From: Paul Mackerras <paulus@samba.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, David Gibson <dwg@au1.ibm.com>
Subject: Re: [PATCH -V6 05/27] powerpc: New hugepage directory format
Date: Wed, 24 Apr 2013 15:47:35 +1000 [thread overview]
Message-ID: <20130424054734.GA2073@drongo> (raw)
In-Reply-To: <1366624861-24948-6-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
On Mon, Apr 22, 2013 at 03:30:39PM +0530, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
[snip]
> /*
> - * Use the top bit of the higher-level page table entries to indicate whether
> - * the entries we point to contain hugepages. This works because we know that
> - * the page tables live in kernel space. If we ever decide to support having
> - * page tables at arbitrary addresses, this breaks and will have to change.
> - */
> -#ifdef CONFIG_PPC64
> -#define PD_HUGE 0x8000000000000000
> -#else
> -#define PD_HUGE 0x80000000
> -#endif
I think this is a good thing to do ultimately, but if you do this you
also need to fix arch/powerpc/kernel/head_fsl_booke.S:
#ifdef CONFIG_PTE_64BIT
#ifdef CONFIG_HUGETLB_PAGE
#define FIND_PTE \
rlwinm r12, r10, 13, 19, 29; /* Compute pgdir/pmd offset */ \
lwzx r11, r12, r11; /* Get pgd/pmd entry */ \
rlwinm. r12, r11, 0, 0, 20; /* Extract pt base address */ \
blt 1000f; /* Normal non-huge page */ \
beq 2f; /* Bail if no table */ \
oris r11, r11, PD_HUGE@h; /* Put back address bit */ \
andi. r10, r11, HUGEPD_SHIFT_MASK@l; /* extract size field */ \
xor r12, r10, r11; /* drop size bits from pointer */ \
b 1001f; \
and this, from arch/powerpc/mm/tlb_low_64e.S:
cmpdi cr0,r14,0
bge tlb_miss_fault_bolted /* Bad pgd entry or hugepage; bail */
(of which there are several similar instances in that file).
If you want to avoid fixing these bits of assembly code (and any
others I missed in my quick scan), you'll need to keep the definition
of PD_HUGE, at least on anything not 64-bit Book3S.
Paul.
next prev parent reply other threads:[~2013-04-24 5:47 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-22 10:00 [PATCH -V6 00/27] THP support for PPC64 Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 01/27] powerpc: Use signed formatting when printing error Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 02/27] powerpc: Save DAR and DSISR in pt_regs on MCE Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 03/27] powerpc: Don't hard code the size of pte page Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 04/27] powerpc: Don't truncate pgd_index wrongly Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 05/27] powerpc: New hugepage directory format Aneesh Kumar K.V
2013-04-23 7:01 ` Paul Mackerras
2013-04-23 8:42 ` Aneesh Kumar K.V
2013-04-24 5:47 ` Paul Mackerras [this message]
2013-04-25 6:00 ` Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 06/27] powerpc: Switch 16GB and 16MB explicit hugepages to a different page table format Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 07/27] powerpc: Reduce the PTE_INDEX_SIZE Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 08/27] powerpc: Move the pte free routines from common header Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 09/27] powerpc: Reduce PTE table memory wastage Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 10/27] powerpc: Use encode avpn where we need only avpn values Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 11/27] powerpc: Decode the pte-lp-encoding bits correctly Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 12/27] powerpc: Fix hpte_decode to use the correct decoding for page sizes Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 13/27] powerpc: print both base and actual page size on hash failure Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 14/27] powerpc: Print page size info during boot Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 15/27] powerpc: Update tlbie/tlbiel as per ISA doc Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 16/27] mm/THP: HPAGE_SHIFT is not a #define on some arch Aneesh Kumar K.V
2013-04-22 15:43 ` Andrea Arcangeli
2013-04-22 10:00 ` [PATCH -V6 17/27] mm/THP: Add pmd args to pgtable deposit and withdraw APIs Aneesh Kumar K.V
2013-04-22 15:46 ` Andrea Arcangeli
2013-04-22 10:00 ` [PATCH -V6 18/27] mm/THP: withdraw the pgtable after pmdp related operations Aneesh Kumar K.V
2013-04-22 15:49 ` Andrea Arcangeli
2013-04-24 9:08 ` Aneesh Kumar K.V
2013-04-24 15:14 ` Andrea Arcangeli
2013-04-25 6:11 ` Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 19/27] powerpc/THP: Double the PMD table size for THP Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 20/27] powerpc/THP: Implement transparent hugepages for ppc64 Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 21/27] powerpc: move find_linux_pte_or_hugepte and gup_hugepte to common code Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 22/27] powerpc: Update find_linux_pte_or_hugepte to handle transparent hugepages Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 23/27] powerpc: Replace find_linux_pte with find_linux_pte_or_hugepte Aneesh Kumar K.V
2013-04-24 6:29 ` Paul Mackerras
2013-04-22 10:00 ` [PATCH -V6 24/27] powerpc: Update gup_pmd_range to handle transparent hugepages Aneesh Kumar K.V
2013-04-22 10:00 ` [PATCH -V6 25/27] powerpc/THP: Add code to handle HPTE faults for large pages Aneesh Kumar K.V
2013-04-22 10:01 ` [PATCH -V6 26/27] powerpc/THP: Enable THP on PPC64 Aneesh Kumar K.V
2013-04-22 10:01 ` [PATCH -V6 27/27] powerpc: Optimize hugepage invalidate Aneesh Kumar K.V
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