ARC: Fix PAE40 boot failures due to PTE truncation

So a benign looking cleanup which macro'ized PAGE_SHIFT shifts turned
out to be bad (since it was done non-sensically across the board).

It caused boot failures with PAE40 as forced cast to (unsigned long)
from newly introduced virt_to_pfn() was causing truncatiion of the
(long long) pte/paddr values.

It is OK to use this in accessors dealing with kernel virtual address,
pointers etc, but not for PTE values themelves.

Fixes: cJ2ff5cf2735c ("ARC: mm: Use virt_to_pfn() for addr >> PAGE_SHIFT pattern)
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index 36da89e2c853ef0551bfcee0f145454e23a81dd6..533e5a0c6ba52cdc458a33f9d678d9f9a62c1bce 100644 (file)
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -72,6 +72,13 @@ typedef unsigned long pgprot_t;
 
 typedef pte_t * pgtable_t;
 
+/*
+ * Use virt_to_pfn with caution:
+ * If used in pte or paddr related macros, it could cause truncation
+ * in PAE40 builds
+ * As a rule of thumb, only use it in helpers starting with virt_
+ * You have been warned !
+ */
 #define virt_to_pfn(kaddr)     (__pa(kaddr) >> PAGE_SHIFT)
 
 #define ARCH_PFN_OFFSET                virt_to_pfn(CONFIG_LINUX_LINK_BASE)
@@ -85,7 +92,7 @@ typedef pte_t * pgtable_t;
  * virt here means link-address/program-address as embedded in object code.
  * And for ARC, link-addr = physical address
  */
-#define __pa(vaddr)  ((unsigned long)vaddr)
+#define __pa(vaddr)  ((unsigned long)(vaddr))
 #define __va(paddr)  ((void *)((unsigned long)(paddr)))
 
 #define virt_to_page(kaddr)    \

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 7d6c93e63adf3af60a0642b03b3ae798061b1e65..10d4b8b8e5450e83468f96f16d9ad18b5c62d3b0 100644 (file)
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -278,14 +278,13 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
 #define pmd_present(x)                 (pmd_val(x))
 #define pmd_clear(xp)                  do { pmd_val(*(xp)) = 0; } while (0)
 
-#define pte_page(pte)  \
-       (mem_map + virt_to_pfn(pte_val(pte) - CONFIG_LINUX_LINK_BASE))
-
+#define pte_page(pte)          pfn_to_page(pte_pfn(pte))
 #define mk_pte(page, prot)     pfn_pte(page_to_pfn(page), prot)
-#define pte_pfn(pte)           virt_to_pfn(pte_val(pte))
-#define pfn_pte(pfn, prot)     (__pte(((pte_t)(pfn) << PAGE_SHIFT) | \
-                                pgprot_val(prot)))
-#define __pte_index(addr)      (virt_to_pfn(addr) & (PTRS_PER_PTE - 1))
+#define pfn_pte(pfn, prot)     (__pte(((pte_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
+
+/* Don't use virt_to_pfn for macros below: could cause truncations for PAE40*/
+#define pte_pfn(pte)           (pte_val(pte) >> PAGE_SHIFT)
+#define __pte_index(addr)      (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 
 /*
  * pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system)