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* of: Improve prom_update_property() functionDong Aisheng2012-07-11
| | | | | | | | | | | prom_update_property() currently fails if the property doesn't actually exist yet which isn't what we want. Change to add-or-update instead of update-only, then we can remove a lot duplicated lines. Suggested-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org> Acked-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/pseries: Add pseries update notifier for OFDT prop changesKent Yoder2012-05-13
| | | | | | | | | | | This adds an update notifier mechanism for changes to properties in the device tree. One use of this would be a device driver that needs to act on changes to it's properties in the device tree after a live migration or a dynamic activation that is triggered by updates to ofdt properties. Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com> Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/pseries: Improve error code on reconfiguration notifier failureAkinobu Mita2011-06-29
| | | | | | | | | | | | | | | Reconfiguration notifier call for device node may fail by several reasons, but it always assumes kmalloc failures. This enables reconfiguration notifier call chain to get the actual error code rather than -ENOMEM by converting all reconfiguration notifier calls to return encapsulate error code with notifier_from_errno(). Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/pseries: Introduce pSeries_reconfig_notify()Akinobu Mita2011-06-29
| | | | | | | | | | | | | | This introduces pSeries_reconfig_notify() as a just wrapper of blocking_notifier_call_chain() for pSeries_reconfig_chain. This is a preparation to improvement of error code on reconfiguration notifier failure. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* llseek: automatically add .llseek fopArnd Bergmann2010-10-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
* powerpc/pseries: Use kstrdupJulia Lawall2010-07-08
| | | | | | | | | | | | | | | | | | | | | | | | | | Use kstrdup when the goal of an allocation is copy a string into the allocated region. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression from,to; expression flag,E1,E2; statement S; @@ - to = kmalloc(strlen(from) + 1,flag); + to = kstrdup(from, flag); ... when != \(from = E1 \| to = E1 \) if (to==NULL || ...) S ... when != \(from = E2 \| to = E2 \) - strcpy(to, from); // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo2010-03-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* powerpc/pseries: Kernel DLPAR InfrastructureNathan Fontenot2009-12-09
| | | | | | | | | | | | | | | | | | | | | | The Dynamic Logical Partitioning capabilities of the powerpc pseries platform allows for the addition and removal of resources (i.e. CPU's, memory, and PCI devices) from a partition. The removal of a resource involves removing the resource's node from the device tree and then returning the resource to firmware via the rtas set-indicator call. To add a resource, it is first obtained from firmware via the rtas set-indicator call and then a new device tree node is created using the ibm,configure-coinnector rtas call and added to the device tree. This patch provides the kernel DLPAR infrastructure in a new filed named dlpar.c. The functionality provided is for acquiring and releasing a resource from firmware and the parsing of information returned from the ibm,configure-connector rtas call. Additionally this exports the pSeries reconfiguration notifier chain so that it can be invoked when device tree updates are made. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Move /proc/ppc64 to /proc/powerpc and add symlinkBenjamin Herrenschmidt2009-10-30
| | | | | | | | Some of the stuff in /proc/ppc64 such as the RTAS bits are actually useful to some 32-bit platforms. Rename the file, and create a symlink on 64-bit for backward compatibility Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/pseries: Fix to handle slb resize across migrationBrian King2009-09-02
| | | | | | | | | | | | | | | | | | | The SLB can change sizes across a live migration, which was not being handled, resulting in possible machine crashes during migration if migrating to a machine which has a smaller max SLB size than the source machine. Fix this by first reducing the SLB size to the minimum possible value, which is 32, prior to migration. Then during the device tree update which occurs after migration, we make the call to ensure the SLB gets updated. Also add the slb_size to the lparcfg output so that the migration tools can check to make sure the kernel has this capability before allowing migration in scenarios where the SLB size will change. BenH: Fixed #include <asm/mmu-hash64.h> -> <asm/mmu.h> to avoid breaking ppc32 build Signed-off-by: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc/pseries: Failed reconfig notifier chain call cleanupNathan Fontenot2009-03-23
| | | | | | | | | | | The return code from invoking the notifier chain when updating the ibm,dynamic-memory property is not handled properly. In failure cases (rc == NOTIFY_BAD) we should be restoring the original value of the property. In success (rc == NOTIFY_OK) we should be returning zero from the calling routine. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* powerpc: Check rc of notifier chain for memory removeNathan Fontenot2008-09-15
| | | | | | | | | | | | | | | The return code from invocation of the notifier for pSeries_reconfig_chain during update of the device tree is not checked. This causes writes to /proc/ppc64/ofdt to update memory properties (i.e. ibm,dyamic-reconfiguration-memory) to always return success, instead of the result of the notifier chain. This happens specifically when we remove/add memory from the device tree on machines using memory specified in the ibm,dynamic-reconfiguration-memory property of the device tree. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc/pseries: Update the device tree correctly for drconf memory add/removeNathan Fontenot2008-07-03
| | | | | | | | | | | | | | | | | | | | | This updates the device tree manipulation routines so that memory add/remove of lmbs represented under the ibm,dynamic-reconfiguration-memory node of the device tree invokes the hotplug notifier chain. This change is needed because of the change in the way memory is represented under the ibm,dynamic-reconfiguration-memory node. All lmbs are described in the ibm,dynamic-memory property instead of having a separate node for each lmb as in previous device tree layouts. This requires the update_node() routine to check for updates to the ibm,dynamic-memory property and invoke the hotplug notifier chain. This also updates the pseries hotplug notifier to be able to gather information for lmbs represented under the ibm,dynamic-reconfiguration-memory node and have the lmbs added/removed. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc/pseries: Allow phandle to be specified in formats other than decimalNathan Fontenot2008-07-03
| | | | | | | | | | | | | | | Allow the phandle passed to the /proc/ppc64/ofdt file to be specified in formats other than decimal. This allows us to easily specify phandle values in hex that would otherwise appear as negative integers. This is an issue on systems where the value of /proc/device-tree/ibm,dynamic-reconfiguration-memory.ibm,phandle is fffffff9. Having to pass this to the ofdt file as a string results in a large negative number, and simple_strtoul() does not handle negative numbers. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* powerpc: use non-racy method for proc entries creationDenis V. Lunev2008-04-29
| | | | | | | | | | | | | | | Use proc_create()/proc_create_data() to make sure that ->proc_fops and ->data be setup before gluing PDE to main tree. Add correct ->owner to proc_fops to fix reading/module unloading race. Signed-off-by: Denis V. Lunev <den@openvz.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [POWERPC] Replace remaining __FUNCTION__ occurrencesHarvey Harrison2008-04-01
| | | | | | | | | __FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [POWERPC] arch/powerpc/platforms/pseries: Add missing of_node_putJulia Lawall2008-02-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Of_get_parent and of_find_compatible_node do an of_node_get, and thus a corresponding of_code_put is needed in the error case. The problem was found using the following semantic match. (http://www.emn.fr/x-info/coccinelle/) // <smpl> @@ type T,T1,T2; identifier E; statement S; expression x1,x2,x3; int ret; @@ T E; ... * E = \(of_get_parent\|of_find_compatible_node\)(...); if (E == NULL) S ... when != of_node_put(...,(T1)E,...) when != if (E != NULL) { ... of_node_put(...,(T1)E,...); ...} when != x1 = (T1)E when != E = x3; when any if (...) { ... when != of_node_put(...,(T2)E,...) when != if (E != NULL) { ... of_node_put(...,(T2)E,...); ...} when != x2 = (T2)E ( * return; | * return ret; ) } // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Kumar Gala <galak@gate.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [POWERPC] Generalise device_node flag interfaceMichael Ellerman2007-07-10
| | | | | | | | | The struct device_node currently has a _flags variable, although it's only used for one flag - OF_DYNAMIC. Generalise the flag accessors so we can use them with other flags in future. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] mark struct file_operations const 2Arjan van de Ven2007-02-12
| | | | | | | | | | | | Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. [akpm@osdl.org: sparc64 fix] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] proc: remove useless (and buggy) ->nlink settingsAlexey Dobriyan2007-02-11
| | | | | | | | | | | | | | | | | | | | | Bug: pnx8550 code creates directory but resets ->nlink to 1. create_proc_entry() et al will correctly set ->nlink for you. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Corey Minyard <minyard@acm.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Greg KH <greg@kroah.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [POWERPC] Replace kmalloc+memset with kzallocYan Burman2006-12-04
| | | | | | | Replace kmalloc+memset with kzalloc. Signed-off-by: Yan Burman <burman.yan@gmail.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* Merge ../linux-2.6Paul Mackerras2006-03-28
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| * [PATCH] Notifier chain update: API changesAlan Stern2006-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel's implementation of notifier chains is unsafe. There is no protection against entries being added to or removed from a chain while the chain is in use. The issues were discussed in this thread: http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2 We noticed that notifier chains in the kernel fall into two basic usage classes: "Blocking" chains are always called from a process context and the callout routines are allowed to sleep; "Atomic" chains can be called from an atomic context and the callout routines are not allowed to sleep. We decided to codify this distinction and make it part of the API. Therefore this set of patches introduces three new, parallel APIs: one for blocking notifiers, one for atomic notifiers, and one for "raw" notifiers (which is really just the old API under a new name). New kinds of data structures are used for the heads of the chains, and new routines are defined for registration, unregistration, and calling a chain. The three APIs are explained in include/linux/notifier.h and their implementation is in kernel/sys.c. With atomic and blocking chains, the implementation guarantees that the chain links will not be corrupted and that chain callers will not get messed up by entries being added or removed. For raw chains the implementation provides no guarantees at all; users of this API must provide their own protections. (The idea was that situations may come up where the assumptions of the atomic and blocking APIs are not appropriate, so it should be possible for users to handle these things in their own way.) There are some limitations, which should not be too hard to live with. For atomic/blocking chains, registration and unregistration must always be done in a process context since the chain is protected by a mutex/rwsem. Also, a callout routine for a non-raw chain must not try to register or unregister entries on its own chain. (This did happen in a couple of places and the code had to be changed to avoid it.) Since atomic chains may be called from within an NMI handler, they cannot use spinlocks for synchronization. Instead we use RCU. The overhead falls almost entirely in the unregister routine, which is okay since unregistration is much less frequent that calling a chain. Here is the list of chains that we adjusted and their classifications. None of them use the raw API, so for the moment it is only a placeholder. ATOMIC CHAINS ------------- arch/i386/kernel/traps.c: i386die_chain arch/ia64/kernel/traps.c: ia64die_chain arch/powerpc/kernel/traps.c: powerpc_die_chain arch/sparc64/kernel/traps.c: sparc64die_chain arch/x86_64/kernel/traps.c: die_chain drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list kernel/panic.c: panic_notifier_list kernel/profile.c: task_free_notifier net/bluetooth/hci_core.c: hci_notifier net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain net/ipv6/addrconf.c: inet6addr_chain net/netfilter/nf_conntrack_core.c: nf_conntrack_chain net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain net/netlink/af_netlink.c: netlink_chain BLOCKING CHAINS --------------- arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain arch/s390/kernel/process.c: idle_chain arch/x86_64/kernel/process.c idle_notifier drivers/base/memory.c: memory_chain drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list drivers/macintosh/adb.c: adb_client_list drivers/macintosh/via-pmu.c sleep_notifier_list drivers/macintosh/via-pmu68k.c sleep_notifier_list drivers/macintosh/windfarm_core.c wf_client_list drivers/usb/core/notify.c usb_notifier_list drivers/video/fbmem.c fb_notifier_list kernel/cpu.c cpu_chain kernel/module.c module_notify_list kernel/profile.c munmap_notifier kernel/profile.c task_exit_notifier kernel/sys.c reboot_notifier_list net/core/dev.c netdev_chain net/decnet/dn_dev.c: dnaddr_chain net/ipv4/devinet.c: inetaddr_chain It's possible that some of these classifications are wrong. If they are, please let us know or submit a patch to fix them. Note that any chain that gets called very frequently should be atomic, because the rwsem read-locking used for blocking chains is very likely to incur cache misses on SMP systems. (However, if the chain's callout routines may sleep then the chain cannot be atomic.) The patch set was written by Alan Stern and Chandra Seetharaman, incorporating material written by Keith Owens and suggestions from Paul McKenney and Andrew Morton. [jes@sgi.com: restructure the notifier chain initialization macros] Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] powerpc: Kill _machine and hard-coded platform numbersBenjamin Herrenschmidt2006-03-28
|/ | | | | | | | | | | | | | | | This removes statically assigned platform numbers and reworks the powerpc platform probe code to use a better mechanism. With this, board support files can simply declare a new machine type with a macro, and implement a probe() function that uses the flattened device-tree to detect if they apply for a given machine. We now have a machine_is() macro that replaces the comparisons of _machine with the various PLATFORM_* constants. This commit also changes various drivers to use the new macro instead of looking at _machine. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] powerpc: Add support for changing properties from userspaceDave C Boutcher2006-01-13
| | | | | | | | | Add support to reconfigure the device tree through the existing proc filesystem interface. Add "add_property", "remove_property", and "update_property" commands to the existing interface. Signed-off-by: Dave Boutcher <sleddog@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] powerpc: merge code values for identifying platformsPaul Mackerras2005-11-09
| | | | | | | | | | | | This patch merges platform codes. systemcfg->platform is no longer used, systemcfg use in general is deprecated as much as possible (and renamed _systemcfg before it gets completely moved elsewhere in a future patch), _machine is now used on ppc64 along as ppc32. Platform codes aren't gone yet but we are getting a step closer. A bunch of asm code in head[_64].S is also turned into C code. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] kfree cleanup: archJesper Juhl2005-11-07
| | | | | | | | | | | This is the arch/ part of the big kfree cleanup patch. Remove pointless checks for NULL prior to calling kfree() in arch/. Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Acked-by: Grant Grundler <grundler@parisc-linux.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* powerpc: move pSeries files to arch/powerpc/platforms/pseriesPaul Mackerras2005-10-10
Signed-off-by: Paul Mackerras <paulus@samba.org>