[PATCH] elf: early conversion of elf p_flags to mprotect flags
Cupertino Miranda
cupertino.miranda@oracle.com
Wed Jun 4 15:58:47 GMT 2025
PING! :)
On 14-05-2025 16:18, Cupertino Miranda wrote:
> Hi everyone,
>
> This patch is related to a change requested by Florian in respect to
> adding support for MTE stack mode, to which stacks in general needed to
> be protected with PROT_MTE.
>
> Both the files dl-mmap-prot.[ch] and the function name __pf_to_prot,
> should likely be renamed. Please advise.
>
> No regressions for x86-64.
>
> Looking forward to your comments.
>
> Cheers,
> Cupertino
>
> This patch replaces _dl_stack_flags global variable by
> _dl_stack_prot_flags.
> The advantage is that any convertion from p_flags to final used mprotect
> flags occurs at loading of p_flags. It avoids repeated spurious
> convertions of _dl_stack_flags, for example in allocate_thread_stack.
>
> This modification was suggested in:
> https://sourceware.org/pipermail/libc-alpha/2025-March/165537.html
> ---
> elf/Makefile | 4 ++-
> elf/dl-execstack-tunable.c | 2 +-
> elf/dl-load.c | 20 ++++---------
> elf/dl-mmap-prot.c | 41 ++++++++++++++++++++++++++
> elf/dl-mmap-prot.h | 26 ++++++++++++++++
> elf/dl-support.c | 7 ++---
> elf/rtld.c | 5 +++-
> nptl/allocatestack.c | 12 ++------
> support/support_stack_alloc.c | 9 +++---
> sysdeps/alpha/stackinfo.h | 6 ++--
> sysdeps/arm/stackinfo.h | 6 ++--
> sysdeps/generic/ldsodefs.h | 1 +
> sysdeps/generic/stackinfo.h | 2 +-
> sysdeps/hppa/stackinfo.h | 6 ++--
> sysdeps/i386/stackinfo.h | 6 ++--
> sysdeps/m68k/stackinfo.h | 6 ++--
> sysdeps/mach/htl/pt-stack-alloc.c | 2 +-
> sysdeps/mach/hurd/dl-execstack.c | 2 +-
> sysdeps/microblaze/stackinfo.h | 6 ++--
> sysdeps/mips/stackinfo.h | 6 ++--
> sysdeps/or1k/stackinfo.h | 6 ++--
> sysdeps/powerpc/powerpc32/stackinfo.h | 4 +--
> sysdeps/s390/stackinfo.h | 6 ++--
> sysdeps/sh/stackinfo.h | 6 ++--
> sysdeps/sparc/stackinfo.h | 6 ++--
> sysdeps/unix/sysv/linux/dl-execstack.c | 2 +-
> sysdeps/unix/sysv/linux/spawni.c | 5 +---
> sysdeps/x86_64/stackinfo.h | 6 ++--
> 28 files changed, 133 insertions(+), 83 deletions(-)
> create mode 100644 elf/dl-mmap-prot.c
> create mode 100644 elf/dl-mmap-prot.h
>
> diff --git a/elf/Makefile b/elf/Makefile
> index ed1b0223da..a2e592b50f 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -69,6 +69,7 @@ dl-routines = \
> dl-lookup-direct \
> dl-minimal-malloc \
> dl-misc \
> + dl-mmap-prot \
> dl-object \
> dl-open \
> dl-origin \
> @@ -139,6 +140,7 @@ rtld-routines = \
> dl-hwcaps_split \
> dl-libc_freeres \
> dl-minimal \
> + dl-mmap-prot \
> dl-mutex \
> dl-profile \
> dl-sysdep \
> @@ -2154,7 +2156,7 @@ $(objpfx)execstack-default: $(first-word $(wildcard $(sysdirs:%=%/stackinfo.h)))
> $(make-target-directory)
> { echo '#include <elf.h>'; \
> echo '#include <stackinfo.h>'; \
> - echo '#if (DEFAULT_STACK_PERMS & PF_X) == 0'; \
> + echo '#if (DEFAULT_STACK_PROT_PERMS & PROT_EXEC) == 0'; \
> echo '@@@execstack-no@@@'; \
> echo '#else'; \
> echo '@@@execstack-yes@@@'; \
> diff --git a/elf/dl-execstack-tunable.c b/elf/dl-execstack-tunable.c
> index e3b638aeaa..b2511ea031 100644
> --- a/elf/dl-execstack-tunable.c
> +++ b/elf/dl-execstack-tunable.c
> @@ -25,7 +25,7 @@ _dl_handle_execstack_tunable (void)
> switch (TUNABLE_GET (glibc, rtld, execstack, int32_t, NULL))
> {
> case stack_tunable_mode_disable:
> - if ((__glibc_unlikely (GL(dl_stack_flags)) & PF_X))
> + if ((__glibc_unlikely (GL(dl_stack_prot_flags)) & PROT_EXEC))
> _dl_fatal_printf (
> "Fatal glibc error: executable stack is not allowed\n");
> break;
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index bf29ec725d..6aae07b9f0 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -74,6 +74,7 @@ struct filebuf
> #include <dl-unmap-segments.h>
> #include <dl-machine-reject-phdr.h>
> #include <dl-prop.h>
> +#include <dl-mmap-prot.h>
> #include <not-cancel.h>
>
> #include <endian.h>
> @@ -1096,7 +1097,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
> /* On most platforms presume that PT_GNU_STACK is absent and the stack is
> * executable. Other platforms default to a nonexecutable stack and don't
> * need PT_GNU_STACK to do so. */
> - unsigned int stack_flags = DEFAULT_STACK_PERMS;
> + unsigned int stack_flags = DEFAULT_STACK_PROT_PERMS;
>
> {
> /* Scan the program header table, collecting its load commands. */
> @@ -1171,18 +1172,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
> DIAG_POP_NEEDS_COMMENT;
>
> /* Optimize a common case. */
> -#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
> - c->prot = (PF_TO_PROT
> - >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
> -#else
> - c->prot = 0;
> - if (ph->p_flags & PF_R)
> - c->prot |= PROT_READ;
> - if (ph->p_flags & PF_W)
> - c->prot |= PROT_WRITE;
> - if (ph->p_flags & PF_X)
> - c->prot |= PROT_EXEC;
> -#endif
> + c->prot = __pf_to_prot (ph->p_flags);
> break;
>
> case PT_TLS:
> @@ -1219,7 +1209,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
> break;
>
> case PT_GNU_STACK:
> - stack_flags = ph->p_flags;
> + stack_flags = __pf_to_prot (ph->p_flags);
> break;
>
> case PT_GNU_RELRO:
> @@ -1319,7 +1309,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
> /* Adjust the PT_PHDR value by the runtime load address. */
> l->l_phdr = (ElfW(Phdr) *) ((ElfW(Addr)) l->l_phdr + l->l_addr);
>
> - if (__glibc_unlikely ((stack_flags &~ GL(dl_stack_flags)) & PF_X))
> + if (__glibc_unlikely ((stack_flags &~ GL(dl_stack_prot_flags)) & PROT_EXEC))
> {
> /* The stack is presently not executable, but this module
> requires that it be executable. Only tries to change the
> diff --git a/elf/dl-mmap-prot.c b/elf/dl-mmap-prot.c
> new file mode 100644
> index 0000000000..6b665d84d4
> --- /dev/null
> +++ b/elf/dl-mmap-prot.c
> @@ -0,0 +1,41 @@
> +/* Convertion from elf p_flags to mmap prot ones.
> + Copyright (C) 2025 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <dl-mmap-prot.h>
> +#include <ldsodefs.h>
> +#include <sys/mman.h>
> +#include <stackinfo.h>
> +
> +int _dl_stack_prot_flags = DEFAULT_STACK_PROT_PERMS;
> +
> +int
> +__pf_to_prot (ElfW(Word) value)
> +{
> +#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
> + return (PF_TO_PROT >> ((value & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
> +#else
> + ElfW(Word) ret = 0;
> + if (value & PF_R)
> + ret |= PROT_READ;
> + if (value & PF_W)
> + ret |= PROT_WRITE;
> + if (value & PF_X)
> + ret |= PROT_EXEC;
> + return ret;
> +#endif
> +}
> diff --git a/elf/dl-mmap-prot.h b/elf/dl-mmap-prot.h
> new file mode 100644
> index 0000000000..94286e598f
> --- /dev/null
> +++ b/elf/dl-mmap-prot.h
> @@ -0,0 +1,26 @@
> +/* Convertion from elf p_flags to mmap prot ones.
> + Copyright (C) 2025 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#ifndef _DL_MMAP_PROT_H
> +#define _DL_MMAP_PROT_H
> +
> +#include <link.h>
> +
> +int __pf_to_prot (ElfW(Word) value);
> +
> +#endif /* _DL_MMAP_PROT_H */
> diff --git a/elf/dl-support.c b/elf/dl-support.c
> index 7b2a1c35d5..2484fa83e4 100644
> --- a/elf/dl-support.c
> +++ b/elf/dl-support.c
> @@ -45,6 +45,7 @@
> #include <array_length.h>
> #include <dl-symbol-redir-ifunc.h>
> #include <dl-tunables.h>
> +#include <dl-mmap-prot.h>
>
> extern char *__progname;
> char **_dl_argv = &__progname; /* This is checked for some error messages. */
> @@ -166,10 +167,6 @@ enum dso_sort_algorithm _dl_dso_sort_algo;
> /* The value of the FPU control word the kernel will preset in hardware. */
> fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
>
> -/* Prevailing state of the stack. Generally this includes PF_X, indicating it's
> - * executable but this isn't true for all platforms. */
> -ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS;
> -
> #if PTHREAD_IN_LIBC
> list_t _dl_stack_used;
> list_t _dl_stack_user;
> @@ -322,7 +319,7 @@ _dl_non_dynamic_init (void)
> {
> /* Check if the stack is nonexecutable. */
> case PT_GNU_STACK:
> - _dl_stack_flags = ph->p_flags;
> + _dl_stack_prot_flags = __pf_to_prot (ph->p_flags);
> break;
>
> case PT_GNU_RELRO:
> diff --git a/elf/rtld.c b/elf/rtld.c
> index 3af8ee63c3..fb76521c27 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -52,6 +52,7 @@
> #include <dl-find_object.h>
> #include <dl-audit-check.h>
> #include <dl-call_tls_init_tp.h>
> +#include <dl-mmap-prot.h>
>
> #include <assert.h>
>
> @@ -322,7 +323,7 @@ struct rtld_global _rtld_global =
> #include <dl-procruntime.c>
> /* Generally the default presumption without further information is an
> * executable stack but this is not true for all platforms. */
> - ._dl_stack_flags = DEFAULT_STACK_PERMS,
> + ._dl_stack_prot_flags = DEFAULT_STACK_PROT_PERMS,
> #ifdef _LIBC_REENTRANT
> ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
> ._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
> @@ -1197,6 +1198,7 @@ rtld_setup_main_map (struct link_map *main_map)
>
> case PT_GNU_STACK:
> GL(dl_stack_flags) = ph->p_flags;
> + GL(dl_stack_prot_flags) = __pf_to_prot (ph->p_flags);
> break;
>
> case PT_GNU_RELRO:
> @@ -1502,6 +1504,7 @@ dl_main (const ElfW(Phdr) *phdr,
> if (ph->p_type == PT_GNU_STACK)
> {
> GL(dl_stack_flags) = ph->p_flags;
> + GL(dl_stack_prot_flags) = __pf_to_prot (ph->p_flags);
> break;
> }
>
> diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
> index 800ca89720..4c2aacdd10 100644
> --- a/nptl/allocatestack.c
> +++ b/nptl/allocatestack.c
> @@ -150,17 +150,11 @@ get_cached_stack (size_t *sizep, void **memp)
> and fallback to ALLOCATE_GUARD_PROT_NONE if the madvise call fails. */
> static int allocate_stack_mode = ALLOCATE_GUARD_MADV_GUARD;
>
> -static inline int stack_prot (void)
> -{
> - return (PROT_READ | PROT_WRITE
> - | ((GL(dl_stack_flags) & PF_X) ? PROT_EXEC : 0));
> -}
> -
> static void *
> allocate_thread_stack (size_t size, size_t guardsize)
> {
> /* MADV_ADVISE_GUARD does not require an additional PROT_NONE mapping. */
> - int prot = stack_prot ();
> + int prot = GL(dl_stack_prot_flags);
>
> if (atomic_load_relaxed (&allocate_stack_mode) == ALLOCATE_GUARD_PROT_NONE)
> /* If a guard page is required, avoid committing memory by first allocate
> @@ -216,7 +210,7 @@ setup_stack_prot (char *mem, size_t size, struct pthread *pd,
> }
> else
> {
> - const int prot = stack_prot ();
> + const int prot = GL(dl_stack_prot_flags);
> char *guardend = guard + guardsize;
> #if _STACK_GROWS_DOWN
> /* As defined at guard_position, for architectures with downward stack
> @@ -294,7 +288,7 @@ adjust_stack_prot (char *mem, size_t size, const struct pthread *pd,
> }
> else if (pd->stack_mode == ALLOCATE_GUARD_PROT_NONE)
> {
> - const int prot = stack_prot ();
> + const int prot = GL(dl_stack_prot_flags);
> #if _STACK_GROWS_DOWN
> return __mprotect (mem + guardsize, slacksize, prot) == 0;
> #else
> diff --git a/support/support_stack_alloc.c b/support/support_stack_alloc.c
> index 5e576bea74..132e7b4f70 100644
> --- a/support/support_stack_alloc.c
> +++ b/support/support_stack_alloc.c
> @@ -64,11 +64,10 @@ support_stack_alloc (size_t size)
> MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE|MAP_STACK,
> -1);
> /* Some architecture still requires executable stack for the signal return
> - trampoline, although PF_X could be overridden if PT_GNU_STACK is present.
> - However since glibc does not export such information with a proper ABI,
> - it uses the historical permissions. */
> - int prot = PROT_READ | PROT_WRITE
> - | (DEFAULT_STACK_PERMS & PF_X ? PROT_EXEC : 0);
> + trampoline, although PROT_EXEC could be overridden if PT_GNU_STACK is
> + present. However since glibc does not export such information with a
> + proper ABI, it uses the historical permissions. */
> + int prot = DEFAULT_STACK_PROT_PERMS;
> xmprotect (alloc_base + guardsize, stacksize, prot);
> memset (alloc_base + guardsize, 0xA5, stacksize);
> return (struct support_stack) { alloc_base + guardsize, stacksize, guardsize };
> diff --git a/sysdeps/alpha/stackinfo.h b/sysdeps/alpha/stackinfo.h
> index a469964c10..d69647756b 100644
> --- a/sysdeps/alpha/stackinfo.h
> +++ b/sysdeps/alpha/stackinfo.h
> @@ -26,8 +26,8 @@
> /* On Alpha the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h */
> diff --git a/sysdeps/arm/stackinfo.h b/sysdeps/arm/stackinfo.h
> index 3068352eab..30608f7062 100644
> --- a/sysdeps/arm/stackinfo.h
> +++ b/sysdeps/arm/stackinfo.h
> @@ -26,8 +26,8 @@
> /* On Arm the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h */
> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
> index fc4a3de767..d92e28d6a9 100644
> --- a/sysdeps/generic/ldsodefs.h
> +++ b/sysdeps/generic/ldsodefs.h
> @@ -419,6 +419,7 @@ struct rtld_global
>
> /* Prevailing state of the stack, PF_X indicating it's executable. */
> EXTERN ElfW(Word) _dl_stack_flags;
> + EXTERN int _dl_stack_prot_flags;
>
> /* Flag signalling whether there are gaps in the module ID allocation. */
> EXTERN bool _dl_tls_dtv_gaps;
> diff --git a/sysdeps/generic/stackinfo.h b/sysdeps/generic/stackinfo.h
> index 8abbb3dff7..ab3e72e5c2 100644
> --- a/sysdeps/generic/stackinfo.h
> +++ b/sysdeps/generic/stackinfo.h
> @@ -24,6 +24,6 @@
> #include <elf.h>
>
> #define _STACK_GROWS_DOWN 1
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W)
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE)
>
> #endif
> diff --git a/sysdeps/hppa/stackinfo.h b/sysdeps/hppa/stackinfo.h
> index 53bb11fde0..22920d20a9 100644
> --- a/sysdeps/hppa/stackinfo.h
> +++ b/sysdeps/hppa/stackinfo.h
> @@ -23,9 +23,9 @@
>
> #include <elf.h>
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> /* On PA the stack grows up. */
> #define _STACK_GROWS_UP 1
> diff --git a/sysdeps/i386/stackinfo.h b/sysdeps/i386/stackinfo.h
> index 74e82278d3..8d7a46c405 100644
> --- a/sysdeps/i386/stackinfo.h
> +++ b/sysdeps/i386/stackinfo.h
> @@ -26,9 +26,9 @@
> /* On x86 the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> /* Access to the stack pointer. The macros are used in alloca_account
> for which they need to act as barriers as well, hence the additional
> diff --git a/sysdeps/m68k/stackinfo.h b/sysdeps/m68k/stackinfo.h
> index 7a757df147..77672c71c4 100644
> --- a/sysdeps/m68k/stackinfo.h
> +++ b/sysdeps/m68k/stackinfo.h
> @@ -26,9 +26,9 @@
> /* On m68k the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK
> - is present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK is
> + * present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> /* Access to the stack pointer. */
> #define stackinfo_get_sp() \
> diff --git a/sysdeps/mach/htl/pt-stack-alloc.c b/sysdeps/mach/htl/pt-stack-alloc.c
> index 3e196f8ca7..42762bc0ad 100644
> --- a/sysdeps/mach/htl/pt-stack-alloc.c
> +++ b/sysdeps/mach/htl/pt-stack-alloc.c
> @@ -33,7 +33,7 @@ __pthread_stack_alloc (void **stackaddr, size_t stacksize)
> error_t err;
> vm_prot_t prot = VM_PROT_READ | VM_PROT_WRITE;
>
> - if (GL(dl_stack_flags) & PF_X)
> + if (GL(dl_stack_prot_flags) & PROT_EXEC)
> prot |= VM_PROT_EXECUTE;
>
> err = __vm_map (__mach_task_self (), (vm_offset_t *) stackaddr,
> diff --git a/sysdeps/mach/hurd/dl-execstack.c b/sysdeps/mach/hurd/dl-execstack.c
> index dc4719bd38..9e69169367 100644
> --- a/sysdeps/mach/hurd/dl-execstack.c
> +++ b/sysdeps/mach/hurd/dl-execstack.c
> @@ -38,7 +38,7 @@ _dl_make_stack_executable (const void *stack_endp)
> return errno;
>
> /* Remember that we changed the permission. */
> - GL(dl_stack_flags) |= PF_X;
> + GL(dl_stack_prot_flags) |= PROT_EXEC;
>
> return 0;
> #else
> diff --git a/sysdeps/microblaze/stackinfo.h b/sysdeps/microblaze/stackinfo.h
> index 8960bd3d25..51d40a7732 100644
> --- a/sysdeps/microblaze/stackinfo.h
> +++ b/sysdeps/microblaze/stackinfo.h
> @@ -27,8 +27,8 @@
> /* On MicroBlaze the stack grows down. */
> # define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -# define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h. */
> diff --git a/sysdeps/mips/stackinfo.h b/sysdeps/mips/stackinfo.h
> index 6cce9386d6..107a8ea7c9 100644
> --- a/sysdeps/mips/stackinfo.h
> +++ b/sysdeps/mips/stackinfo.h
> @@ -26,8 +26,8 @@
> /* On MIPS the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h */
> diff --git a/sysdeps/or1k/stackinfo.h b/sysdeps/or1k/stackinfo.h
> index 39cf5c2456..d93a795c51 100644
> --- a/sysdeps/or1k/stackinfo.h
> +++ b/sysdeps/or1k/stackinfo.h
> @@ -27,8 +27,8 @@
> /* On or1k the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R | PF_W | PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h */
> diff --git a/sysdeps/powerpc/powerpc32/stackinfo.h b/sysdeps/powerpc/powerpc32/stackinfo.h
> index 31cba55805..50a3b367c6 100644
> --- a/sysdeps/powerpc/powerpc32/stackinfo.h
> +++ b/sysdeps/powerpc/powerpc32/stackinfo.h
> @@ -26,7 +26,7 @@
> /* On PPC the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* PF_X can be overridden if PT_GNU_STACK is present but is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* PROT_EXEC can be overridden if PT_GNU_STACK is present but is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h */
> diff --git a/sysdeps/s390/stackinfo.h b/sysdeps/s390/stackinfo.h
> index 657ab3487f..9be764495a 100644
> --- a/sysdeps/s390/stackinfo.h
> +++ b/sysdeps/s390/stackinfo.h
> @@ -26,8 +26,8 @@
> /* On s390 the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h */
> diff --git a/sysdeps/sh/stackinfo.h b/sysdeps/sh/stackinfo.h
> index 8f7bf163be..e502993d24 100644
> --- a/sysdeps/sh/stackinfo.h
> +++ b/sysdeps/sh/stackinfo.h
> @@ -26,8 +26,8 @@
> /* On SH the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h */
> diff --git a/sysdeps/sparc/stackinfo.h b/sysdeps/sparc/stackinfo.h
> index 23a74ed7fe..a4a0eb15c9 100644
> --- a/sysdeps/sparc/stackinfo.h
> +++ b/sysdeps/sparc/stackinfo.h
> @@ -26,8 +26,8 @@
> /* On sparc the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> #endif /* stackinfo.h */
> diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/sysv/linux/dl-execstack.c
> index 6db9601656..81edcc8567 100644
> --- a/sysdeps/unix/sysv/linux/dl-execstack.c
> +++ b/sysdeps/unix/sysv/linux/dl-execstack.c
> @@ -36,7 +36,7 @@ _dl_make_stack_executable (const void *stack_endp)
> return errno;
>
> /* Remember that we changed the permission. */
> - GL(dl_stack_flags) |= PF_X;
> + GL(dl_stack_prot_flags) |= PROT_EXEC;
>
> return 0;
> }
> diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
> index eca1a84254..bc8476ff11 100644
> --- a/sysdeps/unix/sysv/linux/spawni.c
> +++ b/sysdeps/unix/sysv/linux/spawni.c
> @@ -348,9 +348,6 @@ __spawnix (int *pid, const char *file,
> return errno;
> }
>
> - int prot = (PROT_READ | PROT_WRITE
> - | ((GL (dl_stack_flags) & PF_X) ? PROT_EXEC : 0));
> -
> /* Add a slack area for child's stack. */
> size_t argv_size = (argc * sizeof (void *)) + 512;
> /* We need at least a few pages in case the compiler's stack checking is
> @@ -361,7 +358,7 @@ __spawnix (int *pid, const char *file,
> where it might use about 1k extra stack space). */
> argv_size += (32 * 1024);
> size_t stack_size = ALIGN_UP (argv_size, GLRO(dl_pagesize));
> - void *stack = __mmap (NULL, stack_size, prot,
> + void *stack = __mmap (NULL, stack_size, GL (dl_stack_prot_flags),
> MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
> if (__glibc_unlikely (stack == MAP_FAILED))
> return errno;
> diff --git a/sysdeps/x86_64/stackinfo.h b/sysdeps/x86_64/stackinfo.h
> index 416d687869..0e88e6d94e 100644
> --- a/sysdeps/x86_64/stackinfo.h
> +++ b/sysdeps/x86_64/stackinfo.h
> @@ -32,9 +32,9 @@
> /* On x86_64 the stack grows down. */
> #define _STACK_GROWS_DOWN 1
>
> -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
> - * present, but it is presumed absent. */
> -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
> +/* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
> + * is present, but it is presumed absent. */
> +#define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
>
> /* Access to the stack pointer. The macros are used in alloca_account
> for which they need to act as barriers as well, hence the additional
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