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* x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()Tony Luck2016-03-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Returning a 'bool' was very unpopular. Doubly so because the code was just wrong (returning zero for true, one for false; great for shell programming, not so good for C). Change return type to "int". Keep zero as the success indicator because it matches other similar code and people may be more comfortable writing: if (memcpy_mcsafe(to, from, count)) { printk("Sad panda, copy failed\n"); ... } Make the failure return value -EFAULT for now. Reported by: Mika Penttilä <mika.penttila@nextfour.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: mika.penttila@nextfour.com Fixes: 92b0729c34ca ("x86/mm, x86/mce: Add memcpy_mcsafe()") Link: http://lkml.kernel.org/r/695f14233fa7a54fcac4406c706d7fec228e3f4c.1457993040.git.tony.luck@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/mm, x86/mce: Add memcpy_mcsafe()Tony Luck2016-03-081-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | Make use of the EXTABLE_FAULT exception table entries to write a kernel copy routine that doesn't crash the system if it encounters a machine check. Prime use case for this is to copy from large arrays of non-volatile memory used as storage. We have to use an unrolled copy loop for now because current hardware implementations treat a machine check in "rep mov" as fatal. When that is fixed we can simplify. Return type is a "bool". True means that we copied OK, false means that it didn't. Signed-off-by: Tony Luck <tony.luck@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@gmail.com> Link: http://lkml.kernel.org/r/a44e1055efc2d2a9473307b22c91caa437aa3f8b.1456439214.git.tony.luck@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86, kasan: Fix build failure on KASAN=y && KMEMCHECK=y kernelsAndrey Ryabinin2015-10-191-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | Declaration of memcpy() is hidden under #ifndef CONFIG_KMEMCHECK. In asm/efi.h under #ifdef CONFIG_KASAN we #undef memcpy(), due to which the following happens: In file included from arch/x86/kernel/setup.c:96:0: ./arch/x86/include/asm/desc.h: In function ‘native_write_idt_entry’: ./arch/x86/include/asm/desc.h:122:2: error: implicit declaration of function ‘memcpy’ [-Werror=implicit-function-declaration] memcpy(&idt[entry], gate, sizeof(*gate)); ^ cc1: some warnings being treated as errors make[2]: *** [arch/x86/kernel/setup.o] Error 1 We will get rid of that #undef in asm/efi.h eventually. But in the meanwhile move memcpy() declaration out of #ifdefs to fix the build. Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1444994933-28328-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86_64: kasan: add interceptors for memset/memmove/memcpy functionsAndrey Ryabinin2015-02-131-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recently instrumentation of builtin functions calls was removed from GCC 5.0. To check the memory accessed by such functions, userspace asan always uses interceptors for them. So now we should do this as well. This patch declares memset/memmove/memcpy as weak symbols. In mm/kasan/kasan.c we have our own implementation of those functions which checks memory before accessing it. Default memset/memmove/memcpy now now always have aliases with '__' prefix. For files that built without kasan instrumentation (e.g. mm/slub.c) original mem* replaced (via #define) with prefixed variants, cause we don't want to check memory accesses there. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: add hooks for kmemcheckVegard Nossum2009-06-151-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | The hooks that we modify are: - Page fault handler (to handle kmemcheck faults) - Debug exception handler (to hide pages after single-stepping the instruction that caused the page fault) Also redefine memset() to use the optimized version if kmemcheck is enabled. (Thanks to Pekka Enberg for minimizing the impact on the page fault handler.) As kmemcheck doesn't handle MMX/SSE instructions (yet), we also disable the optimized xor code, and rely instead on the generic C implementation in order to avoid false-positive warnings. Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no> [whitespace fixlet] Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Ingo Molnar <mingo@elte.hu> [rebased for mainline inclusion] Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
* x86: Fix ASM_X86__ header guardsH. Peter Anvin2008-10-221-3/+3
| | | | | | | | | Change header guards named "ASM_X86__*" to "_ASM_X86_*" since: a. the double underscore is ugly and pointless. b. no leading underscore violates namespace constraints. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86, um: ... and asm-x86 moveAl Viro2008-10-221-0/+60
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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