arm64: 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 inclues callers
using virt_to_phys on image addresses instead of __pa_symbol. As features
such as CONFIG_VMAP_STACK get enabled for arm64, this becomes increasingly
important. Add checks to catch bad virt_to_phys usage.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1117421268976b62dd4e77cd3a523c10070f3ace..359bca239ba7d3a4b7c3623af67f2581efa2bd07 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -6,6 +6,7 @@ config ARM64
        select ACPI_MCFG if ACPI
        select ACPI_SPCR_TABLE if ACPI
        select ARCH_CLOCKSOURCE_DATA
+       select ARCH_HAS_DEBUG_VIRTUAL
        select ARCH_HAS_DEVMEM_IS_ALLOWED
        select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
        select ARCH_HAS_ELF_RANDOMIZE

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 0ff237a75c0569dda68813be965aee1efc8ec601..7011f0857629dc262ebe8fd18eb91e928f509d53 100644 (file)
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -172,10 +172,33 @@ static inline unsigned long kaslr_offset(void)
  * private definitions which should NOT be used outside memory.h
  * files.  Use virt_to_phys/phys_to_virt/__pa/__va instead.
  */
-#define __virt_to_phys(x) ({                                           \
+
+
+/*
+ * The linear kernel range starts in the middle of the virtual adddress
+ * space. Testing the top bit for the start of the region is a
+ * sufficient check.
+ */
+#define __is_lm_address(addr)  (!!((addr) & BIT(VA_BITS - 1)))
+
+#define __lm_to_phys(addr)     (((addr) & ~PAGE_OFFSET) + PHYS_OFFSET)
+#define __kimg_to_phys(addr)   ((addr) - kimage_voffset)
+
+#define __virt_to_phys_nodebug(x) ({                                   \
        phys_addr_t __x = (phys_addr_t)(x);                             \
-       __x & BIT(VA_BITS - 1) ? (__x & ~PAGE_OFFSET) + PHYS_OFFSET :   \
-                                (__x - kimage_voffset); })
+       __is_lm_address(__x) ? __lm_to_phys(__x) :                      \
+                              __kimg_to_phys(__x);                     \
+})
+
+#define __pa_symbol_nodebug(x) __kimg_to_phys((phys_addr_t)(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
 
 #define __phys_to_virt(x)      ((unsigned long)((x) - PHYS_OFFSET) | PAGE_OFFSET)
 #define __phys_to_kimg(x)      ((unsigned long)((x) + kimage_voffset))
@@ -207,6 +230,8 @@ 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 __pa_nodebug(x)                __virt_to_phys_nodebug((unsigned long)(x))
 #define __va(x)                        ((void *)__phys_to_virt((phys_addr_t)(x)))
 #define pfn_to_kaddr(pfn)      __va((pfn) << PAGE_SHIFT)
 #define virt_to_pfn(x)      __phys_to_pfn(__virt_to_phys((unsigned long)(x)))

diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
index e703fb9defada7bae533eb83aedacb399c5df8f1..9b0ba191e48e387123974ec51be2b72dd7d5d48a 100644 (file)
--- a/arch/arm64/mm/Makefile
+++ b/arch/arm64/mm/Makefile
@@ -6,6 +6,8 @@ obj-$(CONFIG_HUGETLB_PAGE)      += hugetlbpage.o
 obj-$(CONFIG_ARM64_PTDUMP_CORE)        += dump.o
 obj-$(CONFIG_ARM64_PTDUMP_DEBUGFS)     += ptdump_debugfs.o
 obj-$(CONFIG_NUMA)             += numa.o
+obj-$(CONFIG_DEBUG_VIRTUAL)    += physaddr.o
+KASAN_SANITIZE_physaddr.o      += n
 
 obj-$(CONFIG_KASAN)            += kasan_init.o
 KASAN_SANITIZE_kasan_init.o    := n

diff --git a/arch/arm64/mm/physaddr.c b/arch/arm64/mm/physaddr.c
new file mode 100644 (file)
index 0000000..91371da
--- /dev/null
+++ b/arch/arm64/mm/physaddr.c
@@ -0,0 +1,30 @@
+#include <linux/bug.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/mmdebug.h>
+#include <linux/mm.h>
+
+#include <asm/memory.h>
+
+phys_addr_t __virt_to_phys(unsigned long x)
+{
+       WARN(!__is_lm_address(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);