Re: [PATCH v2 14/16] powerpc/64s: Make hash MMU support configurable

Thisa adds Kconfig selection which allows the 64s hash MMU code to be
compiled out if radix is selected and the minimum supported CPU type is
POWER9 or higher, and KVM is not selected.

This saves 128kB kernel image size (90kB text) on powernv_defconfig
minus KVM, 350kB on pseries_defconfig minus KVM, 40kB on a tiny config.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
  arch/powerpc/Kconfig                     |  1 +
  arch/powerpc/kvm/Kconfig                 |  1 +
  arch/powerpc/platforms/Kconfig.cputype   | 21 ++++++++++++++++++---
  arch/powerpc/platforms/cell/Kconfig      |  1 +
  arch/powerpc/platforms/maple/Kconfig     |  1 +
  arch/powerpc/platforms/microwatt/Kconfig |  2 +-
  arch/powerpc/platforms/pasemi/Kconfig    |  1 +
  arch/powerpc/platforms/powermac/Kconfig  |  1 +
  arch/powerpc/platforms/powernv/Kconfig   |  2 +-
  9 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 4b34e408a3e6..5e122c67f6ca 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -936,6 +936,7 @@ config PPC_MEM_KEYS
  	prompt "PowerPC Memory Protection Keys"
  	def_bool y
  	depends on PPC_BOOK3S_64
+	depends on PPC_64S_HASH_MMU
  	select ARCH_USES_HIGH_VMA_FLAGS
  	select ARCH_HAS_PKEYS
  	help

diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index ff581d70f20c..4801424614be 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig

@@ -69,6 +69,7 @@ config KVM_BOOK3S_64
  	select KVM_BOOK3S_64_HANDLER
  	select KVM
  	select KVM_BOOK3S_PR_POSSIBLE if !KVM_BOOK3S_HV_POSSIBLE
+	select PPC_64S_HASH_MMU
  	select SPAPR_TCE_IOMMU if IOMMU_SUPPORT && (PPC_PSERIES || PPC_POWERNV)
  	help
  	  Support running unmodified book3s_64 and book3s_32 guest kernels

diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 01726e7f2c7f..1834cdd9626e 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype

@@ -105,10 +105,9 @@ config PPC_BOOK3S_64
  	select HAVE_MOVE_PMD
  	select HAVE_MOVE_PUD
  	select IRQ_WORK
-	select PPC_64S_HASH_MMU
-	select PPC_MM_SLICES
  	select PPC_HAVE_KUEP
  	select PPC_HAVE_KUAP
+	select PPC_64S_HASH_MMU if !PPC_RADIX_MMU
  
  config PPC_BOOK3E_64
  	bool "Embedded processors"

@@ -131,11 +130,13 @@ choice
  config GENERIC_CPU
  	bool "Generic (POWER4 and above)"
  	depends on PPC64 && !CPU_LITTLE_ENDIAN
+	select PPC_64S_HASH_MMU if PPC_BOOK3S_64
  
  config GENERIC_CPU
  	bool "Generic (POWER8 and above)"
  	depends on PPC64 && CPU_LITTLE_ENDIAN
  	select ARCH_HAS_FAST_MULTIPLIER
+	select PPC_64S_HASH_MMU
  
  config GENERIC_CPU
  	bool "Generic 32 bits powerpc"

@@ -144,24 +145,29 @@ config GENERIC_CPU
  config CELL_CPU
  	bool "Cell Broadband Engine"
  	depends on PPC_BOOK3S_64 && !CPU_LITTLE_ENDIAN
+	select PPC_64S_HASH_MMU
  
  config POWER5_CPU
  	bool "POWER5"
  	depends on PPC_BOOK3S_64 && !CPU_LITTLE_ENDIAN
+	select PPC_64S_HASH_MMU
  
  config POWER6_CPU
  	bool "POWER6"
  	depends on PPC_BOOK3S_64 && !CPU_LITTLE_ENDIAN
+	select PPC_64S_HASH_MMU
  
  config POWER7_CPU
  	bool "POWER7"
  	depends on PPC_BOOK3S_64
  	select ARCH_HAS_FAST_MULTIPLIER
+	select PPC_64S_HASH_MMU
  
  config POWER8_CPU
  	bool "POWER8"
  	depends on PPC_BOOK3S_64
  	select ARCH_HAS_FAST_MULTIPLIER
+	select PPC_64S_HASH_MMU
  
  config POWER9_CPU
  	bool "POWER9"

@@ -366,7 +372,15 @@ config SPE
  	  If in doubt, say Y here.
  
  config PPC_64S_HASH_MMU
-	bool
+	bool "Hash MMU Support"
+	depends on PPC_BOOK3S_64

+	help
+	  Enable support for the Power ISA Hash style MMU. This is implemented
+	  by all IBM Power and other Book3S CPUs.
+
+	  If you're unsure, say Y.
  
  config PPC_RADIX_MMU
  	bool "Radix MMU Support"

@@ -381,6 +395,7 @@ config PPC_RADIX_MMU
  config PPC_RADIX_MMU_DEFAULT
  	bool "Default to using the Radix MMU when possible"
  	depends on PPC_RADIX_MMU
+	depends on PPC_64S_HASH_MMU
  	default y
  	help
  	  When the hardware supports the Radix MMU, default to using it unless

diff --git a/arch/powerpc/platforms/cell/Kconfig b/arch/powerpc/platforms/cell/Kconfig
index db4465c51b56..faa894714a2a 100644
--- a/arch/powerpc/platforms/cell/Kconfig
+++ b/arch/powerpc/platforms/cell/Kconfig

@@ -8,6 +8,7 @@ config PPC_CELL_COMMON
  	select PPC_DCR_MMIO
  	select PPC_INDIRECT_PIO
  	select PPC_INDIRECT_MMIO
+	select PPC_64S_HASH_MMU
  	select PPC_HASH_MMU_NATIVE
  	select PPC_RTAS
  	select IRQ_EDGE_EOI_HANDLER

diff --git a/arch/powerpc/platforms/maple/Kconfig b/arch/powerpc/platforms/maple/Kconfig
index 7fd84311ade5..4c058cc57c90 100644
--- a/arch/powerpc/platforms/maple/Kconfig
+++ b/arch/powerpc/platforms/maple/Kconfig

@@ -9,6 +9,7 @@ config PPC_MAPLE
  	select GENERIC_TBSYNC
  	select PPC_UDBG_16550
  	select PPC_970_NAP
+	select PPC_64S_HASH_MMU
  	select PPC_HASH_MMU_NATIVE
  	select PPC_RTAS
  	select MMIO_NVRAM

diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig
index 62b51e37fc05..823192e9d38a 100644
--- a/arch/powerpc/platforms/microwatt/Kconfig
+++ b/arch/powerpc/platforms/microwatt/Kconfig

@@ -5,7 +5,7 @@ config PPC_MICROWATT
  	select PPC_XICS
  	select PPC_ICS_NATIVE
  	select PPC_ICP_NATIVE
-	select PPC_HASH_MMU_NATIVE
+	select PPC_HASH_MMU_NATIVE if PPC_64S_HASH_MMU
  	select PPC_UDBG_16550
  	select ARCH_RANDOM
  	help

diff --git a/arch/powerpc/platforms/pasemi/Kconfig b/arch/powerpc/platforms/pasemi/Kconfig
index bc7137353a7f..85ae18ddd911 100644
--- a/arch/powerpc/platforms/pasemi/Kconfig
+++ b/arch/powerpc/platforms/pasemi/Kconfig

@@ -5,6 +5,7 @@ config PPC_PASEMI
  	select MPIC
  	select FORCE_PCI
  	select PPC_UDBG_16550
+	select PPC_64S_HASH_MMU
  	select PPC_HASH_MMU_NATIVE
  	select MPIC_BROKEN_REGREAD
  	help

diff --git a/arch/powerpc/platforms/powermac/Kconfig b/arch/powerpc/platforms/powermac/Kconfig
index 2b56df145b82..130707ec9f99 100644
--- a/arch/powerpc/platforms/powermac/Kconfig
+++ b/arch/powerpc/platforms/powermac/Kconfig

@@ -6,6 +6,7 @@ config PPC_PMAC
  	select FORCE_PCI
  	select PPC_INDIRECT_PCI if PPC32
  	select PPC_MPC106 if PPC32
+	select PPC_64S_HASH_MMU if PPC64
  	select PPC_HASH_MMU_NATIVE
  	select ZONE_DMA if PPC32
  	default y

diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig
index cd754e116184..161dfe024085 100644
--- a/arch/powerpc/platforms/powernv/Kconfig
+++ b/arch/powerpc/platforms/powernv/Kconfig

@@ -2,7 +2,7 @@
  config PPC_POWERNV
  	depends on PPC64 && PPC_BOOK3S
  	bool "IBM PowerNV (Non-Virtualized) platform support"
-	select PPC_HASH_MMU_NATIVE
+	select PPC_HASH_MMU_NATIVE if PPC_64S_HASH_MMU
  	select PPC_XICS
  	select PPC_ICP_NATIVE
  	select PPC_XIVE_NATIVE