1 files changed, 114 insertions, 0 deletions
diff --git a/arch/arm/kernel/elf.c b/arch/arm/kernel/elf.c
new file mode 100644
index 000000000..182422981
--- /dev/null
+++ b/arch/arm/kernel/elf.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/personality.h>
+#include <linux/binfmts.h>
+#include <linux/elf.h>
+#include <linux/elf-fdpic.h>
+#include <asm/system_info.h>
+
+int elf_check_arch(const struct elf32_hdr *x)
+{
+	unsigned int eflags;
+
+	/* Make sure it's an ARM executable */
+	if (x->e_machine != EM_ARM)
+		return 0;
+
+	/* Make sure the entry address is reasonable */
+	if (x->e_entry & 1) {
+		if (!(elf_hwcap & HWCAP_THUMB))
+			return 0;
+	} else if (x->e_entry & 3)
+		return 0;
+
+	eflags = x->e_flags;
+	if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
+		unsigned int flt_fmt;
+
+		/* APCS26 is only allowed if the CPU supports it */
+		if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT))
+			return 0;
+
+		flt_fmt = eflags & (EF_ARM_VFP_FLOAT | EF_ARM_SOFT_FLOAT);
+
+		/* VFP requires the supporting code */
+		if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP))
+			return 0;
+	}
+	return 1;
+}
+EXPORT_SYMBOL(elf_check_arch);
+
+void elf_set_personality(const struct elf32_hdr *x)
+{
+	unsigned int eflags = x->e_flags;
+	unsigned int personality = current->personality & ~PER_MASK;
+
+	/*
+	 * We only support Linux ELF executables, so always set the
+	 * personality to LINUX.
+	 */
+	personality |= PER_LINUX;
+
+	/*
+	 * APCS-26 is only valid for OABI executables
+	 */
+	if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN &&
+	    (eflags & EF_ARM_APCS_26))
+		personality &= ~ADDR_LIMIT_32BIT;
+	else
+		personality |= ADDR_LIMIT_32BIT;
+
+	set_personality(personality);
+
+	/*
+	 * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0
+	 * and CP1, we only enable access to the iWMMXt coprocessor if the
+	 * binary is EABI or softfloat (and thus, guaranteed not to use
+	 * FPA instructions.)
+	 */
+	if (elf_hwcap & HWCAP_IWMMXT &&
+	    eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) {
+		set_thread_flag(TIF_USING_IWMMXT);
+	} else {
+		clear_thread_flag(TIF_USING_IWMMXT);
+	}
+}
+EXPORT_SYMBOL(elf_set_personality);
+
+/*
+ * Set READ_IMPLIES_EXEC if:
+ *  - the binary requires an executable stack
+ *  - we're running on a CPU which doesn't support NX.
+ */
+int arm_elf_read_implies_exec(int executable_stack)
+{
+	if (executable_stack != EXSTACK_DISABLE_X)
+		return 1;
+	if (cpu_architecture() < CPU_ARCH_ARMv6)
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL(arm_elf_read_implies_exec);
+
+#if defined(CONFIG_MMU) && defined(CONFIG_BINFMT_ELF_FDPIC)
+
+void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params,
+			       struct elf_fdpic_params *interp_params,
+			       unsigned long *start_stack,
+			       unsigned long *start_brk)
+{
+	elf_set_personality(&exec_params->hdr);
+
+	exec_params->load_addr = 0x8000;
+	interp_params->load_addr = ELF_ET_DYN_BASE;
+	*start_stack = TASK_SIZE - SZ_16M;
+
+	if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_INDEPENDENT) {
+		exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT;
+		exec_params->flags |= ELF_FDPIC_FLAG_CONSTDISP;
+	}
+}
+
+#endif