From 961888b1d76d84efc66a8f5604b06ac12ac2f978 Mon Sep 17 00:00:00 2001 From: Rui Wang Date: Mon, 18 Dec 2017 16:34:10 +0800 Subject: [PATCH] selftests/x86/mpx: Fix incorrect bounds with old _sigfault For distributions with old userspace header files, the _sigfault structure is different. mpx-mini-test fails with the following error: [root@Purley]# mpx-mini-test_64 tabletest XSAVE is supported by HW & OS XSAVE processor supported state mask: 0x2ff XSAVE OS supported state mask: 0x2ff BNDREGS: size: 64 user: 1 supervisor: 0 aligned: 0 BNDCSR: size: 64 user: 1 supervisor: 0 aligned: 0 starting mpx bounds table test ERROR: siginfo bounds do not match shadow bounds for register 0 Fix it by using the correct offset of _lower/_upper in _sigfault. RHEL needs this patch to work. Signed-off-by: Rui Wang Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dave.hansen@linux.intel.com Fixes: e754aedc26ef ("x86/mpx, selftests: Add MPX self test") Link: http://lkml.kernel.org/r/1513586050-1641-1-git-send-email-rui.y.wang@intel.com Signed-off-by: Ingo Molnar --- tools/testing/selftests/x86/mpx-mini-test.c | 32 +++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/x86/mpx-mini-test.c b/tools/testing/selftests/x86/mpx-mini-test.c index ec0f6b45ce8b..9c0325e1ea68 100644 --- a/tools/testing/selftests/x86/mpx-mini-test.c +++ b/tools/testing/selftests/x86/mpx-mini-test.c @@ -315,11 +315,39 @@ static inline void *__si_bounds_upper(siginfo_t *si) return si->si_upper; } #else + +/* + * This deals with old version of _sigfault in some distros: + * + +old _sigfault: + struct { + void *si_addr; + } _sigfault; + +new _sigfault: + struct { + void __user *_addr; + int _trapno; + short _addr_lsb; + union { + struct { + void __user *_lower; + void __user *_upper; + } _addr_bnd; + __u32 _pkey; + }; + } _sigfault; + * + */ + static inline void **__si_bounds_hack(siginfo_t *si) { void *sigfault = &si->_sifields._sigfault; void *end_sigfault = sigfault + sizeof(si->_sifields._sigfault); - void **__si_lower = end_sigfault; + int *trapno = (int*)end_sigfault; + /* skip _trapno and _addr_lsb */ + void **__si_lower = (void**)(trapno + 2); return __si_lower; } @@ -331,7 +359,7 @@ static inline void *__si_bounds_lower(siginfo_t *si) static inline void *__si_bounds_upper(siginfo_t *si) { - return (*__si_bounds_hack(si)) + sizeof(void *); + return *(__si_bounds_hack(si) + 1); } #endif