一介绍：
`.ARM.exidx` is the section containing information for unwinding the stack. If your C program has functions that print out a stack backtrace, the functions will likely depend on this section being present.
相关的编译选项 `-funwind-tables
二问题：
cannot locate symbol "__exidx_start" referenced by
可以在linker script中添加（诸如此类的未定义现象可以在linker script中解决 或者通过编译选项解决）
__exidx_start = .;
.ARM.exidx : { *(.ARM.exidx* .gnu.linkonce.armexidx.*) } >sram
__exidx_end = .;
原文：http://blog.csdn.net/jianchenglee/article/details/32705643