On Wed, Aug 12, 2015 at 11:17 AM, Boris Ostrovsky
On 08/12/2015 01:46 PM, Peter Zijlstra wrote:Is the problem just that it's being misdetected as supporting asm
On Wed, Aug 12, 2015 at 07:21:05PM +0200, Peter Zijlstra wrote:
On Wed, Aug 12, 2015 at 09:27:38AM -0400, Boris Ostrovsky wrote:Could you feed the below to your compiler? Its a bit cumbersome, but
Incidentally, 11276d53 ("locking/static_keys: Add a new static_keyUgh bugger.
interface") breaks old-ish compilers (gcc version 4.4.4 20100503 (Red
In file included from
/home/build/linux-boris/arch/x86/include/asm/jump_label.h: In function
operand 0 probably doesnât match constraints
impossible constraint in âasmâ
make: *** [arch/x86/kernel/nmi.o] Error 1
make: *** [arch/x86/kernel] Error 2
make: *** [arch/x86] Error 2
I bet its that: &((char *)key)[branch] business, an earlier variant
thereof tripped up more recent GCCs too.
So its an __always_inline function, and both argument are always compile
time constants, @key is the address of an object in static storage (a
global) and @branch is a simple 0/1 at the call site.
Now we wish to compute (unsigned long)key + branch at compile/link time
to feed to the assembler as an immediate, which should be possible,
given its all 'constants'.
It just appears GCC is having a hard time with this.
Let me see if I have a sufficiently old GCC around to play with.
its the next best I could come up with...
No, it produces the same error. This is Fedora 13, btw, uses gcc 4.4.4.
goto? What does gcc -E say?