On Fri, 2018-01-19 at 16:33 +0200, Andy Shevchenko wrote: > Since non atomic readq() and writeq() were added some of the drivers > would like to use it in a manner of: > > #include <io-64-nonatomic-lo-hi.h> > ... > pr_debug("Debug value of some register: %016llx\n", readq(addr)); > > However, lo_hi_readq() always returns __u64 data, while readq() > on x86_64 defines it as unsigned long. and thus compiler warns > about type mismatch, although they are both 64-bit on x86_64. > > Convert readq() and writeq() on x86 to operate on deterministic > 64-bit type. The most of architectures in the kernel already are > using > either unsigned long long, or u64 type for readq() / writeq(). > This change propagates consistency in that sense. > > While this is not an issue per se, though if someone wants to address > it, > the anchor could be the commit > > 797a796a13df ("asm-generic: architecture independent readq/writeq > for 32bit environment") > > where non-atomic variants had been introduced. > > Note, there are only few users of above pattern and they will not be > affected because they do cast returned value. The actual warning has > been issued on not-yet-upstreamed code. > > Potentially we might get a new warnings if some 64-bit only code > assigns returned value to unsigned long type of variable. This is > assumed to be addressed on case-by-case basis. > > Reported-by: lkp <l...@intel.com> > Cc: Hitoshi Mitake <mit...@dcl.info.waseda.ac.jp> > Cc: "Mehta, Sohil" <sohil.me...@intel.com> > Signed-off-by: Andy Shevchenko <andriy.shevche...@linux.intel.com> > --- > arch/x86/include/asm/io.h | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h > index 95e948627fd0..365f5ba9222b 100644 > --- a/arch/x86/include/asm/io.h > +++ b/arch/x86/include/asm/io.h > @@ -94,10 +94,10 @@ build_mmio_write(__writel, "l", unsigned int, > "r", ) > > #ifdef CONFIG_X86_64 > > -build_mmio_read(readq, "q", unsigned long, "=r", :"memory") > -build_mmio_read(__readq, "q", unsigned long, "=r", ) > -build_mmio_write(writeq, "q", unsigned long, "r", :"memory") > -build_mmio_write(__writeq, "q", unsigned long, "r", ) > +build_mmio_read(readq, "q", unsigned long long, "=r", :"memory") > +build_mmio_read(__readq, "q", unsigned long long, "=r", ) > +build_mmio_write(writeq, "q", unsigned long long, "r", :"memory") > +build_mmio_write(__writeq, "q", unsigned long long, "r", ) > > #define readq_relaxed(a) __readq(a) > #define writeq_relaxed(v, a) __writeq(v, a)
The patch works for me: Tested-by: Sohil Mehta <sohil.me...@intel.com> Sohil