linux/include/asm-generic/vmlinux.lds.h, branch v2.6.28

Merge branch 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2008-10-20T20:35:07Z

* 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (131 commits) tracing/fastboot: improve help text tracing/stacktrace: improve help text tracing/fastboot: fix initcalls disposition in bootgraph.pl tracing/fastboot: fix bootgraph.pl initcall name regexp tracing/fastboot: fix issues and improve output of bootgraph.pl tracepoints: synchronize unregister static inline tracepoints: tracepoint_synchronize_unregister() ftrace: make ftrace_test_p6nop disassembler-friendly markers: fix synchronize marker unregister static inline tracing/fastboot: add better resolution to initcall debug/tracing trace: add build-time check to avoid overrunning hex buffer ftrace: fix hex output mode of ftrace tracing/fastboot: fix initcalls disposition in bootgraph.pl tracing/fastboot: fix printk format typo in boot tracer ftrace: return an error when setting a nonexistent tracer ftrace: make some tracers reentrant ring-buffer: make reentrant ring-buffer: move page indexes into page headers tracing/fastboot: only trace non-module initcalls ftrace: move pc counter in irqtrace ... Manually fix conflicts: - init/main.c: initcall tracing - kernel/module.c: verbose level vs tracepoints - scripts/bootgraph.pl: fallout from cherry-picking commits.

driver core: basic infrastructure for per-module dynamic debug messages

2008-10-16T16:24:47Z

Base infrastructure to enable per-module debug messages. I've introduced CONFIG_DYNAMIC_PRINTK_DEBUG, which when enabled centralizes control of debugging statements on a per-module basis in one /proc file, currently, /dynamic_printk/modules. When, CONFIG_DYNAMIC_PRINTK_DEBUG, is not set, debugging statements can still be enabled as before, often by defining 'DEBUG' for the proper compilation unit. Thus, this patch set has no affect when CONFIG_DYNAMIC_PRINTK_DEBUG is not set. The infrastructure currently ties into all pr_debug() and dev_dbg() calls. That is, if CONFIG_DYNAMIC_PRINTK_DEBUG is set, all pr_debug() and dev_dbg() calls can be dynamically enabled/disabled on a per-module basis. Future plans include extending this functionality to subsystems, that define their own debug levels and flags. Usage: Dynamic debugging is controlled by the debugfs file, /dynamic_printk/modules. This file contains a list of the modules that can be enabled. The format of the file is as follows: . . . : Name of the module in which the debug call resides : whether the messages are enabled or not For example: snd_hda_intel enabled=0 fixup enabled=1 driver enabled=0 Enable a module: $echo "set enabled=1 " > dynamic_printk/modules Disable a module: $echo "set enabled=0 " > dynamic_printk/modules Enable all modules: $echo "set enabled=1 all" > dynamic_printk/modules Disable all modules: $echo "set enabled=0 all" > dynamic_printk/modules Finally, passing "dynamic_printk" at the command line enables debugging for all modules. This mode can be turned off via the above disable command. [gkh: minor cleanups and tweaks to make the build work quietly] Signed-off-by: Jason Baron Signed-off-by: Greg Kroah-Hartman

ftrace: create __mcount_loc section

2008-10-14T08:34:40Z

This patch creates a section in the kernel called "__mcount_loc". This will hold a list of pointers to the mcount relocation for each call site of mcount. For example: objdump -dr init/main.o [...] Disassembly of section .text: 0000000000000000 : 0: 55 push %rbp [...] 000000000000017b : 17b: 55 push %rbp 17c: 48 89 e5 mov %rsp,%rbp 17f: 53 push %rbx 180: 48 83 ec 08 sub $0x8,%rsp 184: e8 00 00 00 00 callq 189 185: R_X86_64_PC32 mcount+0xfffffffffffffffc [...] We will add a section to point to each function call. .section __mcount_loc,"a",@progbits [...] .quad .text + 0x185 [...] The offset to of the mcount call site in init_post is an offset from the start of the section, and not the start of the function init_post. The mcount relocation is at the call site 0x185 from the start of the .text section. .text + 0x185 == init_post + 0xa We need a way to add this __mcount_loc section in a way that we do not lose the relocations after final link. The .text section here will be attached to all other .text sections after final link and the offsets will be meaningless. We need to keep track of where these .text sections are. To do this, we use the start of the first function in the section. do_one_initcall. We can make a tmp.s file with this function as a reference to the start of the .text section. .section __mcount_loc,"a",@progbits [...] .quad do_one_initcall + 0x185 [...] Then we can compile the tmp.s into a tmp.o gcc -c tmp.s -o tmp.o And link it into back into main.o. ld -r main.o tmp.o -o tmp_main.o mv tmp_main.o main.o But we have a problem. What happens if the first function in a section is not exported, and is a static function. The linker will not let the tmp.o use it. This case exists in main.o as well. Disassembly of section .init.text: 0000000000000000 : 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: e8 00 00 00 00 callq 9 5: R_X86_64_PC32 mcount+0xfffffffffffffffc The first function in .init.text is a static function. 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices The lowercase 't' means that set_reset_devices is local and is not exported. If we simply try to link the tmp.o with the set_reset_devices we end up with two symbols: one local and one global. .section __mcount_loc,"a",@progbits .quad set_reset_devices + 0x10 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices U set_reset_devices We still have an undefined reference to set_reset_devices, and if we try to compile the kernel, we will end up with an undefined reference to set_reset_devices, or even worst, it could be exported someplace else, and then we will have a reference to the wrong location. To handle this case, we make an intermediate step using objcopy. We convert set_reset_devices into a global exported symbol before linking it with tmp.o and set it back afterwards. 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 T set_reset_devices 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 T set_reset_devices 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices Now we have a section in main.o called __mcount_loc that we can place somewhere in the kernel using vmlinux.ld.S and access it to convert all these locations that call mcount into nops before starting SMP and thus, eliminating the need to do this with kstop_machine. Note, A well documented perl script (scripts/recordmcount.pl) is used to do all this in one location. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar

tracing: Kernel Tracepoints

2008-10-14T08:28:28Z

Implementation of kernel tracepoints. Inspired from the Linux Kernel Markers. Allows complete typing verification by declaring both tracing statement inline functions and probe registration/unregistration static inline functions within the same macro "DEFINE_TRACE". No format string is required. See the tracepoint Documentation and Samples patches for usage examples. Taken from the documentation patch : "A tracepoint placed in code provides a hook to call a function (probe) that you can provide at runtime. A tracepoint can be "on" (a probe is connected to it) or "off" (no probe is attached). When a tracepoint is "off" it has no effect, except for adding a tiny time penalty (checking a condition for a branch) and space penalty (adding a few bytes for the function call at the end of the instrumented function and adds a data structure in a separate section). When a tracepoint is "on", the function you provide is called each time the tracepoint is executed, in the execution context of the caller. When the function provided ends its execution, it returns to the caller (continuing from the tracepoint site). You can put tracepoints at important locations in the code. They are lightweight hooks that can pass an arbitrary number of parameters, which prototypes are described in a tracepoint declaration placed in a header file." Addition and removal of tracepoints is synchronized by RCU using the scheduler (and preempt_disable) as guarantees to find a quiescent state (this is really RCU "classic"). The update side uses rcu_barrier_sched() with call_rcu_sched() and the read/execute side uses "preempt_disable()/preempt_enable()". We make sure the previous array containing probes, which has been scheduled for deletion by the rcu callback, is indeed freed before we proceed to the next update. It therefore limits the rate of modification of a single tracepoint to one update per RCU period. The objective here is to permit fast batch add/removal of probes on _different_ tracepoints. Changelog : - Use #name ":" #proto as string to identify the tracepoint in the tracepoint table. This will make sure not type mismatch happens due to connexion of a probe with the wrong type to a tracepoint declared with the same name in a different header. - Add tracepoint_entry_free_old. - Change __TO_TRACE to get rid of the 'i' iterator. Masami Hiramatsu : Tested on x86-64. Performance impact of a tracepoint : same as markers, except that it adds about 70 bytes of instructions in an unlikely branch of each instrumented function (the for loop, the stack setup and the function call). It currently adds a memory read, a test and a conditional branch at the instrumentation site (in the hot path). Immediate values will eventually change this into a load immediate, test and branch, which removes the memory read which will make the i-cache impact smaller (changing the memory read for a load immediate removes 3-4 bytes per site on x86_32 (depending on mov prefixes), or 7-8 bytes on x86_64, it also saves the d-cache hit). About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. Quoting Hideo Aoki about Markers : I evaluated overhead of kernel marker using linux-2.6-sched-fixes git tree, which includes several markers for LTTng, using an ia64 server. While the immediate trace mark feature isn't implemented on ia64, there is no major performance regression. So, I think that we don't have any issues to propose merging marker point patches into Linus's tree from the viewpoint of performance impact. I prepared two kernels to evaluate. The first one was compiled without CONFIG_MARKERS. The second one was enabled CONFIG_MARKERS. I downloaded the original hackbench from the following URL: http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c I ran hackbench 5 times in each condition and calculated the average and difference between the kernels. The parameter of hackbench: every 50 from 50 to 800 The number of CPUs of the server: 2, 4, and 8 Below is the results. As you can see, major performance regression wasn't found in any case. Even if number of processes increases, differences between marker-enabled kernel and marker- disabled kernel doesn't increase. Moreover, if number of CPUs increases, the differences doesn't increase either. Curiously, marker-enabled kernel is better than marker-disabled kernel in more than half cases, although I guess it comes from the difference of memory access pattern. * 2 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 4.811 | 4.872 | +0.061 | +1.27 | 100 | 9.854 | 10.309 | +0.454 | +4.61 | 150 | 15.602 | 15.040 | -0.562 | -3.6 | 200 | 20.489 | 20.380 | -0.109 | -0.53 | 250 | 25.798 | 25.652 | -0.146 | -0.56 | 300 | 31.260 | 30.797 | -0.463 | -1.48 | 350 | 36.121 | 35.770 | -0.351 | -0.97 | 400 | 42.288 | 42.102 | -0.186 | -0.44 | 450 | 47.778 | 47.253 | -0.526 | -1.1 | 500 | 51.953 | 52.278 | +0.325 | +0.63 | 550 | 58.401 | 57.700 | -0.701 | -1.2 | 600 | 63.334 | 63.222 | -0.112 | -0.18 | 650 | 68.816 | 68.511 | -0.306 | -0.44 | 700 | 74.667 | 74.088 | -0.579 | -0.78 | 750 | 78.612 | 79.582 | +0.970 | +1.23 | 800 | 85.431 | 85.263 | -0.168 | -0.2 | -------------------------------------------------------------- * 4 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.586 | 2.584 | -0.003 | -0.1 | 100 | 5.254 | 5.283 | +0.030 | +0.56 | 150 | 8.012 | 8.074 | +0.061 | +0.76 | 200 | 11.172 | 11.000 | -0.172 | -1.54 | 250 | 13.917 | 14.036 | +0.119 | +0.86 | 300 | 16.905 | 16.543 | -0.362 | -2.14 | 350 | 19.901 | 20.036 | +0.135 | +0.68 | 400 | 22.908 | 23.094 | +0.186 | +0.81 | 450 | 26.273 | 26.101 | -0.172 | -0.66 | 500 | 29.554 | 29.092 | -0.461 | -1.56 | 550 | 32.377 | 32.274 | -0.103 | -0.32 | 600 | 35.855 | 35.322 | -0.533 | -1.49 | 650 | 39.192 | 38.388 | -0.804 | -2.05 | 700 | 41.744 | 41.719 | -0.025 | -0.06 | 750 | 45.016 | 44.496 | -0.520 | -1.16 | 800 | 48.212 | 47.603 | -0.609 | -1.26 | -------------------------------------------------------------- * 8 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.094 | 2.072 | -0.022 | -1.07 | 100 | 4.162 | 4.273 | +0.111 | +2.66 | 150 | 6.485 | 6.540 | +0.055 | +0.84 | 200 | 8.556 | 8.478 | -0.078 | -0.91 | 250 | 10.458 | 10.258 | -0.200 | -1.91 | 300 | 12.425 | 12.750 | +0.325 | +2.62 | 350 | 14.807 | 14.839 | +0.032 | +0.22 | 400 | 16.801 | 16.959 | +0.158 | +0.94 | 450 | 19.478 | 19.009 | -0.470 | -2.41 | 500 | 21.296 | 21.504 | +0.208 | +0.98 | 550 | 23.842 | 23.979 | +0.137 | +0.57 | 600 | 26.309 | 26.111 | -0.198 | -0.75 | 650 | 28.705 | 28.446 | -0.259 | -0.9 | 700 | 31.233 | 31.394 | +0.161 | +0.52 | 750 | 34.064 | 33.720 | -0.344 | -1.01 | 800 | 36.320 | 36.114 | -0.206 | -0.57 | -------------------------------------------------------------- Signed-off-by: Mathieu Desnoyers Acked-by: Masami Hiramatsu Acked-by: 'Peter Zijlstra' Signed-off-by: Ingo Molnar

Merge commit '63cc8c75156462d4b42cbdd76c293b7eee7ddbfe':

2008-09-05T07:24:30Z

"percpu: introduce DEFINE_PER_CPU_PAGE_ALIGNED() macro" into x86/core Conflicts: arch/x86/kernel/cpu/common.c Signed-off-by: Ingo Molnar

Missing symbol prefix on vmlinux.lds.h

2008-08-01T19:46:41Z

ARCH=h8300: init/main.c:781: undefined reference to `___early_initcall_end' Same problem have __start___bug_table __stop___bug_table __tracedata_start __tracedata_end __per_cpu_start __per_cpu_end When defining a symbol in vmlinux.lds, use the VMLINUX_SYMBOL macro. VMLINUX_SYMBOL adds a prefix charactor. You can't just use straight symbol names in common header files as they dont take into consideration weird arch-specific ABI conventions. in the case of Blackfin/h8300, the ABI dictates that any C-visible symbols have an underscore prefixed to them. Thus all symbols in vmlinux.lds.h need to be wrapped in VMLINUX_SYMBOL() so that each arch can put hide this magic in their own files. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Yoshinori Sato Cc: Jeremy Fitzhardinge Cc: "Mike Frysinger" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next

2008-07-27T16:59:59Z

* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next: (25 commits) setlocalversion: do not describe if there is nothing to describe kconfig: fix typos: "Suport" -> "Support" kconfig: make defconfig is no longer chatty kconfig: make oldconfig is now less chatty kconfig: speed up all*config + randconfig kconfig: set all new symbols automatically kconfig: add diffconfig utility kbuild: remove Module.markers during mrproper kbuild: sparse needs CF not CHECKFLAGS kernel-doc: handle/strip __init vmlinux.lds: move __attribute__((__cold__)) functions back into final .text section init: fix URL of "The GNU Accounting Utilities" kbuild: add arch/$ARCH/include to search path kbuild: asm symlink support for arch/$ARCH/include kbuild: support arch/$ARCH/include for tags, cscope kbuild: prepare headers_* for arch/$ARCH/include kbuild: install all headers when arch is changed kbuild: make clean removes *.o.* as well kbuild: optimize headers_* targets kbuild: only one call for include/ in make headers_* ...

Better interface for hooking early initcalls

2008-07-26T19:00:04Z

Added early initcall (pre-SMP) support, using an identical interface to that of regular initcalls. Functions called from do_pre_smp_initcalls() could be converted to use this cleaner interface. This is required by CPU hotplug, because early users have to register notifiers before going SMP. One such CPU hotplug user is the relay interface with buffer-only channels, which needs to register such a notifier, to be usable in early code. This in turn is used by kmemtrace. Signed-off-by: Eduard - Gabriel Munteanu Cc: Tom Zanussi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

vmlinux.lds: move attribute((cold)) functions back into final .text section

2008-07-25T20:12:37Z

Due to the addition of __attribute__((__cold__)) to a few symbols without adjusting the linker scripts, those symbols currently may end up outside the [_stext,_etext) range, as they get placed in .text.unlikely by (at least) gcc 4.3.0. This may confuse code not only outside of the kernel, symbol_put_addr()'s BUG() could also trigger. Hence we need to add .text.unlikely (and for future uses of __attribute__((__hot__)) also .text.hot) to the TEXT_TEXT() macro. Issue observed by Lukas Lipavsky. Signed-off-by: Jan Beulich Tested-by: Lukas Lipavsky Cc: Signed-off-by: Sam Ravnborg

Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6

2008-07-17T00:25:46Z

* 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6: (72 commits) Revert "x86/PCI: ACPI based PCI gap calculation" PCI: remove unnecessary volatile in PCIe hotplug struct controller x86/PCI: ACPI based PCI gap calculation PCI: include linux/pm_wakeup.h for device_set_wakeup_capable PCI PM: Fix pci_prepare_to_sleep x86/PCI: Fix PCI config space for domains > 0 Fix acpi_pm_device_sleep_wake() by providing a stub for CONFIG_PM_SLEEP=n PCI: Simplify PCI device PM code PCI PM: Introduce pci_prepare_to_sleep and pci_back_from_sleep PCI ACPI: Rework PCI handling of wake-up ACPI: Introduce new device wakeup flag 'prepared' ACPI: Introduce acpi_device_sleep_wake function PCI: rework pci_set_power_state function to call platform first PCI: Introduce platform_pci_power_manageable function ACPI: Introduce acpi_bus_power_manageable function PCI: make pci_name use dev_name PCI: handle pci_name() being const PCI: add stub for pci_set_consistent_dma_mask() PCI: remove unused arch pcibios_update_resource() functions PCI: fix pci_setup_device()'s sprinting into a const buffer ... Fixed up conflicts in various files (arch/x86/kernel/setup_64.c, arch/x86/pci/irq.c, arch/x86/pci/pci.h, drivers/acpi/sleep/main.c, drivers/pci/pci.c, drivers/pci/pci.h, include/acpi/acpi_bus.h) from x86 and ACPI updates manually.