diff options
Diffstat (limited to 'arch/arm/mm/abort-lv4t.S')
| -rw-r--r-- | arch/arm/mm/abort-lv4t.S | 237 |
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 |