桥后看桥的个人资料 - RAT

桥后看桥桥后看桥

关注数: 50 粉丝数: 78 发帖数: 929 关注贴吧数: 83

[aarch64][bare-metal] g++ 在 aarch64 中传递结构体参数跑飞首先是一段很简单的代码 ```c++ // 初始化 sp 寄存器 extern "C" void _start() {asm volatile("ldr x11, =stack_top\n\t""mov sp, x11\n\t""bl main\n\t");} // qemu 中的串口地址，用于串口输出 void putc(char character) { *(char *)0x9000000 = character; } // 要传递的结构体 struct param_t {char data[15];}; // 测试函数 void callee(param_t var) { putc('a'); void main() {putc('0');callee({});putc('1');} ``` 编译： aarch64-elf-g++ -ffreestanding -nostdlib -Wl,--entry=_start -Wl,--section-start=.text=0x40100000 -Wl,--defsym=stack_top=0x40101000 -o aarch64_minimal main.cpp 在 qemu 中运行： qemu-system-aarch64 -nographic -serial stdio -monitor telnet::2333,server,nowait -m 1024M -machine virt -cpu cortex-a72 -kernel aarch64_minimal 预期的输出应该是 `0a1`，但是当 param_t 结构体中 data 数组的大小为 15 时只能输出 `0`，改成 16 则能输出符合预期的结果。楼主的初步排查结论： 1. 与 aapcs64 相关，涉及到结构体参数的传递规范，参考：http://tieba.baidu.com/mo/q/checkurl?url=https%3A%2F%2Fgithub.com%2FARM-software%2Fabi-aa%2Fblob%2F2982a9f3b512a5bfdc9e3fea5d3b298f9165c36b%2Faapcs64%2Faapcs64.rst%23682parameter-passing-rules&urlrefer=9d1181ae2c09be548f7662ee2bd1a2f72. 不涉及到浮点寄存器 3. 栈的相关设置没有问题这是对应的反汇编代码 ```shell aarch64_minimal:file format elf64-littleaarch64 Disassembly of section .text: 0000000040100000 <_start>: 40100000: 58000d4b ldrx11, 0x401001a8 40100004: 9100017f movsp, x11 40100008: 94000053 bl0x40100154 4010000c: d503201f nop 40100010: d65f03c0 ret 0000000040100014 <_Z4putcc>: 40100014: d10043ff subsp, sp, #0x10 40100018: 39003fe0 strbw0, [sp, #0xf] 4010001c: d2a12000 movx0, #0x9000000 // =150994944 40100020: 39403fe1 ldrbw1, [sp, #0xf] 40100024: 39000001 strbw1, [x0] 40100028: d503201f nop 4010002c: 910043ff addsp, sp, #0x10 40100030: d65f03c0 ret 0000000040100034 <_Z6callee7param_t>: 40100034: a9be7bfd stpx29, x30, [sp, #-0x20]! 40100038: 910003fd movx29, sp 4010003c: aa0003e2 movx2, x0 40100040: aa0103e0 movx0, x1 40100044: f9000be2 strx2, [sp, #0x10] 40100048: 92401c03 andx3, x0, #0xff 4010004c: 394063e1 ldrbw1, [sp, #0x18] 40100050: 52800002 movw2, #0x0 // =0 40100054: 0a020021 andw1, w1, w2 40100058: 2a0103e2 movw2, w1 4010005c: 2a0303e1 movw1, w3 40100060: 2a010041 orrw1, w2, w1 40100064: 390063e1 strbw1, [sp, #0x18] 40100068: d348fc01 lsrx1, x0, #8 4010006c: 92401c23 andx3, x1, #0xff 40100070: 394067e1 ldrbw1, [sp, #0x19] 40100074: 52800002 movw2, #0x0 // =0 40100078: 0a020021 andw1, w1, w2 4010007c: 2a0103e2 movw2, w1 40100080: 2a0303e1 movw1, w3 40100084: 2a010041 orrw1, w2, w1 40100088: 390067e1 strbw1, [sp, #0x19] 4010008c: d350fc01 lsrx1, x0, #16 40100090: 92401c23 andx3, x1, #0xff 40100094: 39406be1 ldrbw1, [sp, #0x1a] 40100098: 52800002 movw2, #0x0 // =0 4010009c: 0a020021 andw1, w1, w2 401000a0: 2a0103e2 movw2, w1 401000a4: 2a0303e1 movw1, w3 401000a8: 2a010041 orrw1, w2, w1 401000ac: 39006be1 strbw1, [sp, #0x1a] 401000b0: d358fc01 lsrx1, x0, #24 401000b4: 92401c23 andx3, x1, #0xff 401000b8: 39406fe1 ldrbw1, [sp, #0x1b] 401000bc: 52800002 movw2, #0x0 // =0 401000c0: 0a020021 andw1, w1, w2 401000c4: 2a0103e2 movw2, w1 401000c8: 2a0303e1 movw1, w3 401000cc: 2a010041 orrw1, w2, w1 401000d0: 39006fe1 strbw1, [sp, #0x1b] 401000d4: d360fc01 lsrx1, x0, #32 401000d8: 92401c23 andx3, x1, #0xff 401000dc: 394073e1 ldrbw1, [sp, #0x1c] 401000e0: 52800002 movw2, #0x0 // =0 401000e4: 0a020021 andw1, w1, w2 401000e8: 2a0103e2 movw2, w1 401000ec: 2a0303e1 movw1, w3 401000f0: 2a010041 orrw1, w2, w1 401000f4: 390073e1 strbw1, [sp, #0x1c] 401000f8: d368fc01 lsrx1, x0, #40 401000fc: 92401c23 andx3, x1, #0xff 40100100: 394077e1 ldrbw1, [sp, #0x1d] 40100104: 52800002 movw2, #0x0 // =0 40100108: 0a020021 andw1, w1, w2 4010010c: 2a0103e2 movw2, w1 40100110: 2a0303e1 movw1, w3 40100114: 2a010041 orrw1, w2, w1 40100118: 390077e1 strbw1, [sp, #0x1d] 4010011c: d370fc00 lsrx0, x0, #48 40100120: 92401c02 andx2, x0, #0xff 40100124: 39407be0 ldrbw0, [sp, #0x1e] 40100128: 52800001 movw1, #0x0 // =0 4010012c: 0a010000 andw0, w0, w1 40100130: 2a0003e1 movw1, w0 40100134: 2a0203e0 movw0, w2 40100138: 2a000020 orrw0, w1, w0 4010013c: 39007be0 strbw0, [sp, #0x1e] 40100140: 52800c20 movw0, #0x61 // =97 40100144: 97ffffb4 bl0x40100014 <_Z4putcc> 40100148: d503201f nop 4010014c: a8c27bfd ldpx29, x30, [sp], #0x20 40100150: d65f03c0 ret 0000000040100154 : 40100154: a9be7bfd stpx29, x30, [sp, #-0x20]! 40100158: 910003fd movx29, sp 4010015c: 52800600 movw0, #0x30 // =48 40100160: 97ffffad bl0x40100014 <_Z4putcc> 40100164: 910043e0 addx0, sp, #0x10 40100168: 4f00041f moviv31.4s, #0x0 4010016c: 9e6603e1 fmovx1, d31 40100170: f9000001 strx1, [x0] 40100174: 9e6603e1 fmovx1, d31 40100178: f8007001 sturx1, [x0, #0x7] 4010017c: f9400be2 ldrx2, [sp, #0x10] 40100180: f9400fe0 ldrx0, [sp, #0x18] 40100184: d340dc01 ubfxx1, x0, #0, #56 40100188: aa0203e0 movx0, x2 4010018c: 97ffffaa bl0x40100034 <_Z6callee7param_t> 40100190: 52800620 movw0, #0x31 // =49 40100194: 97ffffa0 bl0x40100014 <_Z4putcc> 40100198: d503201f nop 4010019c: a8c27bfd ldpx29, x30, [sp], #0x20 401001a0: d65f03c0 ret 401001a4: 00000000 udf#0x0 401001a8: 00 10 10 40 .word0x40101000 401001ac: 00 00 00 00 .word0x00000000 ```

我先放一个服务器在这里正版太空时代原版，欢迎大家来丸

几年的配置询价 cpu: 1700 主板: 华硕 b350f gaming 内存: 金士顿掠食者3200 c16 8*2 显卡: evga 1080ti hybridd2 电源: 酷冷至尊 v650 散热: as120 硬盘: 海康 c2000 1t 机箱: 乔思伯 U4 17 年入的，不知道现在什么行情，有老哥指点下吗

1 下一页