The patch titled powerpc: 8xx: fix swap has been added to the -mm tree. Its filename is powerpc-8xx-fix-swap.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: powerpc: 8xx: fix swap From: Vitaly Bordug <vitb@xxxxxxxxxxxxxxxxxxx> This makes swap routines operate correctly on the ppc_8xx based machines. Code has been revalidated on mpc885ads (8M sdram) with recent kernel. Based on patch from Yuri Tikhonov <yur@xxxxxxxxxxx> to do the same on arch/ppc instance. Recent kernel's size makes swap feature very important on low-memory platforms, those are actually non-operable without it. Signed-off-by: Yuri Tikhonov <yur@xxxxxxxxxxx> Signed-off-by: Vitaly Bordug <vitb@xxxxxxxxxxxxxxxxxxx> Cc: Kumar Gala <galak@xxxxxxxxxxxxxxxxxxx> Cc: Scott Wood <scottwood@xxxxxxxxxxxxx> Cc: Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/powerpc/kernel/head_8xx.S | 30 +++++++++++++++++++++++++- include/asm-powerpc/pgtable-ppc32.h | 8 ------ 2 files changed, 29 insertions(+), 9 deletions(-) diff -puN arch/powerpc/kernel/head_8xx.S~powerpc-8xx-fix-swap arch/powerpc/kernel/head_8xx.S --- a/arch/powerpc/kernel/head_8xx.S~powerpc-8xx-fix-swap +++ a/arch/powerpc/kernel/head_8xx.S @@ -332,8 +332,18 @@ InstructionTLBMiss: mfspr r11, SPRN_MD_TWC /* ....and get the pte address */ lwz r10, 0(r11) /* Get the pte */ +#ifdef CONFIG_SWAP + /* do not set the _PAGE_ACCESSED bit of a non-present page */ + andi. r11, r10, _PAGE_PRESENT + beq 4f + ori r10, r10, _PAGE_ACCESSED + mfspr r11, SPRN_MD_TWC /* get the pte address again */ + stw r10, 0(r11) +4: +#else ori r10, r10, _PAGE_ACCESSED stw r10, 0(r11) +#endif /* The Linux PTE won't go exactly into the MMU TLB. * Software indicator bits 21, 22 and 28 must be clear. @@ -398,8 +408,17 @@ DataStoreTLBMiss: DO_8xx_CPU6(0x3b80, r3) mtspr SPRN_MD_TWC, r11 - mfspr r11, SPRN_MD_TWC /* get the pte address again */ +#ifdef CONFIG_SWAP + /* do not set the _PAGE_ACCESSED bit of a non-present page */ + andi. r11, r10, _PAGE_PRESENT + beq 4f ori r10, r10, _PAGE_ACCESSED +4: + /* and update pte in table */ +#else + ori r10, r10, _PAGE_ACCESSED +#endif + mfspr r11, SPRN_MD_TWC /* get the pte address again */ stw r10, 0(r11) /* The Linux PTE won't go exactly into the MMU TLB. @@ -507,7 +526,16 @@ DataTLBError: /* Update 'changed', among others. */ +#ifdef CONFIG_SWAP + ori r10, r10, _PAGE_DIRTY|_PAGE_HWWRITE + /* do not set the _PAGE_ACCESSED bit of a non-present page */ + andi. r11, r10, _PAGE_PRESENT + beq 4f + ori r10, r10, _PAGE_ACCESSED +4: +#else ori r10, r10, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE +#endif mfspr r11, SPRN_MD_TWC /* Get pte address again */ stw r10, 0(r11) /* and update pte in table */ diff -puN include/asm-powerpc/pgtable-ppc32.h~powerpc-8xx-fix-swap include/asm-powerpc/pgtable-ppc32.h --- a/include/asm-powerpc/pgtable-ppc32.h~powerpc-8xx-fix-swap +++ a/include/asm-powerpc/pgtable-ppc32.h @@ -339,14 +339,6 @@ extern int icache_44x_need_flush; #define _PMD_PAGE_MASK 0x000c #define _PMD_PAGE_8M 0x000c -/* - * The 8xx TLB miss handler allegedly sets _PAGE_ACCESSED in the PTE - * for an address even if _PAGE_PRESENT is not set, as a performance - * optimization. This is a bug if you ever want to use swap unless - * _PAGE_ACCESSED is 2, which it isn't, or unless you have 8xx-specific - * definitions for __swp_entry etc. below, which would be gross. - * -- paulus - */ #define _PTE_NONE_MASK _PAGE_ACCESSED #else /* CONFIG_6xx */ _ Patches currently in -mm which might be from vitb@xxxxxxxxxxxxxxxxxxx are powerpc-8xx-fix-swap.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html