From: Alastair D'Silva <redacted>

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 <redacted>
---
  arch/powerpc/include/asm/cputable.h | 3 ++-
  arch/powerpc/kernel/dt_cpu_ftrs.c   | 1 +
  2 files changed, 3 insertions(+), 1 deletion(-)

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/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;