Hi Yi, Thank you for the patch! Yet something to improve: [auto build test ERROR on tip/x86/core] [also build test ERROR on v4.19-rc3 next-20180913] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Yi-Sun/Enable-PV-qspinlock-for-Hyper-V/20180913-220827 config: x86_64-fedora-25 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 All error/warnings (new ones prefixed by >>): arch/x86//hyperv/hv_spinlock.c: In function 'hv_init_spinlocks': arch/x86//hyperv/hv_spinlock.c:86:2: error: implicit declaration of function '__pv_init_lock_hash'; did you mean 'spin_lock_bh'? [-Werror=implicit-function-declaration] __pv_init_lock_hash(); ^~~~~~~~~~~~~~~~~~~ spin_lock_bh arch/x86//hyperv/hv_spinlock.c:87:42: error: '__pv_queued_spin_lock_slowpath' undeclared (first use in this function); did you mean 'queued_spin_lock_slowpath'? pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ queued_spin_lock_slowpath arch/x86//hyperv/hv_spinlock.c:87:42: note: each undeclared identifier is reported only once for each function it appears in In file included from arch/x86/include/asm/msr.h:246:0, from arch/x86/include/asm/processor.h:21, 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:81, from include/linux/smp.h:60, from include/linux/kernel_stat.h:5, from arch/x86//hyperv/hv_spinlock.c:22: >> arch/x86/include/asm/paravirt.h:775:35: error: '__raw_callee_save___pv_queued_spin_unlock' undeclared (first use in this function); did you mean '__raw_callee_save_hv_vcpu_is_preempted'? ((struct paravirt_callee_save) { __raw_callee_save_##func }) ^ >> arch/x86//hyperv/hv_spinlock.c:88:35: note: in expansion of macro 'PV_CALLEE_SAVE' pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock); ^~~~~~~~~~~~~~ cc1: some warnings being treated as errors -- arch/x86/hyperv/hv_spinlock.c: In function 'hv_init_spinlocks': arch/x86/hyperv/hv_spinlock.c:86:2: error: implicit declaration of function '__pv_init_lock_hash'; did you mean 'spin_lock_bh'? [-Werror=implicit-function-declaration] __pv_init_lock_hash(); ^~~~~~~~~~~~~~~~~~~ spin_lock_bh arch/x86/hyperv/hv_spinlock.c:87:42: error: '__pv_queued_spin_lock_slowpath' undeclared (first use in this function); did you mean 'queued_spin_lock_slowpath'? pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ queued_spin_lock_slowpath arch/x86/hyperv/hv_spinlock.c:87:42: note: each undeclared identifier is reported only once for each function it appears in In file included from arch/x86/include/asm/msr.h:246:0, from arch/x86/include/asm/processor.h:21, 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:81, from include/linux/smp.h:60, from include/linux/kernel_stat.h:5, from arch/x86/hyperv/hv_spinlock.c:22: >> arch/x86/include/asm/paravirt.h:775:35: error: '__raw_callee_save___pv_queued_spin_unlock' undeclared (first use in this function); did you mean '__raw_callee_save_hv_vcpu_is_preempted'? ((struct paravirt_callee_save) { __raw_callee_save_##func }) ^ arch/x86/hyperv/hv_spinlock.c:88:35: note: in expansion of macro 'PV_CALLEE_SAVE' pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock); ^~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +775 arch/x86/include/asm/paravirt.h 2e47d3e6 include/asm-x86/paravirt.h Glauber de Oliveira Costa 2008-01-30 744 ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 745 /* ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 746 * Generate a thunk around a function which saves all caller-save ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 747 * registers except for the return value. This allows C functions to ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 748 * be called from assembler code where fewer than normal registers are ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 749 * available. It may also help code generation around calls from C ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 750 * code if the common case doesn't use many registers. ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 751 * ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 752 * When a callee is wrapped in a thunk, the caller can assume that all ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 753 * arg regs and all scratch registers are preserved across the ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 754 * call. The return value in rax/eax will not be saved, even for void ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 755 * functions. ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 756 */ 87b240cb arch/x86/include/asm/paravirt.h Josh Poimboeuf 2016-01-21 757 #define PV_THUNK_NAME(func) "__raw_callee_save_" #func ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 758 #define PV_CALLEE_SAVE_REGS_THUNK(func) \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 759 extern typeof(func) __raw_callee_save_##func; \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 760 \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 761 asm(".pushsection .text;" \ 87b240cb arch/x86/include/asm/paravirt.h Josh Poimboeuf 2016-01-21 762 ".globl " PV_THUNK_NAME(func) ";" \ 87b240cb arch/x86/include/asm/paravirt.h Josh Poimboeuf 2016-01-21 763 ".type " PV_THUNK_NAME(func) ", @function;" \ 87b240cb arch/x86/include/asm/paravirt.h Josh Poimboeuf 2016-01-21 764 PV_THUNK_NAME(func) ":" \ 87b240cb arch/x86/include/asm/paravirt.h Josh Poimboeuf 2016-01-21 765 FRAME_BEGIN \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 766 PV_SAVE_ALL_CALLER_REGS \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 767 "call " #func ";" \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 768 PV_RESTORE_ALL_CALLER_REGS \ 87b240cb arch/x86/include/asm/paravirt.h Josh Poimboeuf 2016-01-21 769 FRAME_END \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 770 "ret;" \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 771 ".popsection") ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 772 ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 773 /* Get a reference to a callee-save function */ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 774 #define PV_CALLEE_SAVE(func) \ ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 @775 ((struct paravirt_callee_save) { __raw_callee_save_##func }) ecb93d1c arch/x86/include/asm/paravirt.h Jeremy Fitzhardinge 2009-01-28 776 :::::: The code at line 775 was first introduced by commit :::::: ecb93d1ccd0aac63f03be2db3cac3fa974716f4c x86/paravirt: add register-saving thunks to reduce caller register pressure :::::: TO: Jeremy Fitzhardinge :::::: CC: H. 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