Re: [PATCH] powerpc: Make virt_to_pfn() a static inline

Le 14/08/2023 à 14:37, Michael Ellerman a écrit :

Linus Walleij [off-list ref] writes:

quoted

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.

...

quoted

diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index f2b6bf5687d0..9ee4b6d4a82a 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h

@@ -9,6 +9,7 @@
  #ifndef __ASSEMBLY__
  #include <linux/types.h>
  #include <linux/kernel.h>
+#include <linux/bug.h>
  #else
  #include <asm/types.h>
  #endif

@@ -119,16 +120,6 @@ extern long long virt_phys_offset;
  #define ARCH_PFN_OFFSET		((unsigned long)(MEMORY_START >> PAGE_SHIFT))
  #endif
  
-#define virt_to_pfn(kaddr)	(__pa(kaddr) >> PAGE_SHIFT)
-#define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
-#define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
-
-#define virt_addr_valid(vaddr)	({					\
-	unsigned long _addr = (unsigned long)vaddr;			\
-	_addr >= PAGE_OFFSET && _addr < (unsigned long)high_memory &&	\
-	pfn_valid(virt_to_pfn(_addr));					\
-})
-
  /*
   * On Book-E parts we need __va to parse the device tree and we can't
   * determine MEMORY_START until then.  However we can determine PHYSICAL_START

@@ -233,6 +224,25 @@ extern long long virt_phys_offset;
  #endif
  #endif
  
+#ifndef __ASSEMBLY__
+static inline unsigned long virt_to_pfn(const void *kaddr)
+{
+	return __pa(kaddr) >> PAGE_SHIFT;
+}
+
+static inline const void *pfn_to_kaddr(unsigned long pfn)
+{
+	return (const void *)(((unsigned long)__va(pfn)) << PAGE_SHIFT);

Any reason to do it this way rather than:

+       return __va(pfn << PAGE_SHIFT);

Even cleaner:

	return __va(PFN_PHYS(pfn));

Seems to be equivalent and much cleaner?

cheers