[PATCH 10/18] arm64: ilp32: introduce binfmt_ilp32.c

[Yury Norov]

binfmt_ilp32.c is needed to handle ILP32 binaries

Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Bamvor Zhang Jian <bamvor.zhangjian@xxxxxxxxxx>
---
 arch/arm64/include/asm/elf.h     |  6 +++
 arch/arm64/kernel/Makefile       |  1 +
 arch/arm64/kernel/binfmt_ilp32.c | 97 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 104 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 f259fe8..be29dde 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -175,10 +175,16 @@ 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 abe5040..f661888 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -29,6 +29,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
 
 arm64-obj-$(CONFIG_AARCH32_EL0)		+= sys32.o kuser32.o signal32.o 	\
 					   sys_compat.o entry32.o binfmt_elf32.o
+arm64-obj-$(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..759066e
--- /dev/null
+++ b/arch/arm64/kernel/binfmt_ilp32.c
@@ -0,0 +1,97 @@
+/*
+ * 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