Messages in this thread | | | Date | Sun, 9 Feb 2014 02:05:36 -0800 | From | Andi Kleen <> | Subject | Re: [PATCH v13 8/9] Add 32 bit VDSO time support for 32 bit kernel |
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> EBX is a reserved as the base register when compiling with -fPIC. > Otherwise it get a "error: can't find a register in class 'BREG' while > reloading 'asm'".
In this case you have to dwarf annotate the push/pop
> > > Also I if this calls syscall.S:__kernel_vsyscall it clobbers more registers > > (ecx at least?) and you need to describe that to gcc with a + > > Sine ECX is in use as the second parameter it is still marked as > clobbered.
No input parameters are not clobbered.
> I think it should word... As i know a system call will preserve all > register expect the EAX, which is marked as in and out for this asm() > directive.
Yes the syscall does, but the vsyscall stub does not (for the !0x80 case)
> This is due the -m32 compilation, i will get a log of > "warning: integer constant is too large for 'unsigned long' type", > because a unsigned long is only 32 bit.
Don't explain it to me, put it into a comment.
-Andi
-- ak@linux.intel.com -- Speaking for myself only
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