ARC: Module support

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

2 files changed, 89 insertions, 0 deletions

diff --git a/arch/arc/kernel/Makefile b/arch/arc/kernel/Makefile
index f4885891dabb..f32f65f98850 100644
--- a/arch/arc/kernel/Makefile
+++ b/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
 
diff --git a/arch/arc/kernel/module.c b/arch/arc/kernel/module.c
new file mode 100644
index 000000000000..a1bb70d6e97d
--- /dev/null
+++ b/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;
+
+}