powerpc: Add TIDR CPU feature for POWER9

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 <alastair@d-silva.org>
Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 66fcab1..9c0a308 100644 (file)
--- 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 c904477..4be1c0d 100644 (file)
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -717,6 +717,7 @@ 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;
        }
 
        /*