[uclibc-ng-devel] [PATCH 18/32] [FDPIC] nptl: disable mprotect usage in stack protection

Since mprotect does not work on MMU-less systems, disable it if __ARCH_USE_MMU__ is not defined. * libpthread/nptl/allocatestack.c (change_stack_perm): Call mprotect only if __ARCH_USE_MMU__ is defined. (allocate_stack): Likewise. Signed-off-by: Mickaël Guêné &lt;mickael.guene(a)st.com&gt; Signed-off-by: Christophe Lyon &lt;christophe.lyon(a)st.com&gt; diff --git a/libpthread/nptl/allocatestack.c b/libpthread/nptl/allocatestack.c index 2900517..1379795 100644 --- a/libpthread/nptl/allocatestack.c +++ b/libpthread/nptl/allocatestack.c @@ -328,8 +328,10 @@ change_stack_perm (struct pthread *pd #else # error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP" #endif +#ifdef __ARCH_USE_MMU__ if (mprotect (stack, len, PROT_READ | PROT_WRITE | PROT_EXEC) != 0) return errno; +#endif return 0; } @@ -593,6 +595,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, #elif defined _STACK_GROWS_UP char *guard = (char *) (((uintptr_t) pd - guardsize) & ~pagesize_m1); #endif +#ifdef __ARCH_USE_MMU__ if (mprotect (guard, guardsize, PROT_NONE) != 0) { int err; @@ -618,6 +621,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, return err; } +#endif pd->guardsize = guardsize; } @@ -630,6 +634,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, char *guard = mem + (((size - guardsize) / 2) & ~pagesize_m1); char *oldguard = mem + (((size - pd->guardsize) / 2) & ~pagesize_m1); +#ifdef __ARCH_USE_MMU__ if (oldguard < guard && mprotect (oldguard, guard - oldguard, prot) != 0) goto mprot_error; @@ -647,6 +652,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, pd->guardsize - guardsize, prot) != 0) goto mprot_error; #endif +#endif pd->guardsize = guardsize; } -- 2.6.3