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path: root/arch/i386/kernel/alternative.c
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2007-05-07Revert "[PATCH] x86: __pa and __pa_symbol address space separation"Linus Torvalds
This was broken. It adds complexity, for no good reason. Rather than separate __pa() and __pa_symbol(), we should deprecate __pa_symbol(), and preferably __pa() too - and just use "virt_to_phys()" instead, which is more readable and has nicer semantics. However, right now, just undo the separation, and make __pa_symbol() be the exact same as __pa(). That fixes the bugs this patch introduced, and we can do the fairly obvious cleanups later. Do the new __phys_addr() function (which is now the actual workhorse for the unified __pa()/__pa_symbol()) as a real external function, that way all the potential issues with compile/link-time optimizations of constant symbol addresses go away, and we can also, if we choose to, add more sanity-checking of the argument. Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: Andi Kleen <ak@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-02[PATCH] x86: PARAVIRT: Jeremy Fitzhardinge <jeremy@goop.org>Jeremy Fitzhardinge
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[PATCH] i386: PARAVIRT: Allow boot-time disable of paravirt_ops patchingJeremy Fitzhardinge
Add "noreplace-paravirt" to disable paravirt_ops patching. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-05-02[PATCH] i386: PARAVIRT: add common patching machineryJeremy Fitzhardinge
Implement the actual patching machinery. paravirt_patch_default() contains the logic to automatically patch a callsite based on a few simple rules: - if the paravirt_op function is paravirt_nop, then patch nops - if the paravirt_op function is a jmp target, then jmp to it - if the paravirt_op function is callable and doesn't clobber too much for the callsite, call it directly paravirt_patch_default is suitable as a default implementation of paravirt_ops.patch, will remove most of the expensive indirect calls in favour of either a direct call or a pile of nops. Backends may implement their own patcher, however. There are several helper functions to help with this: paravirt_patch_nop nop out a callsite paravirt_patch_ignore leave the callsite as-is paravirt_patch_call patch a call if the caller and callee have compatible clobbers paravirt_patch_jmp patch in a jmp paravirt_patch_insns patch some literal instructions over the callsite, if they fit This patch also implements more direct patches for the native case, so that when running on native hardware many common operations are implemented inline. 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> Cc: Anthony Liguori <anthony@codemonkey.ws> Acked-by: Ingo Molnar <mingo@elte.hu>
2007-05-02[PATCH] i386: PARAVIRT: rename struct paravirt_patch to paravirt_patch_site ↵Jeremy Fitzhardinge
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[PATCH] i386: PARAVIRT: Remove CONFIG_DEBUG_PARAVIRTJeremy Fitzhardinge
Remove CONFIG_DEBUG_PARAVIRT. When inlining code, this option attempts to trash registers in the patch-site's "clobber" field, on the grounds that this should find bugs with incorrect clobbers. Unfortunately, the clobber field really means "registers modified by this patch site", which includes return values. Because of this, this option has outlived its usefulness, so remove it. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au>
2007-05-02[PATCH] i386: Allow boot-time disable of SMP altinstructionsJeremy Fitzhardinge
Add "noreplace-smp" to disable SMP instruction replacement. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02[PATCH] i386: Remove smp_alt_instructionsJeremy Fitzhardinge
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[PATCH] x86: __pa and __pa_symbol address space separationVivek Goyal
Currently __pa_symbol is for use with symbols in the kernel address map and __pa is for use with pointers into the physical memory map. But the code is implemented so you can usually interchange the two. __pa which is much more common can be implemented much more cheaply if it is it doesn't have to worry about any other kernel address spaces. This is especially true with a relocatable kernel as __pa_symbol needs to peform an extra variable read to resolve the address. There is a third macro that is added for the vsyscall data __pa_vsymbol for finding the physical addesses of vsyscall pages. Most of this patch is simply sorting through the references to __pa or __pa_symbol and using the proper one. A little of it is continuing to use a physical address when we have it instead of recalculating it several times. swapper_pgd is now NULL. leave_mm now uses init_mm.pgd and init_mm.pgd is initialized at boot (instead of compile time) to the physmem virtual mapping of init_level4_pgd. The physical address changed. Except for the for EMPTY_ZERO page all of the remaining references to __pa_symbol appear to be during kernel initialization. So this should reduce the cost of __pa in the common case, even on a relocated kernel. As this is technically a semantic change we need to be on the lookout for anything I missed. But it works for me (tm). Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de>
2007-04-24[PATCH] x86: Remove noreplacement optionAndi Kleen
noreplacement is dangerous on modern systems because it will not replace the context switch FNSAVE with SSE aware FXSAVE. But other places in the kernel still assume SSE and do FXSAVE and the CPU will then access FXSAVE information with FNSAVE and cause corruption. Easiest way to avoid this is to remove the option. It was mostly for paranoia reasons anyways and alternative()s have been stable for some time. Thanks to Jeremy F. for reporting and helping debug it. Signed-off-by: Andi Kleen <ak@suse.de>
2006-12-07[PATCH] paravirt: Patch inline replacements for paravirt interceptsRusty Russell
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>
2006-12-04[PATCH] severing module.h->sched.hAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-10-20[PATCH] Fix potential interrupts during alternative patchingZachary Amsden
Interrupts must be disabled during alternative instruction patching. On systems with high timer IRQ rates, or when running in an emulator, timing differences can result in random kernel panics because of running partially patched instructions. This doesn't yet fix NMIs, which requires extricating the patch code from the late bug checking and is logically separate (and also less likely to cause problems). Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03[PATCH] lockdep: x86 smp alternatives workaroundIngo Molnar
Disable SMP alternatives fixups (the patching in of NOPs on 1-CPU systems) if the lock validator is enabled: there is a binutils section handling bug that causes corrupted instructions when UP instructions are patched in. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-01[PATCH] SMP alternatives: skip with UP kernelsGerd Hoffmann
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>
2006-06-26[PATCH] x86_64: x86_64 version of the smp alternative patch.Gerd Hoffmann
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>
2006-03-23[PATCH] x86: SMP alternativesGerd Hoffmann
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>