ARC: Module support

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/include/asm/module.h

@@ -14,4 +14,8 @@
 
 #include <asm-generic/module.h>
 
+#define MODULE_PROC_FAMILY "ARC700"
+
+#define MODULE_ARCH_VERMAGIC MODULE_PROC_FAMILY
+
 #endif /* _ASM_ARC_MODULE_H */

arch/arc/kernel/Makefile

@@ -12,6 +12,8 @@ obj-y	:= arcksyms.o setup.o irq.o time.o reset.o ptrace.o entry.o process.o
 obj-y	+= signal.o traps.o sys.o troubleshoot.o stacktrace.o clk.o
 obj-y	+= devtree.o
 
+obj-$(CONFIG_MODULES)			+= arcksyms.o module.o
+
 obj-$(CONFIG_ARC_FPU_SAVE_RESTORE)	+= fpu.o
 CFLAGS_fpu.o   += -mdpfp
 

arch/arc/kernel/module.c

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleloader.h>
+#include <linux/kernel.h>
+#include <linux/elf.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+
+static inline void arc_write_me(unsigned short *addr, unsigned long value)
+{
+	*addr = (value & 0xffff0000) >> 16;
+	*(addr + 1) = (value & 0xffff);
+}
+
+int apply_relocate_add(Elf32_Shdr *sechdrs,
+		       const char *strtab,
+		       unsigned int symindex,	/* sec index for sym tbl */
+		       unsigned int relsec,	/* sec index for relo sec */
+		       struct module *module)
+{
+	int i, n;
+	Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr;
+	Elf32_Sym *sym_entry, *sym_sec;
+	Elf32_Addr relocation;
+	Elf32_Addr location;
+	Elf32_Addr sec_to_patch;
+	int relo_type;
+
+	sec_to_patch = sechdrs[sechdrs[relsec].sh_info].sh_addr;
+	sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
+	n = sechdrs[relsec].sh_size / sizeof(*rel_entry);
+
+	pr_debug("\n========== Module Sym reloc ===========================\n");
+	pr_debug("Section to fixup %x\n", sec_to_patch);
+	pr_debug("=========================================================\n");
+	pr_debug("rela->r_off | rela->addend | sym->st_value | ADDR | VALUE\n");
+	pr_debug("=========================================================\n");
+
+	/* Loop thru entries in relocation section */
+	for (i = 0; i < n; i++) {
+
+		/* This is where to make the change */
+		location = sec_to_patch + rel_entry[i].r_offset;
+
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
+		sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);
+
+		relocation = sym_entry->st_value + rel_entry[i].r_addend;
+
+		pr_debug("\t%x\t\t%x\t\t%x  %x %x [%s]\n",
+			rel_entry[i].r_offset, rel_entry[i].r_addend,
+			sym_entry->st_value, location, relocation,
+			strtab + sym_entry->st_name);
+
+		/* This assumes modules are built with -mlong-calls
+		 * so any branches/jumps are absolute 32 bit jmps
+		 * global data access again is abs 32 bit.
+		 * Both of these are handled by same relocation type
+		 */
+		relo_type = ELF32_R_TYPE(rel_entry[i].r_info);
+
+		if (likely(R_ARC_32_ME == relo_type))
+			arc_write_me((unsigned short *)location, relocation);
+		else if (R_ARC_32 == relo_type)
+			*((Elf32_Addr *) location) = relocation;
+		else
+			goto relo_err;
+
+	}
+	return 0;
+
+relo_err:
+	pr_err("%s: unknown relocation: %u\n",
+		module->name, ELF32_R_TYPE(rel_entry[i].r_info));
+	return -ENOEXEC;
+
+}