From 0c4661698c58db2a9efc44f403b893bd4d98f348 Mon Sep 17 00:00:00 2001 From: Joakim Tjernlund Date: Fri, 20 Nov 2009 00:21:08 +0000 Subject: [PATCH] powerpc/8xx: Restore _PAGE_WRITETHRU 8xx has not had WRITETHRU due to lack of bits in the pte. After the recent rewrite of the 8xx TLB code, there are two bits left. Use one of them to WRITETHRU. Perhaps use the last SW bit to PAGE_SPECIAL or PAGE_FILE? Signed-off-by: Joakim Tjernlund Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/pte-8xx.h | 5 +++-- arch/powerpc/kernel/head_8xx.S | 8 ++++++++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/pte-8xx.h b/arch/powerpc/include/asm/pte-8xx.h index 68ba861331ee..d44826e4ff97 100644 --- a/arch/powerpc/include/asm/pte-8xx.h +++ b/arch/powerpc/include/asm/pte-8xx.h @@ -35,11 +35,12 @@ #define _PAGE_SPECIAL 0x0008 /* SW entry, forced to 0 by the TLB miss */ #define _PAGE_DIRTY 0x0100 /* C: page changed */ -/* These 3 software bits must be masked out when the entry is loaded - * into the TLB, 2 SW bits left. +/* These 4 software bits must be masked out when the entry is loaded + * into the TLB, 1 SW bit left(0x0080). */ #define _PAGE_GUARDED 0x0010 /* software: guarded access */ #define _PAGE_ACCESSED 0x0020 /* software: page referenced */ +#define _PAGE_WRITETHRU 0x0040 /* software: caching is write through */ /* Setting any bits in the nibble with the follow two controls will * require a TLB exception handler change. It is assumed unused bits diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 1a28ee8ca318..c4ae85b8f8c0 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -422,6 +422,10 @@ DataStoreTLBMiss: * above. */ rlwimi r11, r10, 0, 27, 27 + /* Insert the WriteThru flag into the TWC from the Linux PTE. + * It is bit 25 in the Linux PTE and bit 30 in the TWC + */ + rlwimi r11, r10, 32-5, 30, 30 DO_8xx_CPU6(0x3b80, r3) mtspr SPRN_MD_TWC, r11 @@ -559,6 +563,10 @@ DARFixed:/* Return from dcbx instruction bug workaround, r10 holds value of DAR * It is bit 27 of both the Linux PTE and the TWC */ rlwimi r11, r10, 0, 27, 27 + /* Insert the WriteThru flag into the TWC from the Linux PTE. + * It is bit 25 in the Linux PTE and bit 30 in the TWC + */ + rlwimi r11, r10, 32-5, 30, 30 DO_8xx_CPU6(0x3b80, r3) mtspr SPRN_MD_TWC, r11 mfspr r11, SPRN_MD_TWC /* get the pte address again */ -- 2.20.1