Norman Feske f54c85e045 Genode application binary interface (ABI)
This patch decouples the kernel-specific implementation of the dynamic
linker from its kernel-agnostic binary interface. The name of the
kernel-specific dynamic linker binary now corresponds to the kernel,
e.g., 'ld-linux.lib.so' or 'ld-nova.lib.so'. Applications are no longer
linked directly against a concrete instance of the dynamic linker but
against a shallow stub called 'ld.lib.so'. This stub contains nothing
but the symbols provided by the dynamic linker. It thereby represents
the Genode ABI.

At system-integration time, the kernel-specific run/boot_dir back ends
integrate the matching the kernel-specific variant of the dynamic linker
as 'ld.lib.so' into the boot image.

The ABI symbol file for the dynamic linker is located at
'base/lib/symbols/ld'. It contains the joint ABI of all supported
architectures. The new utility 'tool/abi_symbols' eases the creation of
such an ABI symbol file for a given shared library. Its result should be
manually inspected and edited as needed.

The patch removes the 'syscall' library from 'base_libs.mk' to avoid
polluting the kernel-agnostic ABI with kernel-specific interfaces.

Issue #2190
Issue #2195
2016-12-23 16:50:28 +01:00

37 lines
1.3 KiB
Makefile

#
# Generic ld.lib.so stub library
#
# This library is used to build kernel-independent dynamically linked
# executables. It does not contain any code or data but only the symbol
# information of the binary interface of the Genode API.
#
# Note that this library is not used as runtime at all. At system-integration
# time, it is transparently replaced by the variant of the dynamic linker that
# matches the used kernel.
#
# The rule for generating 'symbols.s' is defined in the architecture-dependent
# 'spec/<architecture>/ld.mk' file.
#
SRC_S := symbols.s
SYMBOLS := $(BASE_DIR)/lib/symbols/ld
SHARED_LIB := yes
LD_OPT += -Bsymbolic-functions --version-script=$(BASE_DIR)/src/lib/ldso/symbol.map
LD_OPT += -T$(BASE_DIR)/src/lib/ldso/linker.ld
symbols.s: $(MAKEFILE_LIST)
symbols.s: $(SYMBOLS)
$(MSG_CONVERT)$@
$(VERBOSE)\
sed -e "s/^\(\w\+\) D \(\w\+\)\$$/.data; .global \1; .type \1,%object; .size \1,\2; \1:/p" \
-e "s/^\(\w\+\) V/.data; .weak \1; .type \1,%object; \1:/p" \
-e "s/^\(\w\+\) T/.text; .global \1; .type \1,%function; \1:/p" \
-e "s/^\(\w\+\) R/.section .rodata; .global \1; \1:/p" \
-e "s/^\(\w\+\) W/.text; .weak \1; .type \1,%function; \1:/p" \
-e "s/^\(\w\+\) B/.bss; .global \1; .type \1,%object; \1:/p" \
$(SYMBOLS) > $@