[PATCH v2 1/2] powerpc/feature: Fix CPU_FTRS_ALWAYS by removing CPU_FTRS_GENERIC_32

[PATCH v2 1/2] powerpc/feature: Fix CPU_FTRS_ALWAYS by removing CPU_FTRS_GENERIC_32

[Christophe Leroy]

On 8xx, we get the following features:

[    0.000000] cpu_features      = 0x0000000000000100
[    0.000000]   possible        = 0x0000000000000120
[    0.000000]   always          = 0x0000000000000000

This is not correct. As CONFIG_PPC_8xx is mutually exclusive with all
other configurations, the three lines should be equal.

The problem is due to CPU_FTRS_GENERIC_32 which is taken when
CONFIG_BOOK3S_32 is NOT selected. This CPU_FTRS_GENERIC_32 is
pointless because there is no generic configuration supporting
all 32 bits but book3s/32.

Remove this pointless generic features definition to unbreak the
calculation of 'possible' features and 'always' features.

Fixes: 76bc080ef5a3 ("[POWERPC] Make default cputable entries reflect selected CPU family")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/cputable.h | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 93bc70d4c9a1..c596bab134e2 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -409,7 +409,6 @@ static inline void cpu_feature_keys_init(void) { }
 	    CPU_FTR_DBELL | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
 	    CPU_FTR_DEBUG_LVL_EXC | CPU_FTR_EMB_HV | CPU_FTR_ALTIVEC_COMP | \
 	    CPU_FTR_CELL_TB_BUG | CPU_FTR_SMT)
-#define CPU_FTRS_GENERIC_32	(CPU_FTR_COMMON | CPU_FTR_NODSISRALIGN)
 
 /* 64-bit CPUs */
 #define CPU_FTRS_PPC970	(CPU_FTR_LWSYNC | \
@@ -520,8 +519,6 @@ enum {
 	    CPU_FTRS_7447 | CPU_FTRS_7447A | CPU_FTRS_82XX |
 	    CPU_FTRS_G2_LE | CPU_FTRS_E300 | CPU_FTRS_E300C2 |
 	    CPU_FTRS_CLASSIC32 |
-#else
-	    CPU_FTRS_GENERIC_32 |
 #endif
 #ifdef CONFIG_PPC_8xx
 	    CPU_FTRS_8XX |
@@ -596,8 +593,6 @@ enum {
 	    CPU_FTRS_7447 & CPU_FTRS_7447A & CPU_FTRS_82XX &
 	    CPU_FTRS_G2_LE & CPU_FTRS_E300 & CPU_FTRS_E300C2 &
 	    CPU_FTRS_CLASSIC32 &
-#else
-	    CPU_FTRS_GENERIC_32 &
 #endif
 #ifdef CONFIG_PPC_8xx
 	    CPU_FTRS_8XX &
-- 
2.25.0

[PATCH v2 2/2] powerpc/feature: Remove CPU_FTR_NODSISRALIGN

[Christophe Leroy]

CPU_FTR_NODSISRALIGN has not been used since
commit 31bfdb036f12 ("powerpc: Use instruction emulation
infrastructure to handle alignment faults")

Remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v2:
- Applying atfer the removal of CPU_FTRS_GENERIC_32 which remove one use of CPU_FTR_NODSISRALIGN
- Replaced the entry in dt_cpu_feature_match_table[] by a comment instead of removing it blindly.
- Removed the entry in ibm_pa_features[] instead of only clearing the feature bit.
---
 arch/powerpc/include/asm/cputable.h | 22 ++++++++++------------
 arch/powerpc/kernel/dt_cpu_ftrs.c   |  9 +--------
 arch/powerpc/kernel/prom.c          |  1 -
 3 files changed, 11 insertions(+), 21 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index c596bab134e2..0101d5d9d4a6 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -137,7 +137,6 @@ static inline void cpu_feature_keys_init(void) { }
 #define CPU_FTR_DBELL			ASM_CONST(0x00000004)
 #define CPU_FTR_CAN_NAP			ASM_CONST(0x00000008)
 #define CPU_FTR_DEBUG_LVL_EXC		ASM_CONST(0x00000010)
-#define CPU_FTR_NODSISRALIGN		ASM_CONST(0x00000020)
 #define CPU_FTR_FPU_UNAVAILABLE		ASM_CONST(0x00000040)
 #define CPU_FTR_LWSYNC			ASM_CONST(0x00000080)
 #define CPU_FTR_NOEXECUTE		ASM_CONST(0x00000100)
@@ -219,7 +218,7 @@ static inline void cpu_feature_keys_init(void) { }
 
 #ifndef __ASSEMBLY__
 
-#define CPU_FTR_PPCAS_ARCH_V2	(CPU_FTR_NOEXECUTE | CPU_FTR_NODSISRALIGN)
+#define CPU_FTR_PPCAS_ARCH_V2	(CPU_FTR_NOEXECUTE)
 
 #define MMU_FTR_PPCAS_ARCH_V2 	(MMU_FTR_TLBIEL | MMU_FTR_16M_PAGE)
 
@@ -378,33 +377,33 @@ static inline void cpu_feature_keys_init(void) { }
 	    CPU_FTR_COMMON | CPU_FTR_FPU_UNAVAILABLE  | CPU_FTR_NOEXECUTE)
 #define CPU_FTRS_CLASSIC32	(CPU_FTR_COMMON)
 #define CPU_FTRS_8XX	(CPU_FTR_NOEXECUTE)
-#define CPU_FTRS_40X	(CPU_FTR_NODSISRALIGN | CPU_FTR_NOEXECUTE)
-#define CPU_FTRS_44X	(CPU_FTR_NODSISRALIGN | CPU_FTR_NOEXECUTE)
-#define CPU_FTRS_440x6	(CPU_FTR_NODSISRALIGN | CPU_FTR_NOEXECUTE | \
+#define CPU_FTRS_40X	(CPU_FTR_NOEXECUTE)
+#define CPU_FTRS_44X	(CPU_FTR_NOEXECUTE)
+#define CPU_FTRS_440x6	(CPU_FTR_NOEXECUTE | \
 	    CPU_FTR_INDEXED_DCR)
 #define CPU_FTRS_47X	(CPU_FTRS_440x6)
 #define CPU_FTRS_E200	(CPU_FTR_SPE_COMP | \
-	    CPU_FTR_NODSISRALIGN | CPU_FTR_COHERENT_ICACHE | \
+	    CPU_FTR_COHERENT_ICACHE | \
 	    CPU_FTR_NOEXECUTE | \
 	    CPU_FTR_DEBUG_LVL_EXC)
 #define CPU_FTRS_E500	(CPU_FTR_MAYBE_CAN_DOZE | \
-	    CPU_FTR_SPE_COMP | CPU_FTR_MAYBE_CAN_NAP | CPU_FTR_NODSISRALIGN | \
+	    CPU_FTR_SPE_COMP | CPU_FTR_MAYBE_CAN_NAP | \
 	    CPU_FTR_NOEXECUTE)
 #define CPU_FTRS_E500_2	(CPU_FTR_MAYBE_CAN_DOZE | \
 	    CPU_FTR_SPE_COMP | CPU_FTR_MAYBE_CAN_NAP | \
-	    CPU_FTR_NODSISRALIGN | CPU_FTR_NOEXECUTE)
-#define CPU_FTRS_E500MC	(CPU_FTR_NODSISRALIGN | \
+	    CPU_FTR_NOEXECUTE)
+#define CPU_FTRS_E500MC	( \
 	    CPU_FTR_LWSYNC | CPU_FTR_NOEXECUTE | \
 	    CPU_FTR_DBELL | CPU_FTR_DEBUG_LVL_EXC | CPU_FTR_EMB_HV)
 /*
  * e5500/e6500 erratum A-006958 is a timebase bug that can use the
  * same workaround as CPU_FTR_CELL_TB_BUG.
  */
-#define CPU_FTRS_E5500	(CPU_FTR_NODSISRALIGN | \
+#define CPU_FTRS_E5500	( \
 	    CPU_FTR_LWSYNC | CPU_FTR_NOEXECUTE | \
 	    CPU_FTR_DBELL | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
 	    CPU_FTR_DEBUG_LVL_EXC | CPU_FTR_EMB_HV | CPU_FTR_CELL_TB_BUG)
-#define CPU_FTRS_E6500	(CPU_FTR_NODSISRALIGN | \
+#define CPU_FTRS_E6500	( \
 	    CPU_FTR_LWSYNC | CPU_FTR_NOEXECUTE | \
 	    CPU_FTR_DBELL | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
 	    CPU_FTR_DEBUG_LVL_EXC | CPU_FTR_EMB_HV | CPU_FTR_ALTIVEC_COMP | \
@@ -554,7 +553,6 @@ enum {
 #define CPU_FTRS_DT_CPU_BASE			\
 	(CPU_FTR_LWSYNC |			\
 	 CPU_FTR_FPU_UNAVAILABLE |		\
-	 CPU_FTR_NODSISRALIGN |			\
 	 CPU_FTR_NOEXECUTE |			\
 	 CPU_FTR_COHERENT_ICACHE |		\
 	 CPU_FTR_STCX_CHECKS_ADDRESS |		\
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 1098863e17ee..e15fe7f337ba 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -273,13 +273,6 @@ static int __init feat_enable_idle_nap(struct dt_cpu_feature *f)
 	return 1;
 }
 
-static int __init feat_enable_align_dsisr(struct dt_cpu_feature *f)
-{
-	cur_cpu_spec->cpu_features &= ~CPU_FTR_NODSISRALIGN;
-
-	return 1;
-}
-
 static int __init feat_enable_idle_stop(struct dt_cpu_feature *f)
 {
 	u64 lpcr;
@@ -641,7 +634,7 @@ static struct dt_cpu_feature_match __initdata
 	{"tm-suspend-hypervisor-assist", feat_enable, CPU_FTR_P9_TM_HV_ASSIST},
 	{"tm-suspend-xer-so-bug", feat_enable, CPU_FTR_P9_TM_XER_SO_BUG},
 	{"idle-nap", feat_enable_idle_nap, 0},
-	{"alignment-interrupt-dsisr", feat_enable_align_dsisr, 0},
+	/* alignment-interrupt-dsisr ignored */
 	{"idle-stop", feat_enable_idle_stop, 0},
 	{"machine-check-power8", feat_enable_mce_power8, 0},
 	{"performance-monitor-power8", feat_enable_pmu_power8, 0},
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index c1545f22c077..ae3c41730367 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -165,7 +165,6 @@ static struct ibm_pa_feature {
 #ifdef CONFIG_PPC_RADIX_MMU
 	{ .pabyte = 40, .pabit = 0, .mmu_features  = MMU_FTR_TYPE_RADIX | MMU_FTR_GTSE },
 #endif
-	{ .pabyte = 1,  .pabit = 1, .invert = 1, .cpu_features = CPU_FTR_NODSISRALIGN },
 	{ .pabyte = 5,  .pabit = 0, .cpu_features  = CPU_FTR_REAL_LE,
 				    .cpu_user_ftrs = PPC_FEATURE_TRUE_LE },
 	/*
-- 
2.25.0

Re: [PATCH v2 1/2] powerpc/feature: Fix CPU_FTRS_ALWAYS by removing CPU_FTRS_GENERIC_32

[Michael Ellerman]

On Tue, 13 Oct 2020 11:11:20 +0000 (UTC), Christophe Leroy wrote:
> On 8xx, we get the following features:
> 
> [    0.000000] cpu_features      = 0x0000000000000100
> [    0.000000]   possible        = 0x0000000000000120
> [    0.000000]   always          = 0x0000000000000000
> 
> This is not correct. As CONFIG_PPC_8xx is mutually exclusive with all
> other configurations, the three lines should be equal.
> 
> [...]

Patch 2 applied to powerpc/next.

[2/2] powerpc/feature: Remove CPU_FTR_NODSISRALIGN
      https://git.kernel.org/powerpc/c/7d47034551687eb6c15e8431d897a3758fc5f83e

cheers