Re: [PATCH] MIPS: Add support for CONFIG_DEBUG_VIRTUAL

[Florian Fainelli <f.fainelli@gmail.com>]

On 03/28/2017 10:57 AM, Florian Fainelli wrote:
> Provide hooks to intercept bad usages of virt_to_phys() and
> __pa_symbol() throughout the kernel. To make this possible, we need to
> rename the current implement of virt_to_phys() into
> __virt_to_phys_nodebug() and wrap it around depending on
> CONFIG_DEBUG_VIRTUAL.
> 
> A similar thing is needed for __pa_symbol() which is now aliased to
> __phys_addr_symbol() whose implementation is either the direct return of
> RELOC_HIDE or goes through the debug version.

Ping? This may not longer apply cleanly against arch/mips/Kconfig, but
the conflicts should be trivial to resolve.

Thanks.

> 
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
>  arch/mips/Kconfig            |  1 +
>  arch/mips/include/asm/io.h   | 14 +++++++++++++-
>  arch/mips/include/asm/page.h |  9 ++++++++-
>  arch/mips/mm/Makefile        |  2 ++
>  arch/mips/mm/physaddr.c      | 40 ++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 64 insertions(+), 2 deletions(-)
>  create mode 100644 arch/mips/mm/physaddr.c
> 
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 2afb41c52ba0..724457b5a7eb 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -70,6 +70,7 @@ config MIPS
>  	select HAVE_EXIT_THREAD
>  	select HAVE_REGS_AND_STACK_ACCESS_API
>  	select HAVE_ARCH_HARDENED_USERCOPY
> +	select ARCH_HAS_DEBUG_VIRTUAL
>  
>  menu "Machine selection"
>  
> diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
> index ecabc00c1e66..016e12161c9d 100644
> --- a/arch/mips/include/asm/io.h
> +++ b/arch/mips/include/asm/io.h
> @@ -116,11 +116,23 @@ static inline void set_io_port_base(unsigned long base)
>   *     almost all conceivable cases a device driver should not be using
>   *     this function
>   */
> -static inline unsigned long virt_to_phys(volatile const void *address)
> +static inline unsigned long __virt_to_phys_nodebug(volatile const void *address)
>  {
>  	return __pa(address);
>  }
>  
> +#ifdef CONFIG_DEBUG_VIRTUAL
> +extern phys_addr_t __virt_to_phys(volatile const void *x);
> +#else
> +#define __virt_to_phys(x)	__virt_to_phys_nodebug(x)
> +#endif
> +
> +#define virt_to_phys virt_to_phys
> +static inline phys_addr_t virt_to_phys(const volatile void *x)
> +{
> +	return __virt_to_phys(x);
> +}
> +
>  /*
>   *     phys_to_virt    -       map physical address to virtual
>   *     @address: address to remap
> diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
> index 5f987598054f..bf8bd7d77fce 100644
> --- a/arch/mips/include/asm/page.h
> +++ b/arch/mips/include/asm/page.h
> @@ -205,9 +205,16 @@ static inline unsigned long ___pa(unsigned long x)
>   * until GCC 3.x has been retired before we can apply
>   * https://patchwork.linux-mips.org/patch/1541/
>   */
> +#define __pa_symbol_nodebug(x)	__pa(RELOC_HIDE((unsigned long)(x), 0))
> +
> +#ifdef CONFIG_DEBUG_VIRTUAL
> +extern phys_addr_t __phys_addr_symbol(unsigned long x);
> +#else
> +#define __phys_addr_symbol(x)	__pa_symbol_nodebug(x)
> +#endif
>  
>  #ifndef __pa_symbol
> -#define __pa_symbol(x)	__pa(RELOC_HIDE((unsigned long)(x), 0))
> +#define __pa_symbol(x)		__phys_addr_symbol((unsigned long)(x))
>  #endif
>  
>  #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
> diff --git a/arch/mips/mm/Makefile b/arch/mips/mm/Makefile
> index b4cc8811a664..0a1d241c50fb 100644
> --- a/arch/mips/mm/Makefile
> +++ b/arch/mips/mm/Makefile
> @@ -29,3 +29,5 @@ obj-$(CONFIG_R5000_CPU_SCACHE)	+= sc-r5k.o
>  obj-$(CONFIG_RM7000_CPU_SCACHE) += sc-rm7k.o
>  obj-$(CONFIG_MIPS_CPU_SCACHE)	+= sc-mips.o
>  obj-$(CONFIG_SCACHE_DEBUGFS)	+= sc-debugfs.o
> +
> +obj-$(CONFIG_DEBUG_VIRTUAL)	+= physaddr.o
> diff --git a/arch/mips/mm/physaddr.c b/arch/mips/mm/physaddr.c
> new file mode 100644
> index 000000000000..6123a9b3b3c0
> --- /dev/null
> +++ b/arch/mips/mm/physaddr.c
> @@ -0,0 +1,40 @@
> +#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/io.h>
> +#include <asm/page.h>
> +#include <asm/dma.h>
> +
> +static inline bool __debug_virt_addr_valid(unsigned long x)
> +{
> +	if (x >= PAGE_OFFSET && x < (unsigned long)high_memory)
> +		return true;
> +
> +	return false;
> +}
> +
> +phys_addr_t __virt_to_phys(volatile const void *x)
> +{
> +	WARN(!__debug_virt_addr_valid((unsigned long)x),
> +	     "virt_to_phys used for non-linear address: %pK (%pS)\n",
> +	     x, 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)_text ||
> +		       x > (unsigned long)_end);
> +
> +	return __pa_symbol_nodebug(x);
> +}
> +EXPORT_SYMBOL(__phys_addr_symbol);
> 


-- 
Florian