This is the mail archive of the
gdb@sources.redhat.com
mailing list for the GDB project.
Re: kgdb support for gdb: patch 1
Sorry about the compile error. I have done the changes you have suggested
below. Here is a new patch.
-Amit
On Thursday 21 Oct 2004 10:52 pm, Mark Kettenis wrote:
> From: "Amit S. Kale" <amitkale@linsyssoft.com>
> Date: Thu, 21 Oct 2004 18:21:08 +0530
>
> Hi,
>
> I haven't added any support for detecting kernel osabi
> automatically. Detecting it with present kernel binary structure
> is rather shaky. It's safer to let users run the command "set osabi
> Linux-kernel".
>
> Fair enough. Indeed it seems that vmlinux is a fairly standard static
> ELF executable.
>
> I'll be later sending more patches.
>
> Please review it and let me know if it's ok for inclusion in gdb.
>
> Of course it isn't, since this can't compile ;-). You seem to be in
> limbo betwen LINUXKERNEL and LINUX_KERNEL. Please choose the variant
> *with* the underscore.
>
> Anyway, I think for the kernel you shouldn't use the Linux register
> cache layout, bur rather the normal register layout. The Linux
> register cache includes the "orig_eax" pseudo register that is
> implemented by the kernel. My guess is that the kernel itself doesn't
> have it. I'm not completely sure though, but unless you can motivate
> why you do need "orig_eax" please remove these lines:
>
> + set_gdbarch_num_regs (gdbarch, I386_LINUX_NUM_REGS);
> + set_gdbarch_register_name (gdbarch, i386_linux_register_name);
> + set_gdbarch_register_reggroup_p (gdbarch,
> i386_linux_register_reggroup_p);
>
> These lines will need adjustments too:
>
> + tdep->gregset_reg_offset = i386_linux_gregset_reg_offset;
> + tdep->gregset_num_regs = ARRAY_SIZE (i386_linux_gregset_reg_offset);
> + tdep->sizeof_gregset = 17 * 4;
>
> Setting tdep->gregset_num_regs to I386_NUM_GREGS should be OK.
>
> Apart from that, you'll also need to provide a ChangeLog.
>
> Can you post an update patch?
>
> Cheers,
>
> Mark
Index: gdb/gdb/i386-linux-tdep.c
===================================================================
--- gdb.orig/gdb/i386-linux-tdep.c 2004-08-07 02:28:28.000000000 +0530
+++ gdb/gdb/i386-linux-tdep.c 2004-10-26 14:59:29.000000000 +0530
@@ -27,6 +27,7 @@
#include "inferior.h"
#include "osabi.h"
#include "reggroups.h"
+#include "elf-bfd.h"
#include "gdb_string.h"
@@ -416,6 +417,25 @@
set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
}
+static void
+i386_linux_kernel_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ /* Linux Kernel uses ELF format for vmlinux file. */
+ i386_elf_init_abi (info, gdbarch);
+
+ /* We can use the register offsets used for linux applications. Only
+ * first 16 elements of the array will be used for kernel. Offsets of those
+ * are identical for applications and kernel. */
+ tdep->gregset_reg_offset = i386_linux_gregset_reg_offset;
+ tdep->gregset_num_regs = I386_NUM_GREGS;
+ tdep->sizeof_gregset = I386_NUM_GREGS * 4;
+
+ tdep->jb_pc_offset = 20; /* From <bits/setjmp.h>. */
+
+}
+
/* Provide a prototype to silence -Wmissing-prototypes. */
extern void _initialize_i386_linux_tdep (void);
@@ -424,4 +444,6 @@
{
gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_LINUX,
i386_linux_init_abi);
+ gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_LINUX_KERNEL,
+ i386_linux_kernel_init_abi);
}
Index: gdb/gdb/defs.h
===================================================================
--- gdb.orig/gdb/defs.h 2004-10-12 15:36:14.000000000 +0530
+++ gdb/gdb/defs.h 2004-10-26 14:46:27.000000000 +0530
@@ -1031,6 +1031,7 @@
GDB_OSABI_SOLARIS,
GDB_OSABI_OSF1,
GDB_OSABI_LINUX,
+ GDB_OSABI_LINUX_KERNEL,
GDB_OSABI_FREEBSD_AOUT,
GDB_OSABI_FREEBSD_ELF,
GDB_OSABI_NETBSD_AOUT,
Index: gdb/gdb/osabi.c
===================================================================
--- gdb.orig/gdb/osabi.c 2004-07-03 02:57:17.000000000 +0530
+++ gdb/gdb/osabi.c 2004-10-26 14:46:27.000000000 +0530
@@ -57,6 +57,7 @@
"Solaris",
"OSF/1",
"GNU/Linux",
+ "Linux-kernel",
"FreeBSD a.out",
"FreeBSD ELF",
"NetBSD a.out",
Index: gdb/gdb/ChangeLog
===================================================================
--- gdb.orig/gdb/ChangeLog 2004-10-26 14:45:24.000000000 +0530
+++ gdb/gdb/ChangeLog 2004-10-26 14:57:25.000000000 +0530
@@ -1,3 +1,7 @@
+2004-10-26 Amit S. Kale <amitkale@linsyssoft.com>
+ * i386-linux-tdep.c: Added a new osabi Linux-kernel for debugging
+ a remotely running linux kernel.
+
2004-10-25 Andrew Cagney <cagney@gnu.org>
* NEWS: Add Changes since GDB 6.3 section.