35 lines
1.2 KiB
Plaintext
35 lines
1.2 KiB
Plaintext
# 实验篇
|
||
|
||
1. shell 脚本问题
|
||
|
||
*.bxrc 文件中的变量不要用`{}`包起来，例如要用`$OSLAB_PATH`，不要用`${OSLAB_PATH}`。否则会找不到变量。
|
||
|
||
2. 如何使bochs、gdb调试忽略page fault信号？
|
||
|
||
Created a patch "gdbstub.cc.patch" against bochs (version CVS 20080110)
|
||
Bochs always tries to find out the reason of an exception, so that it can generate the right signal for gdb.
|
||
If it fails to find a reason, bochs assigns a value GDBSTUB_STOP_NO_REASON (see bochs.h), which causes
|
||
debug_loop() (see gdbstub.cc) to generate a signal of number 0.
|
||
Signal 0 is problematic to gdb, as gdb doesn't allow us to ignore it.
|
||
Somehow when we simulate linux, we get tons of signal 0's that seem to be caused by page faults.
|
||
This patch makes bochs send SIGSEGV instead of signal 0, so that we can ignore it in gdb.
|
||
|
||
gdbstub.cc
|
||
debug_loop()
|
||
|
||
*** gdbstub.cc.orig Thu Oct 18 18:44:38 2007
|
||
--- gdbstub.cc Sat Jan 12 17:25:22 2008
|
||
*************** static void debug_loop(void)
|
||
*** 489,494 ****
|
||
--- 489,498 ----
|
||
{
|
||
write_signal(&buf[1], SIGTRAP);
|
||
}
|
||
+ else if (last_stop_reason == GDBSTUB_STOP_NO_REASON)
|
||
+ {
|
||
+ write_signal(&buf[1], SIGSEGV);
|
||
+ }
|
||
else
|
||
{
|
||
write_signal(&buf[1], 0);
|