Re: [PATCH 1/2] [v3] m68k: move sun3 into a top-level platform option

Greg Ungerer <gerg@xxxxxxxxxx> · Mon, 4 Nov 2024 23:44:41 +1000

Hi Arnd,

On 31/10/24 05:56, Arnd Bergmann wrote:
From: Arnd Bergmann <arnd@xxxxxxxx>

It is possible to select an m68k MMU build but not actually
enable any of the three MMU options, which then results in a
build failure:

  arch/m68k/include/asm/page.h:10:25: error: 'CONFIG_PAGE_SHIFT' undeclared here (not in a function); did you mean 'CONFIG_LOG_BUF_SHIFT'?

Change the Kconfig selection to ensure that exactly one of the
three options is always enabled whenever an MMU-enabled kernel
is built, but moving CONFIG_SUN3 into a top-level option next
to M68KCLASSIC and COLDFIRE.

All defconfig files should keep working without changes,
but alldefconfig now builds support for the classic MMU.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202408032138.P7sBvIns-lkp@xxxxxxxxx/
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

All looks fine to me, thanks for taking care of this.

Acked-by: Greg Ungerer <gerg@xxxxxxxxxxxxxx>

Regards
Greg



---
v3:
  - fix coldfire+mmu build failure, by taking out the m68020 default

v2:
  - resend
---
  arch/m68k/Kconfig         | 11 +++++------
  arch/m68k/Kconfig.cpu     | 35 ++++++++++++++++++++++-------------
  arch/m68k/Kconfig.machine | 25 -------------------------
  arch/m68k/kernel/Makefile | 12 ++----------
  arch/m68k/kernel/time.c   |  4 ++--
  5 files changed, 31 insertions(+), 56 deletions(-)

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index cc26df907bfe..7c4f7bcc89d7 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -84,24 +84,23 @@ config MMU
  	  support by paged memory management. If unsure, say 'Y'.
  
  config MMU_MOTOROLA
-	bool
+	def_bool MMU && M68KCLASSIC
  	select HAVE_PAGE_SIZE_4KB
  
  config MMU_COLDFIRE
+	def_bool MMU && COLDFIRE
  	select HAVE_PAGE_SIZE_8KB
-	bool
  
  config MMU_SUN3
-	bool
+	def_bool MMU && SUN3
  	select HAVE_PAGE_SIZE_8KB
-	depends on MMU && !MMU_MOTOROLA && !MMU_COLDFIRE
  
  config ARCH_SUPPORTS_KEXEC
-	def_bool M68KCLASSIC && MMU
+	def_bool (M68KCLASSIC || SUN3) && MMU
  
  config BOOTINFO_PROC
  	bool "Export bootinfo in procfs"
-	depends on KEXEC && M68KCLASSIC
+	depends on KEXEC && (M68KCLASSIC || SUN3)
  	help
  	  Say Y to export the bootinfo used to boot the kernel in a
  	  "bootinfo" file in procfs.  This is useful with kexec.
diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu
index c777a129768a..e7b5f6b55947 100644
--- a/arch/m68k/Kconfig.cpu
+++ b/arch/m68k/Kconfig.cpu
@@ -2,7 +2,7 @@
  comment "Processor Type"
  
  choice
-	prompt "CPU family support"
+	prompt "CPU/machine family support"
  	default M68KCLASSIC if MMU
  	default COLDFIRE if !MMU
  	help
@@ -19,7 +19,7 @@ choice
  	  processor, select COLDFIRE.
  
  config M68KCLASSIC
-	bool "Classic M68K CPU family support"
+	bool "Classic M68K CPU/machine family support"
  	select HAVE_ARCH_PFN_VALID
  
  config COLDFIRE
@@ -32,13 +32,23 @@ config COLDFIRE
  	select HAVE_LEGACY_CLK
  	select HAVE_PAGE_SIZE_8KB if !MMU
  
-endchoice
+config SUN3
+	bool "Sun3 machine support"
+	depends on MMU
+	select HAVE_ARCH_PFN_VALID
+	select LEGACY_TIMER_TICK
+	select NO_DMA
+	select M68020
+	help
+	  This option enables support for the Sun 3 series of workstations
+	  (3/50, 3/60, 3/1xx, 3/2xx systems). These use a classic 68020 CPU
+	  but the custom memory management unit makes them incompatible with
+	  all other classic m68k machines, including Sun 3x.
  
-if M68KCLASSIC
+endchoice
  
  config M68000
-	def_bool y
-	depends on !MMU
+	def_bool M68KCLASSIC && !MMU
  	select CPU_HAS_NO_BITFIELDS
  	select CPU_HAS_NO_CAS
  	select CPU_HAS_NO_MULDIV64
@@ -56,7 +66,7 @@ config M68000
  	  a paging MMU.
  
  config M68020
-	bool "68020 support"
+	bool "68020 support" if M68KCLASSIC
  	depends on MMU
  	select FPU
  	select CPU_HAS_ADDRESS_SPACES
@@ -66,9 +76,10 @@ config M68020
  	  68851 MMU (Memory Management Unit) to run Linux/m68k, except on the
  	  Sun 3, which provides its own version.
  
+if M68KCLASSIC && MMU
+
  config M68030
  	bool "68030 support"
-	depends on MMU && !MMU_SUN3
  	select FPU
  	select CPU_HAS_ADDRESS_SPACES
  	help
@@ -78,7 +89,6 @@ config M68030
  
  config M68040
  	bool "68040 support"
-	depends on MMU && !MMU_SUN3
  	select FPU
  	select CPU_HAS_ADDRESS_SPACES
  	help
@@ -89,13 +99,14 @@ config M68040
  
  config M68060
  	bool "68060 support"
-	depends on MMU && !MMU_SUN3
  	select FPU
  	select CPU_HAS_ADDRESS_SPACES
  	help
  	  If you anticipate running this kernel on a computer with a MC68060
  	  processor, say Y. Otherwise, say N.
  
+endif # M68KCLASSIC
+
  config M68328
  	bool
  	depends on !MMU
@@ -117,8 +128,6 @@ config M68VZ328
  	help
  	  Motorola 68VZ328 processor support.
  
-endif # M68KCLASSIC
-
  if COLDFIRE
  
  choice
@@ -325,7 +334,7 @@ comment "Processor Specific Options"
  
  config M68KFPU_EMU
  	bool "Math emulation support"
-	depends on M68KCLASSIC && FPU
+	depends on (M68KCLASSIC || SUN3) && FPU
  	help
  	  At some point in the future, this will cause floating-point math
  	  instructions to be emulated by the kernel on machines that lack a
diff --git a/arch/m68k/Kconfig.machine b/arch/m68k/Kconfig.machine
index d06b1c5d9b0c..de39f23b180e 100644
--- a/arch/m68k/Kconfig.machine
+++ b/arch/m68k/Kconfig.machine
@@ -6,7 +6,6 @@ if M68KCLASSIC
  config AMIGA
  	bool "Amiga support"
  	depends on MMU
-	select MMU_MOTOROLA if MMU
  	select LEGACY_TIMER_TICK
  	help
  	  This option enables support for the Amiga series of computers. If
@@ -16,7 +15,6 @@ config AMIGA
  config ATARI
  	bool "Atari support"
  	depends on MMU
-	select MMU_MOTOROLA if MMU
  	select HAVE_ARCH_NVRAM_OPS
  	select LEGACY_TIMER_TICK
  	help
@@ -31,7 +29,6 @@ config ATARI_KBD_CORE
  config MAC
  	bool "Macintosh support"
  	depends on MMU
-	select MMU_MOTOROLA if MMU
  	select HAVE_ARCH_NVRAM_OPS
  	select HAVE_PATA_PLATFORM
  	select LEGACY_TIMER_TICK
@@ -44,7 +41,6 @@ config MAC
  config APOLLO
  	bool "Apollo support"
  	depends on MMU
-	select MMU_MOTOROLA if MMU
  	select LEGACY_TIMER_TICK
  	help
  	  Say Y here if you want to run Linux on an MC680x0-based Apollo
@@ -53,7 +49,6 @@ config APOLLO
  config VME
  	bool "VME (Motorola and BVM) support"
  	depends on MMU
-	select MMU_MOTOROLA if MMU
  	help
  	  Say Y here if you want to build a kernel for a 680x0 based VME
  	  board.  Boards currently supported include Motorola boards MVME147,
@@ -97,7 +92,6 @@ config BVME6000
  config HP300
  	bool "HP9000/300 and HP9000/400 support"
  	depends on MMU
-	select MMU_MOTOROLA if MMU
  	select LEGACY_TIMER_TICK
  	help
  	  This option enables support for the HP9000/300 and HP9000/400 series
@@ -110,7 +104,6 @@ config SUN3X
  	bool "Sun3x support"
  	depends on MMU
  	select LEGACY_TIMER_TICK
-	select MMU_MOTOROLA if MMU
  	select M68030
  	help
  	  This option enables support for the Sun 3x series of workstations.
@@ -124,7 +117,6 @@ config SUN3X
  config Q40
  	bool "Q40/Q60 support"
  	depends on MMU
-	select MMU_MOTOROLA if MMU
  	select LEGACY_TIMER_TICK
  	help
  	  The Q40 is a Motorola 68040-based successor to the Sinclair QL
@@ -133,22 +125,6 @@ config Q40
  	  Q60. Select your CPU below.  For 68LC060 don't forget to enable FPU
  	  emulation.
  
-config SUN3
-	bool "Sun3 support"
-	depends on MMU
-	depends on !MMU_MOTOROLA
-	select MMU_SUN3 if MMU
-	select LEGACY_TIMER_TICK
-	select NO_DMA
-	select M68020
-	help
-	  This option enables support for the Sun 3 series of workstations
-	  (3/50, 3/60, 3/1xx, 3/2xx systems). Enabling this option requires
-	  that all other hardware types must be disabled, as Sun 3 kernels
-	  are incompatible with all other m68k targets (including Sun 3x!).
-
-	  If you don't want to compile a kernel exclusively for a Sun 3, say N.
-
  config VIRT
  	bool "Virtual M68k Machine support"
  	depends on MMU
@@ -157,7 +133,6 @@ config VIRT
  	select GOLDFISH_TIMER
  	select GOLDFISH_TTY
  	select M68040
-	select MMU_MOTOROLA if MMU
  	select RTC_CLASS
  	select RTC_DRV_GOLDFISH
  	select TTY
diff --git a/arch/m68k/kernel/Makefile b/arch/m68k/kernel/Makefile
index f335bf3268a1..6c732ed3998b 100644
--- a/arch/m68k/kernel/Makefile
+++ b/arch/m68k/kernel/Makefile
@@ -5,16 +5,8 @@
  
  extra-y			+= vmlinux.lds
  
-obj-$(CONFIG_AMIGA)	:= head.o
-obj-$(CONFIG_ATARI)	:= head.o
-obj-$(CONFIG_MAC)	:= head.o
-obj-$(CONFIG_APOLLO)	:= head.o
-obj-$(CONFIG_VME)	:= head.o
-obj-$(CONFIG_HP300)	:= head.o
-obj-$(CONFIG_Q40)	:= head.o
-obj-$(CONFIG_SUN3X)	:= head.o
-obj-$(CONFIG_VIRT)	:= head.o
-obj-$(CONFIG_SUN3)	:= sun3-head.o
+obj-$(CONFIG_MMU_MOTOROLA)	:= head.o
+obj-$(CONFIG_SUN3)		:= sun3-head.o
  
  obj-y	+= entry.o irq.o module.o process.o ptrace.o
  obj-y	+= setup.o signal.o sys_m68k.o syscalltable.o time.o traps.o
diff --git a/arch/m68k/kernel/time.c b/arch/m68k/kernel/time.c
index a97600b2af50..108debb87cfb 100644
--- a/arch/m68k/kernel/time.c
+++ b/arch/m68k/kernel/time.c
@@ -62,7 +62,7 @@ void timer_heartbeat(void)
  }
  #endif /* CONFIG_HEARTBEAT */
  
-#ifdef CONFIG_M68KCLASSIC
+#if defined(CONFIG_M68KCLASSIC) || defined(CONFIG_SUN3)
  /* machine dependent timer functions */
  int (*mach_hwclk) (int, struct rtc_time*);
  EXPORT_SYMBOL(mach_hwclk);
@@ -149,7 +149,7 @@ static int __init rtc_init(void)
  
  module_init(rtc_init);
  #endif /* CONFIG_RTC_DRV_GENERIC */
-#endif /* CONFIG M68KCLASSIC */
+#endif /* CONFIG M68KCLASSIC || SUN3 */
  
  void __init time_init(void)
  {







