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Date: Sun, 14 Aug 2022 12:23:28 -0400 From: Sasha Levin <sashal@...nel.org> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org Cc: Nathan Chancellor <nathan@...nel.org>, Sudip Mukherjee <sudipm.mukherjee@...il.com>, Thomas Bogendoerfer <tsbogend@...ha.franken.de>, Sasha Levin <sashal@...nel.org>, ndesaulniers@...gle.com, macro@...am.me.uk, linux-mips@...r.kernel.org, llvm@...ts.linux.dev Subject: [PATCH AUTOSEL 5.18 39/39] MIPS: tlbex: Explicitly compare _PAGE_NO_EXEC against 0 From: Nathan Chancellor <nathan@...nel.org> [ Upstream commit 74de14fe05dd6b151d73cb0c73c8ec874cbdcde6 ] 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@...il.com> Signed-off-by: Nathan Chancellor <nathan@...nel.org> Signed-off-by: Thomas Bogendoerfer <tsbogend@...ha.franken.de> Signed-off-by: Sasha Levin <sashal@...nel.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 -- 2.35.1
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