| Message ID | 20200521102130.17619-1-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | linux-user: limit check to HOST_LONG_BITS == 32 | expand |
On Thu, 21 May 2020 at 11:22, Alex Bennée <alex.bennee@linaro.org> wrote: > > Newer clangs rightly spot that you can never exceed the full address > space of 64 bit hosts with: > > linux-user/elfload.c:2076:41: error: result of comparison 'unsigned > long' > 18446744073709551615 is always false > [-Werror,-Wtautological-type-limit-compare] > 4685 if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) { > 4686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~ > 4687 1 error generated. > > So lets limit the check to 32 bit hosts only. > > Fixes: ee94743034bf > Reported-by: Thomas Huth <thuth@redhat.com> > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > --- > linux-user/elfload.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > index 01a9323a637..797fbf2337a 100644 > --- a/linux-user/elfload.c > +++ b/linux-user/elfload.c > @@ -2072,6 +2072,7 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr, > image_name, (uint64_t)guest_hiaddr, reserved_va); > exit(EXIT_FAILURE); > } > +#if HOST_LONG_BITS == 32 > } else { > if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) { > error_report("%s: requires more virtual address space " > @@ -2079,6 +2080,7 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr, > image_name, (uint64_t)guest_hiaddr - guest_base); > exit(EXIT_FAILURE); > } > +#endif Could we write this so that we have the #if...#endif conditional nested inside the if { ... } else { ... }, rather than having the two conditional constructs oddly intermeshed? thanks -- PMM
Peter Maydell <peter.maydell@linaro.org> writes: > On Thu, 21 May 2020 at 11:22, Alex Bennée <alex.bennee@linaro.org> wrote: >> >> Newer clangs rightly spot that you can never exceed the full address >> space of 64 bit hosts with: >> >> linux-user/elfload.c:2076:41: error: result of comparison 'unsigned >> long' > 18446744073709551615 is always false >> [-Werror,-Wtautological-type-limit-compare] >> 4685 if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) { >> 4686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~ >> 4687 1 error generated. >> >> So lets limit the check to 32 bit hosts only. >> >> Fixes: ee94743034bf >> Reported-by: Thomas Huth <thuth@redhat.com> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> --- >> linux-user/elfload.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/linux-user/elfload.c b/linux-user/elfload.c >> index 01a9323a637..797fbf2337a 100644 >> --- a/linux-user/elfload.c >> +++ b/linux-user/elfload.c >> @@ -2072,6 +2072,7 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr, >> image_name, (uint64_t)guest_hiaddr, reserved_va); >> exit(EXIT_FAILURE); >> } >> +#if HOST_LONG_BITS == 32 >> } else { >> if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) { >> error_report("%s: requires more virtual address space " >> @@ -2079,6 +2080,7 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr, >> image_name, (uint64_t)guest_hiaddr - guest_base); >> exit(EXIT_FAILURE); >> } >> +#endif > > Could we write this so that we have the #if...#endif > conditional nested inside the if { ... } else { ... }, > rather than having the two conditional constructs > oddly intermeshed? Sure - I thought the compiler would complain about having an empty else leg but I've just checked and it doesn't seem to care. > > thanks > -- PMM -- Alex Bennée
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 01a9323a637..797fbf2337a 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2072,6 +2072,7 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr, image_name, (uint64_t)guest_hiaddr, reserved_va); exit(EXIT_FAILURE); } +#if HOST_LONG_BITS == 32 } else { if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) { error_report("%s: requires more virtual address space " @@ -2079,6 +2080,7 @@ static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr, image_name, (uint64_t)guest_hiaddr - guest_base); exit(EXIT_FAILURE); } +#endif } /*
Newer clangs rightly spot that you can never exceed the full address space of 64 bit hosts with: linux-user/elfload.c:2076:41: error: result of comparison 'unsigned long' > 18446744073709551615 is always false [-Werror,-Wtautological-type-limit-compare] 4685 if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) { 4686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~ 4687 1 error generated. So lets limit the check to 32 bit hosts only. Fixes: ee94743034bf Reported-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- linux-user/elfload.c | 2 ++ 1 file changed, 2 insertions(+) -- 2.20.1