x86-64: make compat_start_thread() match start_thread()
For no real good reason, compat_start_thread() was embedded inline in
<asm/elf.h> whereas the native start_thread() lives in process_*.c.
Move compat_start_thread() to process_64.c, remove gratuitious
differences, and fix a few items which mostly look like bit rot.
In particular, compat_start_thread() didn't do free_thread_xstate(),
which means it was hanging on to the xstate store area even when it
was not needed. It was also not setting old_rsp, but it looks like
that generally shouldn't matter for a 32-bit process.
Note: compat_start_thread *has* to be a macro, since it is tested with
start_thread_ia32() as the out of line function name.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index ad535b6..7cf0a6b 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -356,7 +356,7 @@
percpu_write(old_rsp, new_sp);
regs->cs = __USER_CS;
regs->ss = __USER_DS;
- regs->flags = 0x200;
+ regs->flags = X86_EFLAGS_IF;
set_fs(USER_DS);
/*
* Free the old FP and other extended state
@@ -365,6 +365,27 @@
}
EXPORT_SYMBOL_GPL(start_thread);
+#ifdef CONFIG_IA32_EMULATION
+void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp)
+{
+ loadsegment(fs, 0);
+ loadsegment(ds, __USER32_DS);
+ loadsegment(es, __USER32_DS);
+ load_gs_index(0);
+ regs->ip = new_ip;
+ regs->sp = new_sp;
+ percpu_write(old_rsp, new_sp);
+ regs->cs = __USER32_CS;
+ regs->ss = __USER32_DS;
+ regs->flags = X86_EFLAGS_IF;
+ set_fs(USER_DS);
+ /*
+ * Free the old FP and other extended state
+ */
+ free_thread_xstate(current);
+}
+#endif
+
/*
* switch_to(x,y) should switch tasks from x to y.
*