Commit Graph

14 Commits

Author SHA1 Message Date
Andi Kleen 19d36ccdc3 x86: Fix alternatives and kprobes to remap write-protected kernel text
Reenable kprobes and alternative patching when the kernel text is write
protected by DEBUG_RODATA

Add a general utility function to change write protected text.  The new
function remaps the code using vmap to write it and takes care of CPU
synchronization.  It also does CLFLUSH to make icache recovery faster.

There are some limitations on when the function can be used, see the
comment.

This is a newer version that also changes the paravirt_ops code.
text_poke also supports multi byte patching now.

Contains bug fixes from Zach Amsden and suggestions from Mathieu
Desnoyers.

Cc: Jan Beulich <jbeulich@novell.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Zach Amsden <zach@vmware.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-22 11:03:37 -07:00
Joerg Roedel 6041b57c6c i386: work around miscompilation of alternatives code
A recent change makes my Dell 1501 hang on boot.  It's an AMD MK-36.  I use
an x86_64 kernel.  It is 100% reproducible.

I debugged this problem a bit and my compiler[1]interprets the =A constraint
as %rax instead of %edx:%eax on x86_64 which causes the problem.  The appended
patch provides a workaround for this and fixed the hang on my machine.

[1] gcc version 4.1.3 20070429 (prerelease) (Debian 4.1.2-5)

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Benny Halevy <bhalevy@panasas.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: "Joerg Roedel" <joerg.roedel@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 08:29:32 -07:00
Andi Kleen e859dc553c [PATCH] i386: Implement alternative_io for i386
Ported from x86-64.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:20 +02:00
Jeremy Fitzhardinge 441d40dca0 [PATCH] x86: PARAVIRT: Jeremy Fitzhardinge <jeremy@goop.org>
The other symbols used to delineate the alt-instructions sections have the
form __foo/__foo_end.  Rename parainstructions to match.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:16 +02:00
Jeremy Fitzhardinge 98de032b68 [PATCH] i386: PARAVIRT: rename struct paravirt_patch to paravirt_patch_site for clarity
Rename struct paravirt_patch to paravirt_patch_site, so that it
clearly refers to a callsite, and not the patch which may be applied
to that callsite.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
2007-05-02 19:27:14 +02:00
Jeremy Fitzhardinge d0175ab644 [PATCH] i386: Remove smp_alt_instructions
The .smp_altinstructions section and its corresponding symbols are
completely unused, so remove them.

Also, remove stray #ifdef __KENREL__ in asm-i386/alternative.h

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
2007-05-02 19:27:13 +02:00
Jeremy Fitzhardinge 1353ebb4b4 [PATCH] i386: Clean up asm-i386/bugs.h
Most of asm-i386/bugs.h is code which should be in a C file, so put it there.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-02 19:27:12 +02:00
Rusty Russell 139ec7c416 [PATCH] paravirt: Patch inline replacements for paravirt intercepts
It turns out that the most called ops, by several orders of magnitude,
are the interrupt manipulation ops.  These are obvious candidates for
patching, so mark them up and create infrastructure for it.

The method used is that the ops structure has a patch function, which
is called for each place which needs to be patched: this returns a
number of instructions (the rest are NOP-padded).

Usually we can spare a register (%eax) for the binary patched code to
use, but in a couple of critical places in entry.S we can't: we make
the clobbers explicit at the call site, and manually clobber the
allowed registers in debug mode as an extra check.

And:

Don't abuse CONFIG_DEBUG_KERNEL, add CONFIG_DEBUG_PARAVIRT.

And:

AK:  Fix warnings in x86-64 alternative.c build

And:

AK: Fix compilation with defconfig

And:

^From: Andrew Morton <akpm@osdl.org>

Some binutlises still like to emit references to __stop_parainstructions and
__start_parainstructions.

And:

AK: Fix warnings about unused variables when PARAVIRT is disabled.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
2006-12-07 02:14:08 +01:00
Andi Kleen 8c74932779 [PATCH] i386: Remove alternative_smp
The .fill causes miscompilations with some binutils version.

Instead just patch the lock prefix in the lock constructs. That is the
majority of the cost and should be good enough.

Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-08-30 16:05:15 -07:00
Jan Beulich 61171b8dbd [PATCH] x86: fix x86 cpuid keys used in alternative_smp()
By hard-coding the cpuid keys for alternative_smp() rather than using
the symbolic constant it turned out that incorrect values were used on
both i386 (0x68 instead of 0x69) and x86-64 (0x66 instead of 0x68).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-08-30 16:05:15 -07:00
Gerd Hoffmann 8ec4d41f88 [PATCH] SMP alternatives: skip with UP kernels
Hide the magic in alternative.h and provide some dummy inline functions
for the UP case (gcc should manage to optimize away these calls).  No
changes in module.c.

Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-01 09:56:02 -07:00
Gerd Hoffmann d167a51877 [PATCH] x86_64: x86_64 version of the smp alternative patch.
Changes are largely identical to the i386 version:

 * alternative #define are moved to the new alternative.h file.
 * one new elf section with pointers to the lock prefixes which can be
   nop'ed out for non-smp.
 * two new elf sections simliar to the "classic" alternatives to
   replace SMP code with simpler UP code.
 * fixup headers to use alternative.h instead of defining their own
   LOCK / LOCK_PREFIX macros.

The patch reuses the i386 version of the alternatives code to avoid code
duplication.  The code in alternatives.c was shuffled around a bit to
reduce the number of #ifdefs needed.  It also got some tweaks needed for
x86_64 (vsyscall page handling) and new features (noreplacement option
which was x86_64 only up to now).  Debug printk's are changed from
compile-time to runtime.

Loosely based on a early version from Bastian Blank <waldi@debian.org>

Signed-off-by: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 10:48:14 -07:00
Kirill Smelkov 30343d6c3d [PATCH] x86: compile fix for asm-i386/alternatives.h
compile fix:  <asm-i386/alternative.h>  needs  <asm/types.h> for 'u8' --
just look at struct alt_instr.

My module includes <asm/bitops.h> as the first header, and as of 2.6.17 this
leads to compilation errors.

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:59 -07:00
Gerd Hoffmann 9a0b5817ad [PATCH] x86: SMP alternatives
Implement SMP alternatives, i.e.  switching at runtime between different
code versions for UP and SMP.  The code can patch both SMP->UP and UP->SMP.
The UP->SMP case is useful for CPU hotplug.

With CONFIG_CPU_HOTPLUG enabled the code switches to UP at boot time and
when the number of CPUs goes down to 1, and switches to SMP when the number
of CPUs goes up to 2.

Without CONFIG_CPU_HOTPLUG or on non-SMP-capable systems the code is
patched once at boot time (if needed) and the tables are released
afterwards.

The changes in detail:

  * The current alternatives bits are moved to a separate file,
    the SMP alternatives code is added there.

  * The patch adds some new elf sections to the kernel:
    .smp_altinstructions
	like .altinstructions, also contains a list
	of alt_instr structs.
    .smp_altinstr_replacement
	like .altinstr_replacement, but also has some space to
	save original instruction before replaving it.
    .smp_locks
	list of pointers to lock prefixes which can be nop'ed
	out on UP.
    The first two are used to replace more complex instruction
    sequences such as spinlocks and semaphores.  It would be possible
    to deal with the lock prefixes with that as well, but by handling
    them as special case the table sizes become much smaller.

 * The sections are page-aligned and padded up to page size, so they
   can be free if they are not needed.

 * Splitted the code to release init pages to a separate function and
   use it to release the elf sections if they are unused.

Signed-off-by: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 07:38:04 -08:00