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authorIngo Molnar <mingo@kernel.org>2016-04-13 11:36:44 +0200
committerIngo Molnar <mingo@kernel.org>2016-04-13 11:36:44 +0200
commit95a8e746f82bdda5d8a443b6557c930782d65b86 (patch)
tree6047fecc66e133c10d04be7b0bec89069c3e1654 /drivers/lguest
parentd8d1c35139481ee8e292d91cd3fd35a6b3a316eb (diff)
parenta3125494cff084b098c80bb36fbe2061ffed9d52 (diff)
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Merge branch 'x86/urgent' into x86/asm to pick up dependent fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/lguest')
-rw-r--r--drivers/lguest/interrupts_and_traps.c6
-rw-r--r--drivers/lguest/lg.h1
-rw-r--r--drivers/lguest/x86/core.c6
3 files changed, 11 insertions, 2 deletions
diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c
index eb934b0242e0..67392b6ab845 100644
--- a/drivers/lguest/interrupts_and_traps.c
+++ b/drivers/lguest/interrupts_and_traps.c
@@ -331,7 +331,7 @@ void set_interrupt(struct lg_cpu *cpu, unsigned int irq)
* Actually now I think of it, it's possible that Ron *is* half the Plan 9
* userbase. Oh well.
*/
-static bool could_be_syscall(unsigned int num)
+bool could_be_syscall(unsigned int num)
{
/* Normal Linux IA32_SYSCALL_VECTOR or reserved vector? */
return num == IA32_SYSCALL_VECTOR || num == syscall_vector;
@@ -416,6 +416,10 @@ bool deliver_trap(struct lg_cpu *cpu, unsigned int num)
*
* This routine indicates if a particular trap number could be delivered
* directly.
+ *
+ * Unfortunately, Linux 4.6 started using an interrupt gate instead of a
+ * trap gate for syscalls, so this trick is ineffective. See Mastery for
+ * how we could do this anyway...
*/
static bool direct_trap(unsigned int num)
{
diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h
index ac8ad0461e80..69b3814afd2f 100644
--- a/drivers/lguest/lg.h
+++ b/drivers/lguest/lg.h
@@ -167,6 +167,7 @@ void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
bool send_notify_to_eventfd(struct lg_cpu *cpu);
void init_clockdev(struct lg_cpu *cpu);
bool check_syscall_vector(struct lguest *lg);
+bool could_be_syscall(unsigned int num);
int init_interrupts(void);
void free_interrupts(void);
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index 65f22debf3c6..6e9042e3d2a9 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -429,8 +429,12 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu)
return;
break;
case 32 ... 255:
+ /* This might be a syscall. */
+ if (could_be_syscall(cpu->regs->trapnum))
+ break;
+
/*
- * These values mean a real interrupt occurred, in which case
+ * Other values mean a real interrupt occurred, in which case
* the Host handler has already been run. We just do a
* friendly check if another process should now be run, then
* return to run the Guest again.