[PATCH 1/3] powerpc/va: Add a __va() variant that doesn't do input validation

Aneesh Kumar K.V aneesh.kumar at linux.ibm.com
Fri May 8 00:23:14 AEST 2020


On ppc64, __va(x) do check for input argument to be less than PAGE_OFFSET.
In certain code paths, we want to skip that check. Add a variant ___va(x)
to be used in such cases.

Switch the #define to static inline. __pa() still doesn't benefit from this. But
a static inline done in this patch is better than multi-line #define.
For __va() we get the type checking benefit. We still have to keep the
macro __pa(x) to avoid a large number of compilation errors with the change.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
---
 arch/powerpc/include/asm/page.h         | 38 ++++++++++++++++---------
 arch/powerpc/mm/nohash/book3e_pgtable.c |  2 +-
 2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 3ee8df0f66e0..a3a2725a80ab 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/mmdebug.h>
 #else
 #include <asm/types.h>
 #endif
@@ -208,30 +209,41 @@ static inline bool pfn_valid(unsigned long pfn)
  * the other definitions for __va & __pa.
  */
 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
-#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
+#define ___va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
 #define __pa(x) ((phys_addr_t)(unsigned long)(x) - VIRT_PHYS_OFFSET)
+#define __va(x) ___va(x)
 #else
 #ifdef CONFIG_PPC64
+
+#ifndef __ASSEMBLY__
 /*
  * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET
  * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit.
  * This also results in better code generation.
  */
-#define __va(x)								\
-({									\
-	VIRTUAL_BUG_ON((unsigned long)(x) >= PAGE_OFFSET);		\
-	(void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET);	\
-})
-
-#define __pa(x)								\
-({									\
-	VIRTUAL_BUG_ON((unsigned long)(x) < PAGE_OFFSET);		\
-	(unsigned long)(x) & 0x0fffffffffffffffUL;			\
-})
+static inline void *___va(phys_addr_t addr)
+{
+	return (void *)(addr | PAGE_OFFSET);
+}
+
+static inline void *__va(phys_addr_t addr)
+{
+	VIRTUAL_BUG_ON((unsigned long)(addr) >= PAGE_OFFSET);
+	return ___va(addr);
+}
+
+static inline phys_addr_t ___pa(void *addr)
+{
+	VIRTUAL_BUG_ON((unsigned long)(addr) < PAGE_OFFSET);
+	return (phys_addr_t)((unsigned long)addr & 0x0fffffffffffffffUL);
+}
+#define __pa(x) ___pa((void *)(x))
+#endif /*  __ASSEMBLY__ */
 
 #else /* 32-bit, non book E */
-#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
+#define ___va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
+#define __va(x) ___va(x)
 #endif
 #endif
 
diff --git a/arch/powerpc/mm/nohash/book3e_pgtable.c b/arch/powerpc/mm/nohash/book3e_pgtable.c
index 4637fdd469cf..a8ce309ce740 100644
--- a/arch/powerpc/mm/nohash/book3e_pgtable.c
+++ b/arch/powerpc/mm/nohash/book3e_pgtable.c
@@ -60,7 +60,7 @@ static void __init *early_alloc_pgtable(unsigned long size)
 
 	if (!ptr)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx max_addr=%lx\n",
-		      __func__, size, size, __pa(MAX_DMA_ADDRESS));
+		      __func__, size, size, (unsigned long)__pa(MAX_DMA_ADDRESS));
 
 	return ptr;
 }
-- 
2.26.2



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