Split kerne timekeep ABI structure vdso_sv_tk out of the struct

sysentvec.  This allows the timekeep data to be shared between similar
ABIs which cannot share sysentvec.

Make the timekeep_push_vdso() tick callback to the timekeep structures
instead of sysentvecs.  If several sysentvec share the vdso_sv_tk
structure, we would update the userspace data several times on each
tick, without the change.

Only allocate vdso_sv_tk in the exec_sysvec_init() sysinit when
sysentvec is marked with the new SV_TIMEKEEP flag.  This saves
allocation and update of unneeded vdso_sv_tk for ABIs which do not
provide userspace gettimeofday yet, which are PowerPCs arches right
now.

Make vdso_sv_tk allocator public, namely split out and export
alloc_sv_tk() and alloc_sv_tk_compat32().  ABIs which share timekeep
data now can allocate it manually and share as appropriate.

Requested by:	nwhitehorn
Tested by:	nwhitehorn, pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/i386/i386/elf_machdep.c b/sys/i386/i386/elf_machdep.c
index 81d6e35b3a45..376dd0bc3440 100644
--- a/sys/i386/i386/elf_machdep.c
+++ b/sys/i386/i386/elf_machdep.c
@@ -81,7 +81,8 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
 	.sv_maxssiz	= NULL,
-	.sv_flags	= SV_ABI_FREEBSD | SV_IA32 | SV_ILP32 | SV_SHP,
+	.sv_flags	= SV_ABI_FREEBSD | SV_IA32 | SV_ILP32 | SV_SHP |
+			    SV_TIMEKEEP,
 	.sv_set_syscall_retval = cpu_set_syscall_retval,
 	.sv_fetch_syscall_args = cpu_fetch_syscall_args,
 	.sv_syscallnames = syscallnames,