user/sven/linux.git/include/asm-generic/sections.h, branch v3.0.42

x86: Separate out entry text section

2011-03-08T16:22:11Z

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 Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Nick Piggin Cc: Eric Dumazet 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

asm/sections: add text/data checking functions for arches to override

2009-09-23T14:39:30Z

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 Cc: Ingo Molnar Cc: Robin Getz Cc: Sam Ravnborg Cc: Peter Zijlstra Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel: constructor support

2009-06-18T20:03:57Z

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 Acked-by: Rusty Russell Acked-by: WANG Cong Cc: Sam Ravnborg Cc: Jeff Dike Cc: Andi Kleen Cc: Huang Ying Cc: Li Wei Cc: Michael Ellerman Cc: Ingo Molnar Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86: make percpu symbols zerobased on SMP

2009-01-16T13:19:14Z

[ 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 Signed-off-by: Ingo Molnar

lib: Correct printk %pF to work on all architectures

2008-09-09T18:51:15Z

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 Acked-by: Benjamin Herrenschmidt Acked-by: Tony Luck Acked-by: Kyle McMartin Signed-off-by: Linus Torvalds

remove support for un-needed _extratext section

2008-02-06T18:41:01Z

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 Cc: David Woodhouse Cc: Jon Loeliger Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Sam Ravnborg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] add __[start|end]_rodata sections to asm-generic/sections.h

2006-07-01T16:56:03Z

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 Cc: Martin Schwidefsky Signed-off-by: Heiko Carstens Cc: Andi Kleen Acked-by: Kyle McMartin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] x86_64: Only use asm/sections.h to declare section symbols

2005-11-15T03:55:14Z

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 Signed-off-by: Linus Torvalds

[PATCH] Kprobes: prevent possible race conditions generic

2005-09-07T23:57:59Z

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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] x86_64: Some cleanup in setup64.c

2005-07-29T04:45:58Z

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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds