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From: Tom Rini <trini@kernel.crashing.org>
To: Joakim Tjernlund <joakim.tjernlund@lumentis.se>
Cc: "Linuxppc-Embedded@Ozlabs. Org" <linuxppc-embedded@ozlabs.org>
Subject: Re: [PATCH] Handle I-TLB Error and Miss separately on 8xx
Date: Tue, 18 Jan 2005 13:09:44 -0700	[thread overview]
Message-ID: <20050118200944.GN28724@smtp.west.cox.net> (raw)
In-Reply-To: <JPEALJAFNGDDLOPNDIEEEECGDAAA.joakim.tjernlund@lumentis.se>

On Fri, Jan 14, 2005 at 08:51:44PM +0100, Joakim Tjernlund wrote:

> BTW, there is a simpler fix to the TLB Miss problem.
> In the TLB Miss handlers, just move the 2: label a few instr. upwards to
> the same line as the "li	r21, 0x00f0". That way you will force a 
> TLB error. You can do this for both Data and Instr. Miss handlers.
> The code after where the 2: label used to be can be deleted. 

Like this?  Only lightly tested on my rpxlite on 2.6:


---

 linux-2.6-current-trini/arch/ppc/kernel/head_8xx.S |   22 +--------------------
 1 files changed, 2 insertions(+), 20 deletions(-)

diff -puN arch/ppc/kernel/head_8xx.S~ppc32-mpc8xx-itlbmiss-fix arch/ppc/kernel/head_8xx.S
--- linux-2.6-current/arch/ppc/kernel/head_8xx.S~ppc32-mpc8xx-itlbmiss-fix	2005-01-18 11:55:34.000000000 -0700
+++ linux-2.6-current-trini/arch/ppc/kernel/head_8xx.S	2005-01-18 11:57:11.000000000 -0700
@@ -343,7 +343,7 @@ InstructionTLBMiss:
 	 * set.  All other Linux PTE bits control the behavior
 	 * of the MMU.
 	 */
-	li	r11, 0x00f0
+2:	li	r11, 0x00f0
 	rlwimi	r10, r11, 0, 24, 28	/* Set 24-27, clear 28 */
 	DO_8xx_CPU6(0x2d80, r3)
 	mtspr	MI_RPN, r10	/* Update TLB entry */
@@ -357,15 +357,6 @@ InstructionTLBMiss:
 #endif
 	rfi
 
-2:	mfspr	r10, M_TW	/* Restore registers */
-	lwz	r11, 0(r0)
-	mtcr	r11
-	lwz	r11, 4(r0)
-#ifdef CONFIG_8xx_CPU6
-	lwz	r3, 8(r0)
-#endif
-	b	InstructionAccess
-
 	. = 0x1200
 DataStoreTLBMiss:
 #ifdef CONFIG_8xx_CPU6
@@ -419,7 +410,7 @@ DataStoreTLBMiss:
 	 * set.  All other Linux PTE bits control the behavior
 	 * of the MMU.
 	 */
-	li	r11, 0x00f0
+2:	li	r11, 0x00f0
 	rlwimi	r10, r11, 0, 24, 28	/* Set 24-27, clear 28 */
 	DO_8xx_CPU6(0x3d80, r3)
 	mtspr	MD_RPN, r10	/* Update TLB entry */
@@ -433,15 +424,6 @@ DataStoreTLBMiss:
 #endif
 	rfi
 
-2:	mfspr	r10, M_TW	/* Restore registers */
-	lwz	r11, 0(r0)
-	mtcr	r11
-	lwz	r11, 4(r0)
-#ifdef CONFIG_8xx_CPU6
-	lwz	r3, 8(r0)
-#endif
-	b	DataAccess
-
 /* This is an instruction TLB error on the MPC8xx.  This could be due
  * to many reasons, such as executing guarded memory or illegal instruction
  * addresses.  There is nothing to do but handle a big time error fault.
_

-- 
Tom Rini
http://gate.crashing.org/~trini/

  reply	other threads:[~2005-01-18 20:09 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-12  7:53 [PATCH] Handle I-TLB Error and Miss separately on 8xx Joakim Tjernlund
2005-01-12 14:06 ` Tom Rini
2005-01-12 14:17   ` Joakim Tjernlund
2005-01-12 15:15     ` Tom Rini
2005-01-13 15:16       ` Tom Rini
2005-01-14 14:03         ` Joakim Tjernlund
2005-01-14 17:38           ` Joakim Tjernlund
2005-01-14 17:47             ` Tom Rini
2005-01-14 17:56               ` Joakim Tjernlund
2005-01-14 18:05                 ` Tom Rini
2005-01-14 19:51                   ` Joakim Tjernlund
2005-01-18 20:09                     ` Tom Rini [this message]
2005-01-18 22:02                       ` Joakim Tjernlund
2005-01-19 17:25                         ` Dan Malek
2005-01-19 18:06                           ` Joakim Tjernlund
2005-01-19 18:37                             ` Dan Malek
2005-01-19 19:58                               ` Joakim Tjernlund
2005-01-19  0:30                       ` Joakim Tjernlund
2005-01-19 17:28                         ` Dan Malek
2005-01-19 18:12                           ` Joakim Tjernlund
  -- strict thread matches above, loose matches on Subject: below --
2005-01-07 16:22 Tom Rini

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