From: Paul Mundt <lethal@linux-sh.org>
Date: Mon, 15 Oct 2007 02:01:33 +0000 (+0900)
Subject: sh: Correct pte_page() breakage.
X-Git-Tag: accepted/tizen/common/20141203.182822~26348^2~21
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=afca03574555c9af9a86d5a025f0187d0b77ac32;p=platform%2Fkernel%2Flinux-arm64.git

sh: Correct pte_page() breakage.

As noted by David:

pte_page() is a macro defined as follows;

    include/asm-sh/pgtable.h
    #define pte_page(x)    phys_to_page(pte_val(x)&PTE_PHYS_MASK)

    include/asm-sh/page.h
    #define phys_to_page(phys)    (pfn_to_page(phys >> PAGE_SHIFT))

So as you can see the phys_to_page() macro doesn't wrap the 'phys'
parameter in parentheses so we end up with;

    pte_val(x)&PTE_PHYS_MASK >> PAGE_SHIFT

Which is not what we wanted as '>>' has a higher precedence than bitwise
AND. I dug into the git repository and I believe this bug was added with
this commit (104b8deaa5c0144cccfc7d914413ff80c7176af1);

2006-03-27 KAMEZAWA Hiroyuki [PATCH] unify pfn_to_page: sh pfn_to_page

-#define phys_to_page(phys)     (mem_map + (((phys)-__MEMORY_START) >>
PAGE_SHIFT))
-#define page_to_phys(page)     (((page - mem_map) << PAGE_SHIFT) +
__MEMORY_START)
+#define phys_to_page(phys)     (pfn_to_page(phys >> PAGE_SHIFT))
+#define page_to_phys(page)     (page_to_pfn(page) << PAGE_SHIFT)

Reported-by: David ADDISON <david.addison@st.com>
Reported-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
---

diff --git a/include/asm-sh/page.h b/include/asm-sh/page.h
index cb3d46c..3aa8b07 100644
--- a/include/asm-sh/page.h
+++ b/include/asm-sh/page.h
@@ -128,7 +128,6 @@ typedef struct { unsigned long pgd; } pgd_t;
 #define __va(x)			((void *)((unsigned long)(x)+PAGE_OFFSET))
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
 
-#define phys_to_page(phys)	(pfn_to_page(phys >> PAGE_SHIFT))
 #define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
 
 /* PFN start number, because of __MEMORY_START */
diff --git a/include/asm-sh/pgtable.h b/include/asm-sh/pgtable.h
index cf0dd2b..0b1d7c6 100644
--- a/include/asm-sh/pgtable.h
+++ b/include/asm-sh/pgtable.h
@@ -399,7 +399,7 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
 #define	pmd_bad(x)	(pmd_val(x) & ~PAGE_MASK)
 
 #define pages_to_mb(x)	((x) >> (20-PAGE_SHIFT))
-#define pte_page(x)	phys_to_page(pte_val(x)&PTE_PHYS_MASK)
+#define pte_page(x)	pfn_to_page(pte_pfn(x))
 
 /*
  * The following only work if pte_present() is true.