[v2,1/5] powerpc: Add CPU feature bits for TM bug workarounds on POWER9 v2.2

Message ID 1521628323-14451-2-git-send-email-paulus@ozlabs.org
State New
Headers show
Series
  • KVM & powerpc: Work around POWER9 TM hardware bugs
Related show

Commit Message

Paul Mackerras March 21, 2018, 10:31 a.m.
This adds a CPU feature bit which is set for POWER9 "Nimbus" DD2.2
processors which will be used to enable the hypervisor to assist
hardware with the handling of checkpointed register values while the
CPU is in suspend state, in order to work around hardware bugs.  The
hardware assistance for these workarounds introduced a new hardware
bug relating to the XER[SO] bit.  We add a separate feature bit for
this bug in case future chips fix it while still requiring the
hypervisor assistance with suspend state.

When the dt_cpu_ftrs subsystem is in use, the software assistance can
be enabled using a "tm-suspend-hypervisor-assist" node in the device
tree, and a "tm-suspend-xer-so-bug" node enables the workarounds for
the XER[SO] bug.  In the absence of such nodes, a quirk enables both
for POWER9 "Nimbus" DD2.2 processors.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/include/asm/cputable.h |  7 ++++++-
 arch/powerpc/kernel/cputable.c      | 24 ++++++++++++++++++++++--
 arch/powerpc/kernel/dt_cpu_ftrs.c   |  5 +++++
 3 files changed, 33 insertions(+), 3 deletions(-)

Comments

Michael Ellerman March 26, 2018, 8:57 a.m. | #1
On Wed, 2018-03-21 at 10:31:59 UTC, Paul Mackerras wrote:
> This adds a CPU feature bit which is set for POWER9 "Nimbus" DD2.2
> processors which will be used to enable the hypervisor to assist
> hardware with the handling of checkpointed register values while the
> CPU is in suspend state, in order to work around hardware bugs.  The
> hardware assistance for these workarounds introduced a new hardware
> bug relating to the XER[SO] bit.  We add a separate feature bit for
> this bug in case future chips fix it while still requiring the
> hypervisor assistance with suspend state.
> 
> When the dt_cpu_ftrs subsystem is in use, the software assistance can
> be enabled using a "tm-suspend-hypervisor-assist" node in the device
> tree, and a "tm-suspend-xer-so-bug" node enables the workarounds for
> the XER[SO] bug.  In the absence of such nodes, a quirk enables both
> for POWER9 "Nimbus" DD2.2 processors.
> 
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/b5af4f2793233cf37596e2c1f7b233

cheers
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Patch

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 49fd067..ecee84d 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -213,6 +213,8 @@  static inline void cpu_feature_keys_init(void) { }
 #define CPU_FTR_PMAO_BUG		LONG_ASM_CONST(0x0000020000000000)
 #define CPU_FTR_POWER9_DD1		LONG_ASM_CONST(0x0000040000000000)
 #define CPU_FTR_POWER9_DD2_1		LONG_ASM_CONST(0x0000080000000000)
+#define CPU_FTR_P9_TM_HV_ASSIST		LONG_ASM_CONST(0x0000100000000000)
+#define CPU_FTR_P9_TM_XER_SO_BUG	LONG_ASM_CONST(0x0000200000000000)
 
 #ifndef __ASSEMBLY__
 
@@ -469,6 +471,8 @@  static inline void cpu_feature_keys_init(void) { }
 			     (~CPU_FTR_SAO))
 #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9
 #define CPU_FTRS_POWER9_DD2_1 (CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD2_1)
+#define CPU_FTRS_POWER9_DD2_2 (CPU_FTRS_POWER9 | CPU_FTR_P9_TM_HV_ASSIST | \
+			       CPU_FTR_P9_TM_XER_SO_BUG)
 #define CPU_FTRS_CELL	(CPU_FTR_LWSYNC | \
 	    CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
 	    CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \
@@ -488,7 +492,8 @@  static inline void cpu_feature_keys_init(void) { }
 	     CPU_FTRS_POWER6 | CPU_FTRS_POWER7 | CPU_FTRS_POWER8E | \
 	     CPU_FTRS_POWER8 | CPU_FTRS_POWER8_DD1 | CPU_FTRS_CELL | \
 	     CPU_FTRS_PA6T | CPU_FTR_VSX | CPU_FTRS_POWER9 | \
-	     CPU_FTRS_POWER9_DD1 | CPU_FTRS_POWER9_DD2_1)
+	     CPU_FTRS_POWER9_DD1 | CPU_FTRS_POWER9_DD2_1 | \
+	     CPU_FTRS_POWER9_DD2_2)
 #endif
 #else
 enum {
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index c40a9fc..68052ea 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -553,11 +553,31 @@  static struct cpu_spec __initdata cpu_specs[] = {
 		.machine_check_early	= __machine_check_early_realmode_p9,
 		.platform		= "power9",
 	},
-	{	/* Power9 DD 2.1 or later (see DD2.0 above) */
+	{	/* Power9 DD 2.1 */
+		.pvr_mask		= 0xffffefff,
+		.pvr_value		= 0x004e0201,
+		.cpu_name		= "POWER9 (raw)",
+		.cpu_features		= CPU_FTRS_POWER9_DD2_1,
+		.cpu_user_features	= COMMON_USER_POWER9,
+		.cpu_user_features2	= COMMON_USER2_POWER9,
+		.mmu_features		= MMU_FTRS_POWER9,
+		.icache_bsize		= 128,
+		.dcache_bsize		= 128,
+		.num_pmcs		= 6,
+		.pmc_type		= PPC_PMC_IBM,
+		.oprofile_cpu_type	= "ppc64/power9",
+		.oprofile_type		= PPC_OPROFILE_INVALID,
+		.cpu_setup		= __setup_cpu_power9,
+		.cpu_restore		= __restore_cpu_power9,
+		.flush_tlb		= __flush_tlb_power9,
+		.machine_check_early	= __machine_check_early_realmode_p9,
+		.platform		= "power9",
+	},
+	{	/* Power9 DD2.2 or later */
 		.pvr_mask		= 0xffff0000,
 		.pvr_value		= 0x004e0000,
 		.cpu_name		= "POWER9 (raw)",
-		.cpu_features		= CPU_FTRS_POWER9_DD2_1,
+		.cpu_features		= CPU_FTRS_POWER9_DD2_2,
 		.cpu_user_features	= COMMON_USER_POWER9,
 		.cpu_user_features2	= COMMON_USER2_POWER9,
 		.mmu_features		= MMU_FTRS_POWER9,
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index ee562ff..0a0c601 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -589,6 +589,8 @@  static struct dt_cpu_feature_match __initdata
 	{"virtual-page-class-key-protection", feat_enable, 0},
 	{"transactional-memory", feat_enable_tm, CPU_FTR_TM},
 	{"transactional-memory-v3", feat_enable_tm, 0},
+	{"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},
 	{"idle-stop", feat_enable_idle_stop, 0},
@@ -708,6 +710,9 @@  static __init void cpufeatures_cpu_quirks(void)
 		cur_cpu_spec->cpu_features |= CPU_FTR_POWER9_DD1;
 	else if ((version & 0xffffefff) == 0x004e0201)
 		cur_cpu_spec->cpu_features |= CPU_FTR_POWER9_DD2_1;
+	else if ((version & 0xffffefff) == 0x004e0202)
+		cur_cpu_spec->cpu_features |= CPU_FTR_P9_TM_HV_ASSIST |
+			CPU_FTR_P9_TM_XER_SO_BUG;
 }
 
 static void __init cpufeatures_setup_finished(void)