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Re: A linux patch for a typo
- To: torvalds@transmeta.com (Linus Torvalds)
- Subject: Re: A linux patch for a typo
- From: hjl@lucon.org (H.J. Lu)
- Date: Mon, 25 May 1998 15:53:11 -0700 (PDT)
- Cc: hjl@lucon.org, libc-hacker@cygnus.com, egcs@cygnus.com, linux-gcc@vger.rutgers.edu, kjahds@kjahds.com, lmfken@lmf.ericsson.se, ian@lasermoon.co.uk, mat@lcs.mit.edu, doughera@lafcol.lafayette.edu, brian@mathworks.com, john@etools.com, craig@metrolink.com, imp@village.org, robf@Willows.Com, meissner@cygnus.com, rfg@monkeys.com, roell@xinside.com, burley@gnu.org, linux-binutils-in@polstra.com, galenh@micron.net, ralf@mailhost.uni-koblenz.de
>
>
>
> On Sun, 24 May 1998, H.J. Lu wrote:
> >
> > Here is a patch for typo in linux 2.1.10.3. My upcoming gdb FPU support
> > patch needs it.
>
> Did you even _try_ your patch?
>
> As far as I can tell, if you apply your patch the kernel shouldn't even
> boot, or at least not work correctly. The "pt_regs" structure _has_ to
> match what the kernel actually pushes on the stack, and quite frankly, if
> the user level code ever cares, the user level code is _broken_.
>
> User level code should never EVER touch this structure. If anything you
I am working a gdb patch. It needs to know that.
> have references "struct pt_regs", then that code is YOUR bug, and I don't
> want to know.
>
Here is my copy of the original linux/include/asm-i386/ptrace.h in
kernel 2.1.103. Unless yours is different from mine, please tell me
where are the fields in struct pt_regs for FS and GS. As the result,
my gdb gets the wrong EIP. Maybe those macros have nothing to do with
indexes in struct pt_regs. In anycase, I won't use struct pt_regs in
my gdb patch.
H.J.
----
#ifndef _I386_PTRACE_H
#define _I386_PTRACE_H
#define EBX 0
#define ECX 1
#define EDX 2
#define ESI 3
#define EDI 4
#define EBP 5
#define EAX 6
#define DS 7
#define ES 8
#define FS 9
#define GS 10
#define ORIG_EAX 11
#define EIP 12
#define CS 13
#define EFL 14
#define UESP 15
#define SS 16
/* this struct defines the way the registers are stored on the
stack during a system call. */
struct pt_regs {
long ebx;
long ecx;
long edx;
long esi;
long edi;
long ebp;
long eax;
int xds;
int xes;
long orig_eax;
long eip;
int xcs;
long eflags;
long esp;
int xss;
};
/* Arbitrarily choose the same ptrace numbers as used by the Sparc code. */
#define PTRACE_GETREGS 12
#define PTRACE_SETREGS 13
#define PTRACE_GETFPREGS 14
#define PTRACE_SETFPREGS 15
#ifdef __KERNEL__
#define user_mode(regs) ((VM_MASK & (regs)->eflags) || (3 & (regs)->xcs))
#define instruction_pointer(regs) ((regs)->eip)
extern void show_regs(struct pt_regs *);
#endif
#endif