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This patch adds support for 256KB pages on ppc44x-based boards. For simplification of implementation with 256KB pages we still assume 2-level paging. As a side effect this leads to wasting extra memory space reserved for PTE tables: only 1/4 of pages allocated for PTEs are actually used. But this may be an acceptable trade-off to achieve the high performance we have with big PAGE_SIZEs in some applications (e.g. RAID). Also with 256KB PAGE_SIZE we increase THREAD_SIZE up to 32KB to minimize the risk of stack overflows in the cases of on-stack arrays, which size depends on the page size (e.g. multipage BIOs, NTFS, etc.). With 256KB PAGE_SIZE we need to decrease the PKMAP_ORDER at least down to 9, otherwise all high memory (2 ^ 10 * PAGE_SIZE == 256MB) we'll be occupied by PKMAP addresses leaving no place for vmalloc. We do not separate PKMAP_ORDER for 256K from 16K/64K PAGE_SIZE here; actually that value of 10 in support for 16K/64K had been selected rather intuitively. Thus now for all cases of PAGE_SIZE on ppc44x (including the default, 4KB, one) we have 512 pages for PKMAP. Because ELF standard supports only page sizes up to 64K, then you should use binutils later than 2.17.50.0.3 with '-zmax-page-size' set to 256K for building applications, which are to be run with the 256KB-page sized kernel. If using the older binutils, then you should patch them like follows: --- binutils/bfd/elf32-ppc.c.orig +++ binutils/bfd/elf32-ppc.c -#define ELF_MAXPAGESIZE 0x10000 +#define ELF_MAXPAGESIZE 0x40000 One more restriction we currently have with 256KB page sizes is inability to use shmem safely, so, for now, the 256KB is available only if you turn the CONFIG_SHMEM option off (another variant is to use BROKEN). Though, if you need shmem with 256KB pages, you can always remove the !SHMEM dependency in 'config PPC_256K_PAGES', and use the workaround available here: http://lkml.org/lkml/2008/12/19/20 Signed-off-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Ilya Yanok <yanok@emcraft.com> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
98 lines
3.1 KiB
C
98 lines
3.1 KiB
C
#ifndef _ASM_POWERPC_MMU_44X_H_
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#define _ASM_POWERPC_MMU_44X_H_
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/*
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* PPC440 support
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*/
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#include <asm/page.h>
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#define PPC44x_MMUCR_TID 0x000000ff
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#define PPC44x_MMUCR_STS 0x00010000
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#define PPC44x_TLB_PAGEID 0
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#define PPC44x_TLB_XLAT 1
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#define PPC44x_TLB_ATTRIB 2
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/* Page identification fields */
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#define PPC44x_TLB_EPN_MASK 0xfffffc00 /* Effective Page Number */
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#define PPC44x_TLB_VALID 0x00000200 /* Valid flag */
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#define PPC44x_TLB_TS 0x00000100 /* Translation address space */
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#define PPC44x_TLB_1K 0x00000000 /* Page sizes */
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#define PPC44x_TLB_4K 0x00000010
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#define PPC44x_TLB_16K 0x00000020
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#define PPC44x_TLB_64K 0x00000030
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#define PPC44x_TLB_256K 0x00000040
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#define PPC44x_TLB_1M 0x00000050
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#define PPC44x_TLB_16M 0x00000070
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#define PPC44x_TLB_256M 0x00000090
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/* Translation fields */
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#define PPC44x_TLB_RPN_MASK 0xfffffc00 /* Real Page Number */
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#define PPC44x_TLB_ERPN_MASK 0x0000000f
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/* Storage attribute and access control fields */
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#define PPC44x_TLB_ATTR_MASK 0x0000ff80
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#define PPC44x_TLB_U0 0x00008000 /* User 0 */
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#define PPC44x_TLB_U1 0x00004000 /* User 1 */
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#define PPC44x_TLB_U2 0x00002000 /* User 2 */
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#define PPC44x_TLB_U3 0x00001000 /* User 3 */
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#define PPC44x_TLB_W 0x00000800 /* Caching is write-through */
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#define PPC44x_TLB_I 0x00000400 /* Caching is inhibited */
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#define PPC44x_TLB_M 0x00000200 /* Memory is coherent */
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#define PPC44x_TLB_G 0x00000100 /* Memory is guarded */
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#define PPC44x_TLB_E 0x00000080 /* Memory is guarded */
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#define PPC44x_TLB_PERM_MASK 0x0000003f
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#define PPC44x_TLB_UX 0x00000020 /* User execution */
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#define PPC44x_TLB_UW 0x00000010 /* User write */
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#define PPC44x_TLB_UR 0x00000008 /* User read */
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#define PPC44x_TLB_SX 0x00000004 /* Super execution */
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#define PPC44x_TLB_SW 0x00000002 /* Super write */
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#define PPC44x_TLB_SR 0x00000001 /* Super read */
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/* Number of TLB entries */
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#define PPC44x_TLB_SIZE 64
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#ifndef __ASSEMBLY__
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extern unsigned int tlb_44x_hwater;
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extern unsigned int tlb_44x_index;
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typedef struct {
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unsigned int id;
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unsigned int active;
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unsigned long vdso_base;
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} mm_context_t;
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#endif /* !__ASSEMBLY__ */
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#ifndef CONFIG_PPC_EARLY_DEBUG_44x
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#define PPC44x_EARLY_TLBS 1
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#else
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#define PPC44x_EARLY_TLBS 2
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#define PPC44x_EARLY_DEBUG_VIRTADDR (ASM_CONST(0xf0000000) \
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| (ASM_CONST(CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW) & 0xffff))
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#endif
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/* Size of the TLBs used for pinning in lowmem */
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#define PPC_PIN_SIZE (1 << 28) /* 256M */
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#if (PAGE_SHIFT == 12)
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#define PPC44x_TLBE_SIZE PPC44x_TLB_4K
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#elif (PAGE_SHIFT == 14)
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#define PPC44x_TLBE_SIZE PPC44x_TLB_16K
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#elif (PAGE_SHIFT == 16)
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#define PPC44x_TLBE_SIZE PPC44x_TLB_64K
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#elif (PAGE_SHIFT == 18)
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#define PPC44x_TLBE_SIZE PPC44x_TLB_256K
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#else
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#error "Unsupported PAGE_SIZE"
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#endif
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#define PPC44x_PGD_OFF_SHIFT (32 - PGDIR_SHIFT + PGD_T_LOG2)
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#define PPC44x_PGD_OFF_MASK_BIT (PGDIR_SHIFT - PGD_T_LOG2)
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#define PPC44x_PTE_ADD_SHIFT (32 - PGDIR_SHIFT + PTE_SHIFT + PTE_T_LOG2)
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#define PPC44x_PTE_ADD_MASK_BIT (32 - PTE_T_LOG2 - PTE_SHIFT)
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#endif /* _ASM_POWERPC_MMU_44X_H_ */
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