Messages in this thread | | | From | "Michael S. Zick" <> | Subject | Re: [Bug Fix]: Do 32-bit table calculations in pre-processor | Date | Fri, 3 Jul 2009 15:48:39 -0500 |
| |
On Fri July 3 2009, Yinghai Lu wrote: > On Fri, Jul 3, 2009 at 1:07 PM, Yinghai Lu<yhlu.kernel@gmail.com> wrote: > > On Fri, Jul 3, 2009 at 11:14 AM, Michael S. Zick<lkml@morethan.org> wrote: > >> Here is one I have found useful in my VIA processor bug hunting: > >> > >> diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S > >> index 3068388..2303d86 100644 > >> --- a/arch/x86/kernel/head_32.S > >> +++ b/arch/x86/kernel/head_32.S > >> @@ -61,7 +61,7 @@ > >> > >> /* Enough space to fit pagetables for the low memory linear map */ > >> MAPPING_BEYOND_END = \ > >> - PAGE_TABLE_SIZE(((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT) << PAGE_SHIFT > >> + PAGE_TABLE_SIZE((1<<20) - (__PAGE_OFFSET >> PAGE_SHIFT)) << PAGE_SHIFT > >> > >> /* > >> * Worst-case size of the kernel mapping we need to make: > >> > >> = = = > >> > >> Before: > >> > >> #5 [0000010000 - 0000011000] PGTABLE ==> [0000010000 - 0000011000] > >> #6 [0000011000 - 0000015000] BOOTMAP ==> [0000011000 - 0000015000] > >> > >> After: > >> > >> #5 [0000010000 - 000007d000] PGTABLE ==> [0000010000 - 000007d000] > >> #6 [000007d000 - 0000081000] BOOTMAP ==> [000007d000 - 0000081000] > >> > > > > that PGTABLE is from early resource. and it is filled by init_memory_mapping() > > > > it mean preallocated pgtable to MAPPING_BEYOND_END is small now after > > patch. and init_memory_mapping try to get more. > > > > please send out whole dmesg. with and without your patch. it could > > print out initial mapped before e820 allocation is involved for 32bit > > printk(KERN_DEBUG "initial memory mapped : 0 - %08lx\n", > > max_pfn_mapped<<PAGE_SHIFT); > > > > > > your patch should be right. except to change that 12 to PAGE_SHIFT > > > mean >
Yes, want to get the 8K page machines correct also.
> > >> /* Enough space to fit pagetables for the low memory linear map */ > >> MAPPING_BEYOND_END = \ > >> - PAGE_TABLE_SIZE(((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT) << PAGE_SHIFT > >> + PAGE_TABLE_SIZE((1<<(32 - PAGE_SHIFT)) - (__PAGE_OFFSET >> PAGE_SHIFT)) << PAGE_SHIFT >
You read my mind, thanks.
Mike > YH > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > >
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |