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-rw-r--r--arch/arm/mm/abort-lv4t.S237
1 files changed, 237 insertions, 0 deletions
diff --git a/arch/arm/mm/abort-lv4t.S b/arch/arm/mm/abort-lv4t.S
new file mode 100644
index 000000000..fbd60a120
--- /dev/null
+++ b/arch/arm/mm/abort-lv4t.S
@@ -0,0 +1,237 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+/*
+ * Function: v4t_late_abort
+ *
+ * Params : r2 = pt_regs
+ * : r4 = aborted context pc
+ * : r5 = aborted context psr
+ *
+ * Returns : r4-r5, r9-r11, r13 preserved
+ *
+ * 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 r5, #PSR_T_BIT @ check for thumb mode
+#ifdef CONFIG_CPU_CP15_MMU
+ mrc p15, 0, r1, c5, c0, 0 @ get FSR
+ mrc p15, 0, r0, c6, c0, 0 @ get FAR
+ bic r1, r1, #1 << 11 | 1 << 10 @ clear bits 11 and 10 of FSR
+#else
+ mov r0, #0 @ clear r0, r1 (no FSR/FAR)
+ mov r1, #0
+#endif
+ bne .data_thumb_abort
+ ldr r8, [r4] @ read arm instruction
+ uaccess_disable ip @ disable userspace access
+ 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 */ b do_DataAbort @ ldc rd, [rn], #m @ Same as ldr rd, [rn], #m
+/* d */ b do_DataAbort @ ldc rd, [rn, #m]
+/* e */ b .data_unknown
+/* f */ b .data_unknown
+
+.data_unknown_r9:
+ ldr r9, [sp], #4
+.data_unknown: @ Part of jumptable
+ mov r0, r4
+ mov r1, r8
+ b baddataabort
+
+.data_arm_ldmstm:
+ tst r8, #1 << 21 @ check writeback bit
+ beq do_DataAbort @ no writeback -> no fixup
+ str r9, [sp, #-4]!
+ mov r7, #0x11
+ orr r7, r7, #0x1100
+ and r6, r8, r7
+ and r9, r8, r7, lsl #1
+ add r6, r6, r9, lsr #1
+ and r9, r8, r7, lsl #2
+ add r6, r6, r9, lsr #2
+ and r9, r8, r7, lsl #3
+ add r6, r6, r9, 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 r9, r8, #15 << 16 @ Extract 'n' from instruction
+ ldr r7, [r2, r9, 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, [r2, r9, lsr #14] @ Put register 'Rn'
+ ldr r9, [sp], #4
+ b do_DataAbort
+
+.data_arm_lateldrhpre:
+ tst r8, #1 << 21 @ Check writeback bit
+ beq do_DataAbort @ No writeback -> no fixup
+.data_arm_lateldrhpost:
+ str r9, [sp, #-4]!
+ and r9, 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, r9, r6, lsr #4 @ combine nibbles } else
+ ldreq r6, [r2, r9, lsl #2] @ { load Rm value }
+.data_arm_apply_r6_and_rn:
+ and r9, r8, #15 << 16 @ Extract 'n' from instruction
+ ldr r7, [r2, r9, 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, [r2, r9, lsr #14] @ Put register 'Rn'
+ ldr r9, [sp], #4
+ b do_DataAbort
+
+.data_arm_lateldrpreconst:
+ tst r8, #1 << 21 @ check writeback bit
+ beq do_DataAbort @ no writeback -> no fixup
+.data_arm_lateldrpostconst:
+ movs r6, r8, lsl #20 @ Get offset
+ beq do_DataAbort @ zero -> no fixup
+ str r9, [sp, #-4]!
+ and r9, r8, #15 << 16 @ Extract 'n' from instruction
+ ldr r7, [r2, r9, lsr #14] @ Get register 'Rn'
+ tst r8, #1 << 23 @ Check U bit
+ subne r7, r7, r6, lsr #20 @ Undo increment
+ addeq r7, r7, r6, lsr #20 @ Undo decrement
+ str r7, [r2, r9, lsr #14] @ Put register 'Rn'
+ ldr r9, [sp], #4
+ b do_DataAbort
+
+.data_arm_lateldrprereg:
+ tst r8, #1 << 21 @ check writeback bit
+ beq do_DataAbort @ no writeback -> no fixup
+.data_arm_lateldrpostreg:
+ and r7, r8, #15 @ Extract 'm' from instruction
+ ldr r6, [r2, r7, lsl #2] @ Get register 'Rm'
+ str r9, [sp, #-4]!
+ mov r9, r8, lsr #7 @ get shift count
+ ands r9, r9, #31
+ and r7, r8, #0x70 @ get shift type
+ orreq r7, r7, #8 @ shift count = 0
+ add pc, pc, r7
+ nop
+
+ mov r6, r6, lsl r9 @ 0: LSL #!0
+ b .data_arm_apply_r6_and_rn
+ b .data_arm_apply_r6_and_rn @ 1: LSL #0
+ nop
+ b .data_unknown_r9 @ 2: MUL?
+ nop
+ b .data_unknown_r9 @ 3: MUL?
+ nop
+ mov r6, r6, lsr r9 @ 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_r9 @ 6: MUL?
+ nop
+ b .data_unknown_r9 @ 7: MUL?
+ nop
+ mov r6, r6, asr r9 @ 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_r9 @ A: MUL?
+ nop
+ b .data_unknown_r9 @ B: MUL?
+ nop
+ mov r6, r6, ror r9 @ 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_r9 @ E: MUL?
+ nop
+ b .data_unknown_r9 @ F: MUL?
+
+.data_thumb_abort:
+ ldrh r8, [r4] @ read instruction
+ uaccess_disable ip @ disable userspace access
+ 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 */ b do_DataAbort
+/* 7 */ b do_DataAbort
+/* 8 */ b do_DataAbort
+/* 9 */ b do_DataAbort
+/* 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
+ beq do_DataAbort
+ tst r8, #1 << 10 @ If 'S' (signed) bit is set
+ movne r1, #0 @ it must be a load instr
+ b do_DataAbort
+
+.data_thumb_pushpop:
+ tst r8, #1 << 10
+ beq .data_unknown
+ str r9, [sp, #-4]!
+ and r6, r8, #0x55 @ hweight8(r8) + R bit
+ and r9, r8, #0xaa
+ add r6, r6, r9, lsr #1
+ and r9, r6, #0xcc
+ and r6, r6, #0x33
+ add r6, r6, r9, 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, [r2, #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, [r2, #13 << 2]
+ ldr r9, [sp], #4
+ b do_DataAbort
+
+.data_thumb_ldmstm:
+ str r9, [sp, #-4]!
+ and r6, r8, #0x55 @ hweight8(r8)
+ and r9, r8, #0xaa
+ add r6, r6, r9, lsr #1
+ and r9, r6, #0xcc
+ and r6, r6, #0x33
+ add r6, r6, r9, lsr #2
+ add r6, r6, r6, lsr #4
+ and r9, r8, #7 << 8
+ ldr r7, [r2, r9, lsr #6]
+ and r6, r6, #15 @ number of regs to transfer
+ sub r7, r7, r6, lsl #2 @ always decrement
+ str r7, [r2, r9, lsr #6]
+ ldr r9, [sp], #4
+ b do_DataAbort