Re: [06/12] arch: Declare screen_info in <asm/screen_info.h>

Sui Jingfeng <suijingfeng@xxxxxxxxxxx> · Wed, 5 Jul 2023 09:21:07 +0800

Hi, Thomas


I love your patch, yet after applied your patch, the linux kernel fail 
to compile on my LoongArch machine.


```

  CC      arch/loongarch/kernel/efi.o
arch/loongarch/kernel/efi.c: In function ‘init_screen_info’:
arch/loongarch/kernel/efi.c:77:54: error: invalid application of 
‘sizeof’ to incomplete type ‘struct screen_info’
   77 |         si = early_memremap(screen_info_table, sizeof(*si));
      |                                                      ^
arch/loongarch/kernel/efi.c:82:9: error: ‘screen_info’ undeclared (first 
use in this function)
   82 |         screen_info = *si;
      |         ^~~~~~~~~~~
arch/loongarch/kernel/efi.c:82:9: note: each undeclared identifier is 
reported only once for each function it appears in
arch/loongarch/kernel/efi.c:82:23: error: invalid use of undefined type 
‘struct screen_info’
   82 |         screen_info = *si;
      |                       ^
arch/loongarch/kernel/efi.c:83:29: error: invalid application of 
‘sizeof’ to incomplete type ‘struct screen_info’
   83 |         memset(si, 0, sizeof(*si));
      |                             ^
arch/loongarch/kernel/efi.c:84:34: error: invalid application of 
‘sizeof’ to incomplete type ‘struct screen_info’
   84 |         early_memunmap(si, sizeof(*si));
      |                                  ^
make[3]: *** [scripts/Makefile.build:252: arch/loongarch/kernel/efi.o] 
Error 1
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [scripts/Makefile.build:494: arch/loongarch/kernel] Error 2
make[1]: *** [scripts/Makefile.build:494: arch/loongarch] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:2026: .] Error 2

```

On 2023/6/29 19:45, Thomas Zimmermann wrote:
The variable screen_info does not exist on all architectures. Declare
it in <asm-generic/screen_info.h>. All architectures that do declare it
will provide it via <asm/screen_info.h>.

Add the Kconfig token ARCH_HAS_SCREEN_INFO to guard against access on
architectures that don't provide screen_info.

Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Richard Henderson <richard.henderson@xxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Guo Ren <guoren@xxxxxxxxxx>
Cc: Brian Cain <bcain@xxxxxxxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: WANG Xuerui <kernel@xxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Dinh Nguyen <dinguyen@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Cc: Juerg Haefliger <juerg.haefliger@xxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
Cc: "Russell King (Oracle)" <rmk+kernel@xxxxxxxxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
Cc: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Acked-by: WANG Xuerui <git@xxxxxxxxxx> # loongarch
---
  arch/Kconfig                      |  6 ++++++
  arch/alpha/Kconfig                |  1 +
  arch/arm/Kconfig                  |  1 +
  arch/arm64/Kconfig                |  1 +
  arch/csky/Kconfig                 |  1 +
  arch/hexagon/Kconfig              |  1 +
  arch/ia64/Kconfig                 |  1 +
  arch/loongarch/Kconfig            |  1 +
  arch/mips/Kconfig                 |  1 +
  arch/nios2/Kconfig                |  1 +
  arch/powerpc/Kconfig              |  1 +
  arch/riscv/Kconfig                |  1 +
  arch/sh/Kconfig                   |  1 +
  arch/sparc/Kconfig                |  1 +
  arch/x86/Kconfig                  |  1 +
  arch/xtensa/Kconfig               |  1 +
  drivers/video/Kconfig             |  3 +++
  include/asm-generic/Kbuild        |  1 +
  include/asm-generic/screen_info.h | 12 ++++++++++++
  include/linux/screen_info.h       |  2 +-
  20 files changed, 38 insertions(+), 1 deletion(-)
  create mode 100644 include/asm-generic/screen_info.h

diff --git a/arch/Kconfig b/arch/Kconfig
index 205fd23e0cada..2f58293fd7bcb 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1466,6 +1466,12 @@ config ARCH_HAS_NONLEAF_PMD_YOUNG
  	  address translations. Page table walkers that clear the accessed bit
  	  may use this capability to reduce their search space.
  
+config ARCH_HAS_SCREEN_INFO
+	bool
+	help
+	  Selected by architectures that provide a global instance of
+	  screen_info.
+
  source "kernel/gcov/Kconfig"
  
  source "scripts/gcc-plugins/Kconfig"
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index a5c2b1aa46b02..d749011d88b14 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -4,6 +4,7 @@ config ALPHA
  	default y
  	select ARCH_32BIT_USTAT_F_TINODE
  	select ARCH_HAS_CURRENT_STACK_POINTER
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_MIGHT_HAVE_PC_PARPORT
  	select ARCH_MIGHT_HAVE_PC_SERIO
  	select ARCH_NO_PREEMPT
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 0fb4b218f6658..a9d01ee67a90e 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -15,6 +15,7 @@ config ARM
  	select ARCH_HAS_MEMBARRIER_SYNC_CORE
  	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
  	select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_SETUP_DMA_OPS
  	select ARCH_HAS_SET_MEMORY
  	select ARCH_STACKWALK
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 343e1e1cae10a..21addc4715bb3 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -36,6 +36,7 @@ config ARM64
  	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
  	select ARCH_HAS_PTE_DEVMAP
  	select ARCH_HAS_PTE_SPECIAL
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_SETUP_DMA_OPS
  	select ARCH_HAS_SET_DIRECT_MAP
  	select ARCH_HAS_SET_MEMORY
diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 4df1f8c9d170b..28444e581fc1f 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -10,6 +10,7 @@ config CSKY
  	select ARCH_USE_QUEUED_RWLOCKS
  	select ARCH_USE_QUEUED_SPINLOCKS
  	select ARCH_HAS_CURRENT_STACK_POINTER
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_INLINE_READ_LOCK if !PREEMPTION
  	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
  	select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
index 54eadf2651786..cc683c0a43d34 100644
--- a/arch/hexagon/Kconfig
+++ b/arch/hexagon/Kconfig
@@ -5,6 +5,7 @@ comment "Linux Kernel Configuration for Hexagon"
  config HEXAGON
  	def_bool y
  	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
  	select ARCH_NO_PREEMPT
  	select DMA_GLOBAL_POOL
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index e79f15e32a451..8b1e785e6d53d 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -10,6 +10,7 @@ config IA64
  	bool
  	select ARCH_BINFMT_ELF_EXTRA_PHDRS
  	select ARCH_HAS_DMA_MARK_CLEAN
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_STRNCPY_FROM_USER
  	select ARCH_HAS_STRNLEN_USER
  	select ARCH_MIGHT_HAVE_PC_PARPORT
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index d38b066fc931b..6aab2fb7753da 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -13,6 +13,7 @@ config LOONGARCH
  	select ARCH_HAS_FORTIFY_SOURCE
  	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
  	select ARCH_HAS_PTE_SPECIAL
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
  	select ARCH_INLINE_READ_LOCK if !PREEMPTION
  	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 675a8660cb85a..c0ae09789cb6d 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -10,6 +10,7 @@ config MIPS
  	select ARCH_HAS_KCOV
  	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE if !EVA
  	select ARCH_HAS_PTE_SPECIAL if !(32BIT && CPU_HAS_RIXI)
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_STRNCPY_FROM_USER
  	select ARCH_HAS_STRNLEN_USER
  	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index e5936417d3cd3..7183eea282212 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -3,6 +3,7 @@ config NIOS2
  	def_bool y
  	select ARCH_32BIT_OFF_T
  	select ARCH_HAS_DMA_PREP_COHERENT
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_SYNC_DMA_FOR_CPU
  	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
  	select ARCH_HAS_DMA_SET_UNCACHED
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index bff5820b7cda1..b1acad3076180 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -148,6 +148,7 @@ config PPC
  	select ARCH_HAS_PTE_DEVMAP		if PPC_BOOK3S_64
  	select ARCH_HAS_PTE_SPECIAL
  	select ARCH_HAS_SCALED_CPUTIME		if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_SET_MEMORY
  	select ARCH_HAS_STRICT_KERNEL_RWX	if (PPC_BOOK3S || PPC_8xx || 40x) && !HIBERNATION
  	select ARCH_HAS_STRICT_KERNEL_RWX	if PPC_85xx && !HIBERNATION && !RANDOMIZE_BASE
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5966ad97c30c3..b5a48f8424af9 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -29,6 +29,7 @@ config RISCV
  	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
  	select ARCH_HAS_PMEM_API
  	select ARCH_HAS_PTE_SPECIAL
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_SET_DIRECT_MAP if MMU
  	select ARCH_HAS_SET_MEMORY if MMU
  	select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 04b9550cf0070..001f5149952b4 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -10,6 +10,7 @@ config SUPERH
  	select ARCH_HAS_GIGANTIC_PAGE
  	select ARCH_HAS_GCOV_PROFILE_ALL
  	select ARCH_HAS_PTE_SPECIAL
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
  	select ARCH_HIBERNATION_POSSIBLE if MMU
  	select ARCH_MIGHT_HAVE_PC_PARPORT
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 8535e19062f65..e4bfb80b48cfe 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -13,6 +13,7 @@ config 64BIT
  config SPARC
  	bool
  	default y
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_MIGHT_HAVE_PC_PARPORT if SPARC64 && PCI
  	select ARCH_MIGHT_HAVE_PC_SERIO
  	select DMA_OPS
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 53bab123a8ee4..d7c2bf4ee403d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -91,6 +91,7 @@ config X86
  	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
  	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
  	select ARCH_HAS_COPY_MC			if X86_64
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_SET_MEMORY
  	select ARCH_HAS_SET_DIRECT_MAP
  	select ARCH_HAS_STRICT_KERNEL_RWX
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 3c6e5471f025b..c6cbd7459939c 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -8,6 +8,7 @@ config XTENSA
  	select ARCH_HAS_DMA_PREP_COHERENT if MMU
  	select ARCH_HAS_GCOV_PROFILE_ALL
  	select ARCH_HAS_KCOV
+	select ARCH_HAS_SCREEN_INFO
  	select ARCH_HAS_SYNC_DMA_FOR_CPU if MMU
  	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if MMU
  	select ARCH_HAS_DMA_SET_UNCACHED if MMU
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 8b2b9ac37c3df..d4a72bea56be0 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -21,6 +21,9 @@ config STI_CORE
  config VIDEO_CMDLINE
  	bool
  
+config ARCH_HAS_SCREEN_INFO
+	bool
+
  config VIDEO_NOMODESET
  	bool
  	default n
diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
index 941be574bbe00..5e5d4158a4b4b 100644
--- a/include/asm-generic/Kbuild
+++ b/include/asm-generic/Kbuild
@@ -47,6 +47,7 @@ mandatory-y += percpu.h
  mandatory-y += pgalloc.h
  mandatory-y += preempt.h
  mandatory-y += rwonce.h
+mandatory-y += screen_info.h
  mandatory-y += sections.h
  mandatory-y += serial.h
  mandatory-y += shmparam.h
diff --git a/include/asm-generic/screen_info.h b/include/asm-generic/screen_info.h
new file mode 100644
index 0000000000000..6fd0e50fabfcd
--- /dev/null
+++ b/include/asm-generic/screen_info.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_GENERIC_SCREEN_INFO_H
+#define _ASM_GENERIC_SCREEN_INFO_H
+
+#include <uapi/linux/screen_info.h>
+
+#if defined(CONFIG_ARCH_HAS_SCREEN_INFO)
+extern struct screen_info screen_info;
+#endif
+
+#endif /* _ASM_GENERIC_SCREEN_INFO_H */
diff --git a/include/linux/screen_info.h b/include/linux/screen_info.h
index eab7081392d50..c764b9a51c24b 100644
--- a/include/linux/screen_info.h
+++ b/include/linux/screen_info.h
@@ -4,6 +4,6 @@
  
  #include <uapi/linux/screen_info.h>
  
-extern struct screen_info screen_info;
+#include <asm/screen_info.h>
  
  #endif /* _SCREEN_INFO_H */







