nds32: Loadable modules

This patch adds support for loadable modules.
Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

arch/nds32/include/asm/module.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef _ASM_NDS32_MODULE_H
+#define _ASM_NDS32_MODULE_H
+
+#include <asm-generic/module.h>
+
+#define MODULE_ARCH_VERMAGIC	"NDS32v3"
+
+#endif /* _ASM_NDS32_MODULE_H */

arch/nds32/kernel/module.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/module.h>
+#include <linux/elf.h>
+#include <linux/vmalloc.h>
+#include <linux/moduleloader.h>
+#include <asm/pgtable.h>
+
+void *module_alloc(unsigned long size)
+{
+	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
+				    GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
+				    __builtin_return_address(0));
+}
+
+void module_free(struct module *module, void *region)
+{
+	vfree(region);
+}
+
+int module_frob_arch_sections(Elf_Ehdr * hdr,
+			      Elf_Shdr * sechdrs,
+			      char *secstrings, struct module *mod)
+{
+	return 0;
+}
+
+void do_reloc16(unsigned int val, unsigned int *loc, unsigned int val_mask,
+		unsigned int val_shift, unsigned int loc_mask,
+		unsigned int partial_in_place, unsigned int swap)
+{
+	unsigned int tmp = 0, tmp2 = 0;
+
+	__asm__ __volatile__("\tlhi.bi\t%0, [%2], 0\n"
+			     "\tbeqz\t%3, 1f\n"
+			     "\twsbh\t%0, %1\n"
+			     "1:\n":"=r"(tmp):"0"(tmp), "r"(loc), "r"(swap)
+	    );
+
+	tmp2 = tmp & loc_mask;
+	if (partial_in_place) {
+		tmp &= (!loc_mask);
+		tmp =
+		    tmp2 | ((tmp + ((val & val_mask) >> val_shift)) & val_mask);
+	} else {
+		tmp = tmp2 | ((val & val_mask) >> val_shift);
+	}
+
+	__asm__ __volatile__("\tbeqz\t%3, 2f\n"
+			     "\twsbh\t%0, %1\n"
+			     "2:\n"
+			     "\tshi.bi\t%0, [%2], 0\n":"=r"(tmp):"0"(tmp),
+			     "r"(loc), "r"(swap)
+	    );
+}
+
+void do_reloc32(unsigned int val, unsigned int *loc, unsigned int val_mask,
+		unsigned int val_shift, unsigned int loc_mask,
+		unsigned int partial_in_place, unsigned int swap)
+{
+	unsigned int tmp = 0, tmp2 = 0;
+
+	__asm__ __volatile__("\tlmw.bi\t%0, [%2], %0, 0\n"
+			     "\tbeqz\t%3, 1f\n"
+			     "\twsbh\t%0, %1\n"
+			     "\trotri\t%0, %1, 16\n"
+			     "1:\n":"=r"(tmp):"0"(tmp), "r"(loc), "r"(swap)
+	    );
+
+	tmp2 = tmp & loc_mask;
+	if (partial_in_place) {
+		tmp &= (!loc_mask);
+		tmp =
+		    tmp2 | ((tmp + ((val & val_mask) >> val_shift)) & val_mask);
+	} else {
+		tmp = tmp2 | ((val & val_mask) >> val_shift);
+	}
+
+	__asm__ __volatile__("\tbeqz\t%3, 2f\n"
+			     "\twsbh\t%0, %1\n"
+			     "\trotri\t%0, %1, 16\n"
+			     "2:\n"
+			     "\tsmw.bi\t%0, [%2], %0, 0\n":"=r"(tmp):"0"(tmp),
+			     "r"(loc), "r"(swap)
+	    );
+}
+
+static inline int exceed_limit(int offset, unsigned int val_mask,
+			       struct module *module, Elf32_Rela * rel,
+			       unsigned int relindex, unsigned int reloc_order)
+{
+	int abs_off = offset < 0 ? ~offset : offset;
+
+	if (abs_off & (~val_mask)) {
+		pr_err("\n%s: relocation type %d out of range.\n"
+		       "please rebuild the kernel module with gcc option \"-Wa,-mno-small-text\".\n",
+		       module->name, ELF32_R_TYPE(rel->r_info));
+		pr_err("section %d reloc %d offset 0x%x relative 0x%x.\n",
+		       relindex, reloc_order, rel->r_offset, offset);
+		return true;
+	}
+	return false;
+}
+
+#ifdef __NDS32_EL__
+#define NEED_SWAP 1
+#else
+#define NEED_SWAP 0
+#endif
+
+int
+apply_relocate_add(Elf32_Shdr * sechdrs, const char *strtab,
+		   unsigned int symindex, unsigned int relindex,
+		   struct module *module)
+{
+	Elf32_Shdr *symsec = sechdrs + symindex;
+	Elf32_Shdr *relsec = sechdrs + relindex;
+	Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
+	Elf32_Rela *rel = (void *)relsec->sh_addr;
+	unsigned int i;
+
+	for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rela); i++, rel++) {
+		Elf32_Addr *loc;
+		Elf32_Sym *sym;
+		Elf32_Addr v;
+		s32 offset;
+
+		offset = ELF32_R_SYM(rel->r_info);
+		if (offset < 0
+		    || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
+			pr_err("%s: bad relocation\n", module->name);
+			pr_err("section %d reloc %d\n", relindex, i);
+			return -ENOEXEC;
+		}
+
+		sym = ((Elf32_Sym *) symsec->sh_addr) + offset;
+
+		if (rel->r_offset < 0
+		    || rel->r_offset > dstsec->sh_size - sizeof(u16)) {
+			pr_err("%s: out of bounds relocation\n", module->name);
+			pr_err("section %d reloc %d offset 0x%0x size %d\n",
+			       relindex, i, rel->r_offset, dstsec->sh_size);
+			return -ENOEXEC;
+		}
+
+		loc = (Elf32_Addr *) (dstsec->sh_addr + rel->r_offset);
+		v = sym->st_value + rel->r_addend;
+
+		switch (ELF32_R_TYPE(rel->r_info)) {
+		case R_NDS32_NONE:
+		case R_NDS32_INSN16:
+		case R_NDS32_LABEL:
+		case R_NDS32_LONGCALL1:
+		case R_NDS32_LONGCALL2:
+		case R_NDS32_LONGCALL3:
+		case R_NDS32_LONGCALL4:
+		case R_NDS32_LONGJUMP1:
+		case R_NDS32_LONGJUMP2:
+		case R_NDS32_LONGJUMP3:
+		case R_NDS32_9_FIXED_RELA:
+		case R_NDS32_15_FIXED_RELA:
+		case R_NDS32_17_FIXED_RELA:
+		case R_NDS32_25_FIXED_RELA:
+		case R_NDS32_LOADSTORE:
+		case R_NDS32_DWARF2_OP1_RELA:
+		case R_NDS32_DWARF2_OP2_RELA:
+		case R_NDS32_DWARF2_LEB_RELA:
+		case R_NDS32_RELA_NOP_MIX ... R_NDS32_RELA_NOP_MAX:
+			break;
+
+		case R_NDS32_32_RELA:
+			do_reloc32(v, loc, 0xffffffff, 0, 0, 0, 0);
+			break;
+
+		case R_NDS32_HI20_RELA:
+			do_reloc32(v, loc, 0xfffff000, 12, 0xfff00000, 0,
+				   NEED_SWAP);
+			break;
+
+		case R_NDS32_LO12S3_RELA:
+			do_reloc32(v, loc, 0x00000fff, 3, 0xfffff000, 0,
+				   NEED_SWAP);
+			break;
+
+		case R_NDS32_LO12S2_RELA:
+			do_reloc32(v, loc, 0x00000fff, 2, 0xfffff000, 0,
+				   NEED_SWAP);
+			break;
+
+		case R_NDS32_LO12S1_RELA:
+			do_reloc32(v, loc, 0x00000fff, 1, 0xfffff000, 0,
+				   NEED_SWAP);
+			break;
+
+		case R_NDS32_LO12S0_RELA:
+		case R_NDS32_LO12S0_ORI_RELA:
+			do_reloc32(v, loc, 0x00000fff, 0, 0xfffff000, 0,
+				   NEED_SWAP);
+			break;
+
+		case R_NDS32_9_PCREL_RELA:
+			if (exceed_limit
+			    ((v - (Elf32_Addr) loc), 0x000000ff, module, rel,
+			     relindex, i))
+				return -ENOEXEC;
+			do_reloc16(v - (Elf32_Addr) loc, loc, 0x000001ff, 1,
+				   0xffffff00, 0, NEED_SWAP);
+			break;
+
+		case R_NDS32_15_PCREL_RELA:
+			if (exceed_limit
+			    ((v - (Elf32_Addr) loc), 0x00003fff, module, rel,
+			     relindex, i))
+				return -ENOEXEC;
+			do_reloc32(v - (Elf32_Addr) loc, loc, 0x00007fff, 1,
+				   0xffffc000, 0, NEED_SWAP);
+			break;
+
+		case R_NDS32_17_PCREL_RELA:
+			if (exceed_limit
+			    ((v - (Elf32_Addr) loc), 0x0000ffff, module, rel,
+			     relindex, i))
+				return -ENOEXEC;
+			do_reloc32(v - (Elf32_Addr) loc, loc, 0x0001ffff, 1,
+				   0xffff0000, 0, NEED_SWAP);
+			break;
+
+		case R_NDS32_25_PCREL_RELA:
+			if (exceed_limit
+			    ((v - (Elf32_Addr) loc), 0x00ffffff, module, rel,
+			     relindex, i))
+				return -ENOEXEC;
+			do_reloc32(v - (Elf32_Addr) loc, loc, 0x01ffffff, 1,
+				   0xff000000, 0, NEED_SWAP);
+			break;
+		case R_NDS32_WORD_9_PCREL_RELA:
+			if (exceed_limit
+			    ((v - (Elf32_Addr) loc), 0x000000ff, module, rel,
+			     relindex, i))
+				return -ENOEXEC;
+			do_reloc32(v - (Elf32_Addr) loc, loc, 0x000001ff, 1,
+				   0xffffff00, 0, NEED_SWAP);
+			break;
+
+		case R_NDS32_SDA15S3_RELA:
+		case R_NDS32_SDA15S2_RELA:
+		case R_NDS32_SDA15S1_RELA:
+		case R_NDS32_SDA15S0_RELA:
+			pr_err("%s: unsupported relocation type %d.\n",
+			       module->name, ELF32_R_TYPE(rel->r_info));
+			pr_err
+			    ("Small data section access doesn't work in the kernel space; "
+			     "please rebuild the kernel module with gcc option -mcmodel=large.\n");
+			pr_err("section %d reloc %d offset 0x%x size %d\n",
+			       relindex, i, rel->r_offset, dstsec->sh_size);
+			break;
+
+		default:
+			pr_err("%s: unsupported relocation type %d.\n",
+			       module->name, ELF32_R_TYPE(rel->r_info));
+			pr_err("section %d reloc %d offset 0x%x size %d\n",
+			       relindex, i, rel->r_offset, dstsec->sh_size);
+		}
+	}
+	return 0;
+}
+
+int
+module_finalize(const Elf32_Ehdr * hdr, const Elf_Shdr * sechdrs,
+		struct module *module)
+{
+	return 0;
+}
+
+void module_arch_cleanup(struct module *mod)
+{
+}