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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2008-07-12 09:22:00 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-07-16 09:08:27 (GMT) |
| commit | 6a52e4b1cddd90fbfde8fb67021657936ee74b07 (patch) | |
| tree | c876e1fafe89169f373f6b04739242b5d646fcf7 /arch/x86/xen | |
| parent | 71415c6a0877d5944d5dc3060f3b03513746158d (diff) | |
| download | linux-6a52e4b1cddd90fbfde8fb67021657936ee74b07.tar.xz | |
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 <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/setup.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 3e11779..e3648e6 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 } |