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/kernel/signal.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'arch/mips/kernel/signal.c') diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c index 2fec67bfc457..bf792e2839a6 100644 --- a/arch/mips/kernel/signal.c +++ b/arch/mips/kernel/signal.c @@ -36,7 +36,6 @@ #include #include #include -#include #include #include #include @@ -752,16 +751,15 @@ static int setup_rt_frame(void *sig_return, struct ksignal *ksig, struct mips_abi mips_abi = { #ifdef CONFIG_TRAD_SIGNALS .setup_frame = setup_frame, - .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline), #endif .setup_rt_frame = setup_rt_frame, - .rt_signal_return_offset = - offsetof(struct mips_vdso, rt_signal_trampoline), .restart = __NR_restart_syscall, .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs), .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr), .off_sc_used_math = offsetof(struct sigcontext, sc_used_math), + + .vdso = &vdso_image, }; static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) @@ -801,11 +799,11 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) } if (sig_uses_siginfo(&ksig->ka)) - ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset, + ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn, ksig, regs, oldset); else - ret = abi->setup_frame(vdso + abi->signal_return_offset, ksig, - regs, oldset); + ret = abi->setup_frame(vdso + abi->vdso->off_sigreturn, + ksig, regs, oldset); signal_setup_done(ret, ksig, 0); } -- cgit