selftests: sigaltstack: fix -Wuninitialized

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>
This commit is contained in:
Nick Desaulniers 2023-03-08 11:59:33 -08:00 committed by Shuah Khan
parent 624c60f326
commit 05107edc91
2 changed files with 24 additions and 6 deletions

View File

@ -0,0 +1,23 @@
/* SPDX-License-Identifier: GPL-2.0 */
#if __alpha__
register unsigned long sp asm("$30");
#elif __arm__ || __aarch64__ || __csky__ || __m68k__ || __mips__ || __riscv
register unsigned long sp asm("sp");
#elif __i386__
register unsigned long sp asm("esp");
#elif __loongarch64
register unsigned long sp asm("$sp");
#elif __ppc__
register unsigned long sp asm("r1");
#elif __s390x__
register unsigned long sp asm("%15");
#elif __sh__
register unsigned long sp asm("r15");
#elif __x86_64__
register unsigned long sp asm("rsp");
#elif __XTENSA__
register unsigned long sp asm("a1");
#else
#error "implement current_stack_pointer equivalent"
#endif

View File

@ -20,6 +20,7 @@
#include <sys/auxv.h>
#include "../kselftest.h"
#include "current_stack_pointer.h"
#ifndef SS_AUTODISARM
#define SS_AUTODISARM (1U << 31)
@ -46,12 +47,6 @@ void my_usr1(int sig, siginfo_t *si, void *u)
stack_t stk;
struct stk_data *p;
#if __s390x__
register unsigned long sp asm("%15");
#else
register unsigned long sp asm("sp");
#endif
if (sp < (unsigned long)sstack ||
sp >= (unsigned long)sstack + stack_size) {
ksft_exit_fail_msg("SP is not on sigaltstack\n");