x86: fix broken math-emu with lazy allocation of fpu area
Fix the math emulation that got broken with the recent lazy allocation of FPU
area. init_fpu() need to be added for the math-emulation path aswell
for the FPU area allocation.
math emulation enabled kernel booted fine with this, in the presence
of "no387 nofxsr" boot param.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: hpa@zytor.com
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index e03cc95..eb9ddd8 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -56,6 +56,11 @@
void __init init_thread_xstate(void)
{
+ if (!HAVE_HWFP) {
+ xstate_size = sizeof(struct i387_soft_struct);
+ return;
+ }
+
if (cpu_has_fxsr)
xstate_size = sizeof(struct i387_fxsave_struct);
#ifdef CONFIG_X86_32
@@ -94,7 +99,7 @@
int init_fpu(struct task_struct *tsk)
{
if (tsk_used_math(tsk)) {
- if (tsk == current)
+ if (HAVE_HWFP && tsk == current)
unlazy_fpu(tsk);
return 0;
}
@@ -109,6 +114,15 @@
return -ENOMEM;
}
+#ifdef CONFIG_X86_32
+ if (!HAVE_HWFP) {
+ memset(tsk->thread.xstate, 0, xstate_size);
+ finit();
+ set_stopped_child_used_math(tsk);
+ return 0;
+ }
+#endif
+
if (cpu_has_fxsr) {
struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave;
@@ -330,13 +344,13 @@
struct user_i387_ia32_struct env;
int ret;
- if (!HAVE_HWFP)
- return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
-
ret = init_fpu(target);
if (ret)
return ret;
+ if (!HAVE_HWFP)
+ return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
+
if (!cpu_has_fxsr) {
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.xstate->fsave, 0,
@@ -360,15 +374,15 @@
struct user_i387_ia32_struct env;
int ret;
- if (!HAVE_HWFP)
- return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
-
ret = init_fpu(target);
if (ret)
return ret;
set_stopped_child_used_math(target);
+ if (!HAVE_HWFP)
+ return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
+
if (!cpu_has_fxsr) {
return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&target->thread.xstate->fsave, 0, -1);
@@ -474,18 +488,18 @@
int restore_i387_ia32(struct _fpstate_ia32 __user *buf)
{
int err;
+ struct task_struct *tsk = current;
- if (HAVE_HWFP) {
- struct task_struct *tsk = current;
-
+ if (HAVE_HWFP)
clear_fpu(tsk);
- if (!used_math()) {
- err = init_fpu(tsk);
- if (err)
- return err;
- }
+ if (!used_math()) {
+ err = init_fpu(tsk);
+ if (err)
+ return err;
+ }
+ if (HAVE_HWFP) {
if (cpu_has_fxsr)
err = restore_i387_fxsave(buf);
else