arch/arm64/mm/proc.S

   1 /*
   2  * Based on arch/arm/mm/proc.S
   3  *
   4  * Copyright (C) 2001 Deep Blue Solutions Ltd.
   5  * Copyright (C) 2012 ARM Ltd.
   6  * Author: Catalin Marinas <catalin.marinas@arm.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <linux/init.h>
  22 #include <linux/linkage.h>
  23 #include <asm/assembler.h>
  24 #include <asm/asm-offsets.h>
  25 #include <asm/hwcap.h>
  26 #include <asm/pgtable.h>
  27 #include <asm/pgtable-hwdef.h>
  28 #include <asm/cpufeature.h>
  29 #include <asm/alternative.h>
  30
  31 #ifdef CONFIG_ARM64_64K_PAGES
  32 #define TCR_TG_FLAGS    TCR_TG0_64K | TCR_TG1_64K
  33 #elif defined(CONFIG_ARM64_16K_PAGES)
  34 #define TCR_TG_FLAGS    TCR_TG0_16K | TCR_TG1_16K
  35 #else /* CONFIG_ARM64_4K_PAGES */
  36 #define TCR_TG_FLAGS    TCR_TG0_4K | TCR_TG1_4K
  37 #endif
  38
  39 #define TCR_SMP_FLAGS   TCR_SHARED
  40
  41 /* PTWs cacheable, inner/outer WBWA */
  42 #define TCR_CACHE_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA
  43
  44 #define MAIR(attr, mt)  ((attr) << ((mt) * 8))
  45
  46 /*
  47  *      cpu_do_idle()
  48  *
  49  *      Idle the processor (wait for interrupt).
  50  */
  51 ENTRY(cpu_do_idle)
  52         dsb     sy                              // WFI may enter a low-power mode
  53         wfi
  54         ret
  55 ENDPROC(cpu_do_idle)
  56
  57 #ifdef CONFIG_CPU_PM
  58 /**
  59  * cpu_do_suspend - save CPU registers context
  60  *
  61  * x0: virtual address of context pointer
  62  */
  63 ENTRY(cpu_do_suspend)
  64         mrs     x2, tpidr_el0
  65         mrs     x3, tpidrro_el0
  66         mrs     x4, contextidr_el1
  67         mrs     x5, cpacr_el1
  68         mrs     x6, tcr_el1
  69         mrs     x7, vbar_el1
  70         mrs     x8, mdscr_el1
  71         mrs     x9, oslsr_el1
  72         mrs     x10, sctlr_el1
  73         stp     x2, x3, [x0]
  74         stp     x4, xzr, [x0, #16]
  75         stp     x5, x6, [x0, #32]
  76         stp     x7, x8, [x0, #48]
  77         stp     x9, x10, [x0, #64]
  78         ret
  79 ENDPROC(cpu_do_suspend)
  80
  81 /**
  82  * cpu_do_resume - restore CPU register context
  83  *
  84  * x0: Address of context pointer
  85  */
  86         .pushsection ".idmap.text", "ax"
  87 ENTRY(cpu_do_resume)
  88         ldp     x2, x3, [x0]
  89         ldp     x4, x5, [x0, #16]
  90         ldp     x6, x8, [x0, #32]
  91         ldp     x9, x10, [x0, #48]
  92         ldp     x11, x12, [x0, #64]
  93         msr     tpidr_el0, x2
  94         msr     tpidrro_el0, x3
  95         msr     contextidr_el1, x4
  96         msr     cpacr_el1, x6
  97
  98         /* Don't change t0sz here, mask those bits when restoring */
  99         mrs     x5, tcr_el1
 100         bfi     x8, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
 101
 102         msr     tcr_el1, x8
 103         msr     vbar_el1, x9
 104
 105         /*
 106          * __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
 107          * debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
 108          * exception. Mask them until local_dbg_restore() in cpu_suspend()
 109          * resets them.
 110          */
 111         disable_dbg
 112         msr     mdscr_el1, x10
 113
 114         msr     sctlr_el1, x12
 115         /*
 116          * Restore oslsr_el1 by writing oslar_el1
 117          */
 118         ubfx    x11, x11, #1, #1
 119         msr     oslar_el1, x11
 120         reset_pmuserenr_el0 x0                  // Disable PMU access from EL0
 121         isb
 122         ret
 123 ENDPROC(cpu_do_resume)
 124         .popsection
 125 #endif
 126
 127 /*
 128  *      cpu_do_switch_mm(pgd_phys, tsk)
 129  *
 130  *      Set the translation table base pointer to be pgd_phys.
 131  *
 132  *      - pgd_phys - physical address of new TTB
 133  */
 134 ENTRY(cpu_do_switch_mm)
 135         mmid    x1, x1                          // get mm->context.id
 136         bfi     x0, x1, #48, #16                // set the ASID
 137         msr     ttbr0_el1, x0                   // set TTBR0
 138         isb
 139 alternative_if ARM64_WORKAROUND_CAVIUM_27456
 140         ic      iallu
 141         dsb     nsh
 142         isb
 143 alternative_else_nop_endif
 144         ret
 145 ENDPROC(cpu_do_switch_mm)
 146
 147         .pushsection ".idmap.text", "ax"
 148 /*
 149  * void idmap_cpu_replace_ttbr1(phys_addr_t new_pgd)
 150  *
 151  * This is the low-level counterpart to cpu_replace_ttbr1, and should not be
 152  * called by anything else. It can only be executed from a TTBR0 mapping.
 153  */
 154 ENTRY(idmap_cpu_replace_ttbr1)
 155         mrs     x2, daif
 156         msr     daifset, #0xf
 157
 158         adrp    x1, empty_zero_page
 159         msr     ttbr1_el1, x1
 160         isb
 161
 162         tlbi    vmalle1
 163         dsb     nsh
 164         isb
 165
 166         msr     ttbr1_el1, x0
 167         isb
 168
 169         msr     daif, x2
 170
 171         ret
 172 ENDPROC(idmap_cpu_replace_ttbr1)
 173         .popsection
 174
 175 /*
 176  *      __cpu_setup
 177  *
 178  *      Initialise the processor for turning the MMU on.  Return in x0 the
 179  *      value of the SCTLR_EL1 register.
 180  */
 181         .pushsection ".idmap.text", "ax"
 182 ENTRY(__cpu_setup)
 183         tlbi    vmalle1                         // Invalidate local TLB
 184         dsb     nsh
 185
 186         mov     x0, #3 << 20
 187         msr     cpacr_el1, x0                   // Enable FP/ASIMD
 188         mov     x0, #1 << 12                    // Reset mdscr_el1 and disable
 189         msr     mdscr_el1, x0                   // access to the DCC from EL0
 190         isb                                     // Unmask debug exceptions now,
 191         enable_dbg                              // since this is per-cpu
 192         reset_pmuserenr_el0 x0                  // Disable PMU access from EL0
 193         /*
 194          * Memory region attributes for LPAE:
 195          *
 196          *   n = AttrIndx[2:0]
 197          *                      n       MAIR
 198          *   DEVICE_nGnRnE      000     00000000
 199          *   DEVICE_nGnRE       001     00000100
 200          *   DEVICE_GRE         010     00001100
 201          *   NORMAL_NC          011     01000100
 202          *   NORMAL             100     11111111
 203          *   NORMAL_WT          101     10111011
 204          */
 205         ldr     x5, =MAIR(0x00, MT_DEVICE_nGnRnE) | \
 206                      MAIR(0x04, MT_DEVICE_nGnRE) | \
 207                      MAIR(0x0c, MT_DEVICE_GRE) | \
 208                      MAIR(0x44, MT_NORMAL_NC) | \
 209                      MAIR(0xff, MT_NORMAL) | \
 210                      MAIR(0xbb, MT_NORMAL_WT)
 211         msr     mair_el1, x5
 212         /*
 213          * Prepare SCTLR
 214          */
 215         adr     x5, crval
 216         ldp     w5, w6, [x5]
 217         mrs     x0, sctlr_el1
 218         bic     x0, x0, x5                      // clear bits
 219         orr     x0, x0, x6                      // set bits
 220         /*
 221          * Set/prepare TCR and TTBR. We use 512GB (39-bit) address range for
 222          * both user and kernel.
 223          */
 224         ldr     x10, =TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
 225                         TCR_TG_FLAGS | TCR_ASID16 | TCR_TBI0
 226         tcr_set_idmap_t0sz      x10, x9
 227
 228         /*
 229          * Read the PARange bits from ID_AA64MMFR0_EL1 and set the IPS bits in
 230          * TCR_EL1.
 231          */
 232         mrs     x9, ID_AA64MMFR0_EL1
 233         bfi     x10, x9, #32, #3
 234 #ifdef CONFIG_ARM64_HW_AFDBM
 235         /*
 236          * Hardware update of the Access and Dirty bits.
 237          */
 238         mrs     x9, ID_AA64MMFR1_EL1
 239         and     x9, x9, #0xf
 240         cbz     x9, 2f
 241         cmp     x9, #2
 242         b.lt    1f
 243         orr     x10, x10, #TCR_HD               // hardware Dirty flag update
 244 1:      orr     x10, x10, #TCR_HA               // hardware Access flag update
 245 2:
 246 #endif  /* CONFIG_ARM64_HW_AFDBM */
 247         msr     tcr_el1, x10
 248         ret                                     // return to head.S
 249 ENDPROC(__cpu_setup)
 250
 251         /*
 252          * We set the desired value explicitly, including those of the
 253          * reserved bits. The values of bits EE & E0E were set early in
 254          * el2_setup, which are left untouched below.
 255          *
 256          *                 n n            T
 257          *       U E      WT T UD     US IHBS
 258          *       CE0      XWHW CZ     ME TEEA S
 259          * .... .IEE .... NEAI TE.I ..AD DEN0 ACAM
 260          * 0011 0... 1101 ..0. ..0. 10.. .0.. .... < hardware reserved
 261          * .... .1.. .... 01.1 11.1 ..01 0.01 1101 < software settings
 262          */
 263         .type   crval, #object
 264 crval:
 265         .word   0xfcffffff                      // clear
 266         .word   0x34d5d91d                      // set
 267         .popsection