powerpc: Add a cpu feature CPU_FTR_PMAO_BUG

Some power8 revisions have a hardware bug where we can lose a
Performance Monitor (PMU) exception under certain circumstances.

We will be adding a workaround for this case, see the next commit for
details. The observed behaviour is that writing PMAO doesn't cause an
exception as we would expect, hence the name of the feature.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 617cc767c07681b109c5acd54f667cc3274956b5..bc2347774f0ad4ed111a5c98546fb763de6d8bbd 100644 (file)
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -189,6 +189,7 @@ extern const char *powerpc_base_platform;
 #define        CPU_FTR_HAS_PPR                 LONG_ASM_CONST(0x0200000000000000)
 #define CPU_FTR_DAWR                   LONG_ASM_CONST(0x0400000000000000)
 #define CPU_FTR_DABRX                  LONG_ASM_CONST(0x0800000000000000)
+#define CPU_FTR_PMAO_BUG               LONG_ASM_CONST(0x1000000000000000)
 
 #ifndef __ASSEMBLY__
 
@@ -445,6 +446,7 @@ extern const char *powerpc_base_platform;
            CPU_FTR_ICSWX | CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
            CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_DAWR | \
            CPU_FTR_ARCH_207S | CPU_FTR_TM_COMP)
+#define CPU_FTRS_POWER8E (CPU_FTRS_POWER8 | CPU_FTR_PMAO_BUG)
 #define CPU_FTRS_CELL  (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \
            CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
            CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \
@@ -466,8 +468,8 @@ extern const char *powerpc_base_platform;
 #define CPU_FTRS_POSSIBLE      \
            (CPU_FTRS_POWER3 | CPU_FTRS_RS64 | CPU_FTRS_POWER4 |        \
            CPU_FTRS_PPC970 | CPU_FTRS_POWER5 | CPU_FTRS_POWER6 |       \
-           CPU_FTRS_POWER7 | CPU_FTRS_POWER8 | CPU_FTRS_CELL |         \
-           CPU_FTRS_PA6T | CPU_FTR_VSX)
+           CPU_FTRS_POWER7 | CPU_FTRS_POWER8E | CPU_FTRS_POWER8 |      \
+           CPU_FTRS_CELL | CPU_FTRS_PA6T | CPU_FTR_VSX)
 #endif
 #else
 enum {

diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index 6c8dd5da4de5ea0b8b88196b773d2e39fca1c732..c1faade6506dd581e3baf2aebfd93c7972fbd6dc 100644 (file)
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -510,7 +510,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
                .pvr_mask               = 0xffff0000,
                .pvr_value              = 0x004b0000,
                .cpu_name               = "POWER8E (raw)",
-               .cpu_features           = CPU_FTRS_POWER8,
+               .cpu_features           = CPU_FTRS_POWER8E,
                .cpu_user_features      = COMMON_USER_POWER8,
                .cpu_user_features2     = COMMON_USER2_POWER8,
                .mmu_features           = MMU_FTRS_POWER8,