MIPS: add dynamic relocation support

The code handles relocation entries with the
following relocation types only:
  mips32: R_MIPS_REL32
  mips64: R_MIPS_REL+R_MIPS_64
  xburst: R_MIPS_REL32

Other relocation entries are skipped without
processing. The code must be extended if other
relocation types must be supported.

Add -pie to LDFLAGS_FINAL to generate the .rel.dyn
fixup table, which will be applied to the relocated
image before transferring control to it.

The CONFIG_NEEDS_MANUAL_RELOC is not needed
after the patch, so remove that as well.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
This commit is contained in:
Gabor Juhos 2013-02-12 22:22:13 +01:00 committed by Daniel Schwierzeck
parent 0ba8926e08
commit 04380c651a
6 changed files with 94 additions and 12 deletions

View File

@ -65,4 +65,5 @@ PLATFORM_CPPFLAGS += -G 0 -mabicalls -fpic $(ENDIANNESS)
PLATFORM_CPPFLAGS += -msoft-float
PLATFORM_LDFLAGS += -G 0 -static -n -nostdlib $(ENDIANNESS)
PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections
LDFLAGS_FINAL += --gc-sections
LDFLAGS_FINAL += --gc-sections -pie
OBJCFLAGS += --remove-section=.dynsym

View File

@ -201,6 +201,8 @@ relocate_code:
jr t0
nop
.word __rel_dyn_end
.word __rel_dyn_start
.word __image_copy_end
.word _GLOBAL_OFFSET_TABLE_
.word num_got_entries
@ -227,6 +229,32 @@ in_ram:
blt t2, t3, 1b
addi t4, 4
/* Update dynamic relocations */
lw t1, -16(t0) # t1 <-- __rel_dyn_start
lw t2, -20(t0) # t2 <-- __rel_dyn_end
b 2f # skip first reserved entry
addi t1, 8
1:
lw t3, -4(t1) # t3 <-- relocation info
sub t3, 3
bnez t3, 2f # skip non R_MIPS_REL32 entries
nop
lw t3, -8(t1) # t3 <-- location to fix up in FLASH
lw t4, 0(t3) # t4 <-- original pointer
add t4, s1 # t4 <-- adjusted pointer
add t3, s1 # t3 <-- location to fix up in RAM
sw t4, 0(t3)
2:
blt t1, t2, 1b
addi t1, 8 # each rel.dyn entry is 8 bytes
/*
* Clear BSS
*

View File

@ -31,6 +31,14 @@
#define CONFIG_SYS_MIPS_CACHE_MODE CONF_CM_CACHABLE_NONCOHERENT
#endif
#ifdef CONFIG_SYS_LITTLE_ENDIAN
#define MIPS64_R_INFO(ssym, r_type3, r_type2, r_type) \
(((r_type) << 24) | ((r_type2) << 16) | ((r_type3) << 8) | (ssym))
#else
#define MIPS64_R_INFO(ssym, r_type3, r_type2, r_type) \
((r_type) | ((r_type2) << 8) | ((r_type3) << 16) | (ssym) << 24)
#endif
/*
* For the moment disable interrupts, mark the kernel mode and
* set ST0_KX so that the CPU does not spit fire when using
@ -193,6 +201,8 @@ relocate_code:
jr t0
nop
.dword __rel_dyn_end
.dword __rel_dyn_start
.dword __image_copy_end
.dword _GLOBAL_OFFSET_TABLE_
.dword num_got_entries
@ -219,6 +229,32 @@ in_ram:
blt t2, t3, 1b
daddi t8, 8
/* Update dynamic relocations */
ld t1, -32(t0) # t1 <-- __rel_dyn_start
ld t2, -40(t0) # t2 <-- __rel_dyn_end
b 2f # skip first reserved entry
daddi t1, 16
1:
lw t8, -4(t1) # t8 <-- relocation info
dli t3, MIPS64_R_INFO(0x00, 0x00, 0x12, 0x03)
bne t8, t3, 2f # skip non R_MIPS_REL32 entries
nop
ld t3, -16(t1) # t3 <-- location to fix up in FLASH
ld t8, 0(t3) # t8 <-- original pointer
dadd t8, s1 # t8 <-- adjusted pointer
dadd t3, s1 # t3 <-- location to fix up in RAM
sd t8, 0(t3)
2:
blt t1, t2, 1b
daddi t1, 16 # each rel.dyn entry is 16 bytes
/*
* Clear BSS
*

View File

@ -116,6 +116,8 @@ relocate_code:
jr t0
nop
.word __rel_dyn_end
.word __rel_dyn_start
.word __image_copy_end
.word _GLOBAL_OFFSET_TABLE_
.word num_got_entries
@ -142,6 +144,32 @@ in_ram:
blt t2, t3, 1b
addi t4, 4
/* Update dynamic relocations */
lw t1, -16(t0) # t1 <-- __rel_dyn_start
lw t2, -20(t0) # t2 <-- __rel_dyn_end
b 2f # skip first reserved entry
addi t1, 8
1:
lw t3, -4(t1) # t3 <-- relocation info
sub t3, 3
bnez t3, 2f # skip non R_MIPS_REL32 entries
nop
lw t3, -8(t1) # t3 <-- location to fix up in FLASH
lw t4, 0(t3) # t4 <-- original pointer
add t4, t6 # t4 <-- adjusted pointer
add t3, t6 # t3 <-- location to fix up in RAM
sw t4, 0(t3)
2:
blt t1, t2, 1b
addi t1, 8 # each rel.dyn entry is 8 bytes
/*
* Clear BSS
*

View File

@ -21,6 +21,4 @@
#ifndef _ASM_CONFIG_H_
#define _ASM_CONFIG_H_
#define CONFIG_NEEDS_MANUAL_RELOC
#endif

View File

@ -266,14 +266,6 @@ void board_init_r(gd_t *id, ulong dest_addr)
serial_initialize();
#if defined(CONFIG_NEEDS_MANUAL_RELOC)
/*
* We have to relocate the command table manually
*/
fixup_cmdtable(ll_entry_start(cmd_tbl_t, cmd),
ll_entry_count(cmd_tbl_t, cmd));
#endif /* defined(CONFIG_NEEDS_MANUAL_RELOC) */
/* there are some other pointer constants we must deal with */
#ifndef CONFIG_ENV_IS_NOWHERE
env_name_spec += gd->reloc_off;
@ -284,7 +276,6 @@ void board_init_r(gd_t *id, ulong dest_addr)
/* The Malloc area is immediately below the monitor copy in DRAM */
mem_malloc_init(CONFIG_SYS_MONITOR_BASE + gd->reloc_off -
TOTAL_MALLOC_LEN, TOTAL_MALLOC_LEN);
malloc_bin_reloc();
#ifndef CONFIG_SYS_NO_FLASH
/* configure available FLASH banks */