Building the sigaltstack test with GCC on 64-bit powerpc errors with:
gcc -Wall sas.c -o /home/michael/linux/.build/kselftest/sigaltstack/sas
In file included from sas.c:23:
current_stack_pointer.h:22:2: error: #error "implement current_stack_pointer equivalent"
22 | #error "implement current_stack_pointer equivalent"
| ^~~~~
sas.c: In function ‘my_usr1’:
sas.c:50:13: error: ‘sp’ undeclared (first use in this function); did you mean ‘p’?
50 | if (sp < (unsigned long)sstack ||
| ^~
This happens because GCC doesn't define __ppc__ for 64-bit builds, only
32-bit builds. Instead use __powerpc__ to detect powerpc builds, which
is defined by clang and GCC for 64-bit and 32-bit builds.
Fixes: 05107edc91 ("selftests: sigaltstack: fix -Wuninitialized")
Cc: stable@vger.kernel.org # v6.3+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240520062647.688667-1-mpe@ellerman.id.au
Building sigaltstack with clang via:
$ ARCH=x86 make LLVM=1 -C tools/testing/selftests/sigaltstack/
produces the following warning:
warning: variable 'sp' is uninitialized when used here [-Wuninitialized]
if (sp < (unsigned long)sstack ||
^~
Clang expects these to be declared at global scope; we've fixed this in
the kernel proper by using the macro `current_stack_pointer`. This is
defined in different headers for different target architectures, so just
create a new header that defines the arch-specific register names for
the stack pointer register, and define it for more targets (at least the
ones that support current_stack_pointer/ARCH_HAS_CURRENT_STACK_POINTER).
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Link: https://lore.kernel.org/lkml/CA+G9fYsi3OOu7yCsMutpzKDnBMAzJBCPimBp86LhGBa0eCnEpA@mail.gmail.com/
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
