Re: [RFHelp] Linux, threads, and regsets in thread_db

["H . J . Lu" <hjl at lucon dot org>]

On Tue, Sep 25, 2001 at 12:08:37PM +0200, Mark Kettenis wrote:
> Daniel Jacobowitz <drow@mvista.com> writes:
> 
> > I spent a while this summer making thread debugging work on some more
> > non-x86 targets, with great frustration.  Eventually I reached the
> > decision that my problem was in fact a glibc bug; the attached messages
> > explain it.  Ulrich has categorically (and without explanation, when
> > asked.  sigh.) refused the patch.
> 
> Seems that Ulrich is still confused about the regset issues.  I asked
> the port maintainers to clean this up when I fixed it for i386.  Jakub
> Jellinek cleaned up sparc, but nothing else happened.
> 
> > Could someone on this list at least sanity check my patch?  I have a
> > (disgusting) workaround for GDB if the header is not changed, but I'd
> > much rather someone convince Ulrich that I'm not crazy.  Especially
> > since I can not get the workaround to compile without warnings.  C
> > behaves badly in the presence of casts to/from array types.
> 
> In principle, your patch is the right thing.  There may be
> interactions with <sys/user.h> and <sys/elf.h> though.  Look at the
> i386 port to see how things should be done.
> 

Here is a patch for mips. It seems to work for me.


H.J.
-----
2001-11-14  H.J. Lu  <hjl@gnu.org>

	* sysdeps/unix/sysv/linux/mips/sys/procfs.h: Don't include
	<signal.h>, <sys/ucontext.h> nor <asm/elf.h>. Updated for gdb.

	* sysdeps/unix/sysv/linux/mips/sys/user.h: New.

--- sysdeps/unix/sysv/linux/mips/sys/procfs.h.gdb	Sat Jul  7 16:46:18 2001
+++ sysdeps/unix/sysv/linux/mips/sys/procfs.h	Wed Nov 14 12:30:19 2001
@@ -24,12 +24,19 @@
    used on Linux.  */
 
 #include <features.h>
-#include <signal.h>
 #include <sys/time.h>
 #include <sys/types.h>
-#include <sys/ucontext.h>
 #include <sys/user.h>
-#include <asm/elf.h>
+
+/* ELF register definitions */
+#define ELF_NGREG	45
+#define ELF_NFPREG	33
+
+typedef unsigned long elf_greg_t;
+typedef elf_greg_t elf_gregset_t[ELF_NGREG];
+
+typedef double elf_fpreg_t;
+typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
 
 __BEGIN_DECLS
 
@@ -50,19 +57,10 @@ struct elf_siginfo
    marked with "XXX".  */
 struct elf_prstatus
   {
-#if 0
-    long int pr_flags;			/* XXX Process flags.  */
-    short int pr_why;			/* XXX Reason for process halt.  */
-    short int pr_what;			/* XXX More detailed reason.  */
-#endif
     struct elf_siginfo pr_info;		/* Info associated with signal.  */
     short int pr_cursig;		/* Current signal.  */
     unsigned long int pr_sigpend;	/* Set of pending signals.  */
     unsigned long int pr_sighold;	/* Set of held signals.  */
-#if 0
-    struct sigaltstack pr_altstack;	/* Alternate stack info.  */
-    struct sigaction pr_action;		/* Signal action for current sig.  */
-#endif
     __pid_t pr_pid;
     __pid_t pr_ppid;
     __pid_t pr_pgrp;
@@ -71,9 +69,6 @@ struct elf_prstatus
     struct timeval pr_stime;		/* System time.  */
     struct timeval pr_cutime;		/* Cumulative user time.  */
     struct timeval pr_cstime;		/* Cumulative system time.  */
-#if 0
-    long int pr_instr;			/* Current instruction.  */
-#endif
     elf_gregset_t pr_reg;		/* GP registers.  */
     int pr_fpvalid;			/* True if math copro being used.  */
   };
@@ -101,8 +96,8 @@ struct elf_prpsinfo
 typedef void *psaddr_t;
 
 /* Register sets.  Linux has different names.  */
-typedef gregset_t prgregset_t;
-typedef fpregset_t prfpregset_t;
+typedef elf_gregset_t prgregset_t;
+typedef elf_fpregset_t prfpregset_t;
 
 /* We don't have any differences between processes and threads,
    therefore habe only ine PID type.  */
--- sysdeps/unix/sysv/linux/mips/sys/user.h.gdb	Wed Nov 14 12:04:50 2001
+++ sysdeps/unix/sysv/linux/mips/sys/user.h	Wed Nov 14 12:32:11 2001
@@ -0,0 +1,74 @@
+/* Copyright (C) 2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef _SYS_USER_H
+#define _SYS_USER_H	1
+
+/* The whole purpose of this file is for GDB and GDB only.  Don't read
+   too much into it.  Don't use it for anything other than GDB unless
+   you know what you are doing.  */
+
+#include <asm/reg.h>
+
+/*
+ * Core file format: The core file is written in such a way that gdb
+ * can understand it and provide useful information to the user (under
+ * linux we use the `trad-core' bfd, NOT the irix-core).  The file
+ * contents are as follows:
+ *
+ *  upage: 1 page consisting of a user struct that tells gdb
+ *	what is present in the file.  Directly after this is a
+ *	copy of the task_struct, which is currently not used by gdb,
+ *	but it may come in handy at some point.  All of the registers
+ *	are stored as part of the upage.  The upage should always be
+ *	only one page long.
+ *  data: The data segment follows next.  We use current->end_text to
+ *	current->brk to pick up all of the user variables, plus any memory
+ *	that may have been sbrk'ed.  No attempt is made to determine if a
+ *	page is demand-zero or if a page is totally unused, we just cover
+ *	the entire range.  All of the addresses are rounded in such a way
+ *	that an integral number of pages is written.
+ *  stack: We need the stack information in order to get a meaningful
+ *	backtrace.  We need to write the data from usp to
+ *	current->start_stack, so we round each of these in order to be able
+ *	to write an integer number of pages.
+ */
+struct user {
+	unsigned long	regs[EF_SIZE/4+64];	/* integer and fp regs */
+	size_t		u_tsize;		/* text size (pages) */
+	size_t		u_dsize;		/* data size (pages) */
+	size_t		u_ssize;		/* stack size (pages) */
+	unsigned long	start_code;		/* text starting address */
+	unsigned long	start_data;		/* data starting address */
+	unsigned long	start_stack;		/* stack starting address */
+	long int	signal;			/* signal causing core dump */
+	void*		u_ar0;			/* help gdb find registers */
+	unsigned long	magic;			/* identifies a core file */
+	char		u_comm[32];		/* user command name */
+};
+
+#define PAGE_SHIFT		12
+#define PAGE_SIZE		(1UL << PAGE_SHIFT)
+#define PAGE_MASK		(~(PAGE_SIZE-1))
+#define NBPG			PAGE_SIZE
+#define UPAGES			1
+#define HOST_TEXT_START_ADDR	(u.start_code)
+#define HOST_DATA_START_ADDR	(u.start_data)
+#define HOST_STACK_END_ADDR	(u.start_stack + u.u_ssize * NBPG)
+
+#endif	/* _SYS_USER_H */