Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 2 | * The SH64 TLB miss. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | * |
| 4 | * Original code from fault.c |
| 5 | * Copyright (C) 2000, 2001 Paolo Alberelli |
| 6 | * |
| 7 | * Fast PTE->TLB refill path |
| 8 | * Copyright (C) 2003 Richard.Curnow@superh.com |
| 9 | * |
| 10 | * IMPORTANT NOTES : |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 11 | * The do_fast_page_fault function is called from a context in entry.S |
| 12 | * where very few registers have been saved. In particular, the code in |
| 13 | * this file must be compiled not to use ANY caller-save registers that |
| 14 | * are not part of the restricted save set. Also, it means that code in |
| 15 | * this file must not make calls to functions elsewhere in the kernel, or |
| 16 | * else the excepting context will see corruption in its caller-save |
| 17 | * registers. Plus, the entry.S save area is non-reentrant, so this code |
| 18 | * has to run with SR.BL==1, i.e. no interrupts taken inside it and panic |
| 19 | * on any exception. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | * |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 21 | * This file is subject to the terms and conditions of the GNU General Public |
| 22 | * License. See the file "COPYING" in the main directory of this archive |
| 23 | * for more details. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/signal.h> |
| 26 | #include <linux/sched.h> |
| 27 | #include <linux/kernel.h> |
| 28 | #include <linux/errno.h> |
| 29 | #include <linux/string.h> |
| 30 | #include <linux/types.h> |
| 31 | #include <linux/ptrace.h> |
| 32 | #include <linux/mman.h> |
| 33 | #include <linux/mm.h> |
| 34 | #include <linux/smp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/interrupt.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | #include <asm/system.h> |
| 37 | #include <asm/tlb.h> |
| 38 | #include <asm/io.h> |
| 39 | #include <asm/uaccess.h> |
| 40 | #include <asm/pgalloc.h> |
| 41 | #include <asm/mmu_context.h> |
Paul Mundt | f15cbe6 | 2008-07-29 08:09:44 +0900 | [diff] [blame] | 42 | #include <cpu/registers.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
| 44 | /* Callable from fault.c, so not static */ |
| 45 | inline void __do_tlb_refill(unsigned long address, |
| 46 | unsigned long long is_text_not_data, pte_t *pte) |
| 47 | { |
| 48 | unsigned long long ptel; |
| 49 | unsigned long long pteh=0; |
| 50 | struct tlb_info *tlbp; |
| 51 | unsigned long long next; |
| 52 | |
| 53 | /* Get PTEL first */ |
| 54 | ptel = pte_val(*pte); |
| 55 | |
| 56 | /* |
| 57 | * Set PTEH register |
| 58 | */ |
| 59 | pteh = address & MMU_VPN_MASK; |
| 60 | |
| 61 | /* Sign extend based on neff. */ |
| 62 | #if (NEFF == 32) |
| 63 | /* Faster sign extension */ |
| 64 | pteh = (unsigned long long)(signed long long)(signed long)pteh; |
| 65 | #else |
| 66 | /* General case */ |
| 67 | pteh = (pteh & NEFF_SIGN) ? (pteh | NEFF_MASK) : pteh; |
| 68 | #endif |
| 69 | |
| 70 | /* Set the ASID. */ |
| 71 | pteh |= get_asid() << PTEH_ASID_SHIFT; |
| 72 | pteh |= PTEH_VALID; |
| 73 | |
| 74 | /* Set PTEL register, set_pte has performed the sign extension */ |
| 75 | ptel &= _PAGE_FLAGS_HARDWARE_MASK; /* drop software flags */ |
| 76 | |
| 77 | tlbp = is_text_not_data ? &(cpu_data->itlb) : &(cpu_data->dtlb); |
| 78 | next = tlbp->next; |
| 79 | __flush_tlb_slot(next); |
| 80 | asm volatile ("putcfg %0,1,%2\n\n\t" |
| 81 | "putcfg %0,0,%1\n" |
| 82 | : : "r" (next), "r" (pteh), "r" (ptel) ); |
| 83 | |
| 84 | next += TLB_STEP; |
| 85 | if (next > tlbp->last) next = tlbp->first; |
| 86 | tlbp->next = next; |
| 87 | |
| 88 | } |
| 89 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 90 | static int handle_vmalloc_fault(struct mm_struct *mm, |
| 91 | unsigned long protection_flags, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | unsigned long long textaccess, |
| 93 | unsigned long address) |
| 94 | { |
| 95 | pgd_t *dir; |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 96 | pud_t *pud; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | pmd_t *pmd; |
| 98 | static pte_t *pte; |
| 99 | pte_t entry; |
| 100 | |
| 101 | dir = pgd_offset_k(address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 103 | pud = pud_offset(dir, address); |
| 104 | if (pud_none_or_clear_bad(pud)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 105 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 107 | pmd = pmd_offset(pud, address); |
| 108 | if (pmd_none_or_clear_bad(pmd)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | |
| 111 | pte = pte_offset_kernel(pmd, address); |
| 112 | entry = *pte; |
| 113 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 114 | if (pte_none(entry) || !pte_present(entry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | return 0; |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 116 | if ((pte_val(entry) & protection_flags) != protection_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | |
| 119 | __do_tlb_refill(address, textaccess, pte); |
| 120 | |
| 121 | return 1; |
| 122 | } |
| 123 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 124 | static int handle_tlbmiss(struct mm_struct *mm, |
| 125 | unsigned long long protection_flags, |
| 126 | unsigned long long textaccess, |
| 127 | unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | { |
| 129 | pgd_t *dir; |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 130 | pud_t *pud; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | pmd_t *pmd; |
| 132 | pte_t *pte; |
| 133 | pte_t entry; |
| 134 | |
| 135 | /* NB. The PGD currently only contains a single entry - there is no |
| 136 | page table tree stored for the top half of the address space since |
| 137 | virtual pages in that region should never be mapped in user mode. |
| 138 | (In kernel mode, the only things in that region are the 512Mb super |
| 139 | page (locked in), and vmalloc (modules) + I/O device pages (handled |
| 140 | by handle_vmalloc_fault), so no PGD for the upper half is required |
| 141 | by kernel mode either). |
| 142 | |
| 143 | See how mm->pgd is allocated and initialised in pgd_alloc to see why |
| 144 | the next test is necessary. - RPC */ |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 145 | if (address >= (unsigned long) TASK_SIZE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | /* upper half - never has page table entries. */ |
| 147 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 149 | dir = pgd_offset(mm, address); |
| 150 | if (pgd_none(*dir) || !pgd_present(*dir)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | return 0; |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 152 | if (!pgd_present(*dir)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | return 0; |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 154 | |
| 155 | pud = pud_offset(dir, address); |
| 156 | if (pud_none(*pud) || !pud_present(*pud)) |
| 157 | return 0; |
| 158 | |
| 159 | pmd = pmd_offset(pud, address); |
| 160 | if (pmd_none(*pmd) || !pmd_present(*pmd)) |
| 161 | return 0; |
| 162 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | pte = pte_offset_kernel(pmd, address); |
| 164 | entry = *pte; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 166 | if (pte_none(entry) || !pte_present(entry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | return 0; |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 168 | |
| 169 | /* |
| 170 | * If the page doesn't have sufficient protection bits set to |
| 171 | * service the kind of fault being handled, there's not much |
| 172 | * point doing the TLB refill. Punt the fault to the general |
| 173 | * handler. |
| 174 | */ |
| 175 | if ((pte_val(entry) & protection_flags) != protection_flags) |
| 176 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | |
| 178 | __do_tlb_refill(address, textaccess, pte); |
| 179 | |
| 180 | return 1; |
| 181 | } |
| 182 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 183 | /* |
| 184 | * Put all this information into one structure so that everything is just |
| 185 | * arithmetic relative to a single base address. This reduces the number |
| 186 | * of movi/shori pairs needed just to load addresses of static data. |
| 187 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | struct expevt_lookup { |
| 189 | unsigned short protection_flags[8]; |
| 190 | unsigned char is_text_access[8]; |
| 191 | unsigned char is_write_access[8]; |
| 192 | }; |
| 193 | |
| 194 | #define PRU (1<<9) |
| 195 | #define PRW (1<<8) |
| 196 | #define PRX (1<<7) |
| 197 | #define PRR (1<<6) |
| 198 | |
| 199 | #define DIRTY (_PAGE_DIRTY | _PAGE_ACCESSED) |
| 200 | #define YOUNG (_PAGE_ACCESSED) |
| 201 | |
| 202 | /* Sized as 8 rather than 4 to allow checking the PTE's PRU bit against whether |
| 203 | the fault happened in user mode or privileged mode. */ |
| 204 | static struct expevt_lookup expevt_lookup_table = { |
| 205 | .protection_flags = {PRX, PRX, 0, 0, PRR, PRR, PRW, PRW}, |
| 206 | .is_text_access = {1, 1, 0, 0, 0, 0, 0, 0} |
| 207 | }; |
| 208 | |
| 209 | /* |
| 210 | This routine handles page faults that can be serviced just by refilling a |
| 211 | TLB entry from an existing page table entry. (This case represents a very |
| 212 | large majority of page faults.) Return 1 if the fault was successfully |
| 213 | handled. Return 0 if the fault could not be handled. (This leads into the |
| 214 | general fault handling in fault.c which deals with mapping file-backed |
| 215 | pages, stack growth, segmentation faults, swapping etc etc) |
| 216 | */ |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 217 | asmlinkage int do_fast_page_fault(unsigned long long ssr_md, |
| 218 | unsigned long long expevt, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | unsigned long address) |
| 220 | { |
| 221 | struct task_struct *tsk; |
| 222 | struct mm_struct *mm; |
| 223 | unsigned long long textaccess; |
| 224 | unsigned long long protection_flags; |
| 225 | unsigned long long index; |
| 226 | unsigned long long expevt4; |
| 227 | |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 228 | /* The next few lines implement a way of hashing EXPEVT into a |
| 229 | * small array index which can be used to lookup parameters |
| 230 | * specific to the type of TLBMISS being handled. |
| 231 | * |
| 232 | * Note: |
| 233 | * ITLBMISS has EXPEVT==0xa40 |
| 234 | * RTLBMISS has EXPEVT==0x040 |
| 235 | * WTLBMISS has EXPEVT==0x060 |
| 236 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | expevt4 = (expevt >> 4); |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 238 | /* TODO : xor ssr_md into this expression too. Then we can check |
| 239 | * that PRU is set when it needs to be. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | index = expevt4 ^ (expevt4 >> 5); |
| 241 | index &= 7; |
| 242 | protection_flags = expevt_lookup_table.protection_flags[index]; |
| 243 | textaccess = expevt_lookup_table.is_text_access[index]; |
| 244 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | /* SIM |
| 246 | * Note this is now called with interrupts still disabled |
| 247 | * This is to cope with being called for a missing IO port |
Simon Arlott | 0a35477 | 2007-05-14 08:25:48 +0900 | [diff] [blame] | 248 | * address with interrupts disabled. This should be fixed as |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | * soon as we have a better 'fast path' miss handler. |
| 250 | * |
| 251 | * Plus take care how you try and debug this stuff. |
| 252 | * For example, writing debug data to a port which you |
| 253 | * have just faulted on is not going to work. |
| 254 | */ |
| 255 | |
| 256 | tsk = current; |
| 257 | mm = tsk->mm; |
| 258 | |
| 259 | if ((address >= VMALLOC_START && address < VMALLOC_END) || |
| 260 | (address >= IOBASE_VADDR && address < IOBASE_END)) { |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 261 | if (ssr_md) |
| 262 | /* |
| 263 | * Process-contexts can never have this address |
| 264 | * range mapped |
| 265 | */ |
| 266 | if (handle_vmalloc_fault(mm, protection_flags, |
| 267 | textaccess, address)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | } else if (!in_interrupt() && mm) { |
Paul Mundt | 811d50c | 2007-11-20 17:01:55 +0900 | [diff] [blame] | 270 | if (handle_tlbmiss(mm, protection_flags, textaccess, address)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | } |
| 273 | |
| 274 | return 0; |
| 275 | } |