| Message ID | 20220802175936.2278362-1-nathan@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 74de14fe05dd6b151d73cb0c73c8ec874cbdcde6 |
| Headers | show |
| Series | MIPS: tlbex: Explicitly compare _PAGE_NO_EXEC against 0 | expand |
On Tue, Aug 02, 2022 at 10:59:36AM -0700, Nathan Chancellor wrote: > When CONFIG_XPA is enabled, Clang warns: > > arch/mips/mm/tlbex.c:629:24: error: converting the result of '<<' to a boolean; did you mean '(1 << _PAGE_NO_EXEC_SHIFT) != 0'? [-Werror,-Wint-in-bool-context] > if (cpu_has_rixi && !!_PAGE_NO_EXEC) { > ^ > arch/mips/include/asm/pgtable-bits.h:174:28: note: expanded from macro '_PAGE_NO_EXEC' > # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT) > ^ > arch/mips/mm/tlbex.c:2568:24: error: converting the result of '<<' to a boolean; did you mean '(1 << _PAGE_NO_EXEC_SHIFT) != 0'? [-Werror,-Wint-in-bool-context] > if (!cpu_has_rixi || !_PAGE_NO_EXEC) { > ^ > arch/mips/include/asm/pgtable-bits.h:174:28: note: expanded from macro '_PAGE_NO_EXEC' > # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT) > ^ > 2 errors generated. > > _PAGE_NO_EXEC can be '0' or '1 << _PAGE_NO_EXEC_SHIFT' depending on the > build and runtime configuration, which is what the negation operators > are trying to convey. To silence the warning, explicitly compare against > 0 so the result of the '<<' operator is not implicitly converted to a > boolean. > > According to its documentation, GCC enables -Wint-in-bool-context with > -Wall but this warning is not visible when building the same > configuration with GCC. It appears GCC only warns when compiling C++, > not C, although the documentation makes no note of this: > https://godbolt.org/z/x39q3brxf > > Reported-by: Sudip Mukherjee (Codethink) <sudipm.mukherjee@gmail.com> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- > arch/mips/mm/tlbex.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c > index 8dbbd99fc7e8..be4d4670d649 100644 > --- a/arch/mips/mm/tlbex.c > +++ b/arch/mips/mm/tlbex.c > @@ -626,7 +626,7 @@ static __maybe_unused void build_convert_pte_to_entrylo(u32 **p, > return; > } > > - if (cpu_has_rixi && !!_PAGE_NO_EXEC) { > + if (cpu_has_rixi && _PAGE_NO_EXEC != 0) { > if (fill_includes_sw_bits) { > UASM_i_ROTR(p, reg, reg, ilog2(_PAGE_GLOBAL)); > } else { > @@ -2565,7 +2565,7 @@ static void check_pabits(void) > unsigned long entry; > unsigned pabits, fillbits; > > - if (!cpu_has_rixi || !_PAGE_NO_EXEC) { > + if (!cpu_has_rixi || _PAGE_NO_EXEC == 0) { > /* > * We'll only be making use of the fact that we can rotate bits > * into the fill if the CPU supports RIXI, so don't bother > > base-commit: 7d0d3fa7339ed5a06d6608b7cde9f079eba62bb1 > -- > 2.37.1 applied to mips-next. Thomas.
diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c index 8dbbd99fc7e8..be4d4670d649 100644 --- a/arch/mips/mm/tlbex.c +++ b/arch/mips/mm/tlbex.c @@ -626,7 +626,7 @@ static __maybe_unused void build_convert_pte_to_entrylo(u32 **p, return; } - if (cpu_has_rixi && !!_PAGE_NO_EXEC) { + if (cpu_has_rixi && _PAGE_NO_EXEC != 0) { if (fill_includes_sw_bits) { UASM_i_ROTR(p, reg, reg, ilog2(_PAGE_GLOBAL)); } else { @@ -2565,7 +2565,7 @@ static void check_pabits(void) unsigned long entry; unsigned pabits, fillbits; - if (!cpu_has_rixi || !_PAGE_NO_EXEC) { + if (!cpu_has_rixi || _PAGE_NO_EXEC == 0) { /* * We'll only be making use of the fact that we can rotate bits * into the fill if the CPU supports RIXI, so don't bother
When CONFIG_XPA is enabled, Clang warns: arch/mips/mm/tlbex.c:629:24: error: converting the result of '<<' to a boolean; did you mean '(1 << _PAGE_NO_EXEC_SHIFT) != 0'? [-Werror,-Wint-in-bool-context] if (cpu_has_rixi && !!_PAGE_NO_EXEC) { ^ arch/mips/include/asm/pgtable-bits.h:174:28: note: expanded from macro '_PAGE_NO_EXEC' # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT) ^ arch/mips/mm/tlbex.c:2568:24: error: converting the result of '<<' to a boolean; did you mean '(1 << _PAGE_NO_EXEC_SHIFT) != 0'? [-Werror,-Wint-in-bool-context] if (!cpu_has_rixi || !_PAGE_NO_EXEC) { ^ arch/mips/include/asm/pgtable-bits.h:174:28: note: expanded from macro '_PAGE_NO_EXEC' # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT) ^ 2 errors generated. _PAGE_NO_EXEC can be '0' or '1 << _PAGE_NO_EXEC_SHIFT' depending on the build and runtime configuration, which is what the negation operators are trying to convey. To silence the warning, explicitly compare against 0 so the result of the '<<' operator is not implicitly converted to a boolean. According to its documentation, GCC enables -Wint-in-bool-context with -Wall but this warning is not visible when building the same configuration with GCC. It appears GCC only warns when compiling C++, not C, although the documentation makes no note of this: https://godbolt.org/z/x39q3brxf Reported-by: Sudip Mukherjee (Codethink) <sudipm.mukherjee@gmail.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- arch/mips/mm/tlbex.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) base-commit: 7d0d3fa7339ed5a06d6608b7cde9f079eba62bb1