Module: xenomai-rpm
Branch: for-upstream
Commit: 6bb1b5b22670bd118eabd9240b782a249b3fd6ae
URL:
http://git.xenomai.org/?p=xenomai-rpm.git;a=commit;h=6bb1b5b22670bd118eabd9240b782a249b3fd6ae
Author: Philippe Gerum <r...@xenomai.org>
Date: Mon May 17 15:28:36 2010 +0200
powerpc: use hardened switch_mm() support when available
Newer I-pipe patches allow to call __switch_mm() from non-root
contexts (*). Use this feature to greatly simplify our context
switching code for those kernels.
Another upside is to keep the mm switching innards only known from the
linux core.
(*) __IPIPE_FEATURE_HARDENED_SWITCHMM.
---
include/asm-powerpc/bits/pod.h | 16 ++++++++++++----
1 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/include/asm-powerpc/bits/pod.h b/include/asm-powerpc/bits/pod.h
index 0502212..6fe5e7b 100644
--- a/include/asm-powerpc/bits/pod.h
+++ b/include/asm-powerpc/bits/pod.h
@@ -119,7 +119,11 @@ static inline void xnarch_switch_to(xnarchtcb_t *out_tcb,
next_mm = in_tcb->active_mm;
- if (prev_mm != next_mm) {
+#ifdef __IPIPE_FEATURE_HARDENED_SWITCHMM
+ if (next_mm && likely(prev_mm != next_mm))
+ __switch_mm(prev_mm, next_mm, next);
+#else /* !__IPIPE_FEATURE_HARDENED_SWITCHMM */
+ if (likely(prev_mm != next_mm)) {
#ifdef CONFIG_ALTIVEC
asm volatile ("dssall;\n" :/*empty*/:);
#endif
@@ -133,9 +137,8 @@ static inline void xnarch_switch_to(xnarchtcb_t *out_tcb,
switch_stab(next, next_mm);
}
}
- rthal_thread_switch(out_tcb->tsp, in_tcb->tsp, next == NULL);
#else /* PPC32 */
- if (likely(next_mm != NULL)) {
+ if (likely(next_mm)) {
next->thread.pgdir = next_mm->pgd;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,29)
get_mmu_context(next_mm);
@@ -150,9 +153,14 @@ static inline void xnarch_switch_to(xnarchtcb_t *out_tcb,
current = prev; /* Make sure r2 is valid. */
}
}
- rthal_thread_switch(out_tcb->tsp, in_tcb->tsp);
#endif /* PPC32 */
+#endif /* !__IPIPE_FEATURE_HARDENED_SWITCHMM */
+#ifdef CONFIG_PPC64
+ rthal_thread_switch(out_tcb->tsp, in_tcb->tsp, next == NULL);
+#else
+ rthal_thread_switch(out_tcb->tsp, in_tcb->tsp);
+#endif
barrier();
}
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