From 6a52e4b1cddd90fbfde8fb67021657936ee74b07 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Sat, 12 Jul 2008 02:22:00 -0700 Subject: x86_64: further cleanup of 32-bit compat syscall mechanisms AMD only supports "syscall" from 32-bit compat usermode. Intel and Centaur(?) only support "sysenter" from 32-bit compat usermode. Set the X86 feature bits accordingly, and set up the vdso in accordance with those bits. On the offchance we run on in a 64-bit environment which supports neither syscall nor sysenter from 32-bit mode, then fall back to the int $0x80 vdso. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: H. Peter Anvin --- arch/x86/xen/setup.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'arch/x86/xen') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 3e11779755c3..e3648e64a637 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -83,12 +83,16 @@ static void xen_idle(void) /* * Set the bit indicating "nosegneg" library variants should be used. + * We only need to bother in pure 32-bit mode; compat 32-bit processes + * can have un-truncated segments, so wrapping around is allowed. */ static void __init fiddle_vdso(void) { -#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) - extern const char vdso32_default_start; - u32 *mask = VDSO32_SYMBOL(&vdso32_default_start, NOTE_MASK); +#ifdef CONFIG_X86_32 + u32 *mask; + mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK); + *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; + mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK); *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; #endif } -- cgit v1.2.2