powerpc: Don't handle ALTIVEC/SPE in ASM in _switch(). Do it in C.
_switch() saves and restores ALTIVEC and SPE status.
For altivec this is redundant with what __switch_to() does with
save_sprs() and restore_sprs() and giveup_all() before
calling _switch().
Add support for SPI in save_sprs() and restore_sprs() and
remove things from _switch().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8ab21fd93d6e0047aa71e6509e5e312f14b2991b.1620998075.git.christophe.leroy@csgroup.eu
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 89e34aa..2bd30ac 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1129,6 +1129,10 @@ static inline void save_sprs(struct thread_struct *t)
if (cpu_has_feature(CPU_FTR_ALTIVEC))
t->vrsave = mfspr(SPRN_VRSAVE);
#endif
+#ifdef CONFIG_SPE
+ if (cpu_has_feature(CPU_FTR_SPE))
+ t->spefscr = mfspr(SPRN_SPEFSCR);
+#endif
#ifdef CONFIG_PPC_BOOK3S_64
if (cpu_has_feature(CPU_FTR_DSCR))
t->dscr = mfspr(SPRN_DSCR);
@@ -1159,6 +1163,11 @@ static inline void restore_sprs(struct thread_struct *old_thread,
old_thread->vrsave != new_thread->vrsave)
mtspr(SPRN_VRSAVE, new_thread->vrsave);
#endif
+#ifdef CONFIG_SPE
+ if (cpu_has_feature(CPU_FTR_SPE) &&
+ old_thread->spefscr != new_thread->spefscr)
+ mtspr(SPRN_SPEFSCR, new_thread->spefscr);
+#endif
#ifdef CONFIG_PPC_BOOK3S_64
if (cpu_has_feature(CPU_FTR_DSCR)) {
u64 dscr = get_paca()->dscr_default;
