8

在调试过程中，我收到以下错误消息。

Alignment trap: my_main (29858) PC=0x00170ad8 Instr=0xe5960008 Address=0x00f28daa FSR 0x0f3

我环顾四周，发现了很多关于这个（断开的链接） 实时嵌入式网站的信息。所以现在我知道PCandInstr指的是什么，但我仍然没有找到关于AddressandFSR部分的任何信息。

是什么FSR？Address指的是什么地址？根据proc/xxxx/maps那个地址甚至超出了我的程序范围。有谁知道最后两项是什么意思？我需要这些信息来解决这个对齐问题。

地图输出

00008000-001fe000 r-xp 00000000 03:02 16204      /home/myuser/my_main
00205000-00248000 rw-p 001f5000 03:02 16204      /home/myuser/my_main
00248000-00299000 rwxp 00248000 00:00 0
40000000-40018000 r-xp 00000000 03:01 2095       /lib/ld-2.3.3.so
40018000-4001b000 rw-p 40018000 00:00 0
4001f000-40020000 r--p 00017000 03:01 2095       /lib/ld-2.3.3.so
40020000-40021000 rw-p 00018000 03:01 2095       /lib/ld-2.3.3.so
40021000-40023000 r-xp 00000000 03:01 15724      /usr/lib/libem7.so.1.0.1
40023000-40029000 ---p 00002000 03:01 15724      /usr/lib/libem7.so.1.0.1
40029000-4002b000 rw-p 00000000 03:01 15724      /usr/lib/libem7.so.1.0.1
4002b000-40031000 r-xp 00000000 03:01 2057       /lib/tls/librt-2.3.3.so
40031000-40033000 ---p 00006000 03:01 2057       /lib/tls/librt-2.3.3.so
40033000-40038000 rw-p 00000000 03:01 2057       /lib/tls/librt-2.3.3.so
40038000-40039000 r--p 00005000 03:01 2057       /lib/tls/librt-2.3.3.so
40039000-4003a000 rw-p 00006000 03:01 2057       /lib/tls/librt-2.3.3.so
4003a000-4004a000 r-xp 00000000 03:01 2060       /lib/tls/libpthread-2.3.3.so
4004a000-40051000 rw-p 00008000 03:01 2060       /lib/tls/libpthread-2.3.3.so
40051000-40052000 r--p 0000f000 03:01 2060       /lib/tls/libpthread-2.3.3.so
40052000-40053000 rw-p 00010000 03:01 2060       /lib/tls/libpthread-2.3.3.so
40053000-40055000 rw-p 40053000 00:00 0
40055000-4010e000 r-xp 00000000 03:01 15703      /usr/lib/libstdc++.so.6.0.3
4010e000-40115000 ---p 000b9000 03:01 15703      /usr/lib/libstdc++.so.6.0.3
40115000-40119000 rw-p 000b8000 03:01 15703      /usr/lib/libstdc++.so.6.0.3
40119000-4011f000 rw-p 40119000 00:00 0
4011f000-401b7000 r-xp 00000000 03:01 2076       /lib/tls/libm-2.3.3.so
401b7000-401be000 rw-p 00090000 03:01 2076       /lib/tls/libm-2.3.3.so
401be000-401bf000 r--p 00097000 03:01 2076       /lib/tls/libm-2.3.3.so
401bf000-401c0000 rw-p 00098000 03:01 2076       /lib/tls/libm-2.3.3.so
401c0000-401c8000 r-xp 00000000 03:01 2005       /lib/libgcc_s.so.1
401c8000-401c9000 rw-p 00008000 03:01 2005       /lib/libgcc_s.so.1
401c9000-402cb000 r-xp 00000000 03:01 2078       /lib/tls/libc-2.3.3.so
402cb000-402d1000 ---p 00102000 03:01 2078       /lib/tls/libc-2.3.3.so
402d1000-402d2000 rw-p 00100000 03:01 2078       /lib/tls/libc-2.3.3.so
402d2000-402d4000 r--p 00101000 03:01 2078       /lib/tls/libc-2.3.3.so
402d4000-402d6000 rw-p 00103000 03:01 2078       /lib/tls/libc-2.3.3.so
402d6000-402d8000 rw-p 402d6000 00:00 0
402d8000-402e5000 rw-s 00000000 00:07 0          /SYSV12345678 (deleted)
402e5000-402e6000 ---p 402e5000 00:00 0
402e6000-402f5000 rwxp 402e6000 00:00 0
403c1000-4049d000 rw-p 403c1000 00:00 0
7efeb000-7f000000 rwxp 7efeb000 00:00 0
4

2 回答 2

17 
PC=0x00170ad8

This is telling you the current value of the program counter, it can be used to determine which instruction in your program is causing the trap. If you’re on ARM as I think you are, this is actually the current instruction plus 8, so the instruction causing the trap is located at 0x00170ad0.

Instr=0xe5960008

This is the encoding of the faulting instruction. If this is on ARM, that instruction is ldr r0, [r6, #8]

Address=0x00f28daa

This is telling you the address from which your program attempted to load, causing the fault. Assuming everything else so far is correct, this is r6 + 8, so r6 held 0x00f28da2 at the time of the fault.

FSR 0xf3

This is the value held in the fault status register. It tells you what fault occurred. This particular value is an older encoding (pre-ARMv7) for an Alignment fault.

于 2013-04-10T10:47:16.227 回答
1

很可能您的 CPU 不支持对未对齐地址的值的内存进行读/写。如果您正在访问一个 4 字节变量，那么显然 Address=0x00f28daa 不是 4 的倍数。在任意对齐的地址上只能读取/写入单个字节。

那篇文章解释得很好。

于 2013-04-10T10:11:05.887 回答