From: "Andi Kleen" <ak@suse.de> Remove obsolete comments in vsyscall.c and fix some others. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> --- 25-akpm/arch/x86_64/kernel/vsyscall.c | 24 ++++-------------------- 1 files changed, 4 insertions(+), 20 deletions(-) diff -puN arch/x86_64/kernel/vsyscall.c~x86_64-remove-obsolete-comments-in-vsyscallc-and-fix arch/x86_64/kernel/vsyscall.c --- 25/arch/x86_64/kernel/vsyscall.c~x86_64-remove-obsolete-comments-in-vsyscallc-and-fix Wed Mar 23 15:38:32 2005 +++ 25-akpm/arch/x86_64/kernel/vsyscall.c Wed Mar 23 15:38:32 2005 @@ -9,32 +9,16 @@ * a different vsyscall implementation for Linux/IA32 and for the name. * * vsyscall 1 is located at -10Mbyte, vsyscall 2 is located - * at virtual address -10Mbyte+1024bytes etc... There are at max 8192 + * at virtual address -10Mbyte+1024bytes etc... There are at max 4 * vsyscalls. One vsyscall can reserve more than 1 slot to avoid - * jumping out of line if necessary. + * jumping out of line if necessary. We cannot add more with this + * mechanism because older kernels won't return -ENOSYS. + * If we want more than four we need a vDSO. * * Note: the concept clashes with user mode linux. If you use UML and * want per guest time just set the kernel.vsyscall64 sysctl to 0. */ -/* - * TODO 2001-03-20: - * - * 1) make page fault handler detect faults on page1-page-last of the vsyscall - * virtual space, and make it increase %rip and write -ENOSYS in %rax (so - * we'll be able to upgrade to a new glibc without upgrading kernel after - * we add more vsyscalls. - * 2) Possibly we need a fixmap table for the vsyscalls too if we want - * to avoid SIGSEGV and we want to return -EFAULT from the vsyscalls as well. - * Can we segfault inside a "syscall"? We can fix this anytime and those fixes - * won't be visible for userspace. Not fixing this is a noop for correct programs, - * broken programs will segfault and there's no security risk until we choose to - * fix it. - * - * These are not urgent things that we need to address only before shipping the first - * production binary kernels. - */ - #include <linux/time.h> #include <linux/init.h> #include <linux/kernel.h> _