summaryrefslogtreecommitdiff
path: root/Makefile
AgeCommit message (Collapse)AuthorFilesLines
2009-09-28Linux 2.6.32-rc1v2.6.32-rc2v2.6.32-rc1Linus Torvalds1-2/+2
2009-09-20arm, cris, mips, sparc, powerpc, um, xtensa: fix build with bash 4.0Sam Ravnborg1-5/+0
Albin Tonnerre <albin.tonnerre@free-electrons.com> reported: Bash 4 filters out variables which contain a dot in them. This happends to be the case of CPPFLAGS_vmlinux.lds. This is rather unfortunate, as it now causes build failures when using SHELL=/bin/bash to compile, or when bash happens to be used by make (eg when it's /bin/sh) Remove the common definition of CPPFLAGS_vmlinux.lds by pushing relevant stuff to either Makefile.build or the arch specific kernel/Makefile where we build the linker script. This is also nice cleanup as we move the information out where it is used. Notes for the different architectures touched: arm - we use an already exported symbol cris - we use a config symbol aleady available [Not build tested] mips - the jiffies complexity has moved to vmlinux.lds.S where we need it. Added a few variables to CPPFLAGS - they are only used by the linker script. [Not build tested] powerpc - removed assignment that is not needed [not build tested] sparc - simplified it using $(BITS) um - introduced a few new exported variables to deal with this xtensa - added options to CPP invocation [not build tested] Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Chris Zankel <chris@zankel.net> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-20kbuild: set -fconserve-stack option for gcc 4.5Andi Kleen1-0/+3
The upcomming gcc 4.5 has a new -fconserve-stack option that tells the inliner to take stack frame size in account. Set it if the compiler supports it. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-20kbuild: Check if linker supports the -X optionAndi Kleen1-1/+1
The new alternative `gold' linker in recent binutils doesn't support the -X option. This breaks allyesconfig builds that have CONFIG_STRIP_ASM_SYMS enabled. Check if the linker really supports the option using ld-option. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-20kbuild: rename ld-option to cc-ldoptionSam Ravnborg1-1/+1
ld-option is misnamed as it test options to gcc, not to ld. Renamed it to reflect this. Cc: Andi Kleen <andi@firstfloor.org> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-20kbuild: save ARCH & CROSS_COMPILE when building a kernelSam Ravnborg1-2/+44
When building a kernel for a different architecture kbuild requires the user always to specify ARCH and CROSS_COMPILE on the command-line. We use the asm symlink to detect if user forgets to specify the correct ARCH value - but that symlink is about to die. And we do now want to loose this check. This patch save the settings of ARCH and CROSS_COMPILE in two files named: include/generated/kernel.arch include/generated/kernel.cross The settings are saved during "make *config" time and always read. If user try to change the settings we error out. This works both for plain builds and for O=... builds. So now you can do: $ mkdir sparc64 $ make O=sparc64 ARCH=sparc64 CROSS_COMPILE=sparc64-linux- defconfig $ cd sparc64 $ make Notice that you no longer need to tell kbuild the settings of ARCH and CROSS_COMPILE when you type make in the output directory. Likewise for plain builds where you do not use O=... Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Roland McGrath <roland@redhat.com>
2009-09-20kbuild: use INSTALLKERNEL to select customized installkernel scriptSam Ravnborg1-1/+3
Replace the use of CROSS_COMPILE to select a customized installkernel script with the possibility to set INSTALLKERNEL to select a custom installkernel script when running make: make INSTALLKERNEL=arm-installkernel install With this patch we are now more consistent across different architectures - they did not all support use of CROSS_COMPILE. The use of CROSS_COMPILE was a hack as this really belongs to gcc/binutils and the installkernel script does not change just because we change toolchain. The use of CROSS_COMPILE caused troubles with an upcoming patch that saves CROSS_COMPILE when a kernel is built - it would no longer be installable. [Thanks to Peter Z. for this hint] This patch undos what Ian did in commit: 0f8e2d62fa04441cd12c08ce521e84e5bd3f8a46 ("use ${CROSS_COMPILE}installkernel in arch/*/boot/install.sh") The patch has been lightly tested on x86 only - but all changes looks obvious. Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Mike Frysinger <vapier@gentoo.org> [blackfin] Acked-by: Russell King <linux@arm.linux.org.uk> [arm] Acked-by: Paul Mundt <lethal@linux-sh.org> [sh] Acked-by: "H. Peter Anvin" <hpa@zytor.com> [x86] Cc: Ian Campbell <icampbell@arcom.com> Cc: Tony Luck <tony.luck@intel.com> [ia64] Cc: Fenghua Yu <fenghua.yu@intel.com> [ia64] Cc: Hirokazu Takata <takata@linux-m32r.org> [m32r] Cc: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Cc: Kyle McMartin <kyle@mcmartin.ca> [parisc] Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> [powerpc] Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390] Cc: Thomas Gleixner <tglx@linutronix.de> [x86] Cc: Ingo Molnar <mingo@redhat.com> [x86] Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-15Merge branch 'for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (46 commits) powerpc64: convert to dynamic percpu allocator sparc64: use embedding percpu first chunk allocator percpu: kill lpage first chunk allocator x86,percpu: use embedding for 64bit NUMA and page for 32bit NUMA percpu: update embedding first chunk allocator to handle sparse units percpu: use group information to allocate vmap areas sparsely vmalloc: implement pcpu_get_vm_areas() vmalloc: separate out insert_vmalloc_vm() percpu: add chunk->base_addr percpu: add pcpu_unit_offsets[] percpu: introduce pcpu_alloc_info and pcpu_group_info percpu: move pcpu_lpage_build_unit_map() and pcpul_lpage_dump_cfg() upward percpu: add @align to pcpu_fc_alloc_fn_t percpu: make @dyn_size mandatory for pcpu_setup_first_chunk() percpu: drop @static_size from first chunk allocators percpu: generalize first chunk allocator selection percpu: build first chunk allocators selectively percpu: rename 4k first chunk allocator to page percpu: improve boot messages percpu: fix pcpu_reclaim() locking ... Fix trivial conflict as by Tejun Heo in kernel/sched.c
2009-09-10Linux 2.6.31v2.6.31Linus Torvalds1-1/+1
2009-09-06Linux 2.6.31-rc9v2.6.31-rc9Linus Torvalds1-1/+1
2009-08-28Linux 2.6.31-rc8v2.6.31-rc8Linus Torvalds1-1/+1
2009-08-22Linux 2.6.31-rc7v2.6.31-rc7Linus Torvalds1-1/+1
2009-08-14Merge branch 'percpu-for-linus' into percpu-for-nextTejun Heo1-6/+6
Conflicts: arch/sparc/kernel/smp_64.c arch/x86/kernel/cpu/perf_counter.c arch/x86/kernel/setup_percpu.c drivers/cpufreq/cpufreq_ondemand.c mm/percpu.c Conflicts in core and arch percpu codes are mostly from commit ed78e1e078dd44249f88b1dd8c76dafb39567161 which substituted many num_possible_cpus() with nr_cpu_ids. As for-next branch has moved all the first chunk allocators into mm/percpu.c, the changes are moved from arch code to mm/percpu.c. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14Linux 2.6.31-rc6v2.6.31-rc6Linus Torvalds1-1/+1
2009-08-01Linux 2.6.31-rc5v2.6.31-rc5Linus Torvalds1-1/+1
2009-07-23Linux 2.6.31-rc4v2.6.31-rc4Linus Torvalds1-1/+1
2009-07-16Add '-fno-delete-null-pointer-checks' to gcc CFLAGSEugene Teo1-1/+2
Turning on this flag could prevent the compiler from optimising away some "useless" checks for null pointers. Such bugs can sometimes become exploitable at compile time because of the -O2 optimisation. See http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Optimize-Options.html An example that clearly shows this 'problem' is commit 6bf67672. static void __devexit agnx_pci_remove(struct pci_dev *pdev) { struct ieee80211_hw *dev = pci_get_drvdata(pdev); - struct agnx_priv *priv = dev->priv; + struct agnx_priv *priv; AGNX_TRACE; if (!dev) return; + priv = dev->priv; By reverting this patch, and compile it with and without -fno-delete-null-pointer-checks flag, we can see that the check for dev is compiled away. call printk # - testq %r12, %r12 # dev - je .L94 #, movq %r12, %rdi # dev, Clearly the 'fix' is to stop using dev before it is tested, but building with -fno-delete-null-pointer-checks flag at least makes it harder to abuse. Signed-off-by: Eugene Teo <eugeneteo@kernel.sg> Acked-by: Eric Paris <eparis@redhat.com> Acked-by: Wang Cong <amwang@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-14Linux 2.6.31-rc3v2.6.31-rc3Linus Torvalds1-1/+1
2009-07-12Don't use '-fwrapv' compiler option: it's buggy in gcc-4.1.xLinus Torvalds1-1/+1
This causes kernel images that don't run init to completion with certain broken gcc versions. This fixes kernel bugzilla entry: http://bugzilla.kernel.org/show_bug.cgi?id=13012 I suspect the gcc problem is this: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28230 Fix the problem by using the -fno-strict-overflow flag instead, which not only does not exist in the known-to-be-broken versions of gcc (it was introduced later than fwrapv), but seems to be much less disturbing to gcc too: the difference in the generated code by -fno-strict-overflow are smaller (compared to using neither flag) than when using -fwrapv. Reported-by: Barry K. Nathan <barryn@pobox.com> Pushed-by: Frans Pop <elendil@planet.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-04Linux 2.6.31-rc2v2.6.31-rc2Linus Torvalds1-1/+1
2009-07-04Merge branch 'master' into for-nextTejun Heo1-2/+2
Pull linus#master to merge PER_CPU_DEF_ATTRIBUTES and alpha build fix changes. As alpha in percpu tree uses 'weak' attribute instead of inline assembly, there's no need for __used attribute. Conflicts: arch/alpha/include/asm/percpu.h arch/mn10300/kernel/vmlinux.lds.S include/linux/percpu-defs.h
2009-06-27kbuild: finally remove the obsolete variable $TOPDIRAmerigo Wang1-3/+1
TOPDIR is obsolete, it can be finally removed now. Signed-off-by: WANG Cong <amwang@redhat.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-06-27Kbuild: Disable the -Wformat-security gcc flagFloris Kraak1-1/+2
Some distributions have enabled the gcc flag -Wformat-security by default. This results in a number of warnings about format arguments to functions, sometimes in cases where fixing the warning is not likely to actually fix a bug. Instead of hand patching a dozens of places (possibly more) that produce warnings that get ignored anyway we just turn off the flag in the Makefile. Signed-off-by: Floris Kraak <randakar@gmail.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-06-25Linux 2.6.31-rc1v2.6.31-rc1Linus Torvalds1-2/+2
2009-06-24linker script: throw away .discard sectionTejun Heo1-1/+1
x86 throws away .discard section but no other archs do. Also, .discard is not thrown away while linking modules. Make every arch and module linking throw it away. This will be used to define dummy variables for percpu declarations and definitions. This patch is based on Ivan Kokshaysky's alpha percpu patch. [ Impact: always throw away everything in .discard ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Richard Henderson <rth@twiddle.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Bryan Wu <cooloney@kernel.org> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Tony Luck <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: David S. Miller <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Chris Zankel <chris@zankel.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-19gcov: add gcov profiling infrastructurePeter Oberparleiter1-5/+6
Enable the use of GCC's coverage testing tool gcov [1] with the Linux kernel. gcov may be useful for: * debugging (has this code been reached at all?) * test improvement (how do I change my test to cover these lines?) * minimizing kernel configurations (do I need this option if the associated code is never run?) The profiling patch incorporates the following changes: * change kbuild to include profiling flags * provide functions needed by profiling code * present profiling data as files in debugfs Note that on some architectures, enabling gcc's profiling option "-fprofile-arcs" for the entire kernel may trigger compile/link/ run-time problems, some of which are caused by toolchain bugs and others which require adjustment of architecture code. For this reason profiling the entire kernel is initially restricted to those architectures for which it is known to work without changes. This restriction can be lifted once an architecture has been tested and found compatible with gcc's profiling. Profiling of single files or directories is still available on all platforms (see config help text). [1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.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: Rusty Russell <rusty@rustcorp.com.au> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.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>
2009-06-15Merge branch 'master' of ↵Linus Torvalds1-17/+9
git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next: (53 commits) .gitignore: ignore *.lzma files kbuild: add generic --set-str option to scripts/config kbuild: simplify argument loop in scripts/config kbuild: handle non-existing options in scripts/config kallsyms: generalize text region handling kallsyms: support kernel symbols in Blackfin on-chip memory documentation: make version fix kbuild: fix a compile warning gitignore: Add GNU GLOBAL files to top .gitignore kbuild: fix delay in setlocalversion on readonly source README: fix misleading pointer to the defconf directory vmlinux.lds.h update kernel-doc: cleanup perl script Improve vmlinux.lds.h support for arch specific linker scripts kbuild: fix headers_exports with boolean expression kbuild/headers_check: refine extern check kbuild: fix "Argument list too long" error for "make headers_check", ignore *.patch files Remove bashisms from scripts menu: fix embedded menu presentation ...
2009-06-10Linux 2.6.30v2.6.30Linus Torvalds1-1/+1
2009-06-10kbuild: remove extra ifdef/endif of top MakefileCheng Renquan1-17/+9
The GNU make's origin function know undefined variable well, so the outer ifdef/endif conditional checking is unneeded. From `info make` documentation, origin will return `undefined' if VARIABLE was never defined. `command line' if VARIABLE was defined on the command line. ... Therefore, $(origin V) will get a value anyway, killing ifdef/endif is viable and safe. Furthermore, I've checked the minimal requirements from Documentation/Changes is GNU make 3.79.1, and that version of GNU make has support of origin function well already, so now it's safe to kill the outer conditional checking, without upgrading the minimal requirements. Signed-off-by: Cheng Renquan <crq@kernel.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-06-05kbuild: fix detection of CONFIG_FRAME_WARN=0Mike Frysinger1-1/+1
The checking of CONFIG_FRAME_WARN in the top level Makefile forgot to actually derefence the variable thus leading to an always true check. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Andi Kleen <ak@suse.de> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-03Linux 2.6.30-rc8v2.6.30-rc8Linus Torvalds1-1/+1
2009-05-24Linux 2.6.30-rc7v2.6.30-rc7Linus Torvalds1-2/+2
2009-05-16Linux 2.6.30-rc6v2.6.30-rc6Linus Torvalds1-1/+1
2009-05-09Linux 2.6.30-rc5v2.6.30-rc5Linus Torvalds1-1/+1
2009-05-01kbuild: "make prepare" should be "make modules_prepare"Robert P. J. Day1-1/+1
Correct the Makefile help text to read "make modules_prepare". Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-05-01kbuild: clean Module.markers and modules.order for out-of-tree modulesFrédéric Brière1-1/+3
Signed-off-by: Frédéric Brière <fbriere@fbriere.net> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-04-30Linux 2.6.30-rc4v2.6.30-rc4Linus Torvalds1-2/+2
2009-04-22Linux 2.6.30-rc3v2.6.30-rc3Linus Torvalds1-1/+1
2009-04-19kbuild: support include/generatedSam Ravnborg1-1/+1
We need a location for generated files. Today they are spread over several places and bringing them together to a common place makes it obvious hat is generated and what isreal files. Al Viro originally suggested: include/gen Linus suggested to spell it out. This patch implement support for include/generated All files in include/generated are ignored by git. include/generated is removed during "make mrproper". With this we are ready to implement support for include/generated in the various architctures and in the base kernel. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-15Linux 2.6.30-rc2v2.6.30-rc2Linus Torvalds1-1/+1
2009-04-14Merge branch 'master' of ↵Paul Mundt1-4/+8
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
2009-04-11kbuild: make it possible for the linker to discard local symbols from vmlinuxDavid Howells1-0/+4
Make it possible for the linker to discard local symbols from vmlinux as they cause vmlinux to balloon when CONFIG_KALLSYMS=y and they cause dump_stack() and get_wchan() to produce useless information under some circumstances. With this we add a config option (CONFIG_STRIP_ASM_SYMS) that will cause the build to supply -X to the linker to tell it to strip temporary local symbols. This doesn't seem to cause gdb any problems. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-04-11kbuild: fix a few typos in top-level MakefileKirill Smelkov1-2/+2
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Acked-by: Dmitry Gryazin <gdu@mns.spb.ru> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-04-11sh: Plug in support for ARCH=sh64 using sh SRCARCH.Paul Mundt1-1/+6
This adds in support for building with ARCH=sh64 using the sh SRCARCH. This tidies up the randconfig generation somewhat to make sure that we don't end up with impossible configurations, and without having to rely on things like KCONFIG_ALLCONFIG to detect the proper CPU support subset. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-04-08Linux 2.6.30-rc1v2.6.30-rc1Linus Torvalds1-2/+2
2009-03-27Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2Ingo Molnar1-1/+2
Conflicts: arch/parisc/kernel/irq.c arch/x86/include/asm/fixmap_64.h arch/x86/include/asm/setup.h kernel/irq/handle.c Semantic merge: arch/x86/include/asm/fixmap.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-24Linux 2.6.29v2.6.29Linus Torvalds1-2/+2
2009-03-24Build with -fno-dwarf2-cfi-asmKyle McMartin1-0/+3
With a sufficiently new compiler and binutils, code which wasn't previously generating .eh_frame sections has begun to. Certain architectures (powerpc, in this case) may generate unexpected relocation formats in response to this, preventing modules from loading. While the new relocation types should probably be handled, revert to the previous behaviour with regards to generation of .eh_frame sections. (This was reported against Fedora, which appears to be the only distro doing any building against gcc-4.4 at present: RH bz#486545.) Signed-off-by: Kyle McMartin <kyle@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Alexandre Oliva <aoliva@redhat.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-20Move cc-option to below arch-specific setupLinus Torvalds1-1/+3
Sam Ravnborg says: "We have several architectures that plays strange games with $(CC) and $(CROSS_COMPILE). So we need to postpone any use of $(call cc-option..) until we have included the arch specific Makefile so we try with the correct $(CC) version." Requested-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-19Add '-fwrapv' to gcc CFLAGSLinus Torvalds1-0/+1
This makes sure that gcc doesn't try to optimize away wrapping arithmetic, which the kernel occasionally uses for overflow testing, ie things like if (ptr + offset < ptr) which technically is undefined for non-unsigned types. See http://bugzilla.kernel.org/show_bug.cgi?id=12597 for details. Not all versions of gcc support it, so we need to make it conditional (it looks like it was introduced in gcc-3.4). Reminded-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>