> From: Bruce Richardson [mailto:bruce.richard...@intel.com] > Sent: Friday, 25 August 2023 17.29 > > When doing a build for a system with WAITPKG support and a modern > compiler, we get build errors for the "_umonitor" intrinsic, due to the > casting away of the "volatile" on the parameter. > > ../lib/eal/x86/rte_power_intrinsics.c: In function 'rte_power_monitor': > ../lib/eal/x86/rte_power_intrinsics.c:113:22: error: passing argument 1 > of '_umonitor' discards 'volatile' qualifier from pointer target type > [-Werror=discarded-qualifiers] > 113 | _umonitor(pmc->addr); > | ~~~^~~~~~ > > We can avoid this issue by using RTE_PTR_ADD(..., 0) to cast the pointer > through "uintptr_t" and thereby remove the volatile without warning. > We also ensure comments are correct for each leg of the > ifdef..else..endif block. > > Fixes: 60943c04f3bc ("eal/x86: use intrinsics for power management") > Cc: roret...@linux.microsoft.com > > Signed-off-by: Bruce Richardson <bruce.richard...@intel.com> > ---
[...] > - _umonitor(pmc->addr); > + /* use RTE_PTR_ADD to cast away "volatile" when using the > intrinsic */ Yes. Having a comment here is good, so people don't wonder why the magic has been added. > + _umonitor(RTE_PTR_ADD(pmc->addr, 0)); I think that (void *)(uintptr_t)p is more readable than RTE_PTR_ADD(p, 0), but it's a matter of taste. Regardless, Acked-by: Morten Brørup <m...@smartsharesystems.com>
