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![Alex Smith](/assets/img/avatar_default.png)
Add an initial implementation of a proper (i.e. an ELF shared library) VDSO. With this commit it does not export any symbols, it only replaces the current signal return trampoline page. A later commit will add user implementations of gettimeofday()/clock_gettime(). To support both new toolchains and old ones which don't generate ABI flags section, we define its content manually and then use a tool (genvdso) to patch up the section to have the correct name and type. genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the kernel, and generates a C file containing a "struct mips_vdso_image" containing both the VDSO data and these offsets. This C file is compiled into the kernel. On 64-bit kernels we require a different VDSO for each supported ABI, so we may build up to 3 different VDSOs. The VDSO to use is selected by the mips_abi structure. A kernel/user shared data page is created and mapped below the VDSO image. This is currently empty, but will be used by the user time function implementations which are added later. [markos.chandras@imgtec.com: - Add more comments - Move abi detection in genvdso.h since it's the get_symbol function that needs it. - Add an R6 specific way to calculate the base address of VDSO in order to avoid the branch instruction which affects performance. - Do not patch .gnu.attributes since it's not needed for dynamic linking. - Simplify Makefile a little bit. - checkpatch fixes - Restrict VDSO support for binutils < 2.25 for pre-R6 - Include atomic64.h for O32 variant on MIPS64] Signed-off-by: Alex Smith <alex.smith@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11337/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
24 lines
557 B
Makefile
24 lines
557 B
Makefile
# Fail on warnings - also for files referenced in subdirs
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# -Werror can be disabled for specific files using:
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# CFLAGS_<file.o> := -Wno-error
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subdir-ccflags-y := -Werror
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# platform specific definitions
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include arch/mips/Kbuild.platforms
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obj-y := $(platform-y)
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# make clean traverses $(obj-) without having included .config, so
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# everything ends up here
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obj- := $(platform-)
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# mips object files
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# The object files are linked as core-y files would be linked
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obj-y += kernel/
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obj-y += mm/
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obj-y += net/
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obj-y += vdso/
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ifdef CONFIG_KVM
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obj-y += kvm/
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endif
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