summaryrefslogtreecommitdiffstats
path: root/arch/arm/mm/abort-lv4t.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/mm/abort-lv4t.S')
-rw-r--r--arch/arm/mm/abort-lv4t.S220
1 files changed, 220 insertions, 0 deletions
diff --git a/arch/arm/mm/abort-lv4t.S b/arch/arm/mm/abort-lv4t.S
new file mode 100644
index 000000000000..db743e510214
--- /dev/null
+++ b/arch/arm/mm/abort-lv4t.S
@@ -0,0 +1,220 @@
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+/*
+ * Function: v4t_late_abort
+ *
+ * Params : r2 = address of aborted instruction
+ * : r3 = saved SPSR
+ *
+ * Returns : r0 = address of abort
+ * : r1 = FSR, bit 11 = write
+ * : r2-r8 = corrupted
+ * : r9 = preserved
+ * : sp = pointer to registers
+ *
+ * Purpose : obtain information about current aborted instruction.
+ * Note: we read user space. This means we might cause a data
+ * abort here if the I-TLB and D-TLB aren't seeing the same
+ * picture. Unfortunately, this does happen. We live with it.
+ */
+ENTRY(v4t_late_abort)
+ tst r3, #PSR_T_BIT @ check for thumb mode
+ mrc p15, 0, r1, c5, c0, 0 @ get FSR
+ mrc p15, 0, r0, c6, c0, 0 @ get FAR
+ bne .data_thumb_abort
+ ldr r8, [r2] @ read arm instruction
+ bic r1, r1, #1 << 11 | 1 << 10 @ clear bits 11 and 10 of FSR
+ tst r8, #1 << 20 @ L = 1 -> write?
+ orreq r1, r1, #1 << 11 @ yes.
+ and r7, r8, #15 << 24
+ add pc, pc, r7, lsr #22 @ Now branch to the relevant processing routine
+ nop
+
+/* 0 */ b .data_arm_lateldrhpost @ ldrh rd, [rn], #m/rm
+/* 1 */ b .data_arm_lateldrhpre @ ldrh rd, [rn, #m/rm]
+/* 2 */ b .data_unknown
+/* 3 */ b .data_unknown
+/* 4 */ b .data_arm_lateldrpostconst @ ldr rd, [rn], #m
+/* 5 */ b .data_arm_lateldrpreconst @ ldr rd, [rn, #m]
+/* 6 */ b .data_arm_lateldrpostreg @ ldr rd, [rn], rm
+/* 7 */ b .data_arm_lateldrprereg @ ldr rd, [rn, rm]
+/* 8 */ b .data_arm_ldmstm @ ldm*a rn, <rlist>
+/* 9 */ b .data_arm_ldmstm @ ldm*b rn, <rlist>
+/* a */ b .data_unknown
+/* b */ b .data_unknown
+/* c */ mov pc, lr @ ldc rd, [rn], #m @ Same as ldr rd, [rn], #m
+/* d */ mov pc, lr @ ldc rd, [rn, #m]
+/* e */ b .data_unknown
+/* f */
+.data_unknown: @ Part of jumptable
+ mov r0, r2
+ mov r1, r8
+ mov r2, sp
+ bl baddataabort
+ b ret_from_exception
+
+.data_arm_ldmstm:
+ tst r8, #1 << 21 @ check writeback bit
+ moveq pc, lr @ no writeback -> no fixup
+ mov r7, #0x11
+ orr r7, r7, #0x1100
+ and r6, r8, r7
+ and r2, r8, r7, lsl #1
+ add r6, r6, r2, lsr #1
+ and r2, r8, r7, lsl #2
+ add r6, r6, r2, lsr #2
+ and r2, r8, r7, lsl #3
+ add r6, r6, r2, lsr #3
+ add r6, r6, r6, lsr #8
+ add r6, r6, r6, lsr #4
+ and r6, r6, #15 @ r6 = no. of registers to transfer.
+ and r5, r8, #15 << 16 @ Extract 'n' from instruction
+ ldr r7, [sp, r5, lsr #14] @ Get register 'Rn'
+ tst r8, #1 << 23 @ Check U bit
+ subne r7, r7, r6, lsl #2 @ Undo increment
+ addeq r7, r7, r6, lsl #2 @ Undo decrement
+ str r7, [sp, r5, lsr #14] @ Put register 'Rn'
+ mov pc, lr
+
+.data_arm_lateldrhpre:
+ tst r8, #1 << 21 @ Check writeback bit
+ moveq pc, lr @ No writeback -> no fixup
+.data_arm_lateldrhpost:
+ and r5, r8, #0x00f @ get Rm / low nibble of immediate value
+ tst r8, #1 << 22 @ if (immediate offset)
+ andne r6, r8, #0xf00 @ { immediate high nibble
+ orrne r6, r5, r6, lsr #4 @ combine nibbles } else
+ ldreq r6, [sp, r5, lsl #2] @ { load Rm value }
+.data_arm_apply_r6_and_rn:
+ and r5, r8, #15 << 16 @ Extract 'n' from instruction
+ ldr r7, [sp, r5, lsr #14] @ Get register 'Rn'
+ tst r8, #1 << 23 @ Check U bit
+ subne r7, r7, r6 @ Undo incrmenet
+ addeq r7, r7, r6 @ Undo decrement
+ str r7, [sp, r5, lsr #14] @ Put register 'Rn'
+ mov pc, lr
+
+.data_arm_lateldrpreconst:
+ tst r8, #1 << 21 @ check writeback bit
+ moveq pc, lr @ no writeback -> no fixup
+.data_arm_lateldrpostconst:
+ movs r2, r8, lsl #20 @ Get offset
+ moveq pc, lr @ zero -> no fixup
+ and r5, r8, #15 << 16 @ Extract 'n' from instruction
+ ldr r7, [sp, r5, lsr #14] @ Get register 'Rn'
+ tst r8, #1 << 23 @ Check U bit
+ subne r7, r7, r2, lsr #20 @ Undo increment
+ addeq r7, r7, r2, lsr #20 @ Undo decrement
+ str r7, [sp, r5, lsr #14] @ Put register 'Rn'
+ mov pc, lr
+
+.data_arm_lateldrprereg:
+ tst r8, #1 << 21 @ check writeback bit
+ moveq pc, lr @ no writeback -> no fixup
+.data_arm_lateldrpostreg:
+ and r7, r8, #15 @ Extract 'm' from instruction
+ ldr r6, [sp, r7, lsl #2] @ Get register 'Rm'
+ mov r5, r8, lsr #7 @ get shift count
+ ands r5, r5, #31
+ and r7, r8, #0x70 @ get shift type
+ orreq r7, r7, #8 @ shift count = 0
+ add pc, pc, r7
+ nop
+
+ mov r6, r6, lsl r5 @ 0: LSL #!0
+ b .data_arm_apply_r6_and_rn
+ b .data_arm_apply_r6_and_rn @ 1: LSL #0
+ nop
+ b .data_unknown @ 2: MUL?
+ nop
+ b .data_unknown @ 3: MUL?
+ nop
+ mov r6, r6, lsr r5 @ 4: LSR #!0
+ b .data_arm_apply_r6_and_rn
+ mov r6, r6, lsr #32 @ 5: LSR #32
+ b .data_arm_apply_r6_and_rn
+ b .data_unknown @ 6: MUL?
+ nop
+ b .data_unknown @ 7: MUL?
+ nop
+ mov r6, r6, asr r5 @ 8: ASR #!0
+ b .data_arm_apply_r6_and_rn
+ mov r6, r6, asr #32 @ 9: ASR #32
+ b .data_arm_apply_r6_and_rn
+ b .data_unknown @ A: MUL?
+ nop
+ b .data_unknown @ B: MUL?
+ nop
+ mov r6, r6, ror r5 @ C: ROR #!0
+ b .data_arm_apply_r6_and_rn
+ mov r6, r6, rrx @ D: RRX
+ b .data_arm_apply_r6_and_rn
+ b .data_unknown @ E: MUL?
+ nop
+ b .data_unknown @ F: MUL?
+
+.data_thumb_abort:
+ ldrh r8, [r2] @ read instruction
+ tst r8, #1 << 11 @ L = 1 -> write?
+ orreq r1, r1, #1 << 8 @ yes
+ and r7, r8, #15 << 12
+ add pc, pc, r7, lsr #10 @ lookup in table
+ nop
+
+/* 0 */ b .data_unknown
+/* 1 */ b .data_unknown
+/* 2 */ b .data_unknown
+/* 3 */ b .data_unknown
+/* 4 */ b .data_unknown
+/* 5 */ b .data_thumb_reg
+/* 6 */ mov pc, lr
+/* 7 */ mov pc, lr
+/* 8 */ mov pc, lr
+/* 9 */ mov pc, lr
+/* A */ b .data_unknown
+/* B */ b .data_thumb_pushpop
+/* C */ b .data_thumb_ldmstm
+/* D */ b .data_unknown
+/* E */ b .data_unknown
+/* F */ b .data_unknown
+
+.data_thumb_reg:
+ tst r8, #1 << 9
+ moveq pc, lr
+ tst r8, #1 << 10 @ If 'S' (signed) bit is set
+ movne r1, #0 @ it must be a load instr
+ mov pc, lr
+
+.data_thumb_pushpop:
+ tst r8, #1 << 10
+ beq .data_unknown
+ and r6, r8, #0x55 @ hweight8(r8) + R bit
+ and r2, r8, #0xaa
+ add r6, r6, r2, lsr #1
+ and r2, r6, #0xcc
+ and r6, r6, #0x33
+ add r6, r6, r2, lsr #2
+ movs r7, r8, lsr #9 @ C = r8 bit 8 (R bit)
+ adc r6, r6, r6, lsr #4 @ high + low nibble + R bit
+ and r6, r6, #15 @ number of regs to transfer
+ ldr r7, [sp, #13 << 2]
+ tst r8, #1 << 11
+ addeq r7, r7, r6, lsl #2 @ increment SP if PUSH
+ subne r7, r7, r6, lsl #2 @ decrement SP if POP
+ str r7, [sp, #13 << 2]
+ mov pc, lr
+
+.data_thumb_ldmstm:
+ and r6, r8, #0x55 @ hweight8(r8)
+ and r2, r8, #0xaa
+ add r6, r6, r2, lsr #1
+ and r2, r6, #0xcc
+ and r6, r6, #0x33
+ add r6, r6, r2, lsr #2
+ add r6, r6, r6, lsr #4
+ and r5, r8, #7 << 8
+ ldr r7, [sp, r5, lsr #6]
+ and r6, r6, #15 @ number of regs to transfer
+ sub r7, r7, r6, lsl #2 @ always decrement
+ str r7, [sp, r5, lsr #6]
+ mov pc, lr