This consolidates the four different places that implemented the same
encoding magic for the GDT-slot 32-bit TLS support. The old tls32.c was
renamed and is now only slightly modified to be the shared implementation.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The fs_base and gs_base fields are available in user_regs_struct.
But reading these via ptrace (PTRACE_GETREGS or PTRACE_PEEKUSR) does
not give a reliably useful value. The thread_struct fields are 0
when do_arch_prctl decided to use a GDT slot instead of MSR_FS_BASE,
which it does for a value under 1<<32.
This changes ptrace access to fs_base and gs_base to work like
PTRACE_ARCH_PRCTL does. That is, it reads the base address that
user-mode memory access using the fs/gs instruction prefixes will
use, regardless of how it's being implemented in the kernel. The
MSR vs GDT is an implementation detail that is pretty much hidden
from userland in the actual using, and there is no reason that
ptrace should give the internal implementation picture rather than
the user-mode semantic picture. In the case of setting the value,
this can implicitly change the fsindex/gsindex value (also
separately in user_regs_struct), which is what happens when the
thread calls arch_prctl itself. In a PTRACE_SETREGS, the fs_base
change will come after the fsindex change due to the order of the
struct, and so a change the debugger made to fs_base will have the
effect intended, another part of the user_regs_struct will now
differ when read back from what the debugger wrote.
This makes PTRACE_ARCH_PRCTL obsolete. We could consider declaring
it deprecated and removing it one day, though there is no hurry.
For the foreseeable future, debuggers have to assume an old kernel
that does not report reliable fs_base/gs_base values in user_regs_struct
and stick to PTRACE_ARCH_PRCTL anyway.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Identical handlers of PTRACE_DETACH go into ptrace_request().
Not touching compat code.
Not touching archs that don't call ptrace_request.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Roland McGrath