to handle ILP32 binaries

Signed-off-by: Yury Norov <yno...@caviumnetworks.com>
---
 arch/arm64/include/asm/elf.h     |  6 +++
 arch/arm64/kernel/Makefile       |  1 +
 arch/arm64/kernel/binfmt_ilp32.c | 96 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 103 insertions(+)
 create mode 100644 arch/arm64/kernel/binfmt_ilp32.c

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index a967726..4dcbcec 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -174,10 +174,16 @@ extern int arch_setup_additional_pages(struct 
linux_binprm *bprm,
 
 #define COMPAT_ELF_ET_DYN_BASE         (2 * TASK_SIZE_32 / 3)
 
+#ifndef USE_AARCH64_GREG
 /* 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];
+#else /* AArch64 registers for AARCH64/ILP32 */
+#define COMPAT_ELF_NGREG       ELF_NGREG
+#define compat_elf_greg_t      elf_greg_t
+#define compat_elf_gregset_t   elf_gregset_t
+#endif
 
 /* AArch32 EABI. */
 #define EF_ARM_EABI_MASK               0xff000000
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 60d59cb..bcdd4b2 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -28,6 +28,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
 arm64-obj-$(CONFIG_AARCH32_EL0)                += sys32.o kuser32.o signal32.o 
        \
                                           sys_compat.o entry32.o               
\
                                           ../../arm/kernel/opcodes.o 
binfmt_elf32.o
+arm64-obj-$(CONFIG_ARM64_ILP32)                += binfmt_ilp32.o
 arm64-obj-$(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_ilp32.c b/arch/arm64/kernel/binfmt_ilp32.c
new file mode 100644
index 0000000..416b3f5
--- /dev/null
+++ b/arch/arm64/kernel/binfmt_ilp32.c
@@ -0,0 +1,96 @@
+/*
+ * Support for ILP32 Linux/aarch64 ELF binaries.
+ */
+#define USE_AARCH64_GREG
+
+#include <linux/elfcore-compat.h>
+#include <linux/time.h>
+
+#undef ELF_CLASS
+#define ELF_CLASS      ELFCLASS32
+
+#undef elfhdr
+#undef elf_phdr
+#undef elf_shdr
+#undef elf_note
+#undef elf_addr_t
+#define elfhdr         elf32_hdr
+#define elf_phdr       elf32_phdr
+#define elf_shdr       elf32_shdr
+#define elf_note       elf32_note
+#define elf_addr_t     Elf32_Addr
+
+/*
+ * Some data types as stored in coredump.
+ */
+#define user_long_t            compat_long_t
+#define user_siginfo_t         compat_siginfo_t
+#define copy_siginfo_to_user   copy_siginfo_to_user32
+
+/*
+ * The machine-dependent core note format types are defined in 
elfcore-compat.h,
+ * which requires asm/elf.h to define compat_elf_gregset_t et al.
+ */
+#define elf_prstatus   compat_elf_prstatus
+#define elf_prpsinfo   compat_elf_prpsinfo
+
+/*
+ * Compat version of cputime_to_compat_timeval, perhaps this
+ * should be an inline in <linux/compat.h>.
+ */
+static void cputime_to_compat_timeval(const cputime_t cputime,
+                                     struct compat_timeval *value)
+{
+       struct timeval tv;
+       cputime_to_timeval(cputime, &tv);
+       value->tv_sec = tv.tv_sec;
+       value->tv_usec = tv.tv_usec;
+}
+
+#undef cputime_to_timeval
+#define cputime_to_timeval cputime_to_compat_timeval
+
+/* AARCH64 ILP32 EABI. */
+#undef elf_check_arch
+#define elf_check_arch(x)              (((x)->e_machine == EM_AARCH64) \
+                                       && (x)->e_ident[EI_CLASS] == ELFCLASS32)
+
+#undef SET_PERSONALITY
+#define SET_PERSONALITY(ex)                                            \
+do {                                                                   \
+       set_thread_flag(TIF_32BIT_AARCH64);                             \
+       clear_thread_flag(TIF_32BIT);                                   \
+} while (0)
+
+#undef ARCH_DLINFO
+#define ARCH_DLINFO                                                    \
+do {                                                                   \
+       NEW_AUX_ENT(AT_SYSINFO_EHDR,                                    \
+                   (elf_addr_t)(long)current->mm->context.vdso);       \
+} while (0)
+
+#undef ELF_PLATFORM
+#ifdef __AARCH64EB__
+#define ELF_PLATFORM           ("aarch64_be:ilp32")
+#else
+#define ELF_PLATFORM           ("aarch64:ilp32")
+#endif
+
+#undef ELF_ET_DYN_BASE
+#define ELF_ET_DYN_BASE COMPAT_ELF_ET_DYN_BASE
+
+#undef ELF_HWCAP
+#undef ELF_HWCAP2
+#define ELF_HWCAP                      ((u32) elf_hwcap)
+#define ELF_HWCAP2                     ((u32) (elf_hwcap >> 32))
+
+/*
+ * Rename a few of the symbols that binfmt_elf.c will define.
+ * These are all local so the names don't really matter, but it
+ * might make some debugging less confusing not to duplicate them.
+ */
+#define elf_format             compat_elf_format
+#define init_elf_binfmt                init_compat_elf_binfmt
+#define exit_elf_binfmt                exit_compat_elf_binfmt
+
+#include "../../../fs/binfmt_elf.c"
-- 
2.7.4

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