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author | Paul Mackerras <paulus@samba.org> | 2006-06-15 02:45:18 +0200 |
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committer | Paul Mackerras <paulus@samba.org> | 2006-06-15 02:45:18 +0200 |
commit | bf72aeba2ffef599d1d386425c9e46b82be657cd (patch) | |
tree | ead8e5111dbcfa22e156999d1bb8a96e50f06fef /arch/powerpc/mm/slb.c | |
parent | powerpc: Fix some missed ppc32 mm->context.id conversions (diff) | |
download | linux-bf72aeba2ffef599d1d386425c9e46b82be657cd.tar.xz linux-bf72aeba2ffef599d1d386425c9e46b82be657cd.zip |
powerpc: Use 64k pages without needing cache-inhibited large pages
Some POWER5+ machines can do 64k hardware pages for normal memory but
not for cache-inhibited pages. This patch lets us use 64k hardware
pages for most user processes on such machines (assuming the kernel
has been configured with CONFIG_PPC_64K_PAGES=y). User processes
start out using 64k pages and get switched to 4k pages if they use any
non-cacheable mappings.
With this, we use 64k pages for the vmalloc region and 4k pages for
the imalloc region. If anything creates a non-cacheable mapping in
the vmalloc region, the vmalloc region will get switched to 4k pages.
I don't know of any driver other than the DRM that would do this,
though, and these machines don't have AGP.
When a region gets switched from 64k pages to 4k pages, we do not have
to clear out all the 64k HPTEs from the hash table immediately. We
use the _PAGE_COMBO bit in the Linux PTE to indicate whether the page
was hashed in as a 64k page or a set of 4k pages. If hash_page is
trying to insert a 4k page for a Linux PTE and it sees that it has
already been inserted as a 64k page, it first invalidates the 64k HPTE
before inserting the 4k HPTE. The hash invalidation routines also use
the _PAGE_COMBO bit, to determine whether to look for a 64k HPTE or a
set of 4k HPTEs to remove. With those two changes, we can tolerate a
mix of 4k and 64k HPTEs in the hash table, and they will all get
removed when the address space is torn down.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/mm/slb.c')
-rw-r--r-- | arch/powerpc/mm/slb.c | 29 |
1 files changed, 14 insertions, 15 deletions
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c index 2cc61736feee..6a8bf6c6000e 100644 --- a/arch/powerpc/mm/slb.c +++ b/arch/powerpc/mm/slb.c @@ -60,19 +60,19 @@ static inline void create_slbe(unsigned long ea, unsigned long flags, : "memory" ); } -static void slb_flush_and_rebolt(void) +void slb_flush_and_rebolt(void) { /* If you change this make sure you change SLB_NUM_BOLTED * appropriately too. */ - unsigned long linear_llp, virtual_llp, lflags, vflags; + unsigned long linear_llp, vmalloc_llp, lflags, vflags; unsigned long ksp_esid_data; WARN_ON(!irqs_disabled()); linear_llp = mmu_psize_defs[mmu_linear_psize].sllp; - virtual_llp = mmu_psize_defs[mmu_virtual_psize].sllp; + vmalloc_llp = mmu_psize_defs[mmu_vmalloc_psize].sllp; lflags = SLB_VSID_KERNEL | linear_llp; - vflags = SLB_VSID_KERNEL | virtual_llp; + vflags = SLB_VSID_KERNEL | vmalloc_llp; ksp_esid_data = mk_esid_data(get_paca()->kstack, 2); if ((ksp_esid_data & ESID_MASK) == PAGE_OFFSET) @@ -164,11 +164,10 @@ static inline void patch_slb_encoding(unsigned int *insn_addr, void slb_initialize(void) { - unsigned long linear_llp, virtual_llp; + unsigned long linear_llp, vmalloc_llp, io_llp; static int slb_encoding_inited; extern unsigned int *slb_miss_kernel_load_linear; - extern unsigned int *slb_miss_kernel_load_virtual; - extern unsigned int *slb_miss_user_load_normal; + extern unsigned int *slb_miss_kernel_load_io; #ifdef CONFIG_HUGETLB_PAGE extern unsigned int *slb_miss_user_load_huge; unsigned long huge_llp; @@ -178,18 +177,19 @@ void slb_initialize(void) /* Prepare our SLB miss handler based on our page size */ linear_llp = mmu_psize_defs[mmu_linear_psize].sllp; - virtual_llp = mmu_psize_defs[mmu_virtual_psize].sllp; + io_llp = mmu_psize_defs[mmu_io_psize].sllp; + vmalloc_llp = mmu_psize_defs[mmu_vmalloc_psize].sllp; + get_paca()->vmalloc_sllp = SLB_VSID_KERNEL | vmalloc_llp; + if (!slb_encoding_inited) { slb_encoding_inited = 1; patch_slb_encoding(slb_miss_kernel_load_linear, SLB_VSID_KERNEL | linear_llp); - patch_slb_encoding(slb_miss_kernel_load_virtual, - SLB_VSID_KERNEL | virtual_llp); - patch_slb_encoding(slb_miss_user_load_normal, - SLB_VSID_USER | virtual_llp); + patch_slb_encoding(slb_miss_kernel_load_io, + SLB_VSID_KERNEL | io_llp); DBG("SLB: linear LLP = %04x\n", linear_llp); - DBG("SLB: virtual LLP = %04x\n", virtual_llp); + DBG("SLB: io LLP = %04x\n", io_llp); #ifdef CONFIG_HUGETLB_PAGE patch_slb_encoding(slb_miss_user_load_huge, SLB_VSID_USER | huge_llp); @@ -204,7 +204,7 @@ void slb_initialize(void) unsigned long lflags, vflags; lflags = SLB_VSID_KERNEL | linear_llp; - vflags = SLB_VSID_KERNEL | virtual_llp; + vflags = SLB_VSID_KERNEL | vmalloc_llp; /* Invalidate the entire SLB (even slot 0) & all the ERATS */ asm volatile("isync":::"memory"); @@ -212,7 +212,6 @@ void slb_initialize(void) asm volatile("isync; slbia; isync":::"memory"); create_slbe(PAGE_OFFSET, lflags, 0); - /* VMALLOC space has 4K pages always for now */ create_slbe(VMALLOC_START, vflags, 1); /* We don't bolt the stack for the time being - we're in boot, |