Messages in this thread | | | Date | Tue, 16 Mar 2010 00:02:58 +0530 | From | Rabin Vincent <> | Subject | Re: [PATCH 06/10] ARM: ftrace: add Thumb-2 support |
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On Sun, Mar 14, 2010 at 10:30:15PM +0000, Catalin Marinas wrote: > On Sat, 2010-03-13 at 06:49 +0000, Rabin Vincent wrote: > > - The problem with the "mov lr, pc", is that it does not set the lsb when > > storing the pc in lr. The called function returns with "bx lr", and the > > mode changes to ARM. The blx is to avoid this. > > I'm not familiar with ftrace but why does the called function returns > using "bx lr". Is this generated by the compiler? I had the impression > that if we don't enable interworking, we wouldn't get this instruction > (but haven't tried this yet).
There's nothing special about the called function: it's just a regular C function. GCC uses "bx lr" for the return.
Rabin
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