Peter Zijlstra
2022-May-28 13:52 UTC
[PATCH v3] x86/vmware: use unsigned integer for shifting
On Fri, May 27, 2022 at 11:27:37PM +0530, Shreenidhi Shedi wrote:> From: Shreenidhi Shedi <sshedi at vmware.com> > > Shifting signed 32-bit value by 31 bits is implementation-defined > behaviour. Using unsigned is better option for this.The kernel builds with -fno-strict-overflow and as such this behaviour is well defined.> Fixes: 4cca6ea04d31 ("x86/apic: Allow x2apic without IR on VMware platform")Nothing broken, therefore nothing fixed.
Srivatsa S. Bhat
2022-May-31 12:51 UTC
[PATCH v3] x86/vmware: use unsigned integer for shifting
On 5/28/22 6:52 AM, Peter Zijlstra wrote:> On Fri, May 27, 2022 at 11:27:37PM +0530, Shreenidhi Shedi wrote: >> From: Shreenidhi Shedi <sshedi at vmware.com> >> >> Shifting signed 32-bit value by 31 bits is implementation-defined >> behaviour. Using unsigned is better option for this. > > The kernel builds with -fno-strict-overflow and as such this behaviour > is well defined. >Ah, I see. Thank you, Peter!>> Fixes: 4cca6ea04d31 ("x86/apic: Allow x2apic without IR on VMware platform") > > Nothing broken, therefore nothing fixed. >Agreed. I think using the BIT() macro still provides a nice readability improvement. So, Shreenidhi, could you spin a new version of the patch with the same code changes but with a different commit message about using the BIT() macro to simplify the code, and also include a clarification as to why the existing code is correct (which Peter pointed out), please? Thank you! Regards, Srivatsa VMware Photon OS