ARM: enable elf_fdpic on systems with an MMU

Provide the necessary changes to be able to execute ELF-FDPIC binaries
on ARM systems with an MMU.

The default for CONFIG_BINFMT_ELF_FDPIC is also set to n if the regular
ELF loader is already configured so not to force FDPIC support on
everyone. Given that CONFIG_BINFMT_ELF depends on CONFIG_MMU, this means
CONFIG_BINFMT_ELF_FDPIC will still default to y when !MMU.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Mickael GUENE <mickael.guene@st.com>
Tested-by: Vincent Abriou <vincent.abriou@st.com>
Tested-by: Andras Szemzo <szemzo.andras@gmail.com>

2 files changed, 7 insertions, 2 deletions

diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 6ef70ce8e976..58c2bbd385ad 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -34,8 +34,8 @@ config ARCH_BINFMT_ELF_STATE
 
 config BINFMT_ELF_FDPIC
         bool "Kernel support for FDPIC ELF binaries"
-        default y
-        depends on ((ARM && !MMU) || FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)
+        default y if !BINFMT_ELF
+        depends on (ARM || FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)
         select ELFCORE
         help
           ELF FDPIC binaries are based on ELF, but allow the individual load
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index cf93a4fad012..692e2a1fd2bb 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -377,6 +377,11 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
                                  executable_stack);
         if (retval < 0)
                 goto error;
+#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
+        retval = arch_setup_additional_pages(bprm, !!interpreter_name);
+        if (retval < 0)
+                goto error;
+#endif
 #endif
 
         /* load the executable and interpreter into memory */