It is generally hard to debug across x86 processor mode transitions, and to debug 16-bit real mode code with modern tools. There are a few places in the x86 that still require 16-bit real mode for handoffs (like the reset vector) so you tend to hit this issue more in debugging firmware.
Thanks, Andrew Fish > On Aug 3, 2017, at 8:41 PM, wang xiaofeng <[email protected]> wrote: > > Hi Andrew, > THe problem is solved, after the SEC code switch to protected mode, gdb > can work well now > > > > > > > At 2017-08-04 11:26:16, "wang xiaofeng" <[email protected]> wrote: > HI Andrew, > How can I adjust the debugger to correct mode? Or I have to enable the > debug after swtich to protected mode? > > > > > > > At 2017-08-04 10:57:16, "Andrew Fish" <[email protected] > <mailto:[email protected]>> wrote: > >The reset vector is 16-bit real mode, so you have the debugger in the wrong > >mode. The code should transition to 32 bit protected early in the flow. > > > >Sent from my iPhone > > > >> On Aug 3, 2017, at 7:47 PM, wang xiaofeng <[email protected] > >> <mailto:[email protected]>> wrote: > >> > >> Hello, > >> I am tring to add my own SEC code base on OVMF and run on QEMU. > >> Since the code cannot run I need to step to step trace the assembly code . > >> The hang point is very early before I can use either UDK or debug > >> serial output. I tried to use gdb to connect to QEMU.I start gdb in > >> another terminal, and issue the following commands: > >> (gdb) set architecture i386:x86-64:intel > >> (gdb) target remote localhost:1234 > >> It really stops at the bios first instruction at 0XFFFFFFF0. But gdb > >> shows eip= 0xFFF0 and CS=0xF000(why it not be 0xfff0). After I trigger the > >> command "display /i $pc" > >> It shows the assembly code in 0xFFF0 instead of 0XFFFFFFF0, so the > >> information is incorrect. > >> Anyone knows how to corrently debug the SEC code ? Other debug tool is > >> also ok. > >> Thanks in advance! > >> > >> > >> > >> _______________________________________________ > >> edk2-devel mailing list > >> [email protected] <mailto:[email protected]> > >> https://lists.01.org/mailman/listinfo/edk2-devel > >_______________________________________________ > >edk2-devel mailing list > >[email protected] <mailto:[email protected]> > >https://lists.01.org/mailman/listinfo/edk2-devel > > > > > > 【网易自营|30天无忧退货】不到同款1折价！Tory Burch制造商美式休闲人字拖限时仅29.9元>> > <http://you.163.com/item/detail?id=1185012&from=web_gg_mail_jiaobiao_9> _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
