSR without EE */
 	mtmsrd	r10,1
 #endif /* CONFIG_PPC_BOOK3E */
 	li	r0,0
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index bd7130c..880f360 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -850,9 +850,8 @@ fast_exception_return:
 	REST_GPR(0, r1)
 	REST_8GPRS(2, r1)
 
-	mfmsr	r10
-	rldicl	r10,r10,48,1		/* clear EE */
-	rldicr	r10,r10,16,61		/* clear RI (LE is 0 already) */
+	ld	r10,PACAKMSR(r13)
+	clrrdi	r10,r10,2		/* clear RI */
 	mtmsrd	r10,1
 
 	mtspr	SPRN_SRR1,r12
-- 
1.7.9

next prev parent reply	other threads:[~2012-03-02  9:36 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-02  9:35 [PATCH 00/12] powerpc: Low level spring cleaning Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 01/12] powerpc: Remove legacy iSeries bits from assembly files Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 02/12] powerpc: Use the same interrupt prolog for perfmon as other interrupts Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 03/12] powerpc: Rework runlatch code Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 04/12] powerpc: Improve 64-bit syscall entry/exit Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 05/12] powerpc: Improve behaviour of irq tracing on 64-bit exception entry Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 06/12] powerpc: Disable interrupts in 64-bit kernel FP and vector faults Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 07/12] powerpc: Call do_page_fault() with interrupts off Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 08/12] powerpc: Add support for page fault retry and fatal signals Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 09/12] powerpc/xmon: Add display of soft & hard irq states Benjamin Herrenschmidt
2012-03-02  9:35 ` [PATCH 10/12] powerpc: Fix register clobbering when accumulating stolen time Benjamin Herrenschmidt
2012-03-02  9:35 ` Benjamin Herrenschmidt [this message]
2012-03-02  9:35 ` [PATCH 12/12] powerpc: Rework lazy-interrupt handling Benjamin Herrenschmidt
2012-03-04 23:11   ` Benjamin Herrenschmidt
     [not found] ` <1330680922-6894-4-git-send-email-benh__48089.0872575857$1330681158$gmane$org@kernel.crashing.org>
2012-04-05 21:38   ` [PATCH 03/12] powerpc: Rework runlatch code Andreas Schwab
2012-04-05 22:12     ` Benjamin Herrenschmidt
2012-04-05 23:05       ` Andreas Schwab
2012-04-11  0:46     ` Benjamin Herrenschmidt
2012-04-11  9:09       ` Andreas Schwab

find likely ancestor, descendant, or conflicting patches for this message:
( dfblob:7f4718c dfblob:70354af dfblob:531ba00 dfblob:6c6fa95
dfblob:cc030b7 dfblob:c513beb dfblob:bd7130c dfblob:880f360 )
 OR (
bs:"[PATCH 11/12] powerpc: Replace mfmsr instructions with load from PACA kernel_msr field" )
	(help)

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1330680922-6894-12-git-send-email-benh@kernel.crashing.org \
    --to=benh@kernel.crashing.org \
    --cc=linuxppc-dev@ozlabs.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Be sure your reply has a Subject: header at the top and a blank line before the message body.

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.