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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>
2006-06-23[PATCH] x86: compile fix for asm-i386/alternatives.hKirill Smelkov
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>
2006-03-23[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>