Merge tag 'virt-to-pfn-for-arch-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator into asm-generic

This is an attempt to harden the typing on virt_to_pfn()
and pfn_to_virt().

Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

For symmetry, we do the same with pfn_to_virt().

The problem with this inconsistent typing was pointed out by
Russell King:
https://lore.kernel.org/linux-arm-kernel/YoJDKJXc0MJ2QZTb@shell.armlinux.org.uk/

And confirmed by Andrew Morton:
https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/

So the recognition of the problem is widespread.

These platforms have been chosen as initial conversion targets:

- ARM
- ARM64/Aarch64
- asm-generic (including for example x86)
- m68k

The idea is that if this goes in, it will block further misuse
of the function signatures due to the large compile coverage,
and then I can go in and fix the remaining architectures on a
one-by-one basis.

Some of the patches have been circulated before but were not
picked up by subsystem maintainers, so now the arch tree is
target for this series.

It has passed zeroday builds after a lot of iterations in my
personal tree, but there could be some randconfig outliers.
New added or deeply hidden problems appear all the time so
some minor fallout can be expected.

* tag 'virt-to-pfn-for-arch-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator:
  m68k/mm: Make pfn accessors static inlines
  arm64: memory: Make virt_to_pfn() a static inline
  ARM: mm: Make virt_to_pfn() a static inline
  asm-generic/page.h: Make pfn accessors static inlines
  xen/netback: Pass (void *) to virt_to_page()
  netfs: Pass a pointer to virt_to_page()
  cifs: Pass a pointer to virt_to_page() in cifsglob
  cifs: Pass a pointer to virt_to_page()
  riscv: mm: init: Pass a pointer to virt_to_page()
  ARC: init: Pass a pointer to virt_to_pfn() in init
  m68k: Pass a pointer to virt_to_pfn() virt_to_page()
  fs/proc/kcore.c: Pass a pointer to virt_addr_valid()

Author: arndb

arch/arc/mm/init.c

@@ -87,7 +87,7 @@ void __init setup_arch_memory(void)
 	setup_initial_init_mm(_text, _etext, _edata, _end);
 
 	/* first page of system - kernel .vector starts here */
-	min_low_pfn = virt_to_pfn(CONFIG_LINUX_RAM_BASE);
+	min_low_pfn = virt_to_pfn((void *)CONFIG_LINUX_RAM_BASE);
 
 	/* Last usable page of low mem */
 	max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);

arch/arm/common/sharpsl_param.c

@@ -11,7 +11,7 @@
 #include <linux/module.h>
 #include <linux/string.h>
 #include <asm/mach/sharpsl_param.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 
 /*
  * Certain hardware parameters determined at the time of device manufacture,

arch/arm/include/asm/delay.h

@@ -7,7 +7,7 @@
 #ifndef __ASM_ARM_DELAY_H
 #define __ASM_ARM_DELAY_H
 
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/param.h>	/* HZ */
 
 /*

arch/arm/include/asm/io.h

@@ -23,7 +23,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <asm/byteorder.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm-generic/pci_iomap.h>
 
 /*

arch/arm/include/asm/memory.h

@@ -5,11 +5,16 @@
  *  Copyright (C) 2000-2002 Russell King
  *  modification for nommu, Hyok S. Choi, 2004
  *
- *  Note: this file should not be included by non-asm/.h files
+ *  Note: this file should not be included explicitly, include <asm/page.h>
+ *  to get access to these definitions.
  */
 #ifndef __ASM_ARM_MEMORY_H
 #define __ASM_ARM_MEMORY_H
 
+#ifndef _ASMARM_PAGE_H
+#error "Do not include <asm/memory.h> directly"
+#endif
+
 #include <linux/compiler.h>
 #include <linux/const.h>
 #include <linux/types.h>
@@ -288,10 +293,12 @@ static inline unsigned long __phys_to_virt(phys_addr_t x)
 
 #endif
 
-#define virt_to_pfn(kaddr) \
-	((((unsigned long)(kaddr) - PAGE_OFFSET) >> PAGE_SHIFT) + \
-	 PHYS_PFN_OFFSET)
-
+static inline unsigned long virt_to_pfn(const void *p)
+{
+	unsigned long kaddr = (unsigned long)p;
+	return (((kaddr - PAGE_OFFSET) >> PAGE_SHIFT) +
+		PHYS_PFN_OFFSET);
+}
 #define __pa_symbol_nodebug(x)	__virt_to_phys_nodebug((x))
 
 #ifdef CONFIG_DEBUG_VIRTUAL

arch/arm/include/asm/page.h

@@ -161,10 +161,10 @@ extern int pfn_valid(unsigned long);
 #define pfn_valid pfn_valid
 #endif
 
-#include <asm/memory.h>
-
 #endif /* !__ASSEMBLY__ */
 
+#include <asm/memory.h>
+
 #define VM_DATA_DEFAULT_FLAGS	VM_DATA_FLAGS_TSK_EXEC
 
 #include <asm-generic/getorder.h>

arch/arm/include/asm/pgtable.h

@@ -27,7 +27,7 @@ extern struct page *empty_zero_page;
 #else
 
 #include <asm-generic/pgtable-nopud.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/pgtable-hwdef.h>
 
 

arch/arm/include/asm/proc-fns.h

@@ -147,8 +147,6 @@ static inline void init_proc_vtable(const struct processor *p)
 
 extern void cpu_resume(void);
 
-#include <asm/memory.h>
-
 #ifdef CONFIG_MMU
 
 #define cpu_switch_mm(pgd,mm) cpu_do_switch_mm(virt_to_phys(pgd),mm)

arch/arm/include/asm/sparsemem.h

@@ -2,7 +2,7 @@
 #ifndef ASMARM_SPARSEMEM_H
 #define ASMARM_SPARSEMEM_H
 
-#include <asm/memory.h>
+#include <asm/page.h>
 
 /*
  * Two definitions are required for sparsemem:

arch/arm/include/asm/uaccess-asm.h

@@ -5,7 +5,7 @@
 
 #include <asm/asm-offsets.h>
 #include <asm/domain.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/thread_info.h>
 
 	.macro	csdb