[PATCH v5 1/4] pSeries: extended_cede_processor() helper function.

Gautham R Shenoy
2009-10-30T05:23:03Z

This patch provides an extended_cede_processor() helper function
which takes the cede latency hint as an argument. This hint is to be passed
on to the hypervisor to cede to the corresponding state on platforms
which support it.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/lppaca.h | 9 ++++++++-
arch/powerpc/platforms/pseries/plpar_wrappers.h | 22 ++++++++++++++++++++++
arch/powerpc/xmon/xmon.c | 3 ++-
3 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/lppaca.h b/arch/powerpc/include/asm/lppaca.h
index f78f65c..14b592d 100644
--- a/arch/powerpc/include/asm/lppaca.h
+++ b/arch/powerpc/include/asm/lppaca.h
@@ -100,7 +100,14 @@ struct lppaca {
// Used to pass parms from the OS to PLIC for SetAsrAndRfid
u64 saved_gpr3; // Saved GPR3 x20-x27
u64 saved_gpr4; // Saved GPR4 x28-x2F
- u64 saved_gpr5; // Saved GPR5 x30-x37
+ union {
+ u64 saved_gpr5; /* Saved GPR5 x30-x37 */
+ struct {
+ u8 cede_latency_hint; /* x30 */
+ u8 reserved[7]; /* x31-x36 */
+ } fields;
+ } gpr5_dword;
+

u8 dtl_enable_mask; // Dispatch Trace Log mask x38-x38
u8 donate_dedicated_cpu; // Donate dedicated CPU cycles x39-x39
diff --git a/arch/powerpc/platforms/pseries/plpar_wrappers.h b/arch/powerpc/platforms/pseries/plpar_wrappers.h
index a24a6b2..0603c91 100644
--- a/arch/powerpc/platforms/pseries/plpar_wrappers.h
+++ b/arch/powerpc/platforms/pseries/plpar_wrappers.h
@@ -9,11 +9,33 @@ static inline long poll_pending(void)
return plpar_hcall_norets(H_POLL_PENDING);
}

+static inline u8 get_cede_latency_hint(void)
+{
+ return get_lppaca()->gpr5_dword.fields.cede_latency_hint;
+}
+
+static inline void set_cede_latency_hint(u8 latency_hint)
+{
+ get_lppaca()->gpr5_dword.fields.cede_latency_hint = latency_hint;
+}
+
static inline long cede_processor(void)
{
return plpar_hcall_norets(H_CEDE);
}

+static inline long extended_cede_processor(unsigned long latency_hint)
+{
+ long rc;
+ u8 old_latency_hint = get_cede_latency_hint();
+
+ set_cede_latency_hint(latency_hint);
+ rc = cede_processor();
+ set_cede_latency_hint(old_latency_hint);
+
+ return rc;
+}
+
static inline long vpa_call(unsigned long flags, unsigned long cpu,
unsigned long vpa)
{
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index c6f0a71..57124cf 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1623,7 +1623,8 @@ static void super_regs(void)
ptrLpPaca->saved_srr0, ptrLpPaca->saved_srr1);
printf(" Saved Gpr3=%.16lx Saved Gpr4=%.16lx \n",
ptrLpPaca->saved_gpr3, ptrLpPaca->saved_gpr4);
- printf(" Saved Gpr5=%.16lx \n", ptrLpPaca->saved_gpr5);
+ printf(" Saved Gpr5=%.16lx \n",
+ ptrLpPaca->gpr5_dword.saved_gpr5);
}
#endif