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Diffstat (limited to 'dev/c/index.html')
| -rw-r--r-- | dev/c/index.html | 90 |
1 files changed, 87 insertions, 3 deletions
diff --git a/dev/c/index.html b/dev/c/index.html index 09374c6..684c7d2 100644 --- a/dev/c/index.html +++ b/dev/c/index.html @@ -7,6 +7,92 @@ <body> <a href="../index.html">Development Index</a> + <h1>System Development</h1> + + <p>System development requires debug kernel know how, + in this example will be used qemu and gdb. A simple init + program is created. Create init.S;</p> + + <pre> + .global _start + _start: + mov $1, %rax + mov $1, %rdi + mov $message, %rsi + mov $message_len, %rdx + syscall + jmp . + message: .ascii "FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR\n" + .equ message_len, . - message + </pre> + + <p>Assemble, link and create simple initial ram disk;</p> + + <pre> + mkdir d + as --64 -o init.o init.S # assemble + ld -o d/init init.o # link + cd d + find . | cpio -o -H newc | gzip > ../rootfs.cpio.gz + </pre> + + <p>Clean temporary directory;</p> + + <pre> + cd .. + rm -r d/ + </pre> + + <p>Can be used C to create init program;</p> + + <pre> + #include <stdio.h> + #include <unistd.h> + + int main() { + printf("FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR\n"); + sleep(0xFFFFFFFF); + return 0; + } + </pre> + + <pre> + $ gcc -static init.c -o init + </pre> + + <p>Test qemu, kernel and simple init program, you should see + "FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR";</p> + + <pre> + $ qemu-system-x86_64 -enable-kvm --kernel arch/x86_64/boot/bzImage \ + --initrd rootfs.cpio.gz + </pre> + + <p>If everything goes well you can start qemu without start CPU at + startup (-S) and with gdb server on TCP port 1234 (-s).</p> + + <pre> + $ qemu-system-x86_64 -enable-kvm --kernel arch/x86/boot/bzImage \ + --initrd rootfs.cpio.gz \ + -S -s + </pre> + + <p>On another terminal start gdb;</p> + + <pre> + gdb \ + -ex "add-auto-load-safe-path $(pwd)" \ + -ex "file vmlinux" \ + -ex 'set arch i386:x86-64:intel' \ + -ex 'target remote localhost:1234' \ + -ex 'break start_kernel' \ + -ex 'continue' \ + -ex 'disconnect' \ + -ex 'set arch i386:x86-64' \ + -ex 'target remote localhost:1234' + </pre> + + <h1>C & GDB</h1> <p><a href="http://blog.fourthbit.com/2013/06/18/creating-an-open-source-program-in-c-with-autotools-part-1-of-2/">C program with autotools</a> @@ -74,7 +160,7 @@ thread 1 </pre> - <p><a href=" http://ftp.gnu.org/old-gnu/Manuals/gdb/html_node/gdb_39.html#SEC40">Stopping and Starting</a> + <p><a href="http://ftp.gnu.org/old-gnu/Manuals/gdb/html_node/gdb_39.html#SEC40">Stopping and Starting</a> multi-thread programs</p> <pre> @@ -86,8 +172,6 @@ <pre> strace -c ./program </pre> - - <a href="../index.html">Development Index</a> <p> This is part of the c9-doc Manual. |