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Code Issues

uClibc: add support for mips non-pic relocations in ldso

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SVN-Revision: 18069
This commit is contained in:
Felix Fietkau 2009-10-19 07:41:29 +00:00
parent 60fb2fd748
commit de6c0303ee
1 changed files with 289 additions and 0 deletions
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289
toolchain/uClibc/patches-0.9.30.1/440-backport_mips_nonpic.patch Normal file
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@ -0,0 +1,289 @@
--- a/include/elf.h
+++ b/include/elf.h
@@ -1547,6 +1547,7 @@ typedef struct
#define STO_MIPS_INTERNAL 0x1
#define STO_MIPS_HIDDEN 0x2
#define STO_MIPS_PROTECTED 0x3
+#define STO_MIPS_PLT 0x8
#define STO_MIPS_SC_ALIGN_UNUSED 0xff
/* MIPS specific values for `st_info'. */
@@ -1692,8 +1693,11 @@ typedef struct
#define R_MIPS_TLS_TPREL64 48 /* TP-relative offset, 64 bit */
#define R_MIPS_TLS_TPREL_HI16 49 /* TP-relative offset, high 16 bits */
#define R_MIPS_TLS_TPREL_LO16 50 /* TP-relative offset, low 16 bits */
+#define R_MIPS_GLOB_DAT 51
+#define R_MIPS_COPY 126
+#define R_MIPS_JUMP_SLOT 127
/* Keep this the last entry. */
-#define R_MIPS_NUM 51
+#define R_MIPS_NUM 128
/* Legal values for p_type field of Elf32_Phdr. */
@@ -1759,7 +1763,13 @@ typedef struct
#define DT_MIPS_COMPACT_SIZE 0x7000002f /* (O32)Size of compact rel section. */
#define DT_MIPS_GP_VALUE 0x70000030 /* GP value for aux GOTs. */
#define DT_MIPS_AUX_DYNAMIC 0x70000031 /* Address of aux .dynamic. */
-#define DT_MIPS_NUM 0x32
+/* The address of .got.plt in an executable using the new non-PIC ABI. */
+#define DT_MIPS_PLTGOT 0x70000032
+/* The base of the PLT in an executable using the new non-PIC ABI if that
+ PLT is writable. For a non-writable PLT, this is omitted or has a zero
+ value. */
+#define DT_MIPS_RWPLT 0x70000034
+#define DT_MIPS_NUM 0x35
/* Legal values for DT_MIPS_FLAGS Elf32_Dyn entry. */
--- a/ldso/ldso/dl-hash.c
+++ b/ldso/ldso/dl-hash.c
@@ -160,6 +160,11 @@ check_match (const ElfW(Sym) *sym, char
/* undefined symbol itself */
return NULL;
+#ifdef __mips__
+ if (sym->st_shndx == SHN_UNDEF && !(sym->st_other & STO_MIPS_PLT))
+ return NULL;
+#endif
+
if (sym->st_value == 0)
/* No value */
return NULL;
--- a/ldso/ldso/mips/dl-sysdep.h
+++ b/ldso/ldso/mips/dl-sysdep.h
@@ -93,10 +93,11 @@ typedef struct
#include <link.h>
-#define ARCH_NUM 3
+#define ARCH_NUM 4
#define DT_MIPS_GOTSYM_IDX (DT_NUM + OS_NUM)
#define DT_MIPS_LOCAL_GOTNO_IDX (DT_NUM + OS_NUM +1)
#define DT_MIPS_SYMTABNO_IDX (DT_NUM + OS_NUM +2)
+#define DT_MIPS_PLTGOT_IDX (DT_NUM + OS_NUM +3)
#define ARCH_DYNAMIC_INFO(dpnt, dynamic, debug_addr) \
do { \
@@ -106,6 +107,8 @@ else if (dpnt->d_tag == DT_MIPS_LOCAL_GO
dynamic[DT_MIPS_LOCAL_GOTNO_IDX] = dpnt->d_un.d_val; \
else if (dpnt->d_tag == DT_MIPS_SYMTABNO) \
dynamic[DT_MIPS_SYMTABNO_IDX] = dpnt->d_un.d_val; \
+else if (dpnt->d_tag == DT_MIPS_PLTGOT) \
+ dynamic[DT_MIPS_PLTGOT_IDX] = dpnt->d_un.d_val; \
else if (dpnt->d_tag == DT_MIPS_RLD_MAP) \
*(ElfW(Addr) *)(dpnt->d_un.d_ptr) = (ElfW(Addr)) debug_addr; \
} while (0)
@@ -114,6 +117,7 @@ else if (dpnt->d_tag == DT_MIPS_RLD_MAP)
#define INIT_GOT(GOT_BASE,MODULE) \
do { \
unsigned long idx; \
+ unsigned long *pltgot; \
\
/* Check if this is the dynamic linker itself */ \
if (MODULE->libtype == program_interpreter) \
@@ -123,6 +127,12 @@ do { \
GOT_BASE[0] = (unsigned long) _dl_runtime_resolve; \
GOT_BASE[1] = (unsigned long) MODULE; \
\
+ pltgot = MODULE->dynamic_info[DT_MIPS_PLTGOT_IDX]; \
+ if (pltgot) { \
+ pltgot[0] = (unsigned long) _dl_runtime_pltresolve; \
+ pltgot[1] = (unsigned long) MODULE; \
+ } \
+ \
/* Add load address displacement to all local GOT entries */ \
idx = 2; \
while (idx < MODULE->dynamic_info[DT_MIPS_LOCAL_GOTNO_IDX]) \
@@ -157,9 +167,9 @@ void _dl_perform_mips_global_got_relocat
#define OFFS_ALIGN 0x7ffff000
#endif /* O32 || N32 */
-#define elf_machine_type_class(type) ELF_RTYPE_CLASS_PLT
-/* MIPS does not have COPY relocs */
-#define DL_NO_COPY_RELOCS
+#define elf_machine_type_class(type) \
+ ((((type) == R_MIPS_JUMP_SLOT) * ELF_RTYPE_CLASS_PLT) \
+ | (((type) == R_MIPS_COPY) * ELF_RTYPE_CLASS_COPY))
#define OFFSET_GP_GOT 0x7ff0
--- a/ldso/ldso/mips/elfinterp.c
+++ b/ldso/ldso/mips/elfinterp.c
@@ -30,6 +30,7 @@
#include "ldso.h"
extern int _dl_runtime_resolve(void);
+extern int _dl_runtime_pltresolve(void);
#define OFFSET_GP_GOT 0x7ff0
@@ -83,6 +84,61 @@ unsigned long __dl_runtime_resolve(unsig
return new_addr;
}
+unsigned long
+__dl_runtime_pltresolve(struct elf_resolve *tpnt, int reloc_entry)
+{
+ int reloc_type;
+ ELF_RELOC *this_reloc;
+ char *strtab;
+ Elf32_Sym *symtab;
+ int symtab_index;
+ char *rel_addr;
+ char *new_addr;
+ char **got_addr;
+ unsigned long instr_addr;
+ char *symname;
+
+ rel_addr = (char *)tpnt->dynamic_info[DT_JMPREL];
+ this_reloc = (ELF_RELOC *)(intptr_t)(rel_addr + reloc_entry);
+ reloc_type = ELF32_R_TYPE(this_reloc->r_info);
+ symtab_index = ELF32_R_SYM(this_reloc->r_info);
+
+ symtab = (Elf32_Sym *)(intptr_t)tpnt->dynamic_info[DT_SYMTAB];
+ strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
+ symname = strtab + symtab[symtab_index].st_name;
+
+ /* Address of the jump instruction to fix up. */
+ instr_addr = ((unsigned long)this_reloc->r_offset +
+ (unsigned long)tpnt->loadaddr);
+ got_addr = (char **)instr_addr;
+
+ /* Get the address of the GOT entry. */
+ new_addr = _dl_find_hash(symname, tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT);
+ if (unlikely(!new_addr)) {
+ _dl_dprintf(2, "%s: can't resolve symbol '%s' in lib '%s'.\n", _dl_progname, symname, tpnt->libname);
+ _dl_exit(1);
+ }
+
+#if defined (__SUPPORT_LD_DEBUG__)
+ if ((unsigned long)got_addr < 0x40000000) {
+ if (_dl_debug_bindings) {
+ _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
+ if (_dl_debug_detail)
+ _dl_dprintf(_dl_debug_file,
+ "\n\tpatched: %x ==> %x @ %x",
+ *got_addr, new_addr, got_addr);
+ }
+ }
+ if (!_dl_debug_nofixups) {
+ *got_addr = new_addr;
+ }
+#else
+ *got_addr = new_addr;
+#endif
+
+ return (unsigned long)new_addr;
+}
+
void _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
unsigned long rel_addr, unsigned long rel_size)
{
@@ -115,6 +171,7 @@ int _dl_parse_relocation_information(str
got = (unsigned long *) tpnt->dynamic_info[DT_PLTGOT];
for (i = 0; i < rel_size; i++, rpnt++) {
+ char *symname = NULL;
reloc_addr = (unsigned long *) (tpnt->loadaddr +
(unsigned long) rpnt->r_offset);
reloc_type = ELF_R_TYPE(rpnt->r_info);
@@ -128,6 +185,16 @@ int _dl_parse_relocation_information(str
old_val = *reloc_addr;
#endif
+ if (reloc_type == R_MIPS_JUMP_SLOT || reloc_type == R_MIPS_COPY) {
+ symname = strtab + symtab[symtab_index].st_name;
+ symbol_addr = (unsigned long)_dl_find_hash(symname,
+ tpnt->symbol_scope,
+ tpnt,
+ elf_machine_type_class(reloc_type));
+ if (unlikely(!symbol_addr && ELF32_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK))
+ return 1;
+ }
+
switch (reloc_type) {
#if _MIPS_SIM == _MIPS_SIM_ABI64
case (R_MIPS_64 << 8) | R_MIPS_REL32:
@@ -148,6 +215,24 @@ int _dl_parse_relocation_information(str
*reloc_addr += (unsigned long) tpnt->loadaddr;
}
break;
+ case R_MIPS_JUMP_SLOT:
+ *reloc_addr = symbol_addr;
+ break;
+ case R_MIPS_COPY:
+ if (symbol_addr) {
+#if defined (__SUPPORT_LD_DEBUG__)
+ if (_dl_debug_move)
+ _dl_dprintf(_dl_debug_file,
+ "\n%s move %d bytes from %x to %x",
+ symname, symtab[symtab_index].st_size,
+ symbol_addr, reloc_addr);
+#endif
+
+ _dl_memcpy((char *)reloc_addr,
+ (char *)symbol_addr,
+ symtab[symtab_index].st_size);
+ }
+ break;
case R_MIPS_NONE:
break;
default:
--- a/ldso/ldso/mips/resolve.S
+++ b/ldso/ldso/mips/resolve.S
@@ -112,3 +112,54 @@ _dl_runtime_resolve:
.end _dl_runtime_resolve
.previous
+/* Assembler veneer called from the PLT header code when using the
+ non-PIC ABI.
+
+ Code in each PLT entry puts the caller's return address into t7 ($15),
+ the PLT entry index into t8 ($24), the address of _dl_runtime_pltresolve
+ into t9 ($25) and the address of .got.plt into gp ($28). __dl_runtime_pltresolve
+ needs a0 ($4) to hold the link map and a1 ($5) to hold the index into
+ .rel.plt (== PLT entry index * 4). */
+
+ .text
+ .align 2
+ .globl _dl_runtime_pltresolve
+ .type _dl_runtime_pltresolve,@function
+ .ent _dl_runtime_pltresolve
+_dl_runtime_pltresolve:
+ .frame $29, 40, $31
+ .set noreorder
+ # Save arguments and sp value in stack.
+ subu $29, 40
+ lw $10, 4($28)
+ # Modify t9 ($25) so as to point .cpload instruction.
+ addiu $25, 12
+ # Compute GP.
+ .cpload $25
+ .set reorder
+
+ /* Store function arguments from registers to stack */
+ sw $15, 36($29)
+ sw $4, 16($29)
+ sw $5, 20($29)
+ sw $6, 24($29)
+ sw $7, 28($29)
+
+ /* Setup functions args and call __dl_runtime_pltresolve. */
+ move $4, $10
+ sll $5, $24, 3
+ jal __dl_runtime_pltresolve
+
+ /* Restore function arguments from stack to registers */
+ lw $31, 36($29)
+ lw $4, 16($29)
+ lw $5, 20($29)
+ lw $6, 24($29)
+ lw $7, 28($29)
+
+ /* Do a tail call to the original function */
+ addiu $29, 40
+ move $25, $2
+ jr $25
+ .end _dl_runtime_pltresolve
+ .previous