Re: [PATCH v7 00/11] KASAN for powerpc/32

Re: [PATCH v7 00/11] KASAN for powerpc/32

[Christophe Leroy]

Le 25/02/2019 à 14:48, Christophe Leroy a écrit :
> This series adds KASAN support to powerpc/32

Looks like only half of defconfigs build ok.

I hope I have now fixes everything. Will run on kisskb tonight and send 
out v8 tomorrow if everything is OK.

Christophe

> 
> Tested on nohash/32 (8xx) and book3s/32 (mpc832x ie 603).
> Boot tested on qemu mac99
> 
> Changes in v7:
> - split in several smaller patches
> - prom_init now has its own string functions
> - full deactivation of powerpc-optimised string functions when KASAN is active
> - shadow area now at a fixed place on very top of kernel virtual space.
> - Early static hash table for hash book3s/32.
> - Full support of both inline and outline instrumentation for both hash and nohash ppc32
> - Earlier full activation of kasan.
> 
> Changes in v6:
> - Fixed oops on module loading (due to access to RO shadow zero area).
> - Added support for hash book3s/32, thanks to Daniel's patch to differ KASAN activation.
> - Reworked handling of optimised string functions (dedicated patch for it)
> - Reordered some files to ease adding of book3e/64 support.
> 
> Changes in v5:
> - Added KASAN_SHADOW_OFFSET in Makefile, otherwise we fallback to KASAN_MINIMAL
> and some stuff like stack instrumentation is not performed
> - Moved calls to kasan_early_init() in head.S because stack instrumentation
> in machine_init was performed before the call to kasan_early_init()
> - Mapping kasan_early_shadow_page RW in kasan_early_init() and
> remaping RO later in kasan_init()
> - Allocating a big memblock() for shadow area, falling back to PAGE_SIZE blocks in case of failure.
> 
> Changes in v4:
> - Comments from Andrey (DISABLE_BRANCH_PROFILING, Activation of reports)
> - Proper initialisation of shadow area in kasan_init()
> - Panic in case Hash table is required.
> - Added comments in patch one to explain why *t = *s becomes memcpy(t, s, ...)
> - Call of kasan_init_tags()
> 
> Changes in v3:
> - Removed the printk() in kasan_early_init() to avoid build failure (see https://github.com/linuxppc/issues/issues/218)
> - Added necessary changes in asm/book3s/32/pgtable.h to get it work on powerpc 603 family
> - Added a few KASAN_SANITIZE_xxx.o := n to successfully boot on powerpc 603 family
> 
> Changes in v2:
> - Rebased.
> - Using __set_pte_at() to build the early table.
> - Worked around and got rid of the patch adding asm/page.h in asm/pgtable-types.h
>      ==> might be fixed independently but not needed for this serie.
> 
> Christophe Leroy (11):
>    powerpc/32: Move early_init() in a separate file
>    powerpc: prepare string/mem functions for KASAN
>    powerpc/prom_init: don't use string functions from lib/
>    powerpc/mm: don't use direct assignation during early boot.
>    powerpc/32: use memset() instead of memset_io() to zero BSS
>    powerpc/32: make KVIRT_TOP dependant on FIXMAP_START
>    powerpc/32: prepare shadow area for KASAN
>    powerpc: disable KASAN instrumentation on early/critical files.
>    powerpc/32: Add KASAN support
>    powerpc/32s: move hash code patching out of MMU_init_hw()
>    powerpc/32s: set up an early static hash table for KASAN.
> 
>   arch/powerpc/Kconfig                         |   6 +
>   arch/powerpc/include/asm/book3s/32/pgtable.h |   2 +-
>   arch/powerpc/include/asm/fixmap.h            |   5 +
>   arch/powerpc/include/asm/kasan.h             |  39 +++++
>   arch/powerpc/include/asm/nohash/32/pgtable.h |   2 +-
>   arch/powerpc/include/asm/string.h            |  32 +++-
>   arch/powerpc/kernel/Makefile                 |  14 +-
>   arch/powerpc/kernel/cputable.c               |  13 +-
>   arch/powerpc/kernel/early_32.c               |  36 +++++
>   arch/powerpc/kernel/head_32.S                |  46 ++++--
>   arch/powerpc/kernel/head_40x.S               |   3 +
>   arch/powerpc/kernel/head_44x.S               |   3 +
>   arch/powerpc/kernel/head_8xx.S               |   3 +
>   arch/powerpc/kernel/head_fsl_booke.S         |   3 +
>   arch/powerpc/kernel/prom_init.c              | 213 +++++++++++++++++++++------
>   arch/powerpc/kernel/prom_init_check.sh       |  12 +-
>   arch/powerpc/kernel/setup-common.c           |   3 +
>   arch/powerpc/kernel/setup_32.c               |  28 ----
>   arch/powerpc/lib/Makefile                    |  19 ++-
>   arch/powerpc/lib/copy_32.S                   |  15 +-
>   arch/powerpc/lib/mem_64.S                    |  10 +-
>   arch/powerpc/lib/memcpy_64.S                 |   4 +-
>   arch/powerpc/mm/Makefile                     |   7 +
>   arch/powerpc/mm/init_32.c                    |   1 +
>   arch/powerpc/mm/kasan/Makefile               |   5 +
>   arch/powerpc/mm/kasan/kasan_init_32.c        | 177 ++++++++++++++++++++++
>   arch/powerpc/mm/mem.c                        |   4 +
>   arch/powerpc/mm/mmu_decl.h                   |   2 +
>   arch/powerpc/mm/ppc_mmu_32.c                 |  34 +++--
>   arch/powerpc/mm/ptdump/ptdump.c              |   8 +
>   arch/powerpc/platforms/powermac/Makefile     |   6 +
>   arch/powerpc/purgatory/Makefile              |   3 +
>   arch/powerpc/xmon/Makefile                   |   1 +
>   33 files changed, 640 insertions(+), 119 deletions(-)
>   create mode 100644 arch/powerpc/include/asm/kasan.h
>   create mode 100644 arch/powerpc/kernel/early_32.c
>   create mode 100644 arch/powerpc/mm/kasan/Makefile
>   create mode 100644 arch/powerpc/mm/kasan/kasan_init_32.c
> 

Re: [PATCH v7 07/11] powerpc/32: prepare shadow area for KASAN

[Daniel Axtens]

Christophe Leroy <christophe.leroy@c-s.fr> writes:

> This patch prepares a shadow area for KASAN.
>
> The shadow area will be at the top of the kernel virtual
> memory space above the fixmap area and will occupy one
> eighth of the total kernel virtual memory space.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
>  arch/powerpc/Kconfig              |  5 +++++
>  arch/powerpc/include/asm/fixmap.h |  5 +++++
>  arch/powerpc/include/asm/kasan.h  | 17 +++++++++++++++++
>  arch/powerpc/mm/mem.c             |  4 ++++
>  arch/powerpc/mm/ptdump/ptdump.c   |  8 ++++++++
>  5 files changed, 39 insertions(+)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 652c25260838..f446e016f4a1 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -382,6 +382,11 @@ config PGTABLE_LEVELS
>  	default 3 if PPC_64K_PAGES && !PPC_BOOK3S_64
>  	default 4
>  
> +config KASAN_SHADOW_OFFSET
> +	hex
> +	depends on KASAN
> +	default 0xe0000000
> +

Should this live in Kconfig.debug?

Regards,
Daniel

>  source "arch/powerpc/sysdev/Kconfig"
>  source "arch/powerpc/platforms/Kconfig"
>  
> diff --git a/arch/powerpc/include/asm/fixmap.h b/arch/powerpc/include/asm/fixmap.h
> index b9fbed84ddca..51a1a309c919 100644
> --- a/arch/powerpc/include/asm/fixmap.h
> +++ b/arch/powerpc/include/asm/fixmap.h
> @@ -22,7 +22,12 @@
>  #include <asm/kmap_types.h>
>  #endif
>  
> +#ifdef CONFIG_KASAN
> +#include <asm/kasan.h>
> +#define FIXADDR_TOP	KASAN_SHADOW_START
> +#else
>  #define FIXADDR_TOP	((unsigned long)(-PAGE_SIZE))
> +#endif
>  
>  /*
>   * Here we define all the compile-time 'special' virtual
> diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
> index 2efd0e42cfc9..b554d3bd3e2c 100644
> --- a/arch/powerpc/include/asm/kasan.h
> +++ b/arch/powerpc/include/asm/kasan.h
> @@ -12,4 +12,21 @@
>  #define EXPORT_SYMBOL_KASAN(fn)	EXPORT_SYMBOL(fn)
>  #endif
>  
> +#ifndef __ASSEMBLY__
> +
> +#include <asm/page.h>
> +#include <asm/pgtable-types.h>
> +
> +#define KASAN_SHADOW_SCALE_SHIFT	3
> +
> +#define KASAN_SHADOW_OFFSET	ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET)
> +
> +#define KASAN_SHADOW_START	(KASAN_SHADOW_OFFSET + \
> +				 (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT))
> +
> +#define KASAN_SHADOW_END	0UL
> +
> +#define KASAN_SHADOW_SIZE	(KASAN_SHADOW_END - KASAN_SHADOW_START)
> +
> +#endif /* __ASSEMBLY */
>  #endif
> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index f6787f90e158..4e7fa4eb2dd3 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -309,6 +309,10 @@ void __init mem_init(void)
>  	mem_init_print_info(NULL);
>  #ifdef CONFIG_PPC32
>  	pr_info("Kernel virtual memory layout:\n");
> +#ifdef CONFIG_KASAN
> +	pr_info("  * 0x%08lx..0x%08lx  : kasan shadow mem\n",
> +		KASAN_SHADOW_START, KASAN_SHADOW_END);
> +#endif
>  	pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
>  #ifdef CONFIG_HIGHMEM
>  	pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
> diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
> index 37138428ab55..812ed680024f 100644
> --- a/arch/powerpc/mm/ptdump/ptdump.c
> +++ b/arch/powerpc/mm/ptdump/ptdump.c
> @@ -101,6 +101,10 @@ static struct addr_marker address_markers[] = {
>  	{ 0,	"Fixmap start" },
>  	{ 0,	"Fixmap end" },
>  #endif
> +#ifdef CONFIG_KASAN
> +	{ 0,	"kasan shadow mem start" },
> +	{ 0,	"kasan shadow mem end" },
> +#endif
>  	{ -1,	NULL },
>  };
>  
> @@ -322,6 +326,10 @@ static void populate_markers(void)
>  #endif
>  	address_markers[i++].start_address = FIXADDR_START;
>  	address_markers[i++].start_address = FIXADDR_TOP;
> +#ifdef CONFIG_KASAN
> +	address_markers[i++].start_address = KASAN_SHADOW_START;
> +	address_markers[i++].start_address = KASAN_SHADOW_END;
> +#endif
>  #endif /* CONFIG_PPC64 */
>  }
>  
> -- 
> 2.13.3