97096bed83
The lowest bit of the thumb instruction is 1 by default, which is used to distinguish arm instructions and thumb instructions.
Fixed the problem of misalignment of symbol table when performing binary search
In arm, the lowest bit of the instruction is 1, which is a thumb instruction, and 0, which is an arm instruction.
The nm command was used in mkallsym.sh before, and the result it will return will set the lowest bit of the thumb instruction to 0. There will be a one-byte deviation during binary search, so mkallsyms.py will also set the lowest bit to 0 according to the previous format.
```sh
arm-none-eabi-nm -Cn nuttx | grep hello
0801c384 T hello_main
arm-none-eabi-objdump nuttx -t |grep hello
0801c384 g F .text 0000004c hello_main
arm-none-eabi-readelf nuttx -s |grep hello
4558: 0801c385 76 FUNC GLOBAL DEFAULT 1 hello_main
```
However, in the following case, when you need to find the function address according to the symbol name and execute the corresponding function, the lowest address obtained is 0. It will follow the arm instruction, causing an exception.
```c
void sym_test(void)
{
printf("call sym_test\n");
}
int main(int argc, FAR char *argv[])
{
FAR void *addr = sym_test;
printf("sym_test:%p %pS\n",addr, addr);
printf("sym_test - 1: %pS\n", (char *)addr - 1);
printf("sym_test + 1: %pS\n", (char *)addr + 1);
size_t size;
void (*func)(void);
const struct symtab_s *sym = allsyms_findbyname("sym_test", &size);
printf("sym_test:%p %pS\n",sym, sym);
func = sym->sym_value;
func();
return 0;
}
```
Therefore, you need to change mkallsyms.py back to the correct result and correct the binary search.
Signed-off-by: yinshengkai <yinshengkai@xiaomi.com>
|
||
|---|---|---|
| .github | ||
| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .gitignore | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).
For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.
Getting Started
First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.
Documentation
You can find the current NuttX documentation on the Documentation Page.
Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.
The old NuttX documentation is still available in the Apache wiki.
Supported Boards
NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.
Contributing
If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.
License
The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.