Hello, I found from the manual, (https://sourceware.org/gdb/onlinedocs/gdb/Files.html#:~:text=The%20add%2Dsy mbol%2Dfile%20command,text%20section%20has%20been%20loaded.) By giving "-o 0x10000" I can follow the kernel source in the virtual address. (and follow sources after start_kernel) Thank you. Chan Kim >-----Original Message----- >From: Chan Kim <ckim@xxxxxxxxxx> >Sent: Monday, July 18, 2022 5:43 PM >To: kernelnewbies@xxxxxxxxxxxxxxxxx >Subject: Confused about how to apply add-symbol-file in gdb > >Hello all, > >I thought I know how to apply add-symbol-file command in gdb but now I'm >confused. >I'm using qemu to test booting linux using u-boot. (arm64) I've loaded u- >boot at 0x4000000 and loaded linux Image (binary, not elf) at 0x80010000. >The dtb is loaded at 0x80000000. >(because qemu loads the dtb file at the first address of RAM (which is >0x80000000) I moved kernel image to 0x80010000) After the PC jumps to linux, >I can follow the source while the PC value uses physical address. >I think this is possible that I gave gdb this command. >add-symbol-file vmlinux -s .head.text 0x80010000 -s .text 0x80020000 (using >readelf -e vmlinux command, I can see the section offsets relative to the >start of the Image file. The output starts like this. >Section Headers: > [Nr] Name Type Address Offset > Size EntSize Flags Link Info Align > [ 0] NULL 0000000000000000 00000000 > 0000000000000000 0000000000000000 0 0 0 > [ 1] .head.text PROGBITS ffffffc010000000 00010000 > 0000000000010000 0000000000000000 AX 0 0 65536 > [ 2] .text PROGBITS ffffffc010010000 00020000 > 0000000000aa4dc8 0000000000000008 AX 0 0 2048 > [ 3] .got.plt PROGBITS ffffffc010ab4dc8 00ac4dc8 > 0000000000000018 0000000000000008 WA 0 0 8 > [ 4] .rodata PROGBITS ffffffc010ac0000 00ad0000 > 0000000000645018 0000000000000000 WA 0 0 4096 > [ 5] .pci_fixup PROGBITS ffffffc011105020 01115020 > 00000000000025e0 0000000000000000 A 0 0 16 > [ 6] __ksymtab PROGBITS ffffffc011107600 01117600 > 000000000000b3b8 0000000000000000 A 0 0 4 > [ 7] __ksymtab_gpl PROGBITS ffffffc0111129b8 011229b8 >... > >Now, at the end of __primary_switch function, the PC value becomes virtual. >But I can't follow kernel source from that point. >Until now, I have placed kernel Image at 0x80000000 and dtb was at >0x82800000 and just by giving "add-symbol-file vmlinux" again, there was no >problem following the kernel source in virtual address. >How should I give the add-symbol-file command when the Image is now at >0x80010000?? >Any comment welcome. >Thank you. > >Chan Kim _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
