1e1a0592f8
When memory is tight, modules may need to be loaded into vmalloc() space. The code then has to generate jump trampolines which enable relocations between vmalloc space and physical address space. The code had a bug that was freeing these trampolines even when the module was successfully loaded. Signed-off-by: Felix Fietkau <nbd@nbd.name>
354 lines
8.5 KiB
Diff
354 lines
8.5 KiB
Diff
--- a/arch/mips/Makefile
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+++ b/arch/mips/Makefile
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@@ -93,8 +93,13 @@ all-$(CONFIG_SYS_SUPPORTS_ZBOOT)+= vmlin
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cflags-y += -G 0 -mno-abicalls -fno-pic -pipe -mno-branch-likely
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cflags-y += -msoft-float
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LDFLAGS_vmlinux += -G 0 -static -n -nostdlib
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+ifdef CONFIG_64BIT
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KBUILD_AFLAGS_MODULE += -mlong-calls
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KBUILD_CFLAGS_MODULE += -mlong-calls
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+else
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+KBUILD_AFLAGS_MODULE += -mno-long-calls
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+KBUILD_CFLAGS_MODULE += -mno-long-calls
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+endif
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ifeq ($(CONFIG_RELOCATABLE),y)
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LDFLAGS_vmlinux += --emit-relocs
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--- a/arch/mips/include/asm/module.h
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+++ b/arch/mips/include/asm/module.h
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@@ -11,6 +11,11 @@ struct mod_arch_specific {
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const struct exception_table_entry *dbe_start;
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const struct exception_table_entry *dbe_end;
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struct mips_hi16 *r_mips_hi16_list;
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+
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+ void *phys_plt_tbl;
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+ void *virt_plt_tbl;
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+ unsigned int phys_plt_offset;
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+ unsigned int virt_plt_offset;
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};
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typedef uint8_t Elf64_Byte; /* Type for a 8-bit quantity. */
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--- a/arch/mips/kernel/module.c
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+++ b/arch/mips/kernel/module.c
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@@ -44,14 +44,221 @@ struct mips_hi16 {
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static LIST_HEAD(dbe_list);
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static DEFINE_SPINLOCK(dbe_lock);
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-#ifdef MODULE_START
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+/*
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+ * Get the potential max trampolines size required of the init and
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+ * non-init sections. Only used if we cannot find enough contiguous
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+ * physically mapped memory to put the module into.
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+ */
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+static unsigned int
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+get_plt_size(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
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+ const char *secstrings, unsigned int symindex, bool is_init)
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+{
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+ unsigned long ret = 0;
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+ unsigned int i, j;
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+ Elf_Sym *syms;
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+
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+ /* Everything marked ALLOC (this includes the exported symbols) */
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+ for (i = 1; i < hdr->e_shnum; ++i) {
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+ unsigned int info = sechdrs[i].sh_info;
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+
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+ if (sechdrs[i].sh_type != SHT_REL
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+ && sechdrs[i].sh_type != SHT_RELA)
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+ continue;
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+
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+ /* Not a valid relocation section? */
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+ if (info >= hdr->e_shnum)
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+ continue;
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+
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+ /* Don't bother with non-allocated sections */
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+ if (!(sechdrs[info].sh_flags & SHF_ALLOC))
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+ continue;
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+
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+ /* If it's called *.init*, and we're not init, we're
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+ not interested */
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+ if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
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+ != is_init)
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+ continue;
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+
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+ syms = (Elf_Sym *) sechdrs[symindex].sh_addr;
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+ if (sechdrs[i].sh_type == SHT_REL) {
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+ Elf_Mips_Rel *rel = (void *) sechdrs[i].sh_addr;
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+ unsigned int size = sechdrs[i].sh_size / sizeof(*rel);
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+
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+ for (j = 0; j < size; ++j) {
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+ Elf_Sym *sym;
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+
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+ if (ELF_MIPS_R_TYPE(rel[j]) != R_MIPS_26)
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+ continue;
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+
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+ sym = syms + ELF_MIPS_R_SYM(rel[j]);
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+ if (!is_init && sym->st_shndx != SHN_UNDEF)
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+ continue;
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+
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+ ret += 4 * sizeof(int);
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+ }
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+ } else {
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+ Elf_Mips_Rela *rela = (void *) sechdrs[i].sh_addr;
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+ unsigned int size = sechdrs[i].sh_size / sizeof(*rela);
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+
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+ for (j = 0; j < size; ++j) {
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+ Elf_Sym *sym;
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+
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+ if (ELF_MIPS_R_TYPE(rela[j]) != R_MIPS_26)
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+ continue;
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+
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+ sym = syms + ELF_MIPS_R_SYM(rela[j]);
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+ if (!is_init && sym->st_shndx != SHN_UNDEF)
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+ continue;
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+
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+ ret += 4 * sizeof(int);
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+ }
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+ }
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+ }
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+
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+ return ret;
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+}
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+
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+#ifndef MODULE_START
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+static void *alloc_phys(unsigned long size)
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+{
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+ unsigned order;
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+ struct page *page;
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+ struct page *p;
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+
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+ size = PAGE_ALIGN(size);
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+ order = get_order(size);
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+
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+ page = alloc_pages(GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN |
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+ __GFP_THISNODE, order);
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+ if (!page)
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+ return NULL;
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+
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+ split_page(page, order);
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+
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+ /* mark all pages except for the last one */
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+ for (p = page; p + 1 < page + (size >> PAGE_SHIFT); ++p)
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+ set_bit(PG_owner_priv_1, &p->flags);
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+
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+ for (p = page + (size >> PAGE_SHIFT); p < page + (1 << order); ++p)
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+ __free_page(p);
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+
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+ return page_address(page);
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+}
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+#endif
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+
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+static void free_phys(void *ptr)
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+{
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+ struct page *page;
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+ bool free;
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+
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+ page = virt_to_page(ptr);
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+ do {
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+ free = test_and_clear_bit(PG_owner_priv_1, &page->flags);
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+ __free_page(page);
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+ page++;
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+ } while (free);
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+}
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+
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+
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void *module_alloc(unsigned long size)
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{
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+#ifdef MODULE_START
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return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
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GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
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__builtin_return_address(0));
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+#else
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+ void *ptr;
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+
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+ if (size == 0)
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+ return NULL;
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+
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+ ptr = alloc_phys(size);
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+
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+ /* If we failed to allocate physically contiguous memory,
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+ * fall back to regular vmalloc. The module loader code will
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+ * create jump tables to handle long jumps */
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+ if (!ptr)
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+ return vmalloc(size);
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+
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+ return ptr;
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+#endif
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}
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+
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+static inline bool is_phys_addr(void *ptr)
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+{
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+#ifdef CONFIG_64BIT
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+ return (KSEGX((unsigned long)ptr) == CKSEG0);
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+#else
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+ return (KSEGX(ptr) == KSEG0);
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#endif
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+}
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+
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+/* Free memory returned from module_alloc */
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+void module_memfree(void *module_region)
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+{
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+ if (is_phys_addr(module_region))
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+ free_phys(module_region);
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+ else
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+ vfree(module_region);
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+}
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+
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+static void *__module_alloc(int size, bool phys)
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+{
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+ void *ptr;
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+
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+ if (phys)
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+ ptr = kmalloc(size, GFP_KERNEL);
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+ else
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+ ptr = vmalloc(size);
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+ return ptr;
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+}
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+
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+static void __module_free(void *ptr)
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+{
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+ if (is_phys_addr(ptr))
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+ kfree(ptr);
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+ else
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+ vfree(ptr);
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+}
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+
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+int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
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+ char *secstrings, struct module *mod)
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+{
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+ unsigned int symindex = 0;
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+ unsigned int core_size, init_size;
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+ int i;
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+
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+ mod->arch.phys_plt_offset = 0;
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+ mod->arch.virt_plt_offset = 0;
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+ mod->arch.phys_plt_tbl = NULL;
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+ mod->arch.virt_plt_tbl = NULL;
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+
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+ if (IS_ENABLED(CONFIG_64BIT))
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+ return 0;
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+
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+ for (i = 1; i < hdr->e_shnum; i++)
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+ if (sechdrs[i].sh_type == SHT_SYMTAB)
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+ symindex = i;
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+
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+ core_size = get_plt_size(hdr, sechdrs, secstrings, symindex, false);
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+ init_size = get_plt_size(hdr, sechdrs, secstrings, symindex, true);
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+
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+ if ((core_size + init_size) == 0)
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+ return 0;
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+
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+ mod->arch.phys_plt_tbl = __module_alloc(core_size + init_size, 1);
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+ if (!mod->arch.phys_plt_tbl)
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+ return -ENOMEM;
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+
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+ mod->arch.virt_plt_tbl = __module_alloc(core_size + init_size, 0);
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+ if (!mod->arch.virt_plt_tbl) {
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+ __module_free(mod->arch.phys_plt_tbl);
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+ mod->arch.phys_plt_tbl = NULL;
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+ return -ENOMEM;
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+ }
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+
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+ return 0;
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+}
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int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v)
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{
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@@ -65,8 +272,39 @@ static int apply_r_mips_32_rel(struct mo
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return 0;
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}
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+static Elf_Addr add_plt_entry_to(unsigned *plt_offset,
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+ void *start, Elf_Addr v)
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+{
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+ unsigned *tramp = start + *plt_offset;
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+ *plt_offset += 4 * sizeof(int);
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+
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+ /* adjust carry for addiu */
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+ if (v & 0x00008000)
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+ v += 0x10000;
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+
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+ tramp[0] = 0x3c190000 | (v >> 16); /* lui t9, hi16 */
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+ tramp[1] = 0x27390000 | (v & 0xffff); /* addiu t9, t9, lo16 */
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+ tramp[2] = 0x03200008; /* jr t9 */
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+ tramp[3] = 0x00000000; /* nop */
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+
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+ return (Elf_Addr) tramp;
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+}
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+
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+static Elf_Addr add_plt_entry(struct module *me, void *location, Elf_Addr v)
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+{
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+ if (is_phys_addr(location))
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+ return add_plt_entry_to(&me->arch.phys_plt_offset,
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+ me->arch.phys_plt_tbl, v);
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+ else
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+ return add_plt_entry_to(&me->arch.virt_plt_offset,
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+ me->arch.virt_plt_tbl, v);
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+
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+}
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+
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static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
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{
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+ u32 ofs = *location & 0x03ffffff;
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+
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if (v % 4) {
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pr_err("module %s: dangerous R_MIPS_26 REL relocation\n",
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me->name);
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@@ -74,13 +312,17 @@ static int apply_r_mips_26_rel(struct mo
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}
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if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
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- pr_err("module %s: relocation overflow\n",
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- me->name);
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- return -ENOEXEC;
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+ v = add_plt_entry(me, location, v + (ofs << 2));
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+ if (!v) {
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+ pr_err("module %s: relocation overflow\n",
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+ me->name);
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+ return -ENOEXEC;
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+ }
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+ ofs = 0;
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}
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*location = (*location & ~0x03ffffff) |
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- ((*location + (v >> 2)) & 0x03ffffff);
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+ ((ofs + (v >> 2)) & 0x03ffffff);
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return 0;
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}
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@@ -349,9 +591,36 @@ int module_finalize(const Elf_Ehdr *hdr,
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list_add(&me->arch.dbe_list, &dbe_list);
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spin_unlock_irq(&dbe_lock);
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}
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+
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+ /* Get rid of the fixup trampoline if we're running the module
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+ * from physically mapped address space */
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+ if (me->arch.phys_plt_offset == 0) {
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+ __module_free(me->arch.phys_plt_tbl);
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+ me->arch.phys_plt_tbl = NULL;
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+ }
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+ if (me->arch.virt_plt_offset == 0) {
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+ __module_free(me->arch.virt_plt_tbl);
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+ me->arch.virt_plt_tbl = NULL;
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+ }
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+
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return 0;
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}
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+void module_arch_freeing_init(struct module *mod)
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+{
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+ if (mod->state == MODULE_STATE_LIVE)
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+ return;
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+
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+ if (mod->arch.phys_plt_tbl) {
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+ __module_free(mod->arch.phys_plt_tbl);
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+ mod->arch.phys_plt_tbl = NULL;
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+ }
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+ if (mod->arch.virt_plt_tbl) {
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+ __module_free(mod->arch.virt_plt_tbl);
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+ mod->arch.virt_plt_tbl = NULL;
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+ }
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+}
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+
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void module_arch_cleanup(struct module *mod)
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{
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spin_lock_irq(&dbe_lock);
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