On 01/24/2020 06:19 AM, Christophe Leroy wrote:
Le 24/01/2020 à 06:46, Michael Ellerman a écrit :
If I do this it seems to work, but feels a little dicey:
asm ("" : "=r" (r1));
sp = r1 & (THREAD_SIZE - 1);
Or we could do add in asm/reg.h what we have in boot/reg.h:
register void *__stack_pointer asm("r1");
#define get_sp() (__stack_pointer)
And use get_sp()
It works, and I guess doing it this way is acceptable as it's exactly
what's done for current in asm/current.h with register r2.
Now I (still) get:
sp = get_sp() & (THREAD_SIZE - 1);
b9c: 54 24 04 fe clrlwi r4,r1,19
if (unlikely(sp < 2048)) {
ba4: 2f 84 07 ff cmpwi cr7,r4,2047
Allthough GCC 8.1 what doing exactly the same with the form CLANG don't
like:
register unsigned long r1 asm("r1");
long sp = r1 & (THREAD_SIZE - 1);
b84: 54 24 04 fe clrlwi r4,r1,19
if (unlikely(sp < 2048)) {
b8c: 2f 84 07 ff cmpwi cr7,r4,2047
Christophe
