lab/x1/injector/disable_mmu.S

59 lines
2.3 KiB
ArmAsm
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

.text
.align 2
.global _start
_start:
ldr r0, =0x67800000
cpsid if
mrc p15, 0, r8, c14, c2, 1
bic r8, r8, #1
mcr p15, 0, r8, c14, c2, 1
mrc p15, 0, r8, c14, c3, 1
bic r8, r8, #1
mcr p15, 0, r8, c14, c3, 1
mov r9, #0
mrc p15, 0, r6, c1, c0, 0
bic r6, r6, #4 @ disable dcache
bic r6, r6, #4096 @ disable icache
mcr p15, 0, r6, c1, c0, 0 // write ctrl regs
mcr p15, 0, r9, c7, c5, 0 // invalidate icache
// from: https://www.aps-web.jp/academy/ca/229/#i-2
mov r10,#0 //
mcr p15,2,r10,c0,c0,0 // CSSELR
//
isb //
mrc p15,1,r1,c0,c0,0 // CCSIDR
and r2,r1,#7 // b001=8ワード/
add r2,r2,#4 // DCISW
ldr r4,=0x3FF //
ands r4,r4,r1,LSR #3 // r4
clz r5,r4 // DCISW
ldr r7,=0x7FFF //
ands r7,r7,r1,LSR #13 // r7
// 0x7F=12Kbyte/0xFF=32Kbyte/0x1FF=64Kbyte
loop2:
mov r9,r4 // r9
loop3:
orr r11,r10,r9,LSL r5 //
orr r11,r11,r7,LSL r2 //
mcr p15,0,r11,c7,c6,2 // DCISW/
//
subs r9,r9,#1 // -1
bge loop3 //
subs r7,r7,#1 // -1
bge loop2 //
mcr p15, 0, r9, c8, c7, 0 // invalidate TLB
mcr p15, 0, r9, c7, c5, 6 // invalidate branch predictor array
bic r6, r6, #1 @ disable MMU
mcr p15, 0, r6, c1, c0, 0 // write ctrl regs
mov pc, r0