On 06.06.14 18:27, Aneesh Kumar K.V wrote:
Alexander Graf <agraf@xxxxxxx> writes:
On 05.06.14 14:08, Aneesh Kumar K.V wrote:
virtual time base register is a per VM, per cpu register that needs
to be saved and restored on vm exit and entry. Writing to VTB is not
allowed in the privileged mode.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
For some reason BUG() doesn't always trigger the "execution stops here"
logic in gcc. So I've squashed this patch into yours.
Alex
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 3e7085d..99de6ad 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1206,6 +1206,7 @@ static inline unsigned long mfvtb (void)
* capture that.
*/
BUG();
+ return 0;
}
#ifdef __powerpc64__
you can then drop the include header change. ie,
#include <asm/bug.h>
Yeah, things are even worse than I thought. I've eventually squashed the
following in. a NOP'ed mfspr() won't keep the branch from blr'ing, so
we'd never hit the BUG() anyway.
Alex
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 1f34ef7..c8f3381 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -25,7 +25,6 @@
#ifdef CONFIG_8xx
#include <asm/reg_8xx.h>
#endif /* CONFIG_8xx */
-#include <asm/bug.h>
#define MSR_SF_LG 63 /* Enable 64 bit mode */
#define MSR_ISF_LG 61 /* Interrupt 64b mode valid on
630 */
@@ -1210,12 +1209,6 @@ static inline unsigned long mfvtb (void)
if (cpu_has_feature(CPU_FTR_ARCH_207S))
return mfspr(SPRN_VTB);
#endif
- /*
- * The above mfspr will be a no-op on anything before Power8
- * That can result in random values returned. We need to
- * capture that.
- */
- BUG();
return 0;
}
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