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* asmlinkage_protect replaces prevent_tail_callRoland McGrath2008-04-10
| | | | | | | | | | | | | | | | | | | | | | 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>
* x86: fix UML and -regparm=3Ingo Molnar2008-01-30
| | | | | | | | | | | | introduce the "asmregparm" calling convention: for functions implemented in assembly with a fixed regparm input parameters calling convention. mark the semaphore and rwsem slowpath functions with that. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: unify include/asm-x86/linkage_[32|64].hHarvey Harrison2008-01-30
| | | | | | | | | | | | Remove definitions of FASTCALL/fastcall from linkage_32 as compiled with -regparm=3 by default since 2.6.20 and should no longer be needed. CONFIG X86_64 and CONFIG_X86_ALIGNMENT_16 are mutually exclusive as found in Kconfig.cpu so it should be fine to test them separately. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* i386/x86_64: move headers to include/asm-x86Thomas Gleixner2007-10-11
Move the headers to include/asm-x86 and fixup the header install make rules Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>