x86: mark associated mm when running a task in 32 bit compatibility mode
This patch simply follows the same practice as for setting the TIF_IA32 flag.
In particular, an mm is marked as holding 32-bit tasks when a 32-bit binary is
exec'ed. Both ELF and a.out formats are updated.
Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: Michel Lespinasse <walken@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index bd387e8..6c9dd92 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -501,6 +501,10 @@
/* Make sure to be in 64bit mode */
clear_thread_flag(TIF_IA32);
+ /* Ensure the corresponding mm is not marked. */
+ if (current->mm)
+ current->mm->context.ia32_compat = 0;
+
/* TBD: overwrites user setup. Should have two bits.
But 64bit processes have always behaved this way,
so it's not too bad. The main problem is just that
@@ -516,6 +520,10 @@
set_thread_flag(TIF_IA32);
current->personality |= force_personality32;
+ /* Mark the associated mm as containing 32-bit tasks. */
+ if (current->mm)
+ current->mm->context.ia32_compat = 1;
+
/* Prepare the first "return" to user space */
current_thread_info()->status |= TS_COMPAT;
}
