[PATCH 1/7] powerpc: Add TIDR CPU feature for Power9

[Alastair D'Silva]

From: Alastair D'Silva <alast...@d-silva.org>

This patch adds a CPU feature bit to show whether the CPU has
the TIDR register available, enabling as_notify/wait in userspace.

Signed-off-by: Alastair D'Silva <alast...@d-silva.org>
---
 arch/powerpc/include/asm/cputable.h  | 3 ++-
 arch/powerpc/include/asm/switch_to.h | 1 -
 arch/powerpc/kernel/dt_cpu_ftrs.c    | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h 
b/arch/powerpc/include/asm/cputable.h
index 4e332f3531c5..54c4cbbe57b4 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -215,6 +215,7 @@ static inline void cpu_feature_keys_init(void) { }
 #define CPU_FTR_P9_TM_HV_ASSIST                
LONG_ASM_CONST(0x0000100000000000)
 #define CPU_FTR_P9_TM_XER_SO_BUG       LONG_ASM_CONST(0x0000200000000000)
 #define CPU_FTR_P9_TLBIE_BUG           LONG_ASM_CONST(0x0000400000000000)
+#define CPU_FTR_P9_TIDR                        
LONG_ASM_CONST(0x0000800000000000)
 
 #ifndef __ASSEMBLY__
 
@@ -462,7 +463,7 @@ static inline void cpu_feature_keys_init(void) { }
            CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
            CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
            CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_PKEY | \
-           CPU_FTR_P9_TLBIE_BUG)
+           CPU_FTR_P9_TLBIE_BUG | CPU_FTR_P9_TIDR)
 #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \
                             (~CPU_FTR_SAO))
 #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9
diff --git a/arch/powerpc/include/asm/switch_to.h 
b/arch/powerpc/include/asm/switch_to.h
index be8c9fa23983..5b03d8a82409 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -94,6 +94,5 @@ static inline void clear_task_ebb(struct task_struct *t)
 extern int set_thread_uses_vas(void);
 
 extern int set_thread_tidr(struct task_struct *t);
-extern void clear_thread_tidr(struct task_struct *t);
 
 #endif /* _ASM_POWERPC_SWITCH_TO_H */
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c 
b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 11a3a4fed3fb..10f8b7f55637 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -722,6 +722,7 @@ static __init void cpufeatures_cpu_quirks(void)
        if ((version & 0xffff0000) == 0x004e0000) {
                cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
                cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+               cur_cpu_spec->cpu_features |= CPU_FTR_P9_TIDR;
        }
 }
 
-- 
2.14.3