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authorAlex Smith <alex.smith@imgtec.com>2015-10-21 09:54:38 +0100
committerRalf Baechle <ralf@linux-mips.org>2015-11-11 08:36:36 +0100
commitebb5e78cc63417a35254a791de66e1cc84f963cc (patch)
tree49814946abe594cb8e7a11ce8d0a5fdaabb49d31 /arch/mips/Kbuild
parent22773aa9b95657f0adc2b5342428d9da7a6d5d02 (diff)
downloadop-kernel-dev-ebb5e78cc63417a35254a791de66e1cc84f963cc.zip
op-kernel-dev-ebb5e78cc63417a35254a791de66e1cc84f963cc.tar.gz
MIPS: Initial implementation of a VDSO
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>
Diffstat (limited to 'arch/mips/Kbuild')
-rw-r--r--arch/mips/Kbuild1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/mips/Kbuild b/arch/mips/Kbuild
index dd29533..5c3f688 100644
--- a/arch/mips/Kbuild
+++ b/arch/mips/Kbuild
@@ -17,6 +17,7 @@ obj- := $(platform-)
obj-y += kernel/
obj-y += mm/
obj-y += net/
+obj-y += vdso/
ifdef CONFIG_KVM
obj-y += kvm/
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