diff options
| author | Andi Kleen <ak@suse.de> | 2007-06-23 02:29:25 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-06-22 18:41:19 -0700 |
| commit | 75154f402ef18e459ff97ddece25656b6c2b329c (patch) | |
| tree | 6757b77ee2c712c4b64f334ff8c5b1a41a64083b | |
| parent | e2f1f19272f8de0374ad297b9806f8b6509e0013 (diff) | |
x86_64: Ignore compat mode SYSCALL when IA32_EMULATION is not defined
Previously a program could switch to a compat mode segment and then
execute SYSCALL and it would jump to an uninitialized MSR and crash
the kernel.
Instead supply a dummy target for this case.
Pointed out by Jan Beulich
Cc: jbeulich@novell.com
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/x86_64/kernel/entry.S | 7 | ||||
| -rw-r--r-- | arch/x86_64/kernel/setup64.c | 3 |
2 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S index fa984b53e7e6..a67f87bf4015 100644 --- a/arch/x86_64/kernel/entry.S +++ b/arch/x86_64/kernel/entry.S @@ -1163,3 +1163,10 @@ ENTRY(call_softirq) ret CFI_ENDPROC ENDPROC(call_softirq) + +KPROBE_ENTRY(ignore_sysret) + CFI_STARTPROC + mov $-ENOSYS,%eax + sysret + CFI_ENDPROC +ENDPROC(ignore_sysret) diff --git a/arch/x86_64/kernel/setup64.c b/arch/x86_64/kernel/setup64.c index 64379a80d763..1200aaac403e 100644 --- a/arch/x86_64/kernel/setup64.c +++ b/arch/x86_64/kernel/setup64.c @@ -150,6 +150,8 @@ void pda_init(int cpu) char boot_exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ] __attribute__((section(".bss.page_aligned"))); +extern asmlinkage void ignore_sysret(void); + /* May not be marked __init: used by software suspend */ void syscall_init(void) { @@ -160,6 +162,7 @@ void syscall_init(void) */ wrmsrl(MSR_STAR, ((u64)__USER32_CS)<<48 | ((u64)__KERNEL_CS)<<32); wrmsrl(MSR_LSTAR, system_call); + wrmsrl(MSR_CSTAR, ignore_sysret); #ifdef CONFIG_IA32_EMULATION syscall32_cpu_init (); |