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Message-Id: <20170104223955.22859-4-f.fainelli@gmail.com>
Date: Wed, 4 Jan 2017 14:39:54 -0800
From: Florian Fainelli <f.fainelli@...il.com>
To: linux-arm-kernel@...ts.infradead.org, catalin.marinas@....com,
will.deacon@....com
Cc: Florian Fainelli <f.fainelli@...il.com>, linux@...linux.org.uk,
nicolas.pitre@...aro.org, panand@...hat.com,
chris.brandt@...esas.com, arnd@...db.de, jonathan.austin@....com,
pawel.moll@....com, vladimir.murzin@....com, mark.rutland@....com,
ard.biesheuvel@...aro.org, keescook@...omium.org,
matt@...eblueprint.co.uk, labbott@...oraproject.org,
kirill.shutemov@...ux.intel.com, ben@...adent.org.uk,
js07.lee@...sung.com, stefan@...er.ch,
linux-kernel@...r.kernel.org, linux-mtd@...ts.infradead.org,
cyrille.pitchen@...el.com, richard@....at,
boris.brezillon@...e-electrons.com, computersforpeace@...il.com,
dwmw2@...radead.org
Subject: [PATCH v6 3/4] ARM: Add support for CONFIG_DEBUG_VIRTUAL
x86 has an option: CONFIG_DEBUG_VIRTUAL to do additional checks on
virt_to_phys calls. The goal is to catch users who are calling
virt_to_phys on non-linear addresses immediately. This includes caller
using __virt_to_phys() on image addresses instead of __pa_symbol(). This
is a generally useful debug feature to spot bad code (particulary in
drivers).
Acked-by: Russell King <rmk+kernel@...linux.org.uk>
Acked-by: Laura Abbott <labbott@...hat.com>
Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
arch/arm/Kconfig | 1 +
arch/arm/include/asm/memory.h | 15 ++++++++++--
arch/arm/mm/Makefile | 1 +
arch/arm/mm/physaddr.c | 57 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 72 insertions(+), 2 deletions(-)
create mode 100644 arch/arm/mm/physaddr.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5fab553fd03a..4700294f4e09 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2,6 +2,7 @@ config ARM
bool
default y
select ARCH_CLOCKSOURCE_DATA
+ select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index bee7511c5098..c30d0d82a105 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -213,7 +213,7 @@ extern const void *__pv_table_begin, *__pv_table_end;
: "r" (x), "I" (__PV_BITS_31_24) \
: "cc")
-static inline phys_addr_t __virt_to_phys(unsigned long x)
+static inline phys_addr_t __virt_to_phys_nodebug(unsigned long x)
{
phys_addr_t t;
@@ -245,7 +245,7 @@ static inline unsigned long __phys_to_virt(phys_addr_t x)
#define PHYS_OFFSET PLAT_PHYS_OFFSET
#define PHYS_PFN_OFFSET ((unsigned long)(PHYS_OFFSET >> PAGE_SHIFT))
-static inline phys_addr_t __virt_to_phys(unsigned long x)
+static inline phys_addr_t __virt_to_phys_nodebug(unsigned long x)
{
return (phys_addr_t)x - PAGE_OFFSET + PHYS_OFFSET;
}
@@ -261,6 +261,16 @@ static inline unsigned long __phys_to_virt(phys_addr_t x)
((((unsigned long)(kaddr) - PAGE_OFFSET) >> PAGE_SHIFT) + \
PHYS_PFN_OFFSET)
+#define __pa_symbol_nodebug(x) __virt_to_phys_nodebug((x))
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+extern phys_addr_t __virt_to_phys(unsigned long x);
+extern phys_addr_t __phys_addr_symbol(unsigned long x);
+#else
+#define __virt_to_phys(x) __virt_to_phys_nodebug(x)
+#define __phys_addr_symbol(x) __pa_symbol_nodebug(x)
+#endif
+
/*
* These are *only* valid on the kernel direct mapped RAM memory.
* Note: Drivers should NOT use these. They are the wrong
@@ -283,6 +293,7 @@ static inline void *phys_to_virt(phys_addr_t x)
* Drivers should NOT use these either.
*/
#define __pa(x) __virt_to_phys((unsigned long)(x))
+#define __pa_symbol(x) __phys_addr_symbol(RELOC_HIDE((unsigned long)(x), 0))
#define __va(x) ((void *)__phys_to_virt((phys_addr_t)(x)))
#define pfn_to_kaddr(pfn) __va((phys_addr_t)(pfn) << PAGE_SHIFT)
diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index e8698241ece9..b3dea80715b4 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -14,6 +14,7 @@ endif
obj-$(CONFIG_ARM_PTDUMP) += dump.o
obj-$(CONFIG_MODULES) += proc-syms.o
+obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o
obj-$(CONFIG_ALIGNMENT_TRAP) += alignment.o
obj-$(CONFIG_HIGHMEM) += highmem.o
diff --git a/arch/arm/mm/physaddr.c b/arch/arm/mm/physaddr.c
new file mode 100644
index 000000000000..02e60f495608
--- /dev/null
+++ b/arch/arm/mm/physaddr.c
@@ -0,0 +1,57 @@
+#include <linux/bug.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/mmdebug.h>
+#include <linux/mm.h>
+
+#include <asm/sections.h>
+#include <asm/memory.h>
+#include <asm/fixmap.h>
+#include <asm/dma.h>
+
+#include "mm.h"
+
+static inline bool __virt_addr_valid(unsigned long x)
+{
+ /*
+ * high_memory does not get immediately defined, and there
+ * are early callers of __pa() against PAGE_OFFSET
+ */
+ if (!high_memory && x >= PAGE_OFFSET)
+ return true;
+
+ if (high_memory && x >= PAGE_OFFSET && x < (unsigned long)high_memory)
+ return true;
+
+ /*
+ * MAX_DMA_ADDRESS is a virtual address that may not correspond to an
+ * actual physical address. Enough code relies on __pa(MAX_DMA_ADDRESS)
+ * that we just need to work around it and always return true.
+ */
+ if (x == MAX_DMA_ADDRESS)
+ return true;
+
+ return false;
+}
+
+phys_addr_t __virt_to_phys(unsigned long x)
+{
+ WARN(!__virt_addr_valid(x),
+ "virt_to_phys used for non-linear address: %pK (%pS)\n",
+ (void *)x, (void *)x);
+
+ return __virt_to_phys_nodebug(x);
+}
+EXPORT_SYMBOL(__virt_to_phys);
+
+phys_addr_t __phys_addr_symbol(unsigned long x)
+{
+ /* This is bounds checking against the kernel image only.
+ * __pa_symbol should only be used on kernel symbol addresses.
+ */
+ VIRTUAL_BUG_ON(x < (unsigned long)KERNEL_START ||
+ x > (unsigned long)KERNEL_END);
+
+ return __pa_symbol_nodebug(x);
+}
+EXPORT_SYMBOL(__phys_addr_symbol);
--
2.9.3
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