Messages in this thread | | | Subject | Re: [PATCH v13 8/9] Add 32 bit VDSO time support for 32 bit kernel | From | Stefani Seibold <> | Date | Sun, 09 Feb 2014 11:43:35 +0100 |
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Am Sonntag, den 09.02.2014, 02:05 -0800 schrieb Andi Kleen: > > 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 >
Okay, but i have no idea why and how to supply dwarf2 unwind annotations. Can you give my some hints?
> > > > > 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 will fix this.
> > 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. >
I will place some comments in the source.
- Stefani
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