Section 3.7 of Version 1.2 of the Power8 Processor User's Manual
prescribes that updates to HID0 be preceded by a SYNC instruction and
followed by an ISYNC instruction (Page 91).
Create an inline function name update_hid0() which follows this recipe
and invoke it from the static split core path.
Signed-off-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com>
---
[v1--> v2: Moved defn of update_hid0 to reg.h from kvm_ppc.h]
arch/powerpc/include/asm/reg.h | 13 +++++++++++++
arch/powerpc/platforms/powernv/subcore.c | 4 ++--
2 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index af56b5c..beb98ac 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -12,6 +12,8 @@
#include <linux/stringify.h>
#include <asm/cputable.h>
+#include <asm/barrier.h>
+#include <asm/synch.h>
/* Pickup Book E specific registers. */
#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
@@ -1281,6 +1283,17 @@ struct pt_regs;
extern void ppc_save_regs(struct pt_regs *regs);
+static inline void update_hid0(unsigned long hid0)
+{
+ /*
+ * The HID0 update should at the very least be preceded by a
+ * a SYNC instruction followed by an ISYNC instruction
+ */
+ mb();
+ mtspr(SPRN_HID0, hid0);
+ isync();
+}
+
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_REG_H */
diff --git a/arch/powerpc/platforms/powernv/subcore.c
b/arch/powerpc/platforms/powernv/subcore.c
index f60f80a..37e77bf 100644
--- a/arch/powerpc/platforms/powernv/subcore.c
+++ b/arch/powerpc/platforms/powernv/subcore.c
@@ -190,7 +190,7 @@ static void unsplit_core(void)
hid0 = mfspr(SPRN_HID0);
hid0 &= ~HID0_POWER8_DYNLPARDIS;
- mtspr(SPRN_HID0, hid0);
+ update_hid0(hid0);
update_hid_in_slw(hid0);
while (mfspr(SPRN_HID0) & mask)
@@ -227,7 +227,7 @@ static void split_core(int new_mode)
/* Write new mode */
hid0 = mfspr(SPRN_HID0);
hid0 |= HID0_POWER8_DYNLPARDIS | split_parms[i].value;
- mtspr(SPRN_HID0, hid0);
+ update_hid0(hid0);
update_hid_in_slw(hid0);
/* Wait for it to happen */
--
1.9.3
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