[PATCH 13/24] arm64: introduce binfmt_elf32.c

Yury Norov
2018-05-16T08:18:58Z

As we support more than one compat formats, it looks more reasonable
to not use fs/compat_binfmt.c. Custom binfmt_elf32.c allows to move aarch32
specific definitions there and make code more maintainable and readable.

Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
---
arch/arm64/Kconfig | 1 -
arch/arm64/include/asm/elf.h | 26 +++---------------------
arch/arm64/include/asm/hwcap.h | 2 --
arch/arm64/kernel/Makefile | 2 +-
arch/arm64/kernel/binfmt_elf32.c | 35 ++++++++++++++++++++++++++++++++
5 files changed, 39 insertions(+), 27 deletions(-)
create mode 100644 arch/arm64/kernel/binfmt_elf32.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a16916be20f5..0685754a9f7b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1232,7 +1232,6 @@ config AARCH32_EL0
bool "Kernel support for 32-bit EL0"
def_bool y
depends on ARM64_4K_PAGES || EXPERT
- select COMPAT_BINFMT_ELF if BINFMT_ELF
select HAVE_UID16
select OLD_SIGSUSPEND3
select COMPAT_OLD_SIGACTION
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 023b2fbc1454..f04b27bd9bb6 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -175,36 +175,16 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm,

/* PIE load location for compat arm. Must match ARM ELF_ET_DYN_BASE. */
#define COMPAT_ELF_ET_DYN_BASE 0x000400000UL
+#endif /*CONFIG_COMPAT */

+#ifdef CONFIG_AARCH32_EL0
/* AArch32 registers. */
#define COMPAT_ELF_NGREG 18
typedef unsigned int compat_elf_greg_t;
typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
-
-/* AArch32 EABI. */
-#define EF_ARM_EABI_MASK 0xff000000
-#define compat_elf_check_arch(x) (system_supports_32bit_el0() && \
- ((x)->e_machine == EM_ARM) && \
- ((x)->e_flags & EF_ARM_EABI_MASK))
-
-#define compat_start_thread compat_start_thread
-/*
- * Unlike the native SET_PERSONALITY macro, the compat version maintains
- * READ_IMPLIES_EXEC across an execve() since this is the behaviour on
- * arch/arm/.
- */
-#define COMPAT_SET_PERSONALITY(ex) \
-({ \
- clear_thread_flag(TIF_32BIT_AARCH64); \
- set_thread_flag(TIF_32BIT); \
- })
-#define COMPAT_ARCH_DLINFO
extern int aarch32_setup_vectors_page(struct linux_binprm *bprm,
int uses_interp);
-#define compat_arch_setup_additional_pages \
- aarch32_setup_vectors_page
-
-#endif /* CONFIG_COMPAT */
+#endif /* CONFIG_AARCH32_EL0 */

#endif /* !__ASSEMBLY__ */

diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 2c7fc5d89813..99dfd9277559 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -47,8 +47,6 @@
#define ELF_HWCAP (elf_hwcap)

#ifdef CONFIG_AARCH32_EL0
-#define COMPAT_ELF_HWCAP (compat_elf_hwcap)
-#define COMPAT_ELF_HWCAP2 (compat_elf_hwcap2)
extern unsigned int compat_elf_hwcap, compat_elf_hwcap2;
#endif

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index cff1a78bdf4c..c63e0164fc12 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -27,7 +27,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
$(call if_changed,objcopy)

arm64-obj-$(CONFIG_AARCH32_EL0) += sys32.o kuser32.o signal32.o \
- sys_compat.o entry32.o
+ sys_compat.o entry32.o binfmt_elf32.o
arm64-obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
arm64-obj-$(CONFIG_MODULES) += arm64ksyms.o module.o
arm64-obj-$(CONFIG_ARM64_MODULE_PLTS) += module-plts.o
diff --git a/arch/arm64/kernel/binfmt_elf32.c b/arch/arm64/kernel/binfmt_elf32.c
new file mode 100644
index 000000000000..440fa84f62b3
--- /dev/null
+++ b/arch/arm64/kernel/binfmt_elf32.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Support for AArch32 Linux ELF binaries.
+ */
+
+/* AArch32 EABI. */
+#define EF_ARM_EABI_MASK 0xff000000
+
+#define compat_start_thread compat_start_thread
+/*
+ * Unlike the native SET_PERSONALITY macro, the compat version inherits
+ * READ_IMPLIES_EXEC across a fork() since this is the behaviour on
+ * arch/arm/.
+ */
+#define COMPAT_SET_PERSONALITY(ex) \
+({ \
+ clear_thread_flag(TIF_32BIT_AARCH64); \
+ set_thread_flag(TIF_32BIT); \
+})
+
+#define COMPAT_ARCH_DLINFO
+#define COMPAT_ELF_HWCAP (compat_elf_hwcap)
+#define COMPAT_ELF_HWCAP2 (compat_elf_hwcap2)
+
+#define compat_arch_setup_additional_pages \
+ aarch32_setup_vectors_page
+
+/* AArch32 EABI. */
+#define compat_elf_check_arch(x) (system_supports_32bit_el0() && \
+ ((x)->e_machine == EM_ARM) && \
+ ((x)->e_flags & EF_ARM_EABI_MASK))
+
+
+#include "../../../fs/compat_binfmt_elf.c"
--
2.17.0