* Re: [PATCH v4 1/1] printk: fix zero-valued printk timestamps in early boot
[not found] <20260410203741.997410-2-tim.bird@sony.com>
@ 2026-04-12 11:12 ` kernel test robot
2026-04-12 12:55 ` kernel test robot
1 sibling, 0 replies; 2+ messages in thread
From: kernel test robot @ 2026-04-12 11:12 UTC (permalink / raw)
To: Tim Bird, pmladek, rostedt, john.ogness, senozhatsky
Cc: llvm, oe-kbuild-all, francesco, geert, tglx, shashankbalaji02,
linux-embedded, linux-kernel, Tim Bird
Hi Tim,
kernel test robot noticed the following build warnings:
[auto build test WARNING on linus/master]
[also build test WARNING on v7.0-rc7 next-20260410]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Tim-Bird/printk-fix-zero-valued-printk-timestamps-in-early-boot/20260412-134726
base: linus/master
patch link: https://lore.kernel.org/r/20260410203741.997410-2-tim.bird%40sony.com
patch subject: [PATCH v4 1/1] printk: fix zero-valued printk timestamps in early boot
config: um-defconfig (https://download.01.org/0day-ci/archive/20260412/202604121907.nsngvl5u-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project ae825cb8cea7f3ac8e5e4096f22713845cf5e501)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260412/202604121907.nsngvl5u-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202604121907.nsngvl5u-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from kernel/printk/printk.c:49:
include/linux/early_times.h:20:9: error: call to undeclared function 'rdtsc'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
20 | return rdtsc();
| ^
>> include/linux/early_times.h:45:47: warning: division by zero is undefined [-Wdivision-by-zero]
45 | return (early_unsafe_cycles() * NS_PER_KHZ) / CONFIG_EARLY_CYCLES_KHZ;
| ^ ~~~~~~~~~~~~~~~~~~~~~~~
1 warning and 1 error generated.
vim +45 include/linux/early_times.h
34
35 /* returns a nanosecond value based on early cycles */
36 static inline u64 early_times_ns(void)
37 {
38 if (CONFIG_EARLY_CYCLES_KHZ)
39 /*
40 * Note: the multiply must precede the division to avoid
41 * truncation and loss of resolution
42 * Don't use fancier MULT/SHIFT math here. Since this is
43 * static, the compiler can optimize the math operations.
44 */
> 45 return (early_unsafe_cycles() * NS_PER_KHZ) / CONFIG_EARLY_CYCLES_KHZ;
46 return 0;
47 }
48 #else
49 static inline u64 early_times_ns(void)
50 {
51 return 0;
52 }
53 #endif
54
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH v4 1/1] printk: fix zero-valued printk timestamps in early boot
[not found] <20260410203741.997410-2-tim.bird@sony.com>
2026-04-12 11:12 ` [PATCH v4 1/1] printk: fix zero-valued printk timestamps in early boot kernel test robot
@ 2026-04-12 12:55 ` kernel test robot
1 sibling, 0 replies; 2+ messages in thread
From: kernel test robot @ 2026-04-12 12:55 UTC (permalink / raw)
To: Tim Bird, pmladek, rostedt, john.ogness, senozhatsky
Cc: llvm, oe-kbuild-all, francesco, geert, tglx, shashankbalaji02,
linux-embedded, linux-kernel, Tim Bird
Hi Tim,
kernel test robot noticed the following build errors:
[auto build test ERROR on linus/master]
[also build test ERROR on v7.0-rc7 next-20260410]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Tim-Bird/printk-fix-zero-valued-printk-timestamps-in-early-boot/20260412-134726
base: linus/master
patch link: https://lore.kernel.org/r/20260410203741.997410-2-tim.bird%40sony.com
patch subject: [PATCH v4 1/1] printk: fix zero-valued printk timestamps in early boot
config: um-defconfig (https://download.01.org/0day-ci/archive/20260412/202604122037.R14cnXpl-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project ae825cb8cea7f3ac8e5e4096f22713845cf5e501)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260412/202604122037.R14cnXpl-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202604122037.R14cnXpl-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from kernel/printk/printk.c:49:
>> include/linux/early_times.h:20:9: error: call to undeclared function 'rdtsc'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
20 | return rdtsc();
| ^
include/linux/early_times.h:45:47: warning: division by zero is undefined [-Wdivision-by-zero]
45 | return (early_unsafe_cycles() * NS_PER_KHZ) / CONFIG_EARLY_CYCLES_KHZ;
| ^ ~~~~~~~~~~~~~~~~~~~~~~~
1 warning and 1 error generated.
vim +/rdtsc +20 include/linux/early_times.h
10
11 #ifdef CONFIG_EARLY_CYCLES_KHZ
12 static inline u64 early_unsafe_cycles(void)
13 {
14 #if defined(CONFIG_X86_64)
15 /*
16 * This rdtsc may happen before secure TSC is initialized, and
17 * it is unordered. So please don't use this value for cryptography
18 * or after SMP is initialized.
19 */
> 20 return rdtsc();
21 #elif defined(CONFIG_ARM64)
22 return read_sysreg(cntvct_el0);
23 #elif defined(CONFIG_RISCV_TIMER)
24 u64 val;
25
26 asm volatile("rdtime %0" : "=r"(val));
27 return val;
28 #else
29 return 0;
30 #endif
31 }
32
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 2+ messages in thread