BL2 BL30 BL31 DDRFW改造串口静默
BL2拖到IDA64，以ARM LittleEndian 64bit反汇编，很轻易的找到puts putchar函数，
ROM:000000000000B4B8 putchar ; CODE XREF: sub_6134+28↑p
ROM:000000000000B4B8 ; sub_6174+6C↑p ...
ROM:000000000000B4B8 21 00 00 B0 ADRP X1, #0x10724@PAGE
ROM:000000000000B4BC 21 90 1C 91 ADD X1, X1, #0x10724@PAGEOFF
ROM:000000000000B4C0 21 00 40 B9 LDR W1, [X1]
ROM:000000000000B4C4 41 02 00 35 CBNZ W1, locret_B50C
ROM:000000000000B4C8 1F 28 00 71 CMP W0, #0xA
ROM:000000000000B4CC 21 01 00 54 B.NE loc_B4F0
ROM:000000000000B4D0
ROM:000000000000B4D0 loc_B4D0 ; CODE XREF: putchar+24↓j
ROM:000000000000B4D0 81 01 86 D2 MOV X1, #0x300C
ROM:000000000000B4D4 01 F0 BF F2 MOVK X1, #0xFF80,LSL#16
ROM:000000000000B4D8 21 00 40 B9 LDR W1, [X1]
ROM:000000000000B4DC A1 FF AF 37 TBNZ W1, #0x15, loc_B4D0
ROM:000000000000B4E0 01 00 86 D2 MOV X1, #0x3000
ROM:000000000000B4E4 01 F0 BF F2 MOVK X1, #0xFF80,LSL#16
ROM:000000000000B4E8 A2 01 80 52 MOV W2, #0xD
ROM:000000000000B4EC 22 00 00 B9 STR W2, [X1]
ROM:000000000000B4F0
ROM:000000000000B4F0 loc_B4F0 ; CODE XREF: putchar+14↑j
ROM:000000000000B4F0 ; putchar+44↓j
ROM:000000000000B4F0 81 01 86 D2 MOV X1, #0x300C
ROM:000000000000B4F4 01 F0 BF F2 MOVK X1, #0xFF80,LSL#16
ROM:000000000000B4F8 21 00 40 B9 LDR W1, [X1]
ROM:000000000000B4FC A1 FF AF 37 TBNZ W1, #0x15, loc_B4F0
ROM:000000000000B500 01 00 86 D2 MOV X1, #0x3000
ROM:000000000000B504 01 F0 BF F2 MOVK X1, #0xFF80,LSL#16
ROM:000000000000B508 20 00 00 B9 STR W0, [X1]
ROM:000000000000B50C
ROM:000000000000B50C locret_B50C ; CODE XREF: putchar+C↑j
ROM:000000000000B50C C0 03 5F D6 RET
ROM:000000000000B50C ; End of function putchar
将putchar函数的开头改为
C0 03 5F D6 RET
即可。
BL30拖到IDA，以ARM LittleEndian 反汇编，很轻易的找到puts putchar函数
ROM:00002CB0 putchar ; CODE XREF: putchar+10↓p
ROM:00002CB0 ; j_putchar↓j
ROM:00002CB0 PUSH {R4,LR}
ROM:00002CB2 LDR R3, =0x10009474
ROM:00002CB4 MOV R4, R0
ROM:00002CB6 LDR R3, [R3]
ROM:00002CB8 CBNZ R3, locret_2CDA
ROM:00002CBA CMP R0, #0xA
ROM:00002CBC BNE loc_2CC4
ROM:00002CBE MOVS R0, #0xD
ROM:00002CC0 BL putchar
ROM:00002CC4
ROM:00002CC4 loc_2CC4 ; CODE XREF: putchar+C↑j
ROM:00002CC4 ; putchar+1C↓j
ROM:00002CC4 LDR R3, =0xFF80300C
ROM:00002CC6 LDR R3, [R3]
ROM:00002CC8 TST.W R3, #0x200000
ROM:00002CCC BNE loc_2CC4
ROM:00002CCE LDR R3, =0xFF803000
ROM:00002CD0 STR R4, [R3]
ROM:00002CD2 POP.W {R4,LR}
ROM:00002CD6 B.W maybewait
ROM:00002CDA ; ---------------------------------------------------------------------------
ROM:00002CDA
ROM:00002CDA locret_2CDA ; CODE XREF: putchar+8↑j
ROM:00002CDA POP {R4,PC}
ROM:00002CDA ; End of function putchar
将putchar函数的开头改为
70 47 BX LR
即可。BL31拖到IDA64，以ARM LittleEndian 64bit反汇编，很轻易找到printf函数，再看putchar函数有点奇怪，和之前的不一样
是因为这个程序有inituart初始化函数，将串口设备寄存器基地址FF803000存到了一个全局变量
ROM:0000000000025000 init_uart ; CODE XREF: sub_18698+2C↑p
ROM:0000000000025000 ; sub_187A0+20↑p ...
ROM:0000000000025000 CBZ X0, locret_25010
ROM:0000000000025004 ADRP X3, #UART_BASE@PAGE
ROM:0000000000025008 STR X0, [X3,#UART_BASE@PAGEOFF]
ROM:000000000002500C B loc_25020
ROM:0000000000025010 ; ---------------------------------------------------------------------------
ROM:0000000000025010
ROM:0000000000025010 locret_25010 ; CODE XREF: init_uart↑j
ROM:0000000000025010 RET
ROM:0000000000025010 ; End of function init_uartROM:0000000000025014 putchar ; CODE XREF: sub_23504+14↑p
ROM:0000000000025014 ; sub_23B84+8↑j
ROM:0000000000025014 ADRP X2, #UART_BASE@PAGE
ROM:0000000000025018 LDR X1, [X2,#UART_BASE@PAGEOFF]
ROM:000000000002501C B loc_25028
ROM:0000000000025020 ; ---------------------------------------------------------------------------
ROM:0000000000025020
ROM:0000000000025020 loc_25020 ; CODE XREF: init_uart+C↑j
ROM:0000000000025020 MOV W0, #1
ROM:0000000000025024 RET
ROM:0000000000025028 ; ---------------------------------------------------------------------------
ROM:0000000000025028
ROM:0000000000025028 loc_25028 ; CODE XREF: putchar+8↑j
ROM:0000000000025028 CBZ X1, loc_25054
ROM:000000000002502C CMP W0, #0xA
ROM:0000000000025030 B.NE loc_25044
ROM:0000000000025034
ROM:0000000000025034 loc_25034 ; CODE XREF: putchar+24↓j
ROM:0000000000025034 LDR W2, [X1,#loc_C]
ROM:0000000000025038 TBNZ W2, #0x15, loc_25034
ROM:000000000002503C MOV W2, #0xD
ROM:0000000000025040 STR W2, [X1]
ROM:0000000000025044
ROM:0000000000025044 loc_25044 ; CODE XREF: putchar+1C↑j
ROM:0000000000025044 ; putchar+34↓j
ROM:0000000000025044 LDR W2, [X1,#loc_C]
ROM:0000000000025048 TBNZ W2, #0x15, loc_25044
ROM:000000000002504C STR W0, [X1]
ROM:0000000000025050 RET
ROM:0000000000025054 ; ---------------------------------------------------------------------------
ROM:0000000000025054
ROM:0000000000025054 loc_25054 ; CODE XREF: putchar:loc_25028↑j
ROM:0000000000025054 MOV W0, #0xFFFFFFFF
ROM:0000000000025058 RET
ROM:0000000000025058 ; End of function putchar将putchar函数的开头改为
C0 03 5F D6 RET
即可。
aml_ddr.fw拖到IDA64，以ARM LittleEndian 64bit反汇编，很轻易找到putchar函数
ROM:000000000000A5C4 putchar ; CODE XREF: sub_148+28↑p
ROM:000000000000A5C4 ; sub_188:loc_1C8↑p ...
ROM:000000000000A5C4 01 00 00 B0 ADRP X1, #dword_B718@PAGE
ROM:000000000000A5C8 21 60 1C 91 ADD X1, X1, #dword_B718@PAGEOFF
ROM:000000000000A5CC 21 00 40 B9 LDR W1, [X1]
ROM:000000000000A5D0 41 02 00 35 CBNZ W1, locret_A618
ROM:000000000000A5D4 1F 28 00 71 CMP W0, #0xA
ROM:000000000000A5D8 21 01 00 54 B.NE loc_A5FC
ROM:000000000000A5DC
ROM:000000000000A5DC loc_A5DC ; CODE XREF: putchar+24↓j
ROM:000000000000A5DC 81 01 86 D2 MOV X1, #0x300C
ROM:000000000000A5E0 01 F0 BF F2 MOVK X1, #0xFF80,LSL#16
ROM:000000000000A5E4 21 00 40 B9 LDR W1, [X1]
ROM:000000000000A5E8 A1 FF AF 37 TBNZ W1, #0x15, loc_A5DC
ROM:000000000000A5EC 01 00 86 D2 MOV X1, #0x3000
ROM:000000000000A5F0 01 F0 BF F2 MOVK X1, #0xFF80,LSL#16
ROM:000000000000A5F4 A2 01 80 52 MOV W2, #0xD
ROM:000000000000A5F8 22 00 00 B9 STR W2, [X1]
ROM:000000000000A5FC
ROM:000000000000A5FC loc_A5FC ; CODE XREF: putchar+14↑j
ROM:000000000000A5FC ; putchar+44↓j
ROM:000000000000A5FC 81 01 86 D2 MOV X1, #0x300C
ROM:000000000000A600 01 F0 BF F2 MOVK X1, #0xFF80,LSL#16
ROM:000000000000A604 21 00 40 B9 LDR W1, [X1]
ROM:000000000000A608 A1 FF AF 37 TBNZ W1, #0x15, loc_A5FC
ROM:000000000000A60C 01 00 86 D2 MOV X1, #0x3000
ROM:000000000000A610 01 F0 BF F2 MOVK X1, #0xFF80,LSL#16
ROM:000000000000A614 20 00 00 B9 STR W0, [X1]
ROM:000000000000A618
ROM:000000000000A618 locret_A618 ; CODE XREF: putchar+C↑j
ROM:000000000000A618 C0 03 5F D6 RET
ROM:000000000000A618 ; End of function putchar
将putchar函数的开头改为
C0 03 5F D6 RET
另外文件头部有32字节的SHA256哈希，需要重算，Winhex搞定
bl2.bin bl30.bin bl31.bin aml_ddr.fw覆盖到u-boot/fip/g12b/
重新编译，烧录，引导后就没有bl2 bl3x打印的乱七八糟的东西了。
下面是串口引导记录，uboot仍然有很多乱七八糟的打印，后面我再讲如何去掉这些乱糟糟的东西。
G12B:BL:6e7c85:2a3b91;FEAT:E0F83180:402000;POC:F;RCY:0;EMMC:0;READ:0;CHK:1F;READ:0;CHK:1F;READ:0;CHK:1F;SD?:0;SD:0;READ:0;0.0.0;M3 CHK:0;secure task start!
high task start!
low task start!U-Boot 2015.01 (Dec 31 2019 - 13:12:30)DRAM: 3.8 GiB
Relocation Offset is: d6e46000
spi_post_bind(spifc): req_seq = 0
register usb cfg[0][1] = 00000000d7f394b0
aml_i2c_init_port init regs for 0
MMC: aml_priv->desc_buf = 0x00000000d3e36a70
aml_priv->desc_buf = 0x00000000d3e38db0
SDIO Port B: 0, SDIO Port C: 1
co-phase 0x3, tx-dly 0, clock 400000
co-phase 0x3, tx-dly 0, clock 400000
co-phase 0x3, tx-dly 0, clock 400000
emmc/sd response timeout, cmd8, status=0x3ff2800
emmc/sd response timeout, cmd55, status=0x3ff2800
co-phase 0x3, tx-dly 0, clock 400000
co-phase 0x1, tx-dly 0, clock 40000000
aml_sd_retry_refix[983]:delay = 0x0,gadjust =0x2000
[mmc_startup] mmc refix success
[mmc_init] mmc init success
start dts,buffer=00000000d3e3b620,dt_addr=00000000d3e3b620
check_valid_dts: FDT_ERR_BADMAGIC
get_partition_from_dts() 91: ret -9
get_partition_from_dts() 94: ret -9
get_ptbl_from_dtb()-272: get partition table from dts faild
mmc_device_init()-1254: get partition table from dtb failed
get_ptbl_rsv()-494: magic faild MPT,
mmc_device_init()-1281: dtb&rsv are not exist, no LPT source
get partition info failed !!
Using default environmentIn: serial
Out: serial
Err: serial
