| Message ID | 1445017739-14876-1-git-send-email-peter.maydell@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 10/16/2015 01:48 PM, Peter Maydell wrote: > Avoid undefined behaviour from shifting left into the sign bit: > > hw/ide/ahci.c:551:36: runtime error: left shift of 255 by 24 places cannot be represented in type 'int' > > (Unfortunately C's promotion rules mean that in the expression > "some_uint8_t_variable << 24" the LHS gets promoted to signed > int before shifting.) > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > clang's undefined sanitizer produces a lot of copies of this warning during > 'make check'... > > hw/ide/ahci.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c > index 796be15..21f76ed 100644 > --- a/hw/ide/ahci.c > +++ b/hw/ide/ahci.c > @@ -548,7 +548,7 @@ static void ahci_init_d2h(AHCIDevice *ad) > ad->init_d2h_sent = true; > /* We're emulating receiving the first Reg H2D Fis from the device; > * Update the SIG register, but otherwise proceed as normal. */ > - pr->sig = (ide_state->hcyl << 24) | > + pr->sig = ((uint32_t)ide_state->hcyl << 24) | > (ide_state->lcyl << 16) | > (ide_state->sector << 8) | > (ide_state->nsector & 0xFF); > Reviewed-by: John Snow <jsnow@redhat.com> Since the "patches" tool seems to still be hiccuping, do you want to just apply this directly? --js
On 16 October 2015 at 21:43, John Snow <jsnow@redhat.com> wrote: > > > On 10/16/2015 01:48 PM, Peter Maydell wrote: >> Avoid undefined behaviour from shifting left into the sign bit: >> >> hw/ide/ahci.c:551:36: runtime error: left shift of 255 by 24 places cannot be represented in type 'int' >> >> (Unfortunately C's promotion rules mean that in the expression >> "some_uint8_t_variable << 24" the LHS gets promoted to signed >> int before shifting.) >> >> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> >> --- >> clang's undefined sanitizer produces a lot of copies of this warning during >> 'make check'... >> >> hw/ide/ahci.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c >> index 796be15..21f76ed 100644 >> --- a/hw/ide/ahci.c >> +++ b/hw/ide/ahci.c >> @@ -548,7 +548,7 @@ static void ahci_init_d2h(AHCIDevice *ad) >> ad->init_d2h_sent = true; >> /* We're emulating receiving the first Reg H2D Fis from the device; >> * Update the SIG register, but otherwise proceed as normal. */ >> - pr->sig = (ide_state->hcyl << 24) | >> + pr->sig = ((uint32_t)ide_state->hcyl << 24) | >> (ide_state->lcyl << 16) | >> (ide_state->sector << 8) | >> (ide_state->nsector & 0xFF); >> > > Reviewed-by: John Snow <jsnow@redhat.com> > > Since the "patches" tool seems to still be hiccuping, do you want to > just apply this directly? OK, applied to master. thanks -- PMM
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index 796be15..21f76ed 100644 --- a/hw/ide/ahci.c +++ b/hw/ide/ahci.c @@ -548,7 +548,7 @@ static void ahci_init_d2h(AHCIDevice *ad) ad->init_d2h_sent = true; /* We're emulating receiving the first Reg H2D Fis from the device; * Update the SIG register, but otherwise proceed as normal. */ - pr->sig = (ide_state->hcyl << 24) | + pr->sig = ((uint32_t)ide_state->hcyl << 24) | (ide_state->lcyl << 16) | (ide_state->sector << 8) | (ide_state->nsector & 0xFF);
Avoid undefined behaviour from shifting left into the sign bit: hw/ide/ahci.c:551:36: runtime error: left shift of 255 by 24 places cannot be represented in type 'int' (Unfortunately C's promotion rules mean that in the expression "some_uint8_t_variable << 24" the LHS gets promoted to signed int before shifting.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- clang's undefined sanitizer produces a lot of copies of this warning during 'make check'... hw/ide/ahci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)