powerpc: Define ppr in thread_struct
[PATCH 4/6] powerpc: Define ppr in thread_struct
ppr in thread_struct is used to save PPR and restore it before process exits
from kernel.
This patch sets the default priority to 3 when tasks are created such
that users can use 4 for higher priority tasks.
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 8750204..37f87f0 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -18,6 +18,16 @@
#define TS_FPRWIDTH 1
#endif
+#ifdef CONFIG_PPC64
+/* Default SMT priority is set to 3. Use 11- 13bits to save priority. */
+#define PPR_PRIORITY 3
+#ifdef __ASSEMBLY__
+#define INIT_PPR (PPR_PRIORITY << 50)
+#else
+#define INIT_PPR ((u64)PPR_PRIORITY << 50)
+#endif /* __ASSEMBLY__ */
+#endif /* CONFIG_PPC64 */
+
#ifndef __ASSEMBLY__
#include <linux/compiler.h>
#include <linux/cache.h>
@@ -245,6 +255,7 @@
#ifdef CONFIG_PPC64
unsigned long dscr;
int dscr_inherit;
+ unsigned long ppr; /* used to save/restore SMT priority */
#endif
};
@@ -278,6 +289,7 @@
.fpr = {{0}}, \
.fpscr = { .val = 0, }, \
.fpexc_mode = 0, \
+ .ppr = INIT_PPR, \
}
#endif
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 4e23ba2..e39ca55 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -77,6 +77,7 @@
DEFINE(NMI_MASK, NMI_MASK);
DEFINE(THREAD_DSCR, offsetof(struct thread_struct, dscr));
DEFINE(THREAD_DSCR_INHERIT, offsetof(struct thread_struct, dscr_inherit));
+ DEFINE(TASKTHREADPPR, offsetof(struct task_struct, thread.ppr));
#else
DEFINE(THREAD_INFO, offsetof(struct task_struct, stack));
#endif /* CONFIG_PPC64 */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 8143067..3065d17 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -813,6 +813,8 @@
p->thread.dscr_inherit = current->thread.dscr_inherit;
p->thread.dscr = current->thread.dscr;
}
+ if (cpu_has_feature(CPU_FTR_HAS_PPR))
+ p->thread.ppr = INIT_PPR;
#endif
/*
* The PPC64 ABI makes use of a TOC to contain function