From 9bb6050d40b9936beda5cb1cd15040f6c1b07179 Mon Sep 17 00:00:00 2001 From: Amaury Pouly Date: Wed, 18 Jan 2017 14:36:27 +0100 Subject: hwstub: rewrite exception catching Since we can catch exceptions like data aborts on read/write, it takes very little to also catch exceptions in calls. When extending this with the catching of illegal instructions, the call instruction now becomes much more robust and also for address and instruction probing. Since we can catch several types of exception, rename set_data_abort_jmp to set_exception_jmp. At the same time, simplify the logic in read/write request handlers. Also fix a bug in ARM jump code: it was using stmia r1, {..., pc} as if pc would get current pc + 8 but this is actually implementation defined on older ARMs (typically pc + 12) and deprecated on newer ARMs, so rewrite the code avoid that. The set_exception_jmp() function now also reports the exception type. Change-Id: Icd0dd52d2456b361b27c4776be09c3d13528ed93 --- utils/hwstub/stub/asm/arm/system.S | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) (limited to 'utils/hwstub/stub/asm/arm/system.S') diff --git a/utils/hwstub/stub/asm/arm/system.S b/utils/hwstub/stub/asm/arm/system.S index df6b5a2e81..41551a8004 100644 --- a/utils/hwstub/stub/asm/arm/system.S +++ b/utils/hwstub/stub/asm/arm/system.S @@ -18,32 +18,33 @@ * KIND, either express or implied. * ****************************************************************************/ +#include "system.h" /* Handling of data abort: * the code can register a "longjmp" buffer to restore the context in case of * fault */ .data -data_abort_jmp_ctx_ptr: +exception_jmp_ctx_ptr: /* buffer contains in order: cpsr,r4-r11,sp,lr,pc */ .skip 48 /* = 4 * (cpsr + 11 registers) */ .text -/* Prototype: int set_data_abort_jmp() - * Return: 1 in case of data abort, 0 otherwise */ -.global set_data_abort_jmp -set_data_abort_jmp: +/* Prototype: int set_exception_jmp() + * Return: !=0 in case of exception, 0 otherwise */ +.global set_exception_jmp +set_exception_jmp: mrs r2, cpsr - ldr r1, =data_abort_jmp_ctx_ptr - mov r0, #0 - stmia r1, {r2,r4-r11,sp,lr,pc} /* see PC note below */ - bx lr - mov r0, #1 /* <-- PC points here in stmia */ - bx lr + ldr r1, =exception_jmp_ctx_ptr + mov r0, #EXCEPTION_NONE /* nothing to report */ + stmia r1!, {r2,r4-r11,sp,lr} /* see PC note below */ + mov r3, pc /* see note below */ + str r3, [r1] /* store PC */ + bx lr /* <-- PC points here in mov */ .global data_abort_handler data_abort_handler: /* restore everything from context */ - ldr r1, =data_abort_jmp_ctx_ptr + ldr r1, =exception_jmp_ctx_ptr /* NOTE: we need to restore sp_sys and lr_sys, for this we need the * LDM Rn, {}^ * variant, but we cannot restore PC from it because ^ has a different @@ -54,4 +55,5 @@ data_abort_handler: * because we do not save the abort address and we don't use an abort stack */ ldmia r1, {r0,r4-r11,sp,lr}^ /* this variant cannot have writeback (r1!) */ msr spsr, r0 - ldmia r1, {r0,r4-r11,sp,lr,pc}^ /* reload some registers but we don't care */ + mov r0, #EXCEPTION_ADDR + ldmia r1, {r1,r4-r11,sp,lr,pc}^ /* reload some registers but we don't care */ -- cgit v1.2.3