ptrace has always returned only -EIO for all failures to access
registers. The user_regset calls are allowed to return a more
meaningful variety of errors. The REGSET_XFP calls use -ENODEV
for !cpu_has_fxsr hardware. Make ptrace return the traditional
-EIO instead of the error code from the user_regset call.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When I update kernel 2.6.25 from 2.6.24, gdb does not work.
On 2.6.25, ptrace(PTRACE_GETFPXREGS, ...) returns ENODEV.
But 2.6.24 kernel's ptrace() returns EIO.
It is issue of compatibility.
I attached test program as pt.c and patch for fix it.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <sys/ptrace.h>
#include <sys/types.h>
struct user_fxsr_struct {
unsigned short cwd;
unsigned short swd;
unsigned short twd;
unsigned short fop;
long fip;
long fcs;
long foo;
long fos;
long mxcsr;
long reserved;
long st_space[32]; /* 8*16 bytes for each FP-reg = 128 bytes */
long xmm_space[32]; /* 8*16 bytes for each XMM-reg = 128 bytes */
long padding[56];
};
int main(void)
{
pid_t pid;
pid = fork();
switch(pid){
case -1:/* error */
break;
case 0:/* child */
child();
break;
default:
parent(pid);
break;
}
return 0;
}
int child(void)
{
ptrace(PTRACE_TRACEME);
kill(getpid(), SIGSTOP);
sleep(10);
return 0;
}
int parent(pid_t pid)
{
int ret;
struct user_fxsr_struct fpxregs;
ret = ptrace(PTRACE_GETFPXREGS, pid, 0, &fpxregs);
if(ret < 0){
printf("%d: %s.\n", errno, strerror(errno));
}
kill(pid, SIGCONT);
wait(pid);
return 0;
}
/* in the kerel, at kernel/i387.c get_fpxregs() */
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix the math emulation that got broken with the recent lazy allocation of FPU
area. init_fpu() need to be added for the math-emulation path aswell
for the FPU area allocation.
math emulation enabled kernel booted fine with this, in the presence
of "no387 nofxsr" boot param.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: hpa@zytor.com
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If the task never used fpu, initialize the fpu before restoring the FP
state from the signal handler context. This will allocate the fpu
state, if the task never needed it before.
Reported-and-bisected-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Eric Sesterhenn <snakebyte@gmx.de>
Cc: Frederik Deweerdt <deweerdt@free.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Only allocate the FPU area when the application actually uses FPU, i.e., in the
first lazy FPU trap. This could save memory for non-fpu using apps.
for example: on my system after boot, there are around 300 processes, with
only 17 using FPU.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Split the FPU save area from the task struct. This allows easy migration
of FPU context, and it's generally cleaner. It also allows the following
two optimizations:
1) only allocate when the application actually uses FPU, so in the first
lazy FPU trap. This could save memory for non-fpu using apps. Next patch
does this lazy allocation.
2) allocate the right size for the actual cpu rather than 512 bytes always.
Patches enabling xsave/xrstor support (coming shortly) will take advantage
of this.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
convert_fxsr_to_user() in 2.6.24's i387_32.c did this, and
convert_to_fxsr() also does the inverse, so I assume it's an oversight
that it is no longer being done.
[ mingo@elte.hu:
we encode it this way because there's no space for the 'FPU Last
Instruction Opcode' (->fop) field in the legacy user_i387_ia32_struct
that PTRACE_GETFPREGS/PTRACE_SETFPREGS uses.
it's probably pure legacy - i'd be surprised if any user-space relied on
the FPU Last Opcode in any way. But indeed we used to do it previously
so the most conservative thing is to preserve that piece of information.
]
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This bug got introduced by the recent i387 merge:
commit 4421011120
Author: Roland McGrath <roland@redhat.com>
Date: Wed Jan 30 13:31:50 2008 +0100
x86: x86 i387 user_regset
Current usage of unlazy_fpu() in ptrace specific routines is wrong.
unlazy_fpu() will not init fpu if the task never used math. So the
ptrace calls can expose the parent tasks FPU data in some cases.
Replace it with the init_fpu() which will init the math state, if the
task never used math before.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
This removes a bunch of dead code that is no longer needed now
that the user_regset interfaces are being used for all these jobs.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This revamps the i387 code to be shared across 32-bit, 64-bit,
and 32-on-64. It does so by consolidating the code in one place
based on the user_regset accessor interfaces. This switches
32-bit to using the i387_64.h header and 64-bit to using the
i387.c that was previously i387_32.c, but that's what took the
least cleanup in each file. Here i387.h is stubbed to always
include i387_64.h rather than renaming the file, to keep this
diff smaller and easier to read.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This renames arch/x86/kernel/{i387_32.c => i387.c}.
This is a pure renaming, but paves the way for merging
the 32-bit and 64-bit versions of this code.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
clean up checkpatch warnings/errors on i387_32.c
The old and new i387_32.s (asm listings) were checked with diff to
be identical so it's safe to apply this patch.
Signed-off-by: Cyrill Gorcunov <gorunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Since the x86 merge, lots of files that referenced their own filenames
are no longer correct. Rather than keep them up to date, just delete
them, as they add no real value.
Additionally:
- fix up comment formatting in scx200_32.c
- Remove a credit from myself in setup_64.c from a time when we had no SCM
- remove longwinded history from tsc_32.c which can be figured out from
git.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's really just a single instruction, conditional on whether the CPU
supports FXSR or not, so implement it as such instead of making it a
function that queries FXSR dynamically.
This means that the instruction just gets automatically rewritten to the
correct one at boot-time.
* EXPORT_SYMBOL's moved to other files
* #include <linux/config.h>, <linux/module.h> where needed
* #include's in i386_ksyms.c cleaned up
* After copy-paste, redundant due to Makefiles rules preprocessor directives
removed:
#ifdef CONFIG_FOO
EXPORT_SYMBOL(foo);
#endif
obj-$(CONFIG_FOO) += foo.o
* Tiny reformat to fit in 80 columns
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Roland McGrath