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e02db0aa3e
This patch fix the problem with rootfs on JFFS2 with early printk console turned on. The origin version used TLB63 for temporary early printk mapping. The code expect that kernel is not able to use all 64 TLB entries till early printk console is remapped by ioremap. After that temporary mapping on TLB63 is silently lost. This expectation give the opportunity to have early console pretty early. Microblaze systems with JFFS2 rootfs with early printk console turned on used more than 64 TLB entries before kernel can remap early console. Based on that kernel does access to bad area because early printk mapping is rewritten. This patch introduces tlb_skip variable which dynamically stores number of skipped TLB entries from the TLB0. skip_tlb=2 means that TLB0 and TLB1 should be skipped. MICROBLAZE_TLB_SKIP defines how many TLB is skipped at the kernel start. They can be used for user purpose. TLB 63 is used for temporary LMB mapping (MICROBLAZE_LMB_TLB_ID). Also clean TLBLO when kernel starts. For specific kernel sizes kernel can use just one TLB. Detect this case and use the second TLB for general purpose. Change _tlbia function to flush TLB entries from tlb_skip to TLB_SIZE. Export tlb_skip size through debugfs. Signed-off-by: Michal Simek <monstr@monstr.eu>
126 lines
4.2 KiB
C
126 lines
4.2 KiB
C
/*
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* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2008-2009 PetaLogix
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* Copyright (C) 2006 Atmark Techno, Inc.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#ifndef _ASM_MICROBLAZE_MMU_H
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#define _ASM_MICROBLAZE_MMU_H
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# ifndef CONFIG_MMU
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# include <asm-generic/mmu.h>
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# else /* CONFIG_MMU */
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# ifdef __KERNEL__
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# ifndef __ASSEMBLY__
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/* Default "unsigned long" context */
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typedef unsigned long mm_context_t;
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/* Hardware Page Table Entry */
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typedef struct _PTE {
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unsigned long v:1; /* Entry is valid */
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unsigned long vsid:24; /* Virtual segment identifier */
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unsigned long h:1; /* Hash algorithm indicator */
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unsigned long api:6; /* Abbreviated page index */
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unsigned long rpn:20; /* Real (physical) page number */
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unsigned long :3; /* Unused */
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unsigned long r:1; /* Referenced */
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unsigned long c:1; /* Changed */
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unsigned long w:1; /* Write-thru cache mode */
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unsigned long i:1; /* Cache inhibited */
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unsigned long m:1; /* Memory coherence */
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unsigned long g:1; /* Guarded */
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unsigned long :1; /* Unused */
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unsigned long pp:2; /* Page protection */
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} PTE;
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/* Values for PP (assumes Ks=0, Kp=1) */
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# define PP_RWXX 0 /* Supervisor read/write, User none */
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# define PP_RWRX 1 /* Supervisor read/write, User read */
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# define PP_RWRW 2 /* Supervisor read/write, User read/write */
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# define PP_RXRX 3 /* Supervisor read, User read */
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/* Segment Register */
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typedef struct _SEGREG {
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unsigned long t:1; /* Normal or I/O type */
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unsigned long ks:1; /* Supervisor 'key' (normally 0) */
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unsigned long kp:1; /* User 'key' (normally 1) */
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unsigned long n:1; /* No-execute */
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unsigned long :4; /* Unused */
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unsigned long vsid:24; /* Virtual Segment Identifier */
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} SEGREG;
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extern void _tlbie(unsigned long va); /* invalidate a TLB entry */
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extern void _tlbia(void); /* invalidate all TLB entries */
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/*
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* tlb_skip size stores actual number skipped TLBs from TLB0 - every directy TLB
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* mapping has to increase tlb_skip size.
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*/
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extern u32 tlb_skip;
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# endif /* __ASSEMBLY__ */
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/*
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* The MicroBlaze processor has a TLB architecture identical to PPC-40x. The
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* instruction and data sides share a unified, 64-entry, semi-associative
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* TLB which is maintained totally under software control. In addition, the
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* instruction side has a hardware-managed, 2,4, or 8-entry, fully-associative
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* TLB which serves as a first level to the shared TLB. These two TLBs are
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* known as the UTLB and ITLB, respectively.
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*/
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# define MICROBLAZE_TLB_SIZE 64
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/* For cases when you want to skip some TLB entries */
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# define MICROBLAZE_TLB_SKIP 0
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/* Use the last TLB for temporary access to LMB */
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# define MICROBLAZE_LMB_TLB_ID 63
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/*
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* TLB entries are defined by a "high" tag portion and a "low" data
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* portion. The data portion is 32-bits.
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*
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* TLB entries are managed entirely under software control by reading,
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* writing, and searching using the MTS and MFS instructions.
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*/
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# define TLB_LO 1
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# define TLB_HI 0
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# define TLB_DATA TLB_LO
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# define TLB_TAG TLB_HI
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/* Tag portion */
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# define TLB_EPN_MASK 0xFFFFFC00 /* Effective Page Number */
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# define TLB_PAGESZ_MASK 0x00000380
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# define TLB_PAGESZ(x) (((x) & 0x7) << 7)
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# define PAGESZ_1K 0
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# define PAGESZ_4K 1
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# define PAGESZ_16K 2
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# define PAGESZ_64K 3
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# define PAGESZ_256K 4
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# define PAGESZ_1M 5
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# define PAGESZ_4M 6
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# define PAGESZ_16M 7
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# define TLB_VALID 0x00000040 /* Entry is valid */
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/* Data portion */
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# define TLB_RPN_MASK 0xFFFFFC00 /* Real Page Number */
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# define TLB_PERM_MASK 0x00000300
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# define TLB_EX 0x00000200 /* Instruction execution allowed */
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# define TLB_WR 0x00000100 /* Writes permitted */
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# define TLB_ZSEL_MASK 0x000000F0
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# define TLB_ZSEL(x) (((x) & 0xF) << 4)
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# define TLB_ATTR_MASK 0x0000000F
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# define TLB_W 0x00000008 /* Caching is write-through */
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# define TLB_I 0x00000004 /* Caching is inhibited */
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# define TLB_M 0x00000002 /* Memory is coherent */
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# define TLB_G 0x00000001 /* Memory is guarded from prefetch */
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# endif /* __KERNEL__ */
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# endif /* CONFIG_MMU */
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#endif /* _ASM_MICROBLAZE_MMU_H */
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