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authorAndi Kleen <ak@suse.de>2007-06-22 20:29:25 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-06-22 21:41:19 -0400
commit75154f402ef18e459ff97ddece25656b6c2b329c (patch)
tree6757b77ee2c712c4b64f334ff8c5b1a41a64083b /arch/x86_64
parente2f1f19272f8de0374ad297b9806f8b6509e0013 (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>
Diffstat (limited to 'arch/x86_64')
-rw-r--r--arch/x86_64/kernel/entry.S7
-rw-r--r--arch/x86_64/kernel/setup64.c3
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)
1163 ret 1163 ret
1164 CFI_ENDPROC 1164 CFI_ENDPROC
1165ENDPROC(call_softirq) 1165ENDPROC(call_softirq)
1166
1167KPROBE_ENTRY(ignore_sysret)
1168 CFI_STARTPROC
1169 mov $-ENOSYS,%eax
1170 sysret
1171 CFI_ENDPROC
1172ENDPROC(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)
150char boot_exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ] 150char boot_exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]
151__attribute__((section(".bss.page_aligned"))); 151__attribute__((section(".bss.page_aligned")));
152 152
153extern asmlinkage void ignore_sysret(void);
154
153/* May not be marked __init: used by software suspend */ 155/* May not be marked __init: used by software suspend */
154void syscall_init(void) 156void syscall_init(void)
155{ 157{
@@ -160,6 +162,7 @@ void syscall_init(void)
160 */ 162 */
161 wrmsrl(MSR_STAR, ((u64)__USER32_CS)<<48 | ((u64)__KERNEL_CS)<<32); 163 wrmsrl(MSR_STAR, ((u64)__USER32_CS)<<48 | ((u64)__KERNEL_CS)<<32);
162 wrmsrl(MSR_LSTAR, system_call); 164 wrmsrl(MSR_LSTAR, system_call);
165 wrmsrl(MSR_CSTAR, ignore_sysret);
163 166
164#ifdef CONFIG_IA32_EMULATION 167#ifdef CONFIG_IA32_EMULATION
165 syscall32_cpu_init (); 168 syscall32_cpu_init ();