This is the mail archive of the
binutils@sources.redhat.com
mailing list for the binutils project.
[PATCH] Add support for ARM AAPCS R_ARM_V4BX relocation type
- From: Julian Brown <julian at codesourcery dot com>
- To: binutils at sources dot redhat dot com
- Date: Fri, 28 Jan 2005 15:23:51 +0000
- Subject: [PATCH] Add support for ARM AAPCS R_ARM_V4BX relocation type
Hi,
This patch adds support for the R_ARM_V4BX relocation type to bfd and
ld. This allows objects compiled for the ARMv4 architecture to be
interworking-safe when linked with other objects compiled for ARMv4t,
but also allows pure ARMv4 binaries to be built from the same ARMv4 objects.
In the latter case, the switch "--fix-v4bx" must be passed to the
linker, which causes v4t "BX rM" instructions to be rewritten as "MOV
PC,rM", since v4 processors do not have a BX instruction.
In the former case, the switch should not be used, and R_ARM_V4BX
relocations are ignored.
Tested on i686-pc-linux-gnu and arm-none-eabi.
ChangeLog:
* bfd/bin-in.h (bfd_elf32_arm_set_target_relocs): Update
prototype.
* bfd/bin-in2.h (bfd_elf32_arm_set_target_relocs): Update
prototype.
* bfd/elf32-arm.c (elf32_arm_link_hash_table): Add fix_v4bx
flag.
(bfd_elf32_arm_set_target_relocs): Add formal parameter fix_v4bx
for passing flag value from ld. Set flag value in global hash
table entry.
(elf32_arm_final_link_relocate): Add code to implement
R_ARM_V4BX relocation.
* ld/emultempl/armelf.em (fix_v4bx): New variable.
(arm_elf_create_output_section_statements): Communicate fix_v4bx
flag value to bfd.
(PARSE_AND_LIST_PROLOGUE): Add option token OPTION_FIX_V4BX.
(PARSE_AND_LIST_LONGOPTS): Add option --fix-v4bx.
(PARSE_AND_LIST_OPTIONS): Add option --fix-v4bx.
(PARSE_AND_LIST_ARGS_CASES): Add option OPTION_FIX_V4BX.
--
Julian Brown
CodeSourcery, LLC
? bfd/doc/bfd.info
? bfd/doc/bfd.info-1
? gas/doc/as.info
? gas/doc/as.info-1
Index: bfd/bfd-in.h
===================================================================
RCS file: /cvs/src/src/bfd/bfd-in.h,v
retrieving revision 1.90
diff -c -p -r1.90 bfd-in.h
*** bfd/bfd-in.h 30 Nov 2004 17:45:53 -0000 1.90
--- bfd/bfd-in.h 27 Jan 2005 21:24:02 -0000
*************** extern bfd_boolean bfd_elf32_arm_process
*** 817,823 ****
(bfd *, struct bfd_link_info *, int);
void bfd_elf32_arm_set_target_relocs
! (struct bfd_link_info *, int, char *);
extern bfd_boolean bfd_elf32_arm_get_bfd_for_interworking
(bfd *, struct bfd_link_info *);
--- 817,823 ----
(bfd *, struct bfd_link_info *, int);
void bfd_elf32_arm_set_target_relocs
! (struct bfd_link_info *, int, char *, int);
extern bfd_boolean bfd_elf32_arm_get_bfd_for_interworking
(bfd *, struct bfd_link_info *);
Index: bfd/bfd-in2.h
===================================================================
RCS file: /cvs/src/src/bfd/bfd-in2.h,v
retrieving revision 1.317
diff -c -p -r1.317 bfd-in2.h
*** bfd/bfd-in2.h 25 Jan 2005 20:22:20 -0000 1.317
--- bfd/bfd-in2.h 27 Jan 2005 21:24:06 -0000
*************** extern bfd_boolean bfd_elf32_arm_process
*** 824,830 ****
(bfd *, struct bfd_link_info *, int);
void bfd_elf32_arm_set_target_relocs
! (struct bfd_link_info *, int, char *);
extern bfd_boolean bfd_elf32_arm_get_bfd_for_interworking
(bfd *, struct bfd_link_info *);
--- 824,830 ----
(bfd *, struct bfd_link_info *, int);
void bfd_elf32_arm_set_target_relocs
! (struct bfd_link_info *, int, char *, int);
extern bfd_boolean bfd_elf32_arm_get_bfd_for_interworking
(bfd *, struct bfd_link_info *);
Index: bfd/elf32-arm.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-arm.c,v
retrieving revision 1.17
diff -c -p -r1.17 elf32-arm.c
*** bfd/elf32-arm.c 26 Jan 2005 06:10:43 -0000 1.17
--- bfd/elf32-arm.c 27 Jan 2005 21:24:21 -0000
*************** struct elf32_arm_link_hash_table
*** 1165,1170 ****
--- 1165,1173 ----
/* The relocation to use for R_ARM_TARGET2 relocations. */
int target2_reloc;
+ /* Nonzero to fix BX instructions for ARMv4 targets. */
+ int fix_v4bx;
+
/* The number of bytes in the initial entry in the PLT. */
bfd_size_type plt_header_size;
*************** error_return:
*** 1931,1937 ****
void
bfd_elf32_arm_set_target_relocs (struct bfd_link_info *link_info,
int target1_is_rel,
! char * target2_type)
{
struct elf32_arm_link_hash_table *globals;
--- 1934,1941 ----
void
bfd_elf32_arm_set_target_relocs (struct bfd_link_info *link_info,
int target1_is_rel,
! char * target2_type,
! int fix_v4bx)
{
struct elf32_arm_link_hash_table *globals;
*************** bfd_elf32_arm_set_target_relocs (struct
*** 1949,1954 ****
--- 1953,1959 ----
_bfd_error_handler (_("Invalid TARGET2 relocation type '%s'."),
target2_type);
}
+ globals->fix_v4bx = fix_v4bx;
}
#endif
*************** elf32_arm_final_link_relocate (reloc_how
*** 2985,2990 ****
--- 2990,3011 ----
case R_ARM_RBASE:
return bfd_reloc_notsupported;
+ case R_ARM_V4BX:
+ if (globals->fix_v4bx)
+ {
+ bfd_vma insn = bfd_get_32 (input_bfd, hit_data);
+
+ /* Ensure that we have a BX instruction. */
+ BFD_ASSERT ((insn & 0x0ffffff0) == 0x012fff10);
+
+ /* Preserve Rm (lowest four bits) and the condition code
+ (highest four bits). Other bits encode MOV PC,Rm. */
+ insn = (insn & 0xf000000f) | 0x01a0f000;
+
+ bfd_put_32 (input_bfd, insn, hit_data);
+ }
+ return bfd_reloc_ok;
+
default:
return bfd_reloc_notsupported;
}
Index: ld/emultempl/armelf.em
===================================================================
RCS file: /cvs/src/src/ld/emultempl/armelf.em,v
retrieving revision 1.42
diff -c -p -r1.42 armelf.em
*** ld/emultempl/armelf.em 30 Nov 2004 17:45:54 -0000 1.42
--- ld/emultempl/armelf.em 27 Jan 2005 21:24:28 -0000
*************** static bfd *bfd_for_interwork;
*** 30,35 ****
--- 30,36 ----
static int byteswap_code = 0;
static int target1_is_rel = 0${TARGET1_IS_REL};
static char *target2_type = "${TARGET2_TYPE}";
+ static int fix_v4bx = 0;
static void
gld${EMULATION_NAME}_before_parse (void)
*************** arm_elf_finish (void)
*** 189,195 ****
static void
arm_elf_create_output_section_statements (void)
{
! bfd_elf32_arm_set_target_relocs (&link_info, target1_is_rel, target2_type);
}
EOF
--- 190,197 ----
static void
arm_elf_create_output_section_statements (void)
{
! bfd_elf32_arm_set_target_relocs (&link_info, target1_is_rel, target2_type,
! fix_v4bx);
}
EOF
*************** PARSE_AND_LIST_PROLOGUE='
*** 203,208 ****
--- 205,211 ----
#define OPTION_TARGET1_REL 303
#define OPTION_TARGET1_ABS 304
#define OPTION_TARGET2 305
+ #define OPTION_FIX_V4BX 306
'
PARSE_AND_LIST_SHORTOPTS=p
*************** PARSE_AND_LIST_LONGOPTS='
*** 214,219 ****
--- 217,223 ----
{ "target1-rel", no_argument, NULL, OPTION_TARGET1_REL},
{ "target1-abs", no_argument, NULL, OPTION_TARGET1_ABS},
{ "target2", required_argument, NULL, OPTION_TARGET2},
+ { "fix-v4bx", no_argument, NULL, OPTION_FIX_V4BX},
'
PARSE_AND_LIST_OPTIONS='
*************** PARSE_AND_LIST_OPTIONS='
*** 222,227 ****
--- 226,232 ----
fprintf (file, _(" --target1=rel Interpret R_ARM_TARGET1 as R_ARM_REL32\n"));
fprintf (file, _(" --target1=abs Interpret R_ARM_TARGET1 as R_ARM_ABS32\n"));
fprintf (file, _(" --target2=<type> Specify definition of R_ARM_TARGET2\n"));
+ fprintf (file, _(" --fix-v4bx Rewrite BX rn as MOV pc, rn for ARMv4\n"));
'
PARSE_AND_LIST_ARGS_CASES='
*************** PARSE_AND_LIST_ARGS_CASES='
*** 248,253 ****
--- 253,262 ----
case OPTION_TARGET2:
target2_type = optarg;
break;
+
+ case OPTION_FIX_V4BX:
+ fix_v4bx = 1;
+ break;
'
# We have our own after_open and before_allocation functions, but they call