Re: [PATCH 2/3] powerpc: Split mmu_context handling
From: Stephen Rothwell <hidden>
Date: 2008-12-04 06:17:40
Hi Ben, On Thu, 04 Dec 2008 16:41:48 +1100 Benjamin Herrenschmidt [off-list ref] wrote:
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--- linux-work.orig/arch/powerpc/include/asm/bug.h 2008-12-03 13:50:01.000000000 +1100 +++ linux-work/arch/powerpc/include/asm/bug.h 2008-12-03 13:50:18.000000000 +1100@@ -26,7 +26,7 @@ .previous .endm #else - .macro EMIT_BUG_ENTRY addr,file,line,flags +.macro EMIT_BUG_ENTRY addr,file,line,flags
Please don't make unrelated trivial fixups - they just make us look hard to see if something really changed.
-/* - * switch_mm is the entry point called from the architecture independent +/* switch_mm is the entry point called from the architecture independent
The same goes for just changing the comment style away from the usual ...
-/* - * After we have set current->mm to a new value, this activates +/* After we have set current->mm to a new value, this activates
Ditto
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--- linux-work.orig/arch/powerpc/kernel/head_32.S 2008-12-03 13:50:01.000000000 +1100 +++ linux-work/arch/powerpc/kernel/head_32.S 2008-12-03 13:50:18.000000000 +1100@@ -1050,7 +1051,7 @@ start_here: * We do this here because we know the mmu is disabled, and * will be enabled for real in just a few instructions. */ - lis r5, abatron_pteptrs@h + lis r5, abatron_pteptrs@h\
^ Is this right?
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+++ linux-work/arch/powerpc/mm/mmu_context_hash32.c 2008-12-03 13:50:18.000000000 +1100 +/* + * This function defines the mapping from contexts to VSIDs (virtual + * segment IDs). We use a skew on both the context and the high 4 bits + * of the 32-bit virtual address (the "effective segment ID") in order + * to spread out the entries in the MMU hash table. Note, if this + * function is changed then arch/ppc/mm/hashtable.S will have to be + * changed to correspond. + */ +#define CTX_TO_VSID(ctx, va) (((ctx) * (897 * 16) + ((va) >> 28) * 0x111) \ + & 0xffffff)
Any reason this is not a static inline function? Hmmm, actually it doesn't look like it is used anywhere ... I guess its just for documentation?
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+++ linux-work/arch/powerpc/mm/mmu_context_nohash.c 2008-12-03 13:50:18.000000000 +1100 +#ifdef CONFIG_8xx +#define NO_CONTEXT 16 +#define LAST_CONTEXT 15 +#define FIRST_CONTEXT 0 + +#elif defined(CONFIG_4xx) +#define NO_CONTEXT 256 +#define LAST_CONTEXT 255 +#define FIRST_CONTEXT 1 + +#elif defined(CONFIG_E200) || defined(CONFIG_E500) +#define NO_CONTEXT 256 +#define LAST_CONTEXT 255 +#define FIRST_CONTEXT 1
Why not combine these last two?
+static unsigned long next_mmu_context;
+ /* free up context `next_mmu_context' */ + /* if we shouldn't free context 0, don't... */ + if (next_mmu_context < FIRST_CONTEXT)
If FIRST_CONTEXT is 0, this will generate a compiler warning (as next_mmu_context can't be < 0).
+config PPC_MMU_NOHASH_32 + def_bool y + depends on PPC_MMU_NOHASH && PPC32 + +config PPC_MMU_NOHASH_64 + def_bool y + depends on PPC_MMU_NOHASH && PPC64
Neither of these are used anywhere. -- Cheers, Stephen Rothwell sfr@canb.auug.org.au http://www.canb.auug.org.au/~sfr/
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