arch/arm/mm/abort-lv4t.S

   1 #include <linux/linkage.h>
   2 #include <asm/assembler.h>
   3 /*
   4  * Function: v4t_late_abort
   5  *
   6  * Params  : r2 = pt_regs
   7  *         : r4 = aborted context pc
   8  *         : r5 = aborted context psr
   9  *
  10  * Returns : r4-r5, r10-r11, r13 preserved
  11  *
  12  * Purpose : obtain information about current aborted instruction.
  13  * Note: we read user space.  This means we might cause a data
  14  * abort here if the I-TLB and D-TLB aren't seeing the same
  15  * picture.  Unfortunately, this does happen.  We live with it.
  16  */
  17 ENTRY(v4t_late_abort)
  18         tst     r5, #PSR_T_BIT                  @ check for thumb mode
  19 #ifdef CONFIG_CPU_CP15_MMU
  20         mrc     p15, 0, r1, c5, c0, 0           @ get FSR
  21         mrc     p15, 0, r0, c6, c0, 0           @ get FAR
  22         bic     r1, r1, #1 << 11 | 1 << 10      @ clear bits 11 and 10 of FSR
  23 #else
  24         mov     r0, #0                          @ clear r0, r1 (no FSR/FAR)
  25         mov     r1, #0
  26 #endif
  27         bne     .data_thumb_abort
  28         ldr     r8, [r4]                        @ read arm instruction
  29         tst     r8, #1 << 20                    @ L = 1 -> write?
  30         orreq   r1, r1, #1 << 11                @ yes.
  31         and     r7, r8, #15 << 24
  32         add     pc, pc, r7, lsr #22             @ Now branch to the relevant processing routine
  33         nop
  34
  35 /* 0 */ b       .data_arm_lateldrhpost          @ ldrh  rd, [rn], #m/rm
  36 /* 1 */ b       .data_arm_lateldrhpre           @ ldrh  rd, [rn, #m/rm]
  37 /* 2 */ b       .data_unknown
  38 /* 3 */ b       .data_unknown
  39 /* 4 */ b       .data_arm_lateldrpostconst      @ ldr   rd, [rn], #m
  40 /* 5 */ b       .data_arm_lateldrpreconst       @ ldr   rd, [rn, #m]
  41 /* 6 */ b       .data_arm_lateldrpostreg        @ ldr   rd, [rn], rm
  42 /* 7 */ b       .data_arm_lateldrprereg         @ ldr   rd, [rn, rm]
  43 /* 8 */ b       .data_arm_ldmstm                @ ldm*a rn, <rlist>
  44 /* 9 */ b       .data_arm_ldmstm                @ ldm*b rn, <rlist>
  45 /* a */ b       .data_unknown
  46 /* b */ b       .data_unknown
  47 /* c */ b       do_DataAbort                    @ ldc   rd, [rn], #m    @ Same as ldr   rd, [rn], #m
  48 /* d */ b       do_DataAbort                    @ ldc   rd, [rn, #m]
  49 /* e */ b       .data_unknown
  50 /* f */
  51 .data_unknown:  @ Part of jumptable
  52         mov     r0, r4
  53         mov     r1, r8
  54         b       baddataabort
  55
  56 .data_arm_ldmstm:
  57         tst     r8, #1 << 21                    @ check writeback bit
  58         beq     do_DataAbort                    @ no writeback -> no fixup
  59         mov     r7, #0x11
  60         orr     r7, r7, #0x1100
  61         and     r6, r8, r7
  62         and     r9, r8, r7, lsl #1
  63         add     r6, r6, r9, lsr #1
  64         and     r9, r8, r7, lsl #2
  65         add     r6, r6, r9, lsr #2
  66         and     r9, r8, r7, lsl #3
  67         add     r6, r6, r9, lsr #3
  68         add     r6, r6, r6, lsr #8
  69         add     r6, r6, r6, lsr #4
  70         and     r6, r6, #15                     @ r6 = no. of registers to transfer.
  71         and     r9, r8, #15 << 16               @ Extract 'n' from instruction
  72         ldr     r7, [r2, r9, lsr #14]           @ Get register 'Rn'
  73         tst     r8, #1 << 23                    @ Check U bit
  74         subne   r7, r7, r6, lsl #2              @ Undo increment
  75         addeq   r7, r7, r6, lsl #2              @ Undo decrement
  76         str     r7, [r2, r9, lsr #14]           @ Put register 'Rn'
  77         b       do_DataAbort
  78
  79 .data_arm_lateldrhpre:
  80         tst     r8, #1 << 21                    @ Check writeback bit
  81         beq     do_DataAbort                    @ No writeback -> no fixup
  82 .data_arm_lateldrhpost:
  83         and     r9, r8, #0x00f                  @ get Rm / low nibble of immediate value
  84         tst     r8, #1 << 22                    @ if (immediate offset)
  85         andne   r6, r8, #0xf00                  @ { immediate high nibble
  86         orrne   r6, r9, r6, lsr #4              @   combine nibbles } else
  87         ldreq   r6, [r2, r9, lsl #2]            @ { load Rm value }
  88 .data_arm_apply_r6_and_rn:
  89         and     r9, r8, #15 << 16               @ Extract 'n' from instruction
  90         ldr     r7, [r2, r9, lsr #14]           @ Get register 'Rn'
  91         tst     r8, #1 << 23                    @ Check U bit
  92         subne   r7, r7, r6                      @ Undo incrmenet
  93         addeq   r7, r7, r6                      @ Undo decrement
  94         str     r7, [r2, r9, lsr #14]           @ Put register 'Rn'
  95         b       do_DataAbort
  96
  97 .data_arm_lateldrpreconst:
  98         tst     r8, #1 << 21                    @ check writeback bit
  99         beq     do_DataAbort                    @ no writeback -> no fixup
 100 .data_arm_lateldrpostconst:
 101         movs    r6, r8, lsl #20                 @ Get offset
 102         beq     do_DataAbort                    @ zero -> no fixup
 103         and     r9, r8, #15 << 16               @ Extract 'n' from instruction
 104         ldr     r7, [r2, r9, lsr #14]           @ Get register 'Rn'
 105         tst     r8, #1 << 23                    @ Check U bit
 106         subne   r7, r7, r6, lsr #20             @ Undo increment
 107         addeq   r7, r7, r6, lsr #20             @ Undo decrement
 108         str     r7, [r2, r9, lsr #14]           @ Put register 'Rn'
 109         b       do_DataAbort
 110
 111 .data_arm_lateldrprereg:
 112         tst     r8, #1 << 21                    @ check writeback bit
 113         beq     do_DataAbort                    @ no writeback -> no fixup
 114 .data_arm_lateldrpostreg:
 115         and     r7, r8, #15                     @ Extract 'm' from instruction
 116         ldr     r6, [r2, r7, lsl #2]            @ Get register 'Rm'
 117         mov     r9, r8, lsr #7                  @ get shift count
 118         ands    r9, r9, #31
 119         and     r7, r8, #0x70                   @ get shift type
 120         orreq   r7, r7, #8                      @ shift count = 0
 121         add     pc, pc, r7
 122         nop
 123
 124         mov     r6, r6, lsl r9                  @ 0: LSL #!0
 125         b       .data_arm_apply_r6_and_rn
 126         b       .data_arm_apply_r6_and_rn       @ 1: LSL #0
 127         nop
 128         b       .data_unknown                   @ 2: MUL?
 129         nop
 130         b       .data_unknown                   @ 3: MUL?
 131         nop
 132         mov     r6, r6, lsr r9                  @ 4: LSR #!0
 133         b       .data_arm_apply_r6_and_rn
 134         mov     r6, r6, lsr #32                 @ 5: LSR #32
 135         b       .data_arm_apply_r6_and_rn
 136         b       .data_unknown                   @ 6: MUL?
 137         nop
 138         b       .data_unknown                   @ 7: MUL?
 139         nop
 140         mov     r6, r6, asr r9                  @ 8: ASR #!0
 141         b       .data_arm_apply_r6_and_rn
 142         mov     r6, r6, asr #32                 @ 9: ASR #32
 143         b       .data_arm_apply_r6_and_rn
 144         b       .data_unknown                   @ A: MUL?
 145         nop
 146         b       .data_unknown                   @ B: MUL?
 147         nop
 148         mov     r6, r6, ror r9                  @ C: ROR #!0
 149         b       .data_arm_apply_r6_and_rn
 150         mov     r6, r6, rrx                     @ D: RRX
 151         b       .data_arm_apply_r6_and_rn
 152         b       .data_unknown                   @ E: MUL?
 153         nop
 154         b       .data_unknown                   @ F: MUL?
 155
 156 .data_thumb_abort:
 157         ldrh    r8, [r4]                        @ read instruction
 158         tst     r8, #1 << 11                    @ L = 1 -> write?
 159         orreq   r1, r1, #1 << 8                 @ yes
 160         and     r7, r8, #15 << 12
 161         add     pc, pc, r7, lsr #10             @ lookup in table
 162         nop
 163
 164 /* 0 */ b       .data_unknown
 165 /* 1 */ b       .data_unknown
 166 /* 2 */ b       .data_unknown
 167 /* 3 */ b       .data_unknown
 168 /* 4 */ b       .data_unknown
 169 /* 5 */ b       .data_thumb_reg
 170 /* 6 */ b       do_DataAbort
 171 /* 7 */ b       do_DataAbort
 172 /* 8 */ b       do_DataAbort
 173 /* 9 */ b       do_DataAbort
 174 /* A */ b       .data_unknown
 175 /* B */ b       .data_thumb_pushpop
 176 /* C */ b       .data_thumb_ldmstm
 177 /* D */ b       .data_unknown
 178 /* E */ b       .data_unknown
 179 /* F */ b       .data_unknown
 180
 181 .data_thumb_reg:
 182         tst     r8, #1 << 9
 183         beq     do_DataAbort
 184         tst     r8, #1 << 10                    @ If 'S' (signed) bit is set
 185         movne   r1, #0                          @ it must be a load instr
 186         b       do_DataAbort
 187
 188 .data_thumb_pushpop:
 189         tst     r8, #1 << 10
 190         beq     .data_unknown
 191         and     r6, r8, #0x55                   @ hweight8(r8) + R bit
 192         and     r9, r8, #0xaa
 193         add     r6, r6, r9, lsr #1
 194         and     r9, r6, #0xcc
 195         and     r6, r6, #0x33
 196         add     r6, r6, r9, lsr #2
 197         movs    r7, r8, lsr #9                  @ C = r8 bit 8 (R bit)
 198         adc     r6, r6, r6, lsr #4              @ high + low nibble + R bit
 199         and     r6, r6, #15                     @ number of regs to transfer
 200         ldr     r7, [r2, #13 << 2]
 201         tst     r8, #1 << 11
 202         addeq   r7, r7, r6, lsl #2              @ increment SP if PUSH
 203         subne   r7, r7, r6, lsl #2              @ decrement SP if POP
 204         str     r7, [r2, #13 << 2]
 205         b       do_DataAbort
 206
 207 .data_thumb_ldmstm:
 208         and     r6, r8, #0x55                   @ hweight8(r8)
 209         and     r9, r8, #0xaa
 210         add     r6, r6, r9, lsr #1
 211         and     r9, r6, #0xcc
 212         and     r6, r6, #0x33
 213         add     r6, r6, r9, lsr #2
 214         add     r6, r6, r6, lsr #4
 215         and     r9, r8, #7 << 8
 216         ldr     r7, [r2, r9, lsr #6]
 217         and     r6, r6, #15                     @ number of regs to transfer
 218         sub     r7, r7, r6, lsl #2              @ always decrement
 219         str     r7, [r2, r9, lsr #6]
 220         b       do_DataAbort