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Commit ec6d06ef authored by Laura Abbott's avatar Laura Abbott Committed by Will Deacon
Browse files

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: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarLaura Abbott <labbott@redhat.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 2077be67

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/include/asm/memory.h

+28 −3
Original line number Diff line number Diff line
@@ -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)))

arch/arm64/mm/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/mm/physaddr.c

0 → 100644
+30 −0
Original line number Diff line number Diff line 
#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);