openwrt-xburst/target/linux/generic-2.6/patches-2.6.30/027-mips_module_reloc.patch

Index: linux-2.6.30.4/arch/mips/Makefile
===================================================================
--- linux-2.6.30.4.orig/arch/mips/Makefile	2009-08-06 16:02:25.000000000 +0200
+++ linux-2.6.30.4/arch/mips/Makefile	2009-08-06 16:02:37.000000000 +0200
@@ -83,7 +83,7 @@
 cflags-y			+= -G 0 -mno-abicalls -fno-pic -pipe
 cflags-y			+= -msoft-float
 LDFLAGS_vmlinux			+= -G 0 -static -n -nostdlib
-MODFLAGS			+= -mlong-calls
+MODFLAGS			+= -mno-long-calls
 
 cflags-y += -ffreestanding
 
Index: linux-2.6.30.4/arch/mips/include/asm/module.h
===================================================================
--- linux-2.6.30.4.orig/arch/mips/include/asm/module.h	2009-08-06 16:02:25.000000000 +0200
+++ linux-2.6.30.4/arch/mips/include/asm/module.h	2009-08-06 16:02:37.000000000 +0200
@@ -9,6 +9,11 @@
 	struct list_head dbe_list;
 	const struct exception_table_entry *dbe_start;
 	const struct exception_table_entry *dbe_end;
+
+	void *plt_tbl;
+	unsigned int core_plt_offset;
+	unsigned int core_plt_size;
+	unsigned int init_plt_offset;
 };
 
 typedef uint8_t Elf64_Byte;		/* Type for a 8-bit quantity.  */
Index: linux-2.6.30.4/arch/mips/kernel/module.c
===================================================================
--- linux-2.6.30.4.orig/arch/mips/kernel/module.c	2009-08-06 16:02:36.000000000 +0200
+++ linux-2.6.30.4/arch/mips/kernel/module.c	2009-08-06 16:03:15.000000000 +0200
@@ -43,6 +43,116 @@
 static LIST_HEAD(dbe_list);
 static DEFINE_SPINLOCK(dbe_lock);
 
+/*
+ * Get the potential max trampolines size required of the init and
+ * non-init sections. Only used if we cannot find enough contiguous
+ * physically mapped memory to put the module into.
+ */
+static unsigned int
+get_plt_size(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
+             const char *secstrings, unsigned int symindex, bool is_init)
+{
+	unsigned long ret = 0;
+	unsigned int i, j;
+	Elf_Sym *syms;
+
+	/* Everything marked ALLOC (this includes the exported symbols) */
+	for (i = 1; i < hdr->e_shnum; ++i) {
+		unsigned int info = sechdrs[i].sh_info;
+
+		if (sechdrs[i].sh_type != SHT_REL
+		    && sechdrs[i].sh_type != SHT_RELA)
+			continue;
+
+		/* Not a valid relocation section? */
+		if (info >= hdr->e_shnum)
+			continue;
+
+		/* Don't bother with non-allocated sections */
+		if (!(sechdrs[info].sh_flags & SHF_ALLOC))
+			continue;
+
+		/* If it's called *.init*, and we're not init, we're
+                   not interested */
+		if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
+		    != is_init)
+			continue;
+
+		syms = (Elf_Sym *) sechdrs[symindex].sh_addr;
+		if (sechdrs[i].sh_type == SHT_REL) {
+			Elf_Mips_Rel *rel = (void *) sechdrs[i].sh_addr;
+			unsigned int size = sechdrs[i].sh_size / sizeof(*rel);
+
+			for (j = 0; j < size; ++j) {
+				Elf_Sym *sym;
+
+				if (ELF_MIPS_R_TYPE(rel[j]) != R_MIPS_26)
+					continue;
+
+				sym = syms + ELF_MIPS_R_SYM(rel[j]);
+				if (!is_init && sym->st_shndx != SHN_UNDEF)
+					continue;
+
+				ret += 4 * sizeof(int);
+			}
+		} else {
+			Elf_Mips_Rela *rela = (void *) sechdrs[i].sh_addr;
+			unsigned int size = sechdrs[i].sh_size / sizeof(*rela);
+
+			for (j = 0; j < size; ++j) {
+				Elf_Sym *sym;
+
+				if (ELF_MIPS_R_TYPE(rela[j]) != R_MIPS_26)
+					continue;
+
+				sym = syms + ELF_MIPS_R_SYM(rela[j]);
+				if (!is_init && sym->st_shndx != SHN_UNDEF)
+					continue;
+
+				ret += 4 * sizeof(int);
+			}
+		}
+	}
+
+	return ret;
+}
+
+#ifndef MODULE_START
+static void *alloc_phys(unsigned long size)
+{
+	unsigned order;
+	struct page *page;
+	struct page *p;
+
+	size = PAGE_ALIGN(size);
+	order = get_order(size);
+
+	page = alloc_pages(GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN |
+			__GFP_THISNODE, order);
+	if (!page)
+		return NULL;
+
+	split_page(page, order);
+
+	for (p = page + (size >> PAGE_SHIFT); p < page + (1 << order); ++p)
+		__free_page(p);
+
+	return page_address(page);
+}
+#endif
+
+static void free_phys(void *ptr, unsigned long size)
+{
+	struct page *page;
+	struct page *end;
+
+	page = virt_to_page(ptr);
+	end = page + (PAGE_ALIGN(size) >> PAGE_SHIFT);
+
+	for (; page < end; ++page)
+		__free_page(page);
+}
+
 void *module_alloc(unsigned long size)
 {
 #ifdef MODULE_START
@@ -58,16 +168,45 @@
 
 	return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL);
 #else
+	void *ptr;
+
 	if (size == 0)
 		return NULL;
-	return vmalloc(size);
+
+	ptr = alloc_phys(size);
+
+	/* If we failed to allocate physically contiguous memory,
+	 * fall back to regular vmalloc. The module loader code will
+	 * create jump tables to handle long jumps */
+	if (!ptr)
+		return vmalloc(size);
+
+	return ptr;
+#endif
+}
+
+static inline bool is_phys_addr(void *ptr)
+{
+#ifdef CONFIG_64BIT
+	return (KSEGX((unsigned long)ptr) == CKSEG0);
+#else
+	return (KSEGX(ptr) == KSEG0);
 #endif
 }
 
 /* Free memory returned from module_alloc */
 void module_free(struct module *mod, void *module_region)
 {
-	vfree(module_region);
+	if (is_phys_addr(module_region)) {
+		if (mod->module_init == module_region)
+			free_phys(module_region, mod->init_size);
+		else if (mod->module_core == module_region)
+			free_phys(module_region, mod->core_size);
+		else
+			BUG();
+	} else {
+		vfree(module_region);
+	}
 	/* FIXME: If module_region == mod->init_region, trim exception
            table entries. */
 }
@@ -75,6 +214,24 @@
 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 			      char *secstrings, struct module *mod)
 {
+	unsigned int symindex = 0;
+	unsigned int core_size, init_size;
+	int i;
+
+	for (i = 1; i < hdr->e_shnum; i++)
+		if (sechdrs[i].sh_type == SHT_SYMTAB)
+			symindex = i;
+
+	core_size = get_plt_size(hdr, sechdrs, secstrings, symindex, false);
+	init_size = get_plt_size(hdr, sechdrs, secstrings, symindex, true);
+
+	mod->arch.core_plt_offset = 0;
+	mod->arch.core_plt_size = core_size;
+	mod->arch.init_plt_offset = core_size;
+	mod->arch.plt_tbl = kmalloc(core_size + init_size, GFP_KERNEL);
+	if (!mod->arch.plt_tbl)
+		return -ENOMEM;
+
 	return 0;
 }
 
@@ -97,27 +254,41 @@
 	return 0;
 }
 
-static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
+static Elf_Addr add_plt_entry_to(unsigned *plt_offset,
+				 void *start, Elf_Addr v)
 {
-	if (v % 4) {
-		printk(KERN_ERR "module %s: dangerous relocation\n", me->name);
-		return -ENOEXEC;
-	}
+	unsigned *tramp = start + *plt_offset;
 
-	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
-		printk(KERN_ERR
-		       "module %s: relocation overflow\n",
-		       me->name);
-		return -ENOEXEC;
-	}
+	*plt_offset += 4 * sizeof(int);
+
+	/* adjust carry for addiu */
+	if (v & 0x00008000)
+		v += 0x10000;
+
+	tramp[0] = 0x3c190000 | (v >> 16);      /* lui t9, hi16 */
+	tramp[1] = 0x27390000 | (v & 0xffff);   /* addiu t9, t9, lo16 */
+	tramp[2] = 0x03200008;                  /* jr t9 */
+	tramp[3] = 0x00000000;                  /* nop */
 
-	*location = (*location & ~0x03ffffff) |
-	            ((*location + (v >> 2)) & 0x03ffffff);
+	return (Elf_Addr) tramp;
+}
+
+static Elf_Addr add_plt_entry(struct module *me, void *location, Elf_Addr v)
+{
+	if (location >= me->module_core &&
+	    location < me->module_core + me->core_size)
+		return add_plt_entry_to(&me->arch.core_plt_offset,
+				me->arch.plt_tbl, v);
+
+	if (location >= me->module_init &&
+	    location < me->module_init + me->init_size)
+		return add_plt_entry_to(&me->arch.init_plt_offset,
+				me->arch.plt_tbl, v);
 
 	return 0;
 }
 
-static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
+static int set_r_mips_26(struct module *me, u32 *location, u32 ofs, Elf_Addr v)
 {
 	if (v % 4) {
 		printk(KERN_ERR "module %s: dangerous relocation\n", me->name);
@@ -125,17 +296,31 @@
 	}
 
 	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
-		printk(KERN_ERR
+	    v = add_plt_entry(me, location, v + (ofs << 2));
+		if (!v) {
+			printk(KERN_ERR
 		       "module %s: relocation overflow\n",
 		       me->name);
-		return -ENOEXEC;
+			return -ENOEXEC;
+		}
+		ofs = 0;
 	}
 
-	*location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff);
+	*location = (*location & ~0x03ffffff) | ((ofs + (v >> 2)) & 0x03ffffff);
 
 	return 0;
 }
 
+static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+	return set_r_mips_26(me, location, *location & 0x03ffffff, v);
+}
+
+static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+	return set_r_mips_26(me, location, 0, v);
+}
+
 static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v)
 {
 	struct mips_hi16 *n;
@@ -400,11 +585,23 @@
 		list_add(&me->arch.dbe_list, &dbe_list);
 		spin_unlock_irq(&dbe_lock);
 	}
+
+	/* Get rid of the fixup trampoline if we're running the module
+	 * from physically mapped address space */
+	if (me->arch.core_plt_offset == 0 &&
+	    me->arch.init_plt_offset == me->arch.core_plt_size &&
+	    is_phys_addr(me->module_core)) {
+		kfree(me->arch.plt_tbl);
+		me->arch.plt_tbl = NULL;
+	}
+
 	return 0;
 }
 
 void module_arch_cleanup(struct module *mod)
 {
+	if (mod->arch.plt_tbl)
+		kfree(mod->arch.plt_tbl);
 	spin_lock_irq(&dbe_lock);
 	list_del(&mod->arch.dbe_list);
 	spin_unlock_irq(&dbe_lock);