* [tip:x86/urgent 1/1] arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used @ 2025-06-30 18:43 kernel test robot 2025-06-30 19:27 ` Borislav Petkov 0 siblings, 1 reply; 5+ messages in thread From: kernel test robot @ 2025-06-30 18:43 UTC (permalink / raw) To: Nikunj A Dadhania Cc: llvm, oe-kbuild-all, linux-kernel, x86, Borislav Petkov (AMD) tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/urgent head: 4a35d2b5254af89595fd90dae9ee0c8f990a148d commit: 4a35d2b5254af89595fd90dae9ee0c8f990a148d [1/1] x86/sev: Use TSC_FACTOR for Secure TSC frequency calculation config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20250701/202507010218.3O5Ge0Xt-lkp@intel.com/config) compiler: clang version 20.1.7 (https://github.com/llvm/llvm-project 6146a88f60492b520a36f8f8f3231e15f3cc6082) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250701/202507010218.3O5Ge0Xt-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/202507010218.3O5Ge0Xt-lkp@intel.com/ All warnings (new ones prefixed by >>): >> arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used [-Wunused-but-set-variable] 2170 | unsigned long tsc_freq_mhz, dummy; | ^ 1 warning generated. vim +/dummy +2170 arch/x86/coco/sev/core.c 2167 2168 void __init snp_secure_tsc_init(void) 2169 { > 2170 unsigned long tsc_freq_mhz, dummy; -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [tip:x86/urgent 1/1] arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used 2025-06-30 18:43 [tip:x86/urgent 1/1] arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used kernel test robot @ 2025-06-30 19:27 ` Borislav Petkov 2025-07-01 15:06 ` Nathan Chancellor 0 siblings, 1 reply; 5+ messages in thread From: Borislav Petkov @ 2025-06-30 19:27 UTC (permalink / raw) To: kernel test robot Cc: Nikunj A Dadhania, llvm, oe-kbuild-all, linux-kernel, x86 On Tue, Jul 01, 2025 at 02:43:31AM +0800, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/urgent > head: 4a35d2b5254af89595fd90dae9ee0c8f990a148d > commit: 4a35d2b5254af89595fd90dae9ee0c8f990a148d [1/1] x86/sev: Use TSC_FACTOR for Secure TSC frequency calculation > config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20250701/202507010218.3O5Ge0Xt-lkp@intel.com/config) > compiler: clang version 20.1.7 (https://github.com/llvm/llvm-project 6146a88f60492b520a36f8f8f3231e15f3cc6082) Pff, doesn't fire with clang-19. That damn compiler. gcc used to complain about those but they fixed their interprocedural analysis or whatnot. clang is simply complaining more. /facepalm 1 And the 0day bot - because it doesn't have anything better to do - is doing W=1 builds. I did complain about that waste of resources in the past but nothing happened. /facepalm 2 > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250701/202507010218.3O5Ge0Xt-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/202507010218.3O5Ge0Xt-lkp@intel.com/ > > All warnings (new ones prefixed by >>): > > >> arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used [-Wunused-but-set-variable] > 2170 | unsigned long tsc_freq_mhz, dummy; > | ^ > 1 warning generated. > > > vim +/dummy +2170 arch/x86/coco/sev/core.c > > 2167 > 2168 void __init snp_secure_tsc_init(void) > 2169 { > > 2170 unsigned long tsc_freq_mhz, dummy; And it is actually my damn fault because even if that dummy crap variable was bugging me, I thought we want to "harmonize". /facepalm 3 Which is a total nonsense because that code doesn't build in 32-bit. So this should've stayed like this: diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c index 47d10d9a28e9..36c167333d04 100644 --- a/arch/x86/coco/sev/core.c +++ b/arch/x86/coco/sev/core.c @@ -2167,8 +2167,8 @@ static unsigned long securetsc_get_tsc_khz(void) void __init snp_secure_tsc_init(void) { - unsigned long tsc_freq_mhz, dummy; struct snp_secrets_page *secrets; + unsigned long tsc_freq_mhz; void *mem; if (!cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) @@ -2183,7 +2183,7 @@ void __init snp_secure_tsc_init(void) secrets = (__force struct snp_secrets_page *)mem; setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); - rdmsr(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz, dummy); + rdmsrq(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz); /* Extract the GUEST TSC MHZ from BIT[17:0], rest is reserved space */ tsc_freq_mhz = tsc_freq_mhz & GENMASK_ULL(17, 0); snp_tsc_freq_khz = SNP_SCALE_TSC_FREQ(tsc_freq_mhz * 1000, secrets->tsc_factor); What a f*cking mess. I don't have enough room on my face anymore from facepalms. Oh boy. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [tip:x86/urgent 1/1] arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used 2025-06-30 19:27 ` Borislav Petkov @ 2025-07-01 15:06 ` Nathan Chancellor 2025-07-01 15:29 ` Borislav Petkov 0 siblings, 1 reply; 5+ messages in thread From: Nathan Chancellor @ 2025-07-01 15:06 UTC (permalink / raw) To: Borislav Petkov Cc: kernel test robot, Nikunj A Dadhania, llvm, oe-kbuild-all, linux-kernel, x86 On Mon, Jun 30, 2025 at 09:27:26PM +0200, Borislav Petkov wrote: > On Tue, Jul 01, 2025 at 02:43:31AM +0800, kernel test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/urgent > > head: 4a35d2b5254af89595fd90dae9ee0c8f990a148d > > commit: 4a35d2b5254af89595fd90dae9ee0c8f990a148d [1/1] x86/sev: Use TSC_FACTOR for Secure TSC frequency calculation > > config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20250701/202507010218.3O5Ge0Xt-lkp@intel.com/config) > > compiler: clang version 20.1.7 (https://github.com/llvm/llvm-project 6146a88f60492b520a36f8f8f3231e15f3cc6082) > > Pff, doesn't fire with clang-19. > > That damn compiler. > > gcc used to complain about those but they fixed their interprocedural analysis > or whatnot. > > clang is simply complaining more. Citation needed. This reproduces with Clang 15 (earliest supported on x86 now), Clang 19, and GCC 15 for me. Were you missing W=1? $ x86_64-linux-gcc --version | head -1 x86_64-linux-gcc (GCC) 15.1.0 $ curl -LSso .config https://download.01.org/0day-ci/archive/20250701/202507010218.3O5Ge0Xt-lkp@intel.com/config $ make -skj"$(nproc)" ARCH=x86_64 CROSS_COMPILE=x86_64-linux- W=1 olddefconfig arch/x86/coco/sev/core.o arch/x86/coco/sev/core.c: In function 'snp_secure_tsc_init': arch/x86/coco/sev/core.c:2170:37: warning: variable 'dummy' set but not used [-Wunused-but-set-variable] 2170 | unsigned long tsc_freq_mhz, dummy; | ^~~~~ Cheers, Nathan ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [tip:x86/urgent 1/1] arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used 2025-07-01 15:06 ` Nathan Chancellor @ 2025-07-01 15:29 ` Borislav Petkov 2025-07-02 21:02 ` Nathan Chancellor 0 siblings, 1 reply; 5+ messages in thread From: Borislav Petkov @ 2025-07-01 15:29 UTC (permalink / raw) To: Nathan Chancellor Cc: kernel test robot, Nikunj A Dadhania, llvm, oe-kbuild-all, linux-kernel, x86 On Tue, Jul 01, 2025 at 08:06:44AM -0700, Nathan Chancellor wrote: > Citation needed. This reproduces with Clang 15 (earliest supported on > x86 now), Clang 19, and GCC 15 for me. Were you missing W=1? Nope. $ git checkout -b test 4a35d2b5254af89595fd90dae9ee0c8f990a148d Switched to a new branch 'test' $ make CC=clang-19 HOSTCC=clang-19 W=1 arch/x86/coco/sev/core.o ... LINK /mnt/kernel/kernel/linux/tools/objtool/objtool CC arch/x86/coco/sev/core.o $ clang-19 --version Debian clang version 19.1.7 (1+b1) Target: x86_64-pc-linux-gnu Thread model: posix InstalledDir: /usr/lib/llvm-19/bin -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [tip:x86/urgent 1/1] arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used 2025-07-01 15:29 ` Borislav Petkov @ 2025-07-02 21:02 ` Nathan Chancellor 0 siblings, 0 replies; 5+ messages in thread From: Nathan Chancellor @ 2025-07-02 21:02 UTC (permalink / raw) To: Borislav Petkov Cc: kernel test robot, Nikunj A Dadhania, llvm, oe-kbuild-all, linux-kernel, x86 On Tue, Jul 01, 2025 at 05:29:53PM +0200, Borislav Petkov wrote: > On Tue, Jul 01, 2025 at 08:06:44AM -0700, Nathan Chancellor wrote: > > Citation needed. This reproduces with Clang 15 (earliest supported on > > x86 now), Clang 19, and GCC 15 for me. Were you missing W=1? > > Nope. > > $ git checkout -b test 4a35d2b5254af89595fd90dae9ee0c8f990a148d > Switched to a new branch 'test' > $ make CC=clang-19 HOSTCC=clang-19 W=1 arch/x86/coco/sev/core.o > ... > LINK /mnt/kernel/kernel/linux/tools/objtool/objtool > CC arch/x86/coco/sev/core.o > $ clang-19 --version > Debian clang version 19.1.7 (1+b1) > Target: x86_64-pc-linux-gnu > Thread model: posix > InstalledDir: /usr/lib/llvm-19/bin Spooky, same SHA, build command, and configuration from this thread with Debian clang version 19.1.7 (3+b1) Target: x86_64-pc-linux-gnu Thread model: posix InstalledDir: /usr/lib/llvm-19/bin from unstable Debian (since it is what I base on for my Debian development container) shows it for me... Can't imagine the two Debian patch levels would have caused anything here but it is probably not worth thinking too much more about since it is already resolved. Cheers, Nathan ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2025-07-02 21:02 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-06-30 18:43 [tip:x86/urgent 1/1] arch/x86/coco/sev/core.c:2170:30: warning: variable 'dummy' set but not used kernel test robot 2025-06-30 19:27 ` Borislav Petkov 2025-07-01 15:06 ` Nathan Chancellor 2025-07-01 15:29 ` Borislav Petkov 2025-07-02 21:02 ` Nathan Chancellor
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