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-rw-r--r--arch/alpha/kernel/module.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/arch/alpha/kernel/module.c b/arch/alpha/kernel/module.c
new file mode 100644
index 000000000..cbefa5a77
--- /dev/null
+++ b/arch/alpha/kernel/module.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Kernel module help for Alpha.
+ Copyright (C) 2002 Richard Henderson.
+
+*/
+#include <linux/moduleloader.h>
+#include <linux/elf.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(fmt...)
+#endif
+
+/* Allocate the GOT at the end of the core sections. */
+
+struct got_entry {
+ struct got_entry *next;
+ Elf64_Sxword r_addend;
+ int got_offset;
+};
+
+static inline void
+process_reloc_for_got(Elf64_Rela *rela,
+ struct got_entry *chains, Elf64_Xword *poffset)
+{
+ unsigned long r_sym = ELF64_R_SYM (rela->r_info);
+ unsigned long r_type = ELF64_R_TYPE (rela->r_info);
+ Elf64_Sxword r_addend = rela->r_addend;
+ struct got_entry *g;
+
+ if (r_type != R_ALPHA_LITERAL)
+ return;
+
+ for (g = chains + r_sym; g ; g = g->next)
+ if (g->r_addend == r_addend) {
+ if (g->got_offset == 0) {
+ g->got_offset = *poffset;
+ *poffset += 8;
+ }
+ goto found_entry;
+ }
+
+ g = kmalloc (sizeof (*g), GFP_KERNEL);
+ g->next = chains[r_sym].next;
+ g->r_addend = r_addend;
+ g->got_offset = *poffset;
+ *poffset += 8;
+ chains[r_sym].next = g;
+
+ found_entry:
+ /* Trick: most of the ELF64_R_TYPE field is unused. There are
+ 42 valid relocation types, and a 32-bit field. Co-opt the
+ bits above 256 to store the got offset for this reloc. */
+ rela->r_info |= g->got_offset << 8;
+}
+
+int
+module_frob_arch_sections(Elf64_Ehdr *hdr, Elf64_Shdr *sechdrs,
+ char *secstrings, struct module *me)
+{
+ struct got_entry *chains;
+ Elf64_Rela *rela;
+ Elf64_Shdr *esechdrs, *symtab, *s, *got;
+ unsigned long nsyms, nrela, i;
+
+ esechdrs = sechdrs + hdr->e_shnum;
+ symtab = got = NULL;
+
+ /* Find out how large the symbol table is. Allocate one got_entry
+ head per symbol. Normally this will be enough, but not always.
+ We'll chain different offsets for the symbol down each head. */
+ for (s = sechdrs; s < esechdrs; ++s)
+ if (s->sh_type == SHT_SYMTAB)
+ symtab = s;
+ else if (!strcmp(".got", secstrings + s->sh_name)) {
+ got = s;
+ me->arch.gotsecindex = s - sechdrs;
+ }
+
+ if (!symtab) {
+ printk(KERN_ERR "module %s: no symbol table\n", me->name);
+ return -ENOEXEC;
+ }
+ if (!got) {
+ printk(KERN_ERR "module %s: no got section\n", me->name);
+ return -ENOEXEC;
+ }
+
+ nsyms = symtab->sh_size / sizeof(Elf64_Sym);
+ chains = kcalloc(nsyms, sizeof(struct got_entry), GFP_KERNEL);
+ if (!chains) {
+ printk(KERN_ERR
+ "module %s: no memory for symbol chain buffer\n",
+ me->name);
+ return -ENOMEM;
+ }
+
+ got->sh_size = 0;
+ got->sh_addralign = 8;
+ got->sh_type = SHT_NOBITS;
+
+ /* Examine all LITERAL relocations to find out what GOT entries
+ are required. This sizes the GOT section as well. */
+ for (s = sechdrs; s < esechdrs; ++s)
+ if (s->sh_type == SHT_RELA) {
+ nrela = s->sh_size / sizeof(Elf64_Rela);
+ rela = (void *)hdr + s->sh_offset;
+ for (i = 0; i < nrela; ++i)
+ process_reloc_for_got(rela+i, chains,
+ &got->sh_size);
+ }
+
+ /* Free the memory we allocated. */
+ for (i = 0; i < nsyms; ++i) {
+ struct got_entry *g, *n;
+ for (g = chains[i].next; g ; g = n) {
+ n = g->next;
+ kfree(g);
+ }
+ }
+ kfree(chains);
+
+ return 0;
+}
+
+int
+apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me)
+{
+ Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
+ unsigned long i, n = sechdrs[relsec].sh_size / sizeof(*rela);
+ Elf64_Sym *symtab, *sym;
+ void *base, *location;
+ unsigned long got, gp;
+
+ DEBUGP("Applying relocate section %u to %u\n", relsec,
+ sechdrs[relsec].sh_info);
+
+ base = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr;
+ symtab = (Elf64_Sym *)sechdrs[symindex].sh_addr;
+
+ got = sechdrs[me->arch.gotsecindex].sh_addr;
+ gp = got + 0x8000;
+
+ for (i = 0; i < n; i++) {
+ unsigned long r_sym = ELF64_R_SYM (rela[i].r_info);
+ unsigned long r_type = ELF64_R_TYPE (rela[i].r_info);
+ unsigned long r_got_offset = r_type >> 8;
+ unsigned long value, hi, lo;
+ r_type &= 0xff;
+
+ /* This is where to make the change. */
+ location = base + rela[i].r_offset;
+
+ /* This is the symbol it is referring to. Note that all
+ unresolved symbols have been resolved. */
+ sym = symtab + r_sym;
+ value = sym->st_value + rela[i].r_addend;
+
+ switch (r_type) {
+ case R_ALPHA_NONE:
+ break;
+ case R_ALPHA_REFLONG:
+ *(u32 *)location = value;
+ break;
+ case R_ALPHA_REFQUAD:
+ /* BUG() can produce misaligned relocations. */
+ ((u32 *)location)[0] = value;
+ ((u32 *)location)[1] = value >> 32;
+ break;
+ case R_ALPHA_GPREL32:
+ value -= gp;
+ if ((int)value != value)
+ goto reloc_overflow;
+ *(u32 *)location = value;
+ break;
+ case R_ALPHA_LITERAL:
+ hi = got + r_got_offset;
+ lo = hi - gp;
+ if ((short)lo != lo)
+ goto reloc_overflow;
+ *(u16 *)location = lo;
+ *(u64 *)hi = value;
+ break;
+ case R_ALPHA_LITUSE:
+ break;
+ case R_ALPHA_GPDISP:
+ value = gp - (u64)location;
+ lo = (short)value;
+ hi = (int)(value - lo);
+ if (hi + lo != value)
+ goto reloc_overflow;
+ *(u16 *)location = hi >> 16;
+ *(u16 *)(location + rela[i].r_addend) = lo;
+ break;
+ case R_ALPHA_BRSGP:
+ /* BRSGP is only allowed to bind to local symbols.
+ If the section is undef, this means that the
+ value was resolved from somewhere else. */
+ if (sym->st_shndx == SHN_UNDEF)
+ goto reloc_overflow;
+ if ((sym->st_other & STO_ALPHA_STD_GPLOAD) ==
+ STO_ALPHA_STD_GPLOAD)
+ /* Omit the prologue. */
+ value += 8;
+ fallthrough;
+ case R_ALPHA_BRADDR:
+ value -= (u64)location + 4;
+ if (value & 3)
+ goto reloc_overflow;
+ value = (long)value >> 2;
+ if (value + (1<<21) >= 1<<22)
+ goto reloc_overflow;
+ value &= 0x1fffff;
+ value |= *(u32 *)location & ~0x1fffff;
+ *(u32 *)location = value;
+ break;
+ case R_ALPHA_HINT:
+ break;
+ case R_ALPHA_SREL32:
+ value -= (u64)location;
+ if ((int)value != value)
+ goto reloc_overflow;
+ *(u32 *)location = value;
+ break;
+ case R_ALPHA_SREL64:
+ value -= (u64)location;
+ *(u64 *)location = value;
+ break;
+ case R_ALPHA_GPRELHIGH:
+ value = (long)(value - gp + 0x8000) >> 16;
+ if ((short) value != value)
+ goto reloc_overflow;
+ *(u16 *)location = value;
+ break;
+ case R_ALPHA_GPRELLOW:
+ value -= gp;
+ *(u16 *)location = value;
+ break;
+ case R_ALPHA_GPREL16:
+ value -= gp;
+ if ((short) value != value)
+ goto reloc_overflow;
+ *(u16 *)location = value;
+ break;
+ default:
+ printk(KERN_ERR "module %s: Unknown relocation: %lu\n",
+ me->name, r_type);
+ return -ENOEXEC;
+ reloc_overflow:
+ if (ELF64_ST_TYPE (sym->st_info) == STT_SECTION)
+ printk(KERN_ERR
+ "module %s: Relocation (type %lu) overflow vs section %d\n",
+ me->name, r_type, sym->st_shndx);
+ else
+ printk(KERN_ERR
+ "module %s: Relocation (type %lu) overflow vs %s\n",
+ me->name, r_type, strtab + sym->st_name);
+ return -ENOEXEC;
+ }
+ }
+
+ return 0;
+}
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