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| author | Jan Beulich <JBeulich@novell.com> | 2009-12-18 19:05:51 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-30 13:57:30 +0300 |
| commit | 499a5f1efa0b0ac56ec5d060412aed84ae68e63e (patch) | |
| tree | 4e6bd3e2ed34b4b0736d89203e8f6212106a1f4f /arch/x86/mm/ioremap.c | |
| parent | 39d997b514e12d5aff0dca206eb8996b3957927e (diff) | |
| download | linux-499a5f1efa0b0ac56ec5d060412aed84ae68e63e.tar.xz | |
x86: Lift restriction on the location of FIX_BTMAP_*
The early ioremap fixmap entries cover half (or for 32-bit
non-PAE, a quarter) of a page table, yet they got
uncondtitionally aligned so far to a 256-entry boundary. This is
not necessary if the range of page table entries anyway falls
into a single page table.
This buys back, for (theoretically) 50% of all configurations
(25% of all non-PAE ones), at least some of the lowmem
necessarily lost with commit e621bd18958ef5dbace3129ebe17a0a475e127d9.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B2BB66F0200007800026AD6@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/mm/ioremap.c')
| -rw-r--r-- | arch/x86/mm/ioremap.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index c246d259822d..03c75ffd5c2a 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -422,6 +422,10 @@ void __init early_ioremap_init(void) * The boot-ioremap range spans multiple pmds, for which * we are not prepared: */ +#define __FIXADDR_TOP (-PAGE_SIZE) + BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) + != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); +#undef __FIXADDR_TOP if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) { WARN_ON(1); printk(KERN_WARNING "pmd %p != %p\n", |