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* x86: Separate out entry text sectionJiri Olsa2011-03-081-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Put x86 entry code into a separate link section: .entry.text. Separating the entry text section seems to have performance benefits - caused by more efficient instruction cache usage. Running hackbench with perf stat --repeat showed that the change compresses the icache footprint. The icache load miss rate went down by about 15%: before patch: 19417627 L1-icache-load-misses ( +- 0.147% ) after patch: 16490788 L1-icache-load-misses ( +- 0.180% ) The motivation of the patch was to fix a particular kprobes bug that relates to the entry text section, the performance advantage was discovered accidentally. Whole perf output follows: - results for current tip tree: Performance counter stats for './hackbench/hackbench 10' (500 runs): 19417627 L1-icache-load-misses ( +- 0.147% ) 2676914223 instructions # 0.497 IPC ( +- 0.079% ) 5389516026 cycles ( +- 0.144% ) 0.206267711 seconds time elapsed ( +- 0.138% ) - results for current tip tree with the patch applied: Performance counter stats for './hackbench/hackbench 10' (500 runs): 16490788 L1-icache-load-misses ( +- 0.180% ) 2717734941 instructions # 0.502 IPC ( +- 0.079% ) 5414756975 cycles ( +- 0.148% ) 0.206747566 seconds time elapsed ( +- 0.137% ) Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: masami.hiramatsu.pt@hitachi.com Cc: ananth@in.ibm.com Cc: davem@davemloft.net Cc: 2nddept-manager@sdl.hitachi.co.jp LKML-Reference: <20110307181039.GB15197@jolsa.redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* asm/sections: add text/data checking functions for arches to overrideMike Frysinger2009-09-231-0/+16
| | | | | | | | | | | | | | | | | Some ports (like the Blackfin arch) have a discontiguous memory map which means there may be text or data that falls outside of the standard range of the start/end text/data symbols. Creating some helper functions allows these non-standard ports to declare these regions without adversely affecting anyone else. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Robin Getz <rgetz@blackfin.uclinux.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: constructor supportPeter Oberparleiter2009-06-181-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | Call constructors (gcc-generated initcall-like functions) during kernel start and module load. Constructors are e.g. used for gcov data initialization. Disable constructor support for usermode Linux to prevent conflicts with host glibc. Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Li Wei <W.Li@Sun.COM> Cc: Michael Ellerman <michaele@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com> Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: make percpu symbols zerobased on SMPTejun Heo2009-01-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Based on original patch from Christoph Lameter and Mike Travis. ] This patch makes percpu symbols zerobased on x86_64 SMP by adding PERCPU_VADDR() to vmlinux.lds.h which helps setting explicit vaddr on the percpu output section and using it in vmlinux_64.lds.S. A new PHDR is added as existing ones cannot contain sections near address zero. PERCPU_VADDR() also adds a new symbol __per_cpu_load which always points to the vaddr of the loaded percpu data.init region. The following adjustments have been made to accomodate the address change. * code to locate percpu gdt_page in head_64.S is updated to add the load address to the gdt_page offset. * __per_cpu_load is used in places where access to the init data area is necessary. * pda->data_offset is initialized soon after C code is entered as zero value doesn't work anymore. This patch is mostly taken from Mike Travis' "x86_64: Base percpu variables at zero" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lib: Correct printk %pF to work on all architecturesJames Bottomley2008-09-091-0/+6
| | | | | | | | | | | | | | | | | | | It was introduced by "vsprintf: add support for '%pS' and '%pF' pointer formats" in commit 0fe1ef24f7bd0020f29ffe287dfdb9ead33ca0b2. However, the current way its coded doesn't work on parisc64. For two reasons: 1) parisc isn't in the #ifdef and 2) parisc has a different format for function descriptors Make dereference_function_descriptor() more accommodating by allowing architecture overrides. I put the three overrides (for parisc64, ppc64 and ia64) in arch/kernel/module.c because that's where the kernel internal linker which knows how to deal with function descriptors sits. Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Tony Luck <tony.luck@intel.com> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* remove support for un-needed _extratext sectionRobin Getz2008-02-061-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | When passing a zero address to kallsyms_lookup(), the kernel thought it was a valid kernel address, even if it is not. This is because is_ksym_addr() called is_kernel_extratext() and checked against labels that don't exist on many archs (which default as zero). Since PPC was the only kernel which defines _extra_text, (in 2005), and no longer needs it, this patch removes _extra_text support. For some history (provided by Jon): http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019734.html http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019736.html http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019751.html [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Jon Loeliger <jdl@freescale.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] add __[start|end]_rodata sections to asm-generic/sections.hHeiko Carstens2006-07-011-0/+1
| | | | | | | | | | | | | | Add __start_rodata and __end_rodata to sections.h to avoid extern declarations. Needed by s390 code (see following patch). [akpm@osdl.org: update architectures] Cc: Arjan van de Ven <arjan@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Andi Kleen <ak@muc.de> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86_64: Only use asm/sections.h to declare section symbolsAndi Kleen2005-11-141-0/+1
| | | | | | | | | Adding __initdata_* to asm-generic/sections.h Replaces a lot of open coded externs in arch/x86_64/* I had to change __bss_end to __bss_stop to match the other architectures. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Kprobes: prevent possible race conditions genericPrasanna S Panchamukhi2005-09-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | There are possible race conditions if probes are placed on routines within the kprobes files and routines used by the kprobes. For example if you put probe on get_kprobe() routines, the system can hang while inserting probes on any routine such as do_fork(). Because while inserting probes on do_fork(), register_kprobes() routine grabs the kprobes spin lock and executes get_kprobe() routine and to handle probe of get_kprobe(), kprobes_handler() gets executed and tries to grab kprobes spin lock, and spins forever. This patch avoids such possible race conditions by preventing probes on routines within the kprobes file and routines used by kprobes. I have modified the patches as per Andi Kleen's suggestion to move kprobes routines and other routines used by kprobes to a seperate section .kprobes.text. Also moved page fault and exception handlers, general protection fault to .kprobes.text section. These patches have been tested on i386, x86_64 and ppc64 architectures, also compiled on ia64 and sparc64 architectures. Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86_64: Some cleanup in setup64.cAndi Kleen2005-07-281-0/+1
| | | | | | | | | | | | | | Minor cleanup. Move things into their include files, remove obsolete includes, fix indentation, remove obsolete special cases etc. I also added the per cpu section to asm-generic/sections.h and fixed init/main.c to use it. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] ppc32: platform-specific functions missing from kallsyms.David Woodhouse2005-05-051-0/+2
| | | | | | | | | | | | | | | The PPC32 kernel puts platform-specific functions into separate sections so that unneeded parts of it can be freed when we've booted and actually worked out what we're running on today. This makes kallsyms ignore those functions, because they're not between _[se]text or _[se]inittext. Rather than teaching kallsyms about the various pmac/chrp/etc sections, this patch adds '_[se]extratext' markers for kallsyms. Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2Linus Torvalds2005-04-161-0/+13
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!
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