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MIPS: tlbex: Explicitly compare _PAGE_NO_EXEC against 0

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[ 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@gmail.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Nathan Chancellor 2022-08-02 10:59:36 -07:00 committed by Greg Kroah-Hartman
parent 2b7f559152
commit 5d8244d42d
1 changed files with 2 additions and 2 deletions
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4
arch/mips/mm/tlbex.c
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@ -629,7 +629,7 @@ static __maybe_unused void build_convert_pte_to_entrylo(u32 **p,
return; return;
} }
if (cpu_has_rixi && !!_PAGE_NO_EXEC) { if (cpu_has_rixi && _PAGE_NO_EXEC != 0) {
if (fill_includes_sw_bits) { if (fill_includes_sw_bits) {
UASM_i_ROTR(p, reg, reg, ilog2(_PAGE_GLOBAL)); UASM_i_ROTR(p, reg, reg, ilog2(_PAGE_GLOBAL));
} else { } else {
@ -2568,7 +2568,7 @@ static void check_pabits(void)
unsigned long entry; unsigned long entry;
unsigned pabits, fillbits; 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 * 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 * into the fill if the CPU supports RIXI, so don't bother