Messages in this thread | | | Subject | Re: [PATCH] x86 (Linux Tiny): configure out support for some processors | From | Matt Mackall <> | Date | Fri, 08 Feb 2008 17:20:12 -0600 |
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On Fri, 2008-02-08 at 23:47 +0100, Michael Opdenacker wrote: > This patch against x86/mm tries to revive an original patch > from Matt Mackall which didn't get merged at that time. It makes > it possible to disable support code for some processors. This can > be useful to support only the exact processor type used > in a given system. > > I may have made wrong assumptions with the code handling > force_mwait. As force_mwait is only declared in > arch/x86/kernel/cpu/amd.c, which is only compiled > when CONFIG_X86_32 is set, I thought it was safe > to make the code depend on CONFIG_CPU_SUP_AMD, > but I could be wrong. > > Your comments are more than welcome! To make the code > cleaner, I could use empty inline functions instead > of ifdef's, as suggested in Documentation/SubmittingPatches.
Please include the output of size with all these options on and off.
> diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c > index dabdbef..8f9a123 100644 > --- a/arch/x86/kernel/process_32.c > +++ b/arch/x86/kernel/process_32.c > @@ -287,8 +287,10 @@ static void mwait_idle(void) > > static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c) > { > +#ifdef CONFIG_CPU_SUP_AMD > if (force_mwait) > return 1; > +#endif
Probably makes sense to move force_mwait (one word) here and eliminate these ifdefs.
> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c > index 347a8cd..812bfa0 100644 > --- a/arch/x86/mm/init_32.c > +++ b/arch/x86/mm/init_32.c > @@ -211,12 +211,14 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base) > } > } > > +#ifdef CONFIG_CPU_SUP_INTEL > static inline int page_kills_ppro(unsigned long pagenr) > { > if (pagenr >= 0x70000 && pagenr <= 0x7003F) > return 1; > return 0; > } > +#endif > /* > * devmem_is_allowed() checks to see if /dev/mem access to a certain address > @@ -287,7 +289,11 @@ static void __meminit free_new_highpage(struct page *page) > > void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro) > { > - if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) { > + if (page_is_ram(pfn) > +#ifdef CONFIG_CPU_SUP_INTEL > + && !(bad_ppro && page_kills_ppro(pfn)) > +#endif
Yuck. A better way to do this is move the bad_ppro check into page_kills_ppro and then ifdef out -the body- of the inline.
> @@ -592,7 +598,11 @@ void __init mem_init(void) > #ifdef CONFIG_FLATMEM > BUG_ON(!mem_map); > #endif > +#ifdef CONFIG_CPU_SUP_INTEL > bad_ppro = ppro_with_ram_bug(); > +#else > + bad_ppro = 0; > +#endif
Again, move the storage for this, let it get initialized to zero automatically, and initialize it in the CPU-specific code (if ordering allows).
-- Mathematics is the supreme nostalgia of our time.
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