From: Atsushi Nemoto Date: Thu, 2 Feb 2006 16:34:01 +0000 (+0900) Subject: [MIPS] TX49 MFC0 bug workaround X-Git-Tag: v2.6.16-rc3~137^2~2 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c226f2601f55010936f0f3c77ae167a02339f566;p=linux-2.6 [MIPS] TX49 MFC0 bug workaround If mfc0 $12 follows store and the mfc0 is last instruction of a page and fetching the next instruction causes TLB miss, the result of the mfc0 might wrongly contain EXL bit. ERT-TX49H2-027, ERT-TX49H3-012, ERT-TX49HL3-006, ERT-TX49H4-008 Workaround: mask EXL bit of the result or place a nop before mfc0. It doesn't harm to always clear those bits, so we change the code to do so. Signed-off-by: Atsushi Nemoto Signed-off-by: Ralf Baechle --- diff --git a/include/asm-mips/interrupt.h b/include/asm-mips/interrupt.h index 0da5818a2d..774348734f 100644 --- a/include/asm-mips/interrupt.h +++ b/include/asm-mips/interrupt.h @@ -47,6 +47,17 @@ static inline void local_irq_enable(void) * R4000/R4400 need three nops, the R4600 two nops and the R10000 needs * no nops at all. */ +/* + * For TX49, operating only IE bit is not enough. + * + * If mfc0 $12 follows store and the mfc0 is last instruction of a + * page and fetching the next instruction causes TLB miss, the result + * of the mfc0 might wrongly contain EXL bit. + * + * ERT-TX49H2-027, ERT-TX49H3-012, ERT-TX49HL3-006, ERT-TX49H4-008 + * + * Workaround: mask EXL bit of the result or place a nop before mfc0. + */ __asm__ ( " .macro local_irq_disable\n" " .set push \n" @@ -55,8 +66,8 @@ __asm__ ( " di \n" #else " mfc0 $1,$12 \n" - " ori $1,1 \n" - " xori $1,1 \n" + " ori $1,0x1f \n" + " xori $1,0x1f \n" " .set noreorder \n" " mtc0 $1,$12 \n" #endif @@ -96,8 +107,8 @@ __asm__ ( " andi \\result, 1 \n" #else " mfc0 \\result, $12 \n" - " ori $1, \\result, 1 \n" - " xori $1, 1 \n" + " ori $1, \\result, 0x1f \n" + " xori $1, 0x1f \n" " .set noreorder \n" " mtc0 $1, $12 \n" #endif @@ -136,8 +147,8 @@ __asm__ ( #else " mfc0 $1, $12 \n" " andi \\flags, 1 \n" - " ori $1, 1 \n" - " xori $1, 1 \n" + " ori $1, 0x1f \n" + " xori $1, 0x1f \n" " or \\flags, $1 \n" " mtc0 \\flags, $12 \n" #endif