| Message ID | 20220907230556.73536-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | MIPS: BCM47XX: Cast memcmp() of function to (void *) | expand |
On Wed, Sep 07, 2022 at 04:05:56PM -0700, Kees Cook wrote: > Clang is especially sensitive about argument type matching when using > __overloaded functions (like memcmp(), etc). Help it see that function > pointers are just "void *". Avoids this error: > > arch/mips/bcm47xx/prom.c:89:8: error: no matching function for call to 'memcmp' > if (!memcmp(prom_init, prom_init + mem, 32)) > ^~~~~~ > include/linux/string.h:156:12: note: candidate function not viable: no known conversion from 'void (void)' to 'const void *' for 1st argument extern int memcmp(const void *,const void *,__kernel_size_t); > Don't we have the same problem at line 162? (next-20220908)arch/mips/bcm47xx/prom.c: 161 for (extmem = 128 << 20; extmem < 512 << 20; extmem <<= 1) { 162 if (!memcmp(prom_init, (void *)(off + extmem), 16)) 163 break; 164 } -- Gustavo > Cc: Hauke Mehrtens <hauke@hauke-m.de> > Cc: "Rafał Miłecki" <zajec5@gmail.com> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > Cc: linux-mips@vger.kernel.org > Cc: Nathan Chancellor <nathan@kernel.org> > Cc: Nick Desaulniers <ndesaulniers@google.com> > Cc: llvm@lists.linux.dev > Reported-by: kernel test robot <lkp@intel.com> > Link: https://lore.kernel.org/lkml/202209080652.sz2d68e5-lkp@intel.com > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > arch/mips/bcm47xx/prom.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c > index ab203e66ba0d..eb5c04a24531 100644 > --- a/arch/mips/bcm47xx/prom.c > +++ b/arch/mips/bcm47xx/prom.c > @@ -86,7 +86,7 @@ static __init void prom_init_mem(void) > pr_debug("Assume 128MB RAM\n"); > break; > } > - if (!memcmp(prom_init, prom_init + mem, 32)) > + if (!memcmp((void *)prom_init, (void *)prom_init + mem, 32)) > break; > } > lowmem = mem; > -- > 2.34.1 >
On Wed, Sep 07, 2022 at 04:05:56PM -0700, Kees Cook wrote: > Clang is especially sensitive about argument type matching when using > __overloaded functions (like memcmp(), etc). Help it see that function > pointers are just "void *". Avoids this error: > > arch/mips/bcm47xx/prom.c:89:8: error: no matching function for call to 'memcmp' > if (!memcmp(prom_init, prom_init + mem, 32)) > ^~~~~~ > include/linux/string.h:156:12: note: candidate function not viable: no known conversion from 'void (void)' to 'const void *' for 1st argument extern int memcmp(const void *,const void *,__kernel_size_t); > > Cc: Hauke Mehrtens <hauke@hauke-m.de> > Cc: "Rafał Miłecki" <zajec5@gmail.com> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > Cc: linux-mips@vger.kernel.org > Cc: Nathan Chancellor <nathan@kernel.org> > Cc: Nick Desaulniers <ndesaulniers@google.com> > Cc: llvm@lists.linux.dev > Reported-by: kernel test robot <lkp@intel.com> > Link: https://lore.kernel.org/lkml/202209080652.sz2d68e5-lkp@intel.com > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > arch/mips/bcm47xx/prom.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c > index ab203e66ba0d..eb5c04a24531 100644 > --- a/arch/mips/bcm47xx/prom.c > +++ b/arch/mips/bcm47xx/prom.c > @@ -86,7 +86,7 @@ static __init void prom_init_mem(void) > pr_debug("Assume 128MB RAM\n"); > break; > } > - if (!memcmp(prom_init, prom_init + mem, 32)) > + if (!memcmp((void *)prom_init, (void *)prom_init + mem, 32)) > break; > } > lowmem = mem; > -- > 2.34.1 applied to mips-next with the second memcmp(prom_init changed as well. Thomas.
diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c index ab203e66ba0d..eb5c04a24531 100644 --- a/arch/mips/bcm47xx/prom.c +++ b/arch/mips/bcm47xx/prom.c @@ -86,7 +86,7 @@ static __init void prom_init_mem(void) pr_debug("Assume 128MB RAM\n"); break; } - if (!memcmp(prom_init, prom_init + mem, 32)) + if (!memcmp((void *)prom_init, (void *)prom_init + mem, 32)) break; } lowmem = mem;
Clang is especially sensitive about argument type matching when using __overloaded functions (like memcmp(), etc). Help it see that function pointers are just "void *". Avoids this error: arch/mips/bcm47xx/prom.c:89:8: error: no matching function for call to 'memcmp' if (!memcmp(prom_init, prom_init + mem, 32)) ^~~~~~ include/linux/string.h:156:12: note: candidate function not viable: no known conversion from 'void (void)' to 'const void *' for 1st argument extern int memcmp(const void *,const void *,__kernel_size_t); Cc: Hauke Mehrtens <hauke@hauke-m.de> Cc: "Rafał Miłecki" <zajec5@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: linux-mips@vger.kernel.org Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: llvm@lists.linux.dev Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/lkml/202209080652.sz2d68e5-lkp@intel.com Signed-off-by: Kees Cook <keescook@chromium.org> --- arch/mips/bcm47xx/prom.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)