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Commit Message
From: Ulf Samuelsson <ulf@emagii.com>
Signed-off-by: Ulf Samuelsson <ulf@emagii.com>
---
ld/NEWS | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 73 insertions(+), 4 deletions(-)
@@ -1,5 +1,74 @@
-*- text -*-
+* The linker script has a new command to insert a timestamp
+ TIMESTAMP
+ inserts the current time (seconds since Epoch) as a 64-bit value
+
+* The linker script syntax has new commands for debugging a linker script
+ DEBUG ON turns on debugging
+ DEBUG OFF turns off debugging
+
+* The linker script syntax has new commands for handling CRC-32/64 calculations
+ on the '.text' section
+ It uses code from https://www.libcrc.org/
+
+ DIGEST "<label>[#<endian>]" "CRC32" (start, end)
+ DIGEST "<label>[#<endian>]" "CRC64-ECMA" (start, end)
+ DIGEST "<label>[#<endian>]" "CRC64-GO-ISO" (start, end)
+ DIGEST "<label>[#<endian>]" "CRC64-GO-ISO-R" (start, end)
+ DIGEST "<label>[#<endian>]" "CRC64-WE" (start, end)
+ DIGEST "<label>[#<endian>]" "CRC64-XZ" (start, end)
+ DIGEST "<label>[#<endian>]" POLY (<params>) (start, end)
+ DIGEST TABLE "<label>[#<endian>]"
+
+ The CRC32, CRC64-ECMA, CRC64-ISO, CRC64-WE and POLY defines
+ the polynome to use and reserves space for the 32/64-bit CRC in the
+ current section (default ".text"). It also defines a label "<label>".
+ The endian can be specified through "#BE" or "#LE" modifiers for
+ big endian or little endian. This overrides the "-BE" or "-LE" switches on the
+ command line. If no specification is used, little endian
+ digest and table will be emitted.
+ The generated label does not include the modifier.
+
+ When generating a custom polynome you have to supply parameters
+ in the following order
+ * size {32 | 64 }
+ * polynome
+ * initial initial value of crc
+ * xor value xor with this before returning result
+ * input reflect bitreverse input data
+ * output reflect bitreverse result
+ * reciprocal bitreverse polynome
+
+ These terms are explained at
+ http://www.sunshine2k.de/articles/coding/crc/understanding_crc.html
+
+ The 32 bit DIGEST <polynome> command defines some global symbols.
+ ___CRC32___ is the address of the CRC64 checksum
+ ___CRC32_START___ is the address where CRC calculation starts
+ ___CRC32_END___ The CRC calculation ends before this address.
+
+ The 64-bit DIGEST <polynome> command defines some global symbols.
+ ___CRC64___ is the address of the CRC64 checksum
+ ___CRC64_START___ is the address where CRC calculation starts
+ ___CRC64_END___ The CRC calculation ends before this address.
+
+ All three symbols must refer to addresses in the selected section.
+ If they are defined at the end of the linking process, then
+ the CRC## will be calculated between
+
+ ___CRC##_START___ .. ___CRC##_END___ -1
+
+ and the result will be inserted at ___CRC##___.
+
+ ___CRC##___ must be outside the region where CRC is calculated
+
+ The DIGEST TABLE command generates a table for CRC generation.
+ A table is not neccessary, but will speed up the calculation.
+ It defines the ___CRC##_TABLE___ symbol at the start of the table.
+ The user may choose to add this table to his code instead of using
+ the linker.
+
* The linker script syntax has two new commands for inserting text into output
sections:
ASCII (<size>) "string"
@@ -41,16 +110,16 @@ Changes in 2.39:
re-enabled via the --warn-rwx-segments option.
New configure options can also control these new features:
-
+
--enable-warn-execstack=no
will disable the warnings about creating an executable stack.
-
+
--enable-warn-execstack=yes
will make --warn-execstack enabled by default.
-
+
--enable-warn-rwx-segments=no
will make --no-warn-rwx-segments enabled by default.
-
+
--enable-default-execstack=no
will stop the creation of an executable stack simply because an input file
is missing a .note.GNU-stack section, even on architectures where this