Re: [PATCH v6 4/4] powerpc/vdso: Switch VDSO to generic C implementation.

2020-04-07 Thread Naveen N. Rao
Christophe Leroy wrote: powerpc is a bit special for VDSO as well as system calls in the way that it requires setting CR SO bit which cannot be done in C. Therefore, entry/exit needs to be performed in ASM. Implementing __arch_get_vdso_data() would clobbers the link register, requiring the

[PATCH v6 4/4] powerpc/vdso: Switch VDSO to generic C implementation.

2020-04-07 Thread Christophe Leroy
powerpc is a bit special for VDSO as well as system calls in the way that it requires setting CR SO bit which cannot be done in C. Therefore, entry/exit needs to be performed in ASM. Implementing __arch_get_vdso_data() would clobbers the link register, requiring the caller to save it. As the ASM