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. As features such as CONFIG_VMAP_STACK get enabled for arm64, this becomes increasingly important. Add checks to catch bad virt_to_phys usage.
Signed-off-by: Laura Abbott <[email protected]> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/memory.h | 12 +++++++++++- arch/arm64/mm/Makefile | 2 ++ arch/arm64/mm/physaddr.c | 34 ++++++++++++++++++++++++++++++++++ 4 files changed, 48 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/mm/physaddr.c diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 969ef88..83b95bc 100644 --- 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 d773e2c..eac3dbb 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -167,11 +167,19 @@ extern u64 kimage_voffset; * 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) ({ \ +#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); }) +#ifdef CONFIG_DEBUG_VIRTUAL +extern unsigned long __virt_to_phys(unsigned long x); +extern unsigned long __phys_addr_symbol(unsigned long x); +#else +#define __virt_to_phys(x) __virt_to_phys_nodebug(x) +#define __phys_addr_symbol __pa +#endif + #define __phys_to_virt(x) ((unsigned long)((x) - PHYS_OFFSET) | PAGE_OFFSET) #define __phys_to_kimg(x) ((unsigned long)((x) + kimage_voffset)) @@ -202,6 +210,8 @@ 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 54bb209..377f4ab 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -5,6 +5,8 @@ obj-y := dma-mapping.o extable.o fault.o init.o \ obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_ARM64_PTDUMP) += dump.o obj-$(CONFIG_NUMA) += numa.o +CFLAGS_physaddr.o := -DTEXT_OFFSET=$(TEXT_OFFSET) +obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o obj-$(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 index 0000000..874c782 --- /dev/null +++ b/arch/arm64/mm/physaddr.c @@ -0,0 +1,34 @@ +#include <linux/mm.h> + +#include <asm/memory.h> + +unsigned long __virt_to_phys(unsigned long x) +{ + phys_addr_t __x = (phys_addr_t)x; + + if (__x & BIT(VA_BITS - 1)) { + /* + * 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. + */ + return (__x & ~PAGE_OFFSET) + PHYS_OFFSET; + } else { + VIRTUAL_BUG_ON(x < kimage_vaddr || x >= (unsigned long)_end); + return (__x - kimage_voffset); + } +} +EXPORT_SYMBOL(__virt_to_phys); + +unsigned long __phys_addr_symbol(unsigned long x) +{ + phys_addr_t __x = (phys_addr_t)x; + + /* + * This is intentionally different than above to be a tighter check + * for symbols. + */ + VIRTUAL_BUG_ON(x < kimage_vaddr + TEXT_OFFSET || x > (unsigned long) _end); + return (__x - kimage_voffset); +} +EXPORT_SYMBOL(__phys_addr_symbol); -- 2.10.1
