aboutsummaryrefslogtreecommitdiff
path: root/include
AgeCommit message (Collapse)Author
2008-04-17x86: unify smp_call_function_maskGlauber Costa
definition is moved to common header, x86_64 function name now is native_smp_call_function_mask Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: merge smp_send_rescheduleGlauber Costa
function definition is moved to common header, x86_64 version is now called native_smp_send_reschedule Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: move smp_ops extern declaration to common headerGlauber Costa
the smp_ops symbol is temporarily defined in smp_64.c, but it will soon be unified Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: define smp_ops in common headerGlauber Costa
x86_64 will benefit from it Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: merge extern variables definitionsGlauber Costa
move extern definitions that are the same between smp_{32,64}.h to smp.h Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: merge extern function definitionsGlauber Costa
move extern function definitions that are the same between smp_{32,64}.h to smp.h Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: commonize smp.hGlauber Costa
this is the first step of integrating smp.h between x86_64 and i386 Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: fix switch_to() clobbersIngo Molnar
Liu Pingfan noticed that switch_to() clobbers more registers than its asm constraints specify. We get away with this due to luck mostly - schedule() by its nature only has 'local' state which gets reloaded automatically. Fix it nevertheless, we could hit this anytime. it turns out that with the extra constraints gcc manages to make schedule() even more compact: text data bss dec hex filename 28626 684 2640 31950 7cce sched.o.before 28613 684 2640 31937 7cc1 sched.o.after Reported-by: Liu Pingfan <kernelfans@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: clean up switch_to()Ingo Molnar
Make the code more readable and more hackable: - use symbolic asm parameters - use readable indentation - add comments that explains the details No code changed: kernel/sched.o: text data bss dec hex filename 28626 684 2640 31950 7cce sched.o.before 28626 684 2640 31950 7cce sched.o.after md5: 2823d406c18b781975cdb2e7cfea0059 sched.o.before.asm 2823d406c18b781975cdb2e7cfea0059 sched.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: wmb() confusion in system.hPavel Machek
Comment says wmb is a nop, but it is implemented as lock addl below... Should it be compiled to nop if we know we are running on "good" Intel cpu? At least remove confusing comment for now. Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: debug pmd_bad()Ingo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: redo cded932b75ab0a5f9181eIngo Molnar
redo commit cded932b75ab0a5f9181e. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86, tracing: add notrace to asm-x86/linkage.hIngo Molnar
notrace signals that a function should not be traced. Most of the time this is used by tracers to annotate code that cannot be traced - it's in a volatile state (such as in user vdso context or NMI context) or it's in the tracer internals. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: clean up cpu capabilities accessesIngo Molnar
introduce test_cpu_cap() for raw access to the real CPU capabilities as they are present in x86_capability. (cpu_has() will shortcut certain tests during build-time) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: apic_is_clustered_box for vsmpYinghai Lu
quad core 8 socket system will have apic id lifting.the apic id range could be [4, 0x23]. and apic_is_clustered_box will think that need to three clusters and that is larger than 2. So it is treated as a clustered_box. and will get: Marking TSC unstable due to TSCs unsynchronized even if the CPUs have X86_FEATURE_CONSTANT_TSC set. this quick fix will check if the cpu is from AMD. but vsmp still needs that checking... this patch is fix to make sure that vsmp not to be passed. Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: clean up e820_reserve_resources on 64-bitYinghai Lu
e820_resource_resources could use insert_resource instead of request_resource also move code_resource, data_resource, bss_resource, and crashk_res out of e820_reserve_resources. Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: de-macro start_thread()Ingo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: clean up include/asm-x86/processor.hIngo Molnar
basic style cleanup to flush out years of neglect: - consistent indentation - whitespace fixes - consistent comments Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: define outb_pic and inb_pic to stop using outb_p and inb_pDavid P. Reed
x86: define outb_pic and inb_pic to stop using outb_p and inb_p The delay between io port accesses to the PIC is now defined using outb_pic and inb_pic. This fix provides the next step, using udelay(2) to define the *PIC specific* timing requirements, rather than on bus-oriented timing, which is not well calibrated. Again, the primary reason for fixing this is to use proper delay strategy, and in particular to fix crashes that can result from using port 80 writes on machines that have resources on port 80, such as the ENE chips used by Quanta in latops it designs and sells to, e.g. HP. Signed-off-by: David P. Reed <dpreed@reed.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: call vsmp_init explicitlyGlauber Costa
It becomes to early for ioremap, so we use early_ioremap Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ravikiran Thirumalai <kiran@scalemp.com> Acked-by: Shai Fultheim <shai@scalemp.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17x86: remove never used nodenumer in pdaYinghai Lu
Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17x86: make X86_32 pt_regs members unsigned longHarvey Harrison
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17x86: change most X86_32 pt_regs members to unsigned longHarvey Harrison
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17x86: clean up find_e820_area(), 64-bitYinghai Lu
Change size to unsigned long, becase caller and user all used unsigned long. Also make bad_addr take an alignment parameter. Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17x86: add gbpages switchesIngo Molnar
These new controls toggle experimental support for a new CPU feature, the straightforward extension of largepages from the pmd level to the pud level, which allows 1GB (kernel) TLBs instead of 2MB TLBs. Turn it off by default, as this code has not been tested well enough yet. Use the CONFIG_DIRECT_GBPAGES=y .config option or gbpages on the boot line can be used to enable it. If enabled in the .config then nogbpages boot option disables it. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17x86: increase the kernel text limit to 512 MBIngo Molnar
people sometimes do crazy stuff like building really large static arrays into their kernels or building allyesconfig kernels. Give more space to the kernel and push modules up a bit: kernel has 512 MB and modules have 1.5 GB. Should be enough for a few years ;-) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6: it821x: do not describe noraid parameter with its value Pb1200/DBAu1200: fix bad IDE resource size Au1200: IDE driver build fix Au1200: kill IDE driver function prototypes avr32 mustn't select HAVE_IDE
2008-04-17Pb1200/DBAu1200: fix bad IDE resource sizeSergei Shtylyov
The header files for the Pb1200/DBAu1200 boards have wrong definition for the IDE interface's decoded range length -- it should be 512 bytes according to what the IDE driver does. In addition, the IDE platform device claims 1 byte too many for its memory resource -- fix the platform code and the IDE driver in accordance. Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-04-17Au1200: kill IDE driver function prototypesSergei Shtylyov
Fix these warnings emitted when compiling drivers/ide/mips/au1xxx-ide.c: include/asm/mach-au1x00/au1xxx_ide.h:137: warning: 'auide_tune_drive' declared `static' but never defined include/asm/mach-au1x00/au1xxx_ide.h:138: warning: 'auide_tune_chipset' declared `static' but never defined by wiping out the whole "function prototyping" section from the header file <asm-mips/mach-au1x00/au1xxx_ide.h> as it mostly declared functions that are already dead in the IDE driver; move the only useful prototype into the driver. Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-04-16Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: block: update git url for blktrace io context: increment task attachment count in ioc_task_link()
2008-04-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: [TCP]: Add return value indication to tcp_prune_ofo_queue(). PS3: gelic: fix the oops on the broken IE returned from the hypervisor b43legacy: fix DMA mapping leakage mac80211: remove message on receiving unexpected unencrypted frames Update rt2x00 MAINTAINERS entry Add rfkill to MAINTAINERS file rfkill: Fix device type check when toggling states b43legacy: Fix usage of struct device used for DMAing ssb: Fix usage of struct device used for DMAing MAINTAINERS: move to generic repository for iwlwifi b43legacy: fix initvals loading on bcm4303 rtl8187: Add missing priv->vif assignments netconsole: only set CON_PRINTBUFFER if the user specifies a netconsole [CAN]: Update documentation of struct sockaddr_can MAINTAINERS: isdn4linux@listserv.isdn4linux.de is subscribers-only [TCP]: Fix never pruned tcp out-of-order queue. [NET_SCHED] sch_api: fix qdisc_tree_decrease_qlen() loop
2008-04-15acpi thermal trip points increased to 12Krzysztof Helt
The THERMAL_MAX_TRIPS value is set to 10. It is too few for the Compaq AP550 machine which has 12 trip points. Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl> Cc: Len Brown <lenb@kernel.org> Cc: Zhang Rui <rui.zhang@intel.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-15spi: spi_s3c24xx must initialize num_chipselectBen Dooks
The SPI core now expects num_chipselect to be set correctly as due to added checks on the chip being selected before an transfer is allowed. This patch adds a num_cs field to the platform data which needs to be set correctly before adding the SPI platform device. Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-15vfs: fix possible deadlock in ext2, ext3, ext4 when using xattrsJan Kara
mb_cache_entry_alloc() was allocating cache entries with GFP_KERNEL. But filesystems are calling this function while holding xattr_sem so possible recursion into the fs violates locking ordering of xattr_sem and transaction start / i_mutex for ext2-4. Change mb_cache_entry_alloc() so that filesystems can specify desired gfp mask and use GFP_NOFS from all of them. Signed-off-by: Jan Kara <jack@suse.cz> Reported-by: Dave Jones <davej@redhat.com> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-15uml: compile error fixWANG Cong
This patch fixes this error: In file included from /home/wangcong/projects/linux-2.6/arch/um/kernel/smp.c:9: include2/asm/tlb.h: In function `tlb_remove_page': include2/asm/tlb.h:101: error: implicit declaration of function `page_cache_release' And since including <linux/pagemap.h> in <linux/swap.h> will break sparc, we add this #include in uml's own header. Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-15ssb: Fix usage of struct device used for DMAingMichael Buesch
This fixes DMA on architectures where DMA is nontrivial, like PPC64. We must use the host-device's (PCI) struct device for any DMA operation instead of the SSB device. For this we add a new struct device pointer to the SSB device structure that will always point to the right device for DMAing. Without this patch b43 and b44 drivers won't work on complex-DMA architectures, that for example need dev->archdata for DMA operations. Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-04-15io context: increment task attachment count in ioc_task_link()Jens Axboe
Thanks to Nikanth Karthikesan <knikanth@suse.de> for reporting this. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-14Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (31 commits) [BRIDGE]: Fix crash in __ip_route_output_key with bridge netfilter [NETFILTER]: ipt_CLUSTERIP: fix race between clusterip_config_find_get and _entry_put [IPV6] ADDRCONF: Don't generate temporary address for ip6-ip6 interface. [IPV6] ADDRCONF: Ensure disabling multicast RS even if privacy extensions are disabled. [IPV6]: Use appropriate sock tclass setting for routing lookup. [IPV6]: IPv6 extension header structures need to be packed. [IPV6]: Fix ipv6 address fetching in raw6_icmp_error(). [NET]: Return more appropriate error from eth_validate_addr(). [ISDN]: Do not validate ISDN net device address prior to interface-up [NET]: Fix kernel-doc for skb_segment [SOCK] sk_stamp: should be initialized to ktime_set(-1L, 0) net: check for underlength tap writes net: make struct tun_struct private to tun.c [SCTP]: IPv4 vs IPv6 addresses mess in sctp_inet[6]addr_event. [SCTP]: Fix compiler warning about const qualifiers [SCTP]: Fix protocol violation when receiving an error lenght INIT-ACK [SCTP]: Add check for hmac_algo parameter in sctp_verify_param() [NET_SCHED] cls_u32: refcounting fix for u32_delete() [DCCP]: Fix skb->cb conflicts with IP [AX25]: Potential ax25_uid_assoc-s leaks on module unload. ...
2008-04-13[IPV6]: Use appropriate sock tclass setting for routing lookup.YOSHIFUJI Hideaki
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-13[IPV6]: IPv6 extension header structures need to be packed.YOSHIFUJI Hideaki
struct ipv6_opt_hdr is the common structure for IPv6 extension headers, and it is common to increment the pointer to get the real content. On the other hand, since the structure consists only of 1-byte next-header field and 1-byte length field, size of that structure depends on architecture; 2 or 4. Add "packed" attribute to get 2. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-12net: make struct tun_struct private to tun.cRusty Russell
There's no reason for this to be in the header, and it just hurts recompile time. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Max Krasnyanskiy <maxk@qualcomm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-12[SCTP]: Fix compiler warning about const qualifiersVlad Yasevich
Fix 3 warnings about discarding const qualifiers: net/sctp/ulpevent.c:862: warning: passing argument 1 of 'sctp_event2skb' discards qualifiers from pointer target type net/sctp/sm_statefuns.c:4393: warning: passing argument 1 of 'SCTP_ASOC' discards qualifiers from pointer target type net/sctp/socket.c:5874: warning: passing argument 1 of 'cmsg_nxthdr' discards qualifiers from pointer target type Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-12[SCTP]: Fix protocol violation when receiving an error lenght INIT-ACKGui Jianfeng
When receiving an error length INIT-ACK during COOKIE-WAIT, a 0-vtag ABORT will be responsed. This action violates the protocol apparently. This patch achieves the following things. 1 If the INIT-ACK contains all the fixed parameters, use init-tag recorded from INIT-ACK as vtag. 2 If the INIT-ACK doesn't contain all the fixed parameters, just reflect its vtag. Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-11Merge branch 'docs' of git://git.lwn.net/linux-2.6Linus Torvalds
* 'docs' of git://git.lwn.net/linux-2.6: Add additional examples in Documentation/spinlocks.txt Move sched-rt-group.txt to scheduler/ Documentation: move rpc-cache.txt to filesystems/ Documentation: move nfsroot.txt to filesystems/ Spell out behavior of atomic_dec_and_lock() in kerneldoc Fix a typo in highres.txt Fixes to the seq_file document Fill out information on patch tags in SubmittingPatches Add the seq_file documentation
2008-04-11Spell out behavior of atomic_dec_and_lock() in kerneldocJ. Bruce Fields
A little more detail here wouldn't hurt. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2008-04-11Fix "$(AS) -traditional" compile breakage caused by asmlinkage_protectHeiko Carstens
git commit 54a015104136974262afa4b8ddd943ea70dec8a2 ("asmlinkage_protect replaces prevent_tail_call") causes this build failure on s390: AS arch/s390/kernel/entry64.o In file included from arch/s390/kernel/entry64.S:14: include/linux/linkage.h:34: error: syntax error in macro parameter list make[1]: *** [arch/s390/kernel/entry64.o] Error 1 make: *** [arch/s390/kernel] Error 2 and some other architectures. The reason is that some architectures add the "-traditional" flag to the invocation of $(AS), which disables variadic macro argument support. So just surround the new define with an #ifndef __ASSEMBLY__ to prevent any side effects on asm code. Cc: Roland McGrath <roland@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: [NETNS][IPV6] tcp - assign the netns for timewait sockets [IPV4]: Fix byte value boundary check in do_ip_getsockopt(). BNX2X: Correct bringing chip out of reset [NETFILTER]: nf_nat: autoload IPv4 connection tracking [NETFILTER]: xt_hashlimit: fix mask calculation [XFRM]: xfrm_user: fix selector family initialization rt61pci: rt61pci_beacon_update do not free skb twice ssb-mipscore: Fix interrupt vectors ssb-pcicore: Fix IRQ TPS flag handling mac80211: use short_preamble mode from capability if ERP IE not present [NET]: Undo code bloat in hot paths due to print_mac(). [TCP]: Don't allow FRTO to take place while MTU is being probed [TCP]: tcp_simple_retransmit can cause S+L [TCP]: Fix NewReno's fast rexmit/recovery problems with GSOed skb [TCP]: Restore 2.6.24 mark_head_lost behavior for newreno/fack nl80211: fix STA AID bug b43legacy: fix bcm4303 crash iwlwifi: fix n-band association problem ipw2200: set MAC address on radiotap interface libertas: fix mode initialization problem
2008-04-11pnp: increase number of devices supported per protocolBjorn Helgaas
Increase the PNP "number of devices" limit. We currently use an unsigned char, which limits us to 256 devices per protocol. This patch changes that to an unsigned int. Not all backends can take advantage of this: we limit ISAPNP to 10 devices in isapnp_cfg_begin(), and PNPBIOS is limited to 256 devices because the BIOS interfaces use a one-byte device node number. But there is no limit on the number of PNPACPI devices we may have. Large HP Integrity machines have more than 256, which causes the current "unsigned char number" to wrap around. This causes errors like this: pnp: PnP ACPI init kobject_add failed for 00:00 with -EEXIST, don't try to register things with the same name in the same directory. Call Trace: [<a000000100010720>] show_stack+0x40/0xa0 [<a0000001000107b0>] dump_stack+0x30/0x60 [<a0000001001dbdf0>] kobject_add+0x290/0x2c0 [<a0000001002bfd40>] device_add+0x160/0x860 [<a0000001002c0470>] device_register+0x30/0x60 [<a00000010026ba70>] __pnp_add_device+0x130/0x180 [<a00000010026bb70>] pnp_add_device+0xb0/0xe0 [<a0000001007f2730>] pnpacpi_add_device+0x510/0x5a0 [<a0000001007f2810>] pnpacpi_add_device_handler+0x50/0x80 This patch increases the limit to fix this PNPACPI problem. It should not have any adverse effect on ISAPNP or PNPBIOS because their limits are still enforced in the backends. Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-10Add commentary about the new "asmlinkage_protect()" macroLinus Torvalds
It's really a pretty ugly thing to need, and some day it will hopefully be obviated by teaching gcc about the magic calling conventions for the low-level system call code, but in the meantime we can at least add big honking comments about why we need these insane and strange macros. I took my comments from my version of the macro, but I ended up deciding to just pick Roland's version of the actual code instead (with his prettier syntax that uses vararg macros). Thus the previous two commits that actually implement it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-10asmlinkage_protect replaces prevent_tail_callRoland McGrath
The prevent_tail_call() macro works around the problem of the compiler clobbering argument words on the stack, which for asmlinkage functions is the caller's (user's) struct pt_regs. The tail/sibling-call optimization is not the only way that the compiler can decide to use stack argument words as scratch space, which we have to prevent. Other optimizations can do it too. Until we have new compiler support to make "asmlinkage" binding on the compiler's own use of the stack argument frame, we have work around all the manifestations of this issue that crop up. More cases seem to be prevented by also keeping the incoming argument variables live at the end of the function. This makes their original stack slots attractive places to leave those variables, so the compiler tends not clobber them for something else. It's still no guarantee, but it handles some observed cases that prevent_tail_call() did not. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-17 10:40:31 +0000