From ebb5e78cc63417a35254a791de66e1cc84f963cc Mon Sep 17 00:00:00 2001 From: Alex Smith Date: Wed, 21 Oct 2015 09:54:38 +0100 Subject: 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 Signed-off-by: Markos Chandras Cc: Matthew Fortune Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11337/ Signed-off-by: Ralf Baechle --- arch/mips/Kbuild | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/mips/Kbuild') diff --git a/arch/mips/Kbuild b/arch/mips/Kbuild index dd295335891a..5c3f688a5232 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/ -- cgit v1.2.3