| Message ID | 20200714145049.2496163-11-lee.jones@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Rid W=1 warnings in CPUFreq | expand |
On Tue, Jul 14, 2020 at 4:51 PM Lee Jones <lee.jones@linaro.org> wrote: > > If we fail to use a variable, even a 'dummy' one, then the compiler > complains that it is set but not used. We know this is fine, so we > set it to its own value here. > > Fixes the following W=1 kernel build warning(s): > > drivers/cpufreq/powernow-k8.c: In function ‘pending_bit_stuck’: > drivers/cpufreq/powernow-k8.c:89:10: warning: variable ‘hi’ set but not used [-Wunused-but-set-variable] > 89 | u32 lo, hi; > | ^~ > drivers/cpufreq/powernow-k8.c: In function ‘core_voltage_pre_transition’: > drivers/cpufreq/powernow-k8.c:285:14: warning: variable ‘lo’ set but not used [-Wunused-but-set-variable] > 285 | u32 maxvid, lo, rvomult = 1; > | ^~ > > Cc: Andreas Herrmann <herrmann.der.user@googlemail.com> > Cc: Dominik Brodowski <linux@brodo.de> > Cc: Pavel Machek <pavel@ucw.cz> > Cc: Paul Devriendt <paul.devriendt@amd.com> > Cc: Mark Langsdorf <mark.langsdorf@amd.com> > Signed-off-by: Lee Jones <lee.jones@linaro.org> > --- > drivers/cpufreq/powernow-k8.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c > index 3984959eed1d5..b76df81044c4f 100644 > --- a/drivers/cpufreq/powernow-k8.c > +++ b/drivers/cpufreq/powernow-k8.c > @@ -89,6 +89,7 @@ static int pending_bit_stuck(void) > u32 lo, hi; > > rdmsr(MSR_FIDVID_STATUS, lo, hi); > + hi &= hi; /* Silence set but not used warning */ Hmm. What about using __always_unused for this? > return lo & MSR_S_LO_CHANGE_PENDING ? 1 : 0; > } > > @@ -292,6 +293,7 @@ static int core_voltage_pre_transition(struct powernow_k8_data *data, > rvomult = 2; > rvosteps *= rvomult; > rdmsr(MSR_FIDVID_STATUS, lo, maxvid); > + lo &= lo; /* Silence set but not used warning */ > maxvid = 0x1f & (maxvid >> 16); > pr_debug("ph1 maxvid=0x%x\n", maxvid); > if (reqvid < maxvid) /* lower numbers are higher voltages */ > -- > 2.25.1 >
On Tue, 14 Jul 2020, Rafael J. Wysocki wrote: > On Tue, Jul 14, 2020 at 4:51 PM Lee Jones <lee.jones@linaro.org> wrote: > > > > If we fail to use a variable, even a 'dummy' one, then the compiler > > complains that it is set but not used. We know this is fine, so we > > set it to its own value here. > > > > Fixes the following W=1 kernel build warning(s): > > > > drivers/cpufreq/powernow-k8.c: In function ‘pending_bit_stuck’: > > drivers/cpufreq/powernow-k8.c:89:10: warning: variable ‘hi’ set but not used [-Wunused-but-set-variable] > > 89 | u32 lo, hi; > > | ^~ > > drivers/cpufreq/powernow-k8.c: In function ‘core_voltage_pre_transition’: > > drivers/cpufreq/powernow-k8.c:285:14: warning: variable ‘lo’ set but not used [-Wunused-but-set-variable] > > 285 | u32 maxvid, lo, rvomult = 1; > > | ^~ > > > > Cc: Andreas Herrmann <herrmann.der.user@googlemail.com> > > Cc: Dominik Brodowski <linux@brodo.de> > > Cc: Pavel Machek <pavel@ucw.cz> > > Cc: Paul Devriendt <paul.devriendt@amd.com> > > Cc: Mark Langsdorf <mark.langsdorf@amd.com> > > Signed-off-by: Lee Jones <lee.jones@linaro.org> > > --- > > drivers/cpufreq/powernow-k8.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c > > index 3984959eed1d5..b76df81044c4f 100644 > > --- a/drivers/cpufreq/powernow-k8.c > > +++ b/drivers/cpufreq/powernow-k8.c > > @@ -89,6 +89,7 @@ static int pending_bit_stuck(void) > > u32 lo, hi; > > > > rdmsr(MSR_FIDVID_STATUS, lo, hi); > > + hi &= hi; /* Silence set but not used warning */ > > Hmm. > > What about using __always_unused for this? I didn't know you could use that for standard variables. Will fix. > > return lo & MSR_S_LO_CHANGE_PENDING ? 1 : 0; > > } > > > > @@ -292,6 +293,7 @@ static int core_voltage_pre_transition(struct powernow_k8_data *data, > > rvomult = 2; > > rvosteps *= rvomult; > > rdmsr(MSR_FIDVID_STATUS, lo, maxvid); > > + lo &= lo; /* Silence set but not used warning */ > > maxvid = 0x1f & (maxvid >> 16); > > pr_debug("ph1 maxvid=0x%x\n", maxvid); > > if (reqvid < maxvid) /* lower numbers are higher voltages */ > > -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c index 3984959eed1d5..b76df81044c4f 100644 --- a/drivers/cpufreq/powernow-k8.c +++ b/drivers/cpufreq/powernow-k8.c @@ -89,6 +89,7 @@ static int pending_bit_stuck(void) u32 lo, hi; rdmsr(MSR_FIDVID_STATUS, lo, hi); + hi &= hi; /* Silence set but not used warning */ return lo & MSR_S_LO_CHANGE_PENDING ? 1 : 0; } @@ -292,6 +293,7 @@ static int core_voltage_pre_transition(struct powernow_k8_data *data, rvomult = 2; rvosteps *= rvomult; rdmsr(MSR_FIDVID_STATUS, lo, maxvid); + lo &= lo; /* Silence set but not used warning */ maxvid = 0x1f & (maxvid >> 16); pr_debug("ph1 maxvid=0x%x\n", maxvid); if (reqvid < maxvid) /* lower numbers are higher voltages */
If we fail to use a variable, even a 'dummy' one, then the compiler complains that it is set but not used. We know this is fine, so we set it to its own value here. Fixes the following W=1 kernel build warning(s): drivers/cpufreq/powernow-k8.c: In function ‘pending_bit_stuck’: drivers/cpufreq/powernow-k8.c:89:10: warning: variable ‘hi’ set but not used [-Wunused-but-set-variable] 89 | u32 lo, hi; | ^~ drivers/cpufreq/powernow-k8.c: In function ‘core_voltage_pre_transition’: drivers/cpufreq/powernow-k8.c:285:14: warning: variable ‘lo’ set but not used [-Wunused-but-set-variable] 285 | u32 maxvid, lo, rvomult = 1; | ^~ Cc: Andreas Herrmann <herrmann.der.user@googlemail.com> Cc: Dominik Brodowski <linux@brodo.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: Paul Devriendt <paul.devriendt@amd.com> Cc: Mark Langsdorf <mark.langsdorf@amd.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> --- drivers/cpufreq/powernow-k8.c | 2 ++ 1 file changed, 2 insertions(+) -- 2.25.1