/* 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