Hi Sasha, I love your patch! Yet something to improve:
[auto build test ERROR on tip/x86/asm] [also build test ERROR on tip/auto-latest linus/master tip/x86/core v5.7-rc4 next-20200508] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Sasha-Levin/Enable-FSGSBASE-instructions/20200510-032805 base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 2ce0d7f9766f0e49bb54f149c77bae89464932fb config: i386-allyesconfig (attached as .config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce: # save the attached .config to linux build tree make ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <l...@intel.com> All error/warnings (new ones prefixed by >>): In file included from arch/x86/include/uapi/asm/ptrace.h:6:0, from arch/x86/include/asm/ptrace.h:7, from arch/x86/include/asm/math_emu.h:5, from arch/x86/include/asm/processor.h:13, from arch/x86/include/asm/cpufeature.h:5, from arch/x86/include/asm/thread_info.h:53, from include/linux/thread_info.h:38, from arch/x86/include/asm/preempt.h:7, from include/linux/preempt.h:78, from include/linux/spinlock.h:51, from include/linux/mmzone.h:8, from include/linux/gfp.h:6, from include/linux/mm.h:10, from arch/x86/kernel/process.c:6: >> arch/x86/include/uapi/asm/ptrace-abi.h:16:12: error: expected identifier >> before numeric constant #define FS 9 ^ >> arch/x86/kernel/process.h:42:2: note: in expansion of macro 'FS' FS, ^~ In file included from arch/x86/kernel/process.c:46:0: arch/x86/kernel/process.h: In function 'save_base_legacy': >> arch/x86/kernel/process.h:85:18: error: 'struct thread_struct' has no member >> named 'fsbase' prev_p->thread.fsbase = 0; ^ >> arch/x86/kernel/process.h:87:18: error: 'struct thread_struct' has no member >> named 'gsbase' prev_p->thread.gsbase = 0; ^ In file included from arch/x86/include/asm/ptrace.h:5:0, from arch/x86/include/asm/math_emu.h:5, from arch/x86/include/asm/processor.h:13, from arch/x86/include/asm/cpufeature.h:5, from arch/x86/include/asm/thread_info.h:53, from include/linux/thread_info.h:38, from arch/x86/include/asm/preempt.h:7, from include/linux/preempt.h:78, from include/linux/spinlock.h:51, from include/linux/mmzone.h:8, from include/linux/gfp.h:6, from include/linux/mm.h:10, from arch/x86/kernel/process.c:6: arch/x86/kernel/process.h: In function 'save_fsgs': >> arch/x86/kernel/process.h:93:30: error: 'struct thread_struct' has no member >> named 'fsindex' savesegment(fs, task->thread.fsindex); ^ arch/x86/include/asm/segment.h:368:32: note: in definition of macro 'savesegment' asm("mov %%" #seg ",%0":"=r" (value) : : "memory") ^~~~~ >> arch/x86/kernel/process.h:94:30: error: 'struct thread_struct' has no member >> named 'gsindex' savesegment(gs, task->thread.gsindex); ^ arch/x86/include/asm/segment.h:368:32: note: in definition of macro 'savesegment' asm("mov %%" #seg ",%0":"=r" (value) : : "memory") ^~~~~ In file included from arch/x86/kernel/process.c:46:0: arch/x86/kernel/process.h:101:15: error: 'struct thread_struct' has no member named 'fsbase' task->thread.fsbase = rdfsbase(); ^ >> arch/x86/kernel/process.h:101:25: error: implicit declaration of function >> 'rdfsbase'; did you mean 'rb_erase'? [-Werror=implicit-function-declaration] task->thread.fsbase = rdfsbase(); ^~~~~~~~ rb_erase arch/x86/kernel/process.h:102:15: error: 'struct thread_struct' has no member named 'gsbase' task->thread.gsbase = x86_gsbase_read_cpu_inactive(); ^ >> arch/x86/kernel/process.h:102:25: error: implicit declaration of function >> 'x86_gsbase_read_cpu_inactive' [-Werror=implicit-function-declaration] task->thread.gsbase = x86_gsbase_read_cpu_inactive(); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/x86/kernel/process.h:104:38: error: 'struct thread_struct' has no member named 'fsindex' save_base_legacy(task, task->thread.fsindex, FS); ^ arch/x86/kernel/process.h:105:38: error: 'struct thread_struct' has no member named 'gsindex' save_base_legacy(task, task->thread.gsindex, GS); ^ cc1: some warnings being treated as errors vim +85 arch/x86/kernel/process.h 40 41 enum which_selector { > 42 FS, 43 GS 44 }; 45 46 /* 47 * Saves the FS or GS base for an outgoing thread if FSGSBASE extensions are 48 * not available. The goal is to be reasonably fast on non-FSGSBASE systems. 49 * It's forcibly inlined because it'll generate better code and this function 50 * is hot. 51 */ 52 static __always_inline void save_base_legacy(struct task_struct *prev_p, 53 unsigned short selector, 54 enum which_selector which) 55 { 56 if (likely(selector == 0)) { 57 /* 58 * On Intel (without X86_BUG_NULL_SEG), the segment base could 59 * be the pre-existing saved base or it could be zero. On AMD 60 * (with X86_BUG_NULL_SEG), the segment base could be almost 61 * anything. 62 * 63 * This branch is very hot (it's hit twice on almost every 64 * context switch between 64-bit programs), and avoiding 65 * the RDMSR helps a lot, so we just assume that whatever 66 * value is already saved is correct. This matches historical 67 * Linux behavior, so it won't break existing applications. 68 * 69 * To avoid leaking state, on non-X86_BUG_NULL_SEG CPUs, if we 70 * report that the base is zero, it needs to actually be zero: 71 * see the corresponding logic in load_seg_legacy. 72 */ 73 } else { 74 /* 75 * If the selector is 1, 2, or 3, then the base is zero on 76 * !X86_BUG_NULL_SEG CPUs and could be anything on 77 * X86_BUG_NULL_SEG CPUs. In the latter case, Linux 78 * has never attempted to preserve the base across context 79 * switches. 80 * 81 * If selector > 3, then it refers to a real segment, and 82 * saving the base isn't necessary. 83 */ 84 if (which == FS) > 85 prev_p->thread.fsbase = 0; 86 else > 87 prev_p->thread.gsbase = 0; 88 } 89 } 90 91 static __always_inline void save_fsgs(struct task_struct *task) 92 { > 93 savesegment(fs, task->thread.fsindex); > 94 savesegment(gs, task->thread.gsindex); 95 if (static_cpu_has(X86_FEATURE_FSGSBASE)) { 96 /* 97 * If FSGSBASE is enabled, we can't make any useful guesses 98 * about the base, and user code expects us to save the current 99 * value. Fortunately, reading the base directly is efficient. 100 */ > 101 task->thread.fsbase = rdfsbase(); > 102 task->thread.gsbase = x86_gsbase_read_cpu_inactive(); --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org
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