Hi Michael, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 860461e4fcaa76200d2d1a53523e0ff7be92e6e8 commit: 231b232df8f67e7d37af01259c21f2a131c3911e [7032/8629] powerpc/64: Make VDSO32 track COMPAT on 64-bit config: powerpc64-randconfig-r035-20200917 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 1321160a26e7e489baf9b10d6de90a342f898960) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install powerpc64 cross compiling tool for clang build # apt-get install binutils-powerpc64-linux-gnu git checkout 231b232df8f67e7d37af01259c21f2a131c3911e # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>): arch/powerpc/kernel/vdso32/gettimeofday.S: Assembler messages: arch/powerpc/kernel/vdso32/gettimeofday.S:68: Error: missing operand arch/powerpc/kernel/vdso32/gettimeofday.S:69: Warning: invalid register expression arch/powerpc/kernel/vdso32/gettimeofday.S:69: Error: operand out of range (3 is not between 0 and 1) arch/powerpc/kernel/vdso32/gettimeofday.S:69: Error: missing operand arch/powerpc/kernel/vdso32/gettimeofday.S:72: Warning: invalid register expression arch/powerpc/kernel/vdso32/gettimeofday.S:72: Error: operand out of range (3 is not between 0 and 1) arch/powerpc/kernel/vdso32/gettimeofday.S:72: Error: missing operand arch/powerpc/kernel/vdso32/gettimeofday.S:73: Warning: invalid register expression arch/powerpc/kernel/vdso32/gettimeofday.S:73: Error: operand out of range (3 is not between 0 and 1) arch/powerpc/kernel/vdso32/gettimeofday.S:73: Error: missing operand arch/powerpc/kernel/vdso32/gettimeofday.S:86: Error: syntax error; found `@', expected `,' arch/powerpc/kernel/vdso32/gettimeofday.S:86: Error: junk at end of line: `@local' arch/powerpc/kernel/vdso32/gettimeofday.S:110: Warning: invalid register expression arch/powerpc/kernel/vdso32/gettimeofday.S:110: Error: operand out of range (8 is not between 0 and 1) arch/powerpc/kernel/vdso32/gettimeofday.S:110: Error: missing operand arch/powerpc/kernel/vdso32/gettimeofday.S:144: Warning: invalid register expression arch/powerpc/kernel/vdso32/gettimeofday.S:144: Error: missing operand arch/powerpc/kernel/vdso32/gettimeofday.S:213: Warning: invalid register expression arch/powerpc/kernel/vdso32/gettimeofday.S:213: Error: operand out of range (4 is not between 0 and 1) arch/powerpc/kernel/vdso32/gettimeofday.S:213: Error: missing operand clang-12: error: assembler command failed with exit code 1 (use -v to see invocation) # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 231b232df8f67e7d37af01259c21f2a131c3911e vim +40 arch/powerpc/kernel/vdso32/gettimeofday.S 597bc5c00b666f Paul Mackerras 2008-10-27 22 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 23 .text a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 24 /* a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 25 * Exact prototype of gettimeofday a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 26 * a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 27 * int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 28 * a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 29 */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 30 V_FUNCTION_BEGIN(__kernel_gettimeofday) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 31 .cfi_startproc a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 32 mflr r12 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 33 .cfi_register lr,r12 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 34 bfc2eae0ad72a4 Christophe Leroy 2019-12-02 35 mr. r10,r3 /* r10 saves tv */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 36 mr r11,r4 /* r11 saves tz */ ec0895f08f9951 Christophe Leroy 2019-12-02 37 get_datapage r9, r0 74609f4536f2b8 Tony Breeds 2007-06-26 38 beq 3f 6e2f9e9cfd560f Christophe Leroy 2019-12-02 39 LOAD_REG_IMMEDIATE(r7, 1000000) /* load up USEC_PER_SEC */ 8fd63a9ea75284 Paul Mackerras 2010-06-20 @40 bl __do_get_tspec@local /* get sec/usec from tb & kernel */ 8fd63a9ea75284 Paul Mackerras 2010-06-20 41 stw r3,TVAL32_TV_SEC(r10) 8fd63a9ea75284 Paul Mackerras 2010-06-20 42 stw r4,TVAL32_TV_USEC(r10) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 43 74609f4536f2b8 Tony Breeds 2007-06-26 44 3: cmplwi r11,0 /* check if tz is NULL */ bfc2eae0ad72a4 Christophe Leroy 2019-12-02 45 mtlr r12 bfc2eae0ad72a4 Christophe Leroy 2019-12-02 46 crclr cr0*4+so bfc2eae0ad72a4 Christophe Leroy 2019-12-02 47 li r3,0 bfc2eae0ad72a4 Christophe Leroy 2019-12-02 48 beqlr bfc2eae0ad72a4 Christophe Leroy 2019-12-02 49 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 50 lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 51 lwz r5,CFG_TZ_DSTTIME(r9) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 52 stw r4,TZONE_TZ_MINWEST(r11) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 53 stw r5,TZONE_TZ_DSTTIME(r11) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 54 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 55 blr a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 56 .cfi_endproc a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 57 V_FUNCTION_END(__kernel_gettimeofday) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 58 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 59 /* a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 60 * Exact prototype of clock_gettime() a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 61 * a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 62 * int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 63 * a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 64 */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 65 V_FUNCTION_BEGIN(__kernel_clock_gettime) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 66 .cfi_startproc a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 67 /* Check for supported clock IDs */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 @68 cmpli cr0,r3,CLOCK_REALTIME a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 69 cmpli cr1,r3,CLOCK_MONOTONIC 0c37ec2aa88bd8 Benjamin Herrenschmidt 2005-11-14 70 cror cr0*4+eq,cr0*4+eq,cr1*4+eq 654abc69ef2e69 Christophe Leroy 2019-12-02 71 654abc69ef2e69 Christophe Leroy 2019-12-02 72 cmpli cr5,r3,CLOCK_REALTIME_COARSE 654abc69ef2e69 Christophe Leroy 2019-12-02 73 cmpli cr6,r3,CLOCK_MONOTONIC_COARSE 654abc69ef2e69 Christophe Leroy 2019-12-02 74 cror cr5*4+eq,cr5*4+eq,cr6*4+eq 654abc69ef2e69 Christophe Leroy 2019-12-02 75 654abc69ef2e69 Christophe Leroy 2019-12-02 76 cror cr0*4+eq,cr0*4+eq,cr5*4+eq 654abc69ef2e69 Christophe Leroy 2019-12-02 77 bne cr0, .Lgettime_fallback a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 78 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 79 mflr r12 /* r12 saves lr */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 80 .cfi_register lr,r12 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 81 mr r11,r4 /* r11 saves tp */ ec0895f08f9951 Christophe Leroy 2019-12-02 82 get_datapage r9, r0 6e2f9e9cfd560f Christophe Leroy 2019-12-02 83 LOAD_REG_IMMEDIATE(r7, NSEC_PER_SEC) /* load up NSEC_PER_SEC */ 654abc69ef2e69 Christophe Leroy 2019-12-02 84 beq cr5, .Lcoarse_clocks 654abc69ef2e69 Christophe Leroy 2019-12-02 85 .Lprecise_clocks: 654abc69ef2e69 Christophe Leroy 2019-12-02 86 bl __do_get_tspec@local /* get sec/nsec from tb & kernel */ 654abc69ef2e69 Christophe Leroy 2019-12-02 87 bne cr1, .Lfinish /* not monotonic -> all done */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 88 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 89 /* a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 90 * CLOCK_MONOTONIC a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 91 */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 92 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 93 /* now we must fixup using wall to monotonic. We need to snapshot a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 94 * that value and do the counter trick again. Fortunately, we still a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 95 * have the counter value in r8 that was returned by __do_get_xsec. 597bc5c00b666f Paul Mackerras 2008-10-27 96 * At this point, r3,r4 contain our sec/nsec values, r5 and r6 597bc5c00b666f Paul Mackerras 2008-10-27 97 * can be used, r7 contains NSEC_PER_SEC. a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 98 */ a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 99 dd9a994fc68d19 Christophe Leroy 2019-04-04 100 lwz r5,(WTOM_CLOCK_SEC+LOPART)(r9) 597bc5c00b666f Paul Mackerras 2008-10-27 101 lwz r6,WTOM_CLOCK_NSEC(r9) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 102 597bc5c00b666f Paul Mackerras 2008-10-27 103 /* We now have our offset in r5,r6. We create a fake dependency 597bc5c00b666f Paul Mackerras 2008-10-27 104 * on that value and re-check the counter a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 105 */ 597bc5c00b666f Paul Mackerras 2008-10-27 106 or r0,r6,r5 597bc5c00b666f Paul Mackerras 2008-10-27 107 xor r0,r0,r0 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 108 add r9,r9,r0 597bc5c00b666f Paul Mackerras 2008-10-27 109 lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9) a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 110 cmpl cr0,r8,r0 /* check if updated */ 654abc69ef2e69 Christophe Leroy 2019-12-02 111 bne- .Lprecise_clocks 654abc69ef2e69 Christophe Leroy 2019-12-02 112 b .Lfinish_monotonic 654abc69ef2e69 Christophe Leroy 2019-12-02 113 654abc69ef2e69 Christophe Leroy 2019-12-02 114 /* 654abc69ef2e69 Christophe Leroy 2019-12-02 115 * For coarse clocks we get data directly from the vdso data page, so 654abc69ef2e69 Christophe Leroy 2019-12-02 116 * we don't need to call __do_get_tspec, but we still need to do the 654abc69ef2e69 Christophe Leroy 2019-12-02 117 * counter trick. 654abc69ef2e69 Christophe Leroy 2019-12-02 118 */ 654abc69ef2e69 Christophe Leroy 2019-12-02 119 .Lcoarse_clocks: 654abc69ef2e69 Christophe Leroy 2019-12-02 120 lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9) 654abc69ef2e69 Christophe Leroy 2019-12-02 121 andi. r0,r8,1 /* pending update ? loop */ 654abc69ef2e69 Christophe Leroy 2019-12-02 122 bne- .Lcoarse_clocks 654abc69ef2e69 Christophe Leroy 2019-12-02 123 add r9,r9,r0 /* r0 is already 0 */ 654abc69ef2e69 Christophe Leroy 2019-12-02 124 654abc69ef2e69 Christophe Leroy 2019-12-02 125 /* 654abc69ef2e69 Christophe Leroy 2019-12-02 126 * CLOCK_REALTIME_COARSE, below values are needed for MONOTONIC_COARSE 654abc69ef2e69 Christophe Leroy 2019-12-02 127 * too 654abc69ef2e69 Christophe Leroy 2019-12-02 128 */ 654abc69ef2e69 Christophe Leroy 2019-12-02 129 lwz r3,STAMP_XTIME_SEC+LOPART(r9) 654abc69ef2e69 Christophe Leroy 2019-12-02 130 lwz r4,STAMP_XTIME_NSEC+LOPART(r9) 654abc69ef2e69 Christophe Leroy 2019-12-02 131 bne cr6,1f 654abc69ef2e69 Christophe Leroy 2019-12-02 132 654abc69ef2e69 Christophe Leroy 2019-12-02 133 /* CLOCK_MONOTONIC_COARSE */ 654abc69ef2e69 Christophe Leroy 2019-12-02 134 lwz r5,(WTOM_CLOCK_SEC+LOPART)(r9) 654abc69ef2e69 Christophe Leroy 2019-12-02 135 lwz r6,WTOM_CLOCK_NSEC(r9) 654abc69ef2e69 Christophe Leroy 2019-12-02 136 654abc69ef2e69 Christophe Leroy 2019-12-02 137 /* check if counter has updated */ 654abc69ef2e69 Christophe Leroy 2019-12-02 138 or r0,r6,r5 654abc69ef2e69 Christophe Leroy 2019-12-02 139 1: or r0,r0,r3 654abc69ef2e69 Christophe Leroy 2019-12-02 140 or r0,r0,r4 654abc69ef2e69 Christophe Leroy 2019-12-02 141 xor r0,r0,r0 654abc69ef2e69 Christophe Leroy 2019-12-02 142 add r3,r3,r0 654abc69ef2e69 Christophe Leroy 2019-12-02 143 lwz r0,CFG_TB_UPDATE_COUNT+LOPART(r9) 654abc69ef2e69 Christophe Leroy 2019-12-02 144 cmpl cr0,r0,r8 /* check if updated */ 654abc69ef2e69 Christophe Leroy 2019-12-02 145 bne- .Lcoarse_clocks 654abc69ef2e69 Christophe Leroy 2019-12-02 146 654abc69ef2e69 Christophe Leroy 2019-12-02 147 /* Counter has not updated, so continue calculating proper values for 654abc69ef2e69 Christophe Leroy 2019-12-02 148 * sec and nsec if monotonic coarse, or just return with the proper 654abc69ef2e69 Christophe Leroy 2019-12-02 149 * values for realtime. 654abc69ef2e69 Christophe Leroy 2019-12-02 150 */ 654abc69ef2e69 Christophe Leroy 2019-12-02 151 bne cr6, .Lfinish a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 152 597bc5c00b666f Paul Mackerras 2008-10-27 153 /* Calculate and store result. Note that this mimics the C code, a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 154 * which may cause funny results if nsec goes negative... is that a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 155 * possible at all ? a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 156 */ 654abc69ef2e69 Christophe Leroy 2019-12-02 157 .Lfinish_monotonic: 597bc5c00b666f Paul Mackerras 2008-10-27 158 add r3,r3,r5 597bc5c00b666f Paul Mackerras 2008-10-27 159 add r4,r4,r6 597bc5c00b666f Paul Mackerras 2008-10-27 160 cmpw cr0,r4,r7 597bc5c00b666f Paul Mackerras 2008-10-27 161 cmpwi cr1,r4,0 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 162 blt 1f 597bc5c00b666f Paul Mackerras 2008-10-27 163 subf r4,r7,r4 a7f290dad32ee3 Benjamin Herrenschmidt 2005-11-11 164 addi r3,r3,1 654abc69ef2e69 Christophe Leroy 2019-12-02 165 1: bge cr1, .Lfinish 0c37ec2aa88bd8 Benjamin Herrenschmidt 2005-11-14 166 addi r3,r3,-1 597bc5c00b666f Paul Mackerras 2008-10-27 167 add r4,r4,r7 597bc5c00b666f Paul Mackerras 2008-10-27 168 :::::: The code at line 40 was first introduced by commit :::::: 8fd63a9ea7528463211a6c88d500c51851d960c8 powerpc: Rework VDSO gettimeofday to prevent time going backwards :::::: TO: Paul Mackerras <paulus(a)samba.org&gt; :::::: CC: Benjamin Herrenschmidt <benh(a)kernel.crashing.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org