.macro get_bad_stack
ldr r13, _armboot_start @ setup our mode stack
sub r13, r13, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
sub r13, r13, #(CFG_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
str lr, [r13] @ save caller lr / spsr
mrs lr, spsr @ spsr to lr
str lr, [r13, #4]
mov r13, #MODE_SVC @ prepare SVC-Mode MODE_SVC = 0x13
@ msr spsr_c, r13
msr spsr, r13 @ r13 to spsr
mov lr, pc
movs pc, lr
.endm
.macro bad_save_user_regs
sub sp, sp, #S_FRAME_SIZE
stmia sp, {r0 - r12} @ Calling r0-r12
ldr r2, _armboot_start
sub r2, r2, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
sub r2, r2, #(CFG_GBL_DATA_SIZE+8) @ set base 2 words into abort stack
ldmia r2, {r2 - r3} @ get pc, cpsr
add r0, sp, #S_FRAME_SIZE @ restore sp_SVC
add r5, sp, #S_SP
mov r1, lr
stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr
mov r0, sp
.endm
异常时这样顺序执行，红色部分的sp值时多少，我一直没弄清楚.如果sp是R13的话那不就是MODE_SVC = 0x13吗？显然不对啊~ |
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