Commit-ID: 87983c66bc02c9cd8e4a42e7924435145d52bb13 Gitweb: http://git.kernel.org/tip/87983c66bc02c9cd8e4a42e7924435145d52bb13 Author: Andy Lutomirski <[email protected]> AuthorDate: Wed, 29 Oct 2014 14:33:45 -0700 Committer: Thomas Gleixner <[email protected]> CommitDate: Mon, 3 Nov 2014 21:44:57 +0100
x86_64, vsyscall: Turn vsyscalls all the way off when vsyscall==none I see no point in having an unusable read-only page sitting at 0xffffffffff600000 when vsyscall=none. Instead, skip mapping it and remove it from /proc/PID/maps. I kept the ratelimited warning when programs try to use a vsyscall in this mode, since it may help admins avoid confusion. Signed-off-by: Andy Lutomirski <[email protected]> Reviewed-by: Josh Triplett <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> Link: http://lkml.kernel.org/r/0dddbadc1d4e3bfbaf887938ff42afc97a7cc1f2.1414618407.git.l...@amacapital.net Signed-off-by: Thomas Gleixner <[email protected]> --- arch/x86/kernel/vsyscall_64.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 419e83b..2d91262 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -307,6 +307,8 @@ struct vm_area_struct *get_gate_vma(struct mm_struct *mm) if (!mm || mm->context.ia32_compat) return NULL; #endif + if (vsyscall_mode == NONE) + return NULL; return &gate_vma; } @@ -327,7 +329,7 @@ int in_gate_area(struct mm_struct *mm, unsigned long addr) */ int in_gate_area_no_mm(unsigned long addr) { - return (addr & PAGE_MASK) == VSYSCALL_ADDR; + return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR; } void __init map_vsyscall(void) @@ -335,10 +337,12 @@ void __init map_vsyscall(void) extern char __vsyscall_page; unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page); - __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall, - vsyscall_mode == NATIVE - ? PAGE_KERNEL_VSYSCALL - : PAGE_KERNEL_VVAR); + if (vsyscall_mode != NONE) + __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall, + vsyscall_mode == NATIVE + ? PAGE_KERNEL_VSYSCALL + : PAGE_KERNEL_VVAR); + BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) != (unsigned long)VSYSCALL_ADDR); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
