+2006-01-29 Julian Brown <julian@codesourcery.com>
+
+ * NEWS: Mention --vfp11-denorm-fix option.
+ * ld.texinfo: Document above.
+ * emulparams/armelf_linux.sh (OTHER_TEXT_SECTIONS): Add
+ .vfp11_veneer section.
+ * emulparams/armelf.sh (OTHER_TEXT_SECTIONS): Likewise.
+ * emultempl/armelf.em (vfp11_denorm_fix): New static variable.
+ (arm_elf_before_allocation): Call bfd_elf32_arm_set_vfp11_fix,
+ bfd_elf32_arm_init_maps and bfd_elf32_arm_vfp11_erratum_scan.
+ (arm_elf_after_allocation): New function. Call
+ bfd_elf32_arm_vfp11_fix_veneer_locations for all input statements.
+ (arm_elf_create_output_section_statements): Pass vfp11 fix command
+ line option to BFD.
+ (OPTION_VFP11_DENORM_FIX): New option.
+ (PARSE_AND_LIST_LONGOPTS): Handle new option.
+ (PARSE_AND_LIST_OPTIONS): Likewise.
+ (PARSE_AND_LIST_ARGS_CASES): Likewise.
+ (LDEMUL_AFTER_ALLOCATION): Define.
+
2007-01-24 H.J. Lu <hongjiu.lu@intel.com>
* ldgram.y (SIZEOF_HEADERS): Remove duplicated one.
static char *target2_type = "${TARGET2_TYPE}";
static int fix_v4bx = 0;
static int use_blx = 0;
+static bfd_arm_vfp11_fix vfp11_denorm_fix = BFD_ARM_VFP11_FIX_DEFAULT;
static void
gld${EMULATION_NAME}_before_parse (void)
bfd_elf32_arm_set_byteswap_code (&link_info, byteswap_code);
+ /* Choose type of VFP11 erratum fix, or warn if specified fix is unnecessary
+ due to architecture version. */
+ bfd_elf32_arm_set_vfp11_fix (output_bfd, &link_info);
+
/* We should be able to set the size of the interworking stub section. We
can't do it until later if we have dynamic sections, though. */
if (! elf_hash_table (&link_info)->dynamic_sections_created)
/* Here we rummage through the found bfds to collect glue information. */
LANG_FOR_EACH_INPUT_STATEMENT (is)
{
+ /* Initialise mapping tables for code/data. */
+ bfd_elf32_arm_init_maps (is->the_bfd);
+
if (!bfd_elf32_arm_process_before_allocation (is->the_bfd,
- &link_info))
+ &link_info)
+ || !bfd_elf32_arm_vfp11_erratum_scan (is->the_bfd, &link_info))
/* xgettext:c-format */
einfo (_("Errors encountered processing file %s"), is->filename);
}
}
static void
+arm_elf_after_allocation (void)
+{
+ /* Call the standard elf routine. */
+ after_allocation_default ();
+
+ {
+ LANG_FOR_EACH_INPUT_STATEMENT (is)
+ {
+ /* Figure out where VFP11 erratum veneers (and the labels returning
+ from same) have been placed. */
+ bfd_elf32_arm_vfp11_fix_veneer_locations (is->the_bfd, &link_info);
+ }
+ }
+}
+
+static void
arm_elf_finish (void)
{
struct bfd_link_hash_entry * h;
arm_elf_create_output_section_statements (void)
{
bfd_elf32_arm_set_target_relocs (&link_info, target1_is_rel, target2_type,
- fix_v4bx, use_blx);
+ fix_v4bx, use_blx, vfp11_denorm_fix);
}
EOF
#define OPTION_TARGET2 305
#define OPTION_FIX_V4BX 306
#define OPTION_USE_BLX 307
+#define OPTION_VFP11_DENORM_FIX 308
'
PARSE_AND_LIST_SHORTOPTS=p
{ "target2", required_argument, NULL, OPTION_TARGET2},
{ "fix-v4bx", no_argument, NULL, OPTION_FIX_V4BX},
{ "use-blx", no_argument, NULL, OPTION_USE_BLX},
+ { "vfp11-denorm-fix", required_argument, NULL, OPTION_VFP11_DENORM_FIX},
'
PARSE_AND_LIST_OPTIONS='
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"));
fprintf (file, _(" --use-blx Enable use of BLX instructions\n"));
+ fprintf (file, _(" --vfp11-denorm-fix Specify how to fix VFP11 denorm erratum\n"));
'
PARSE_AND_LIST_ARGS_CASES='
case OPTION_USE_BLX:
use_blx = 1;
break;
+
+ case OPTION_VFP11_DENORM_FIX:
+ if (strcmp (optarg, "none") == 0)
+ vfp11_denorm_fix = BFD_ARM_VFP11_FIX_NONE;
+ else if (strcmp (optarg, "scalar") == 0)
+ vfp11_denorm_fix = BFD_ARM_VFP11_FIX_SCALAR;
+ else if (strcmp (optarg, "vector") == 0)
+ vfp11_denorm_fix = BFD_ARM_VFP11_FIX_VECTOR;
+ else
+ einfo (_("Unrecognized VFP11 fix type '\''%s'\''.\n"), optarg);
+ break;
'
# We have our own after_open and before_allocation functions, but they call
# the standard routines, so give them a different name.
LDEMUL_AFTER_OPEN=arm_elf_after_open
LDEMUL_BEFORE_ALLOCATION=arm_elf_before_allocation
+LDEMUL_AFTER_ALLOCATION=arm_elf_after_allocation
LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=arm_elf_create_output_section_statements
# Replace the elf before_parse function with our own.
This option is enabled implicitly for SymbianOS, so there is no need to
specify it if you are using that target.
+@cindex VFP11_DENORM_FIX
+@kindex --vfp11-denorm-fix
+The @samp{--vfp11-denorm-fix} switch enables a link-time workaround for a
+bug in certain VFP11 coprocessor hardware, which sometimes allows
+instructions with denorm operands (which must be handled by support code)
+to have those operands overwritten by subsequent instructions before
+the support code can read the intended values.
+
+The bug may be avoided in scalar mode if you allow at least one
+intervening instruction between a VFP11 instruction which uses a register
+and another instruction which writes to the same register, or at least two
+intervening instructions if vector mode is in use. The bug only affects
+full-compliance floating-point mode: you do not need this workaround if
+you are using "runfast" mode. Please contact ARM for further details.
+
+If you know you are using buggy VFP11 hardware, you can
+enable this workaround by specifying the linker option
+@samp{--vfp-denorm-fix=scalar} if you are using the VFP11 scalar
+mode only, or @samp{--vfp-denorm-fix=vector} if you are using
+vector mode (the latter also works for scalar code). The default is
+@samp{--vfp-denorm-fix=none}.
+
+If the workaround is enabled, instructions are scanned for
+potentially-troublesome sequences, and a veneer is created for each
+such sequence which may trigger the erratum. The veneer consists of the
+first instruction of the sequence and a branch back to the subsequent
+instruction. The original instruction is then replaced with a branch to
+the veneer. The extra cycles required to call and return from the veneer
+are sufficient to avoid the erratum in both the scalar and vector cases.
+
@ifclear GENERIC
@lowersections
@end ifclear
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