diff options
Diffstat (limited to 'arch/x86/kernel/i387.c')
| -rw-r--r-- | arch/x86/kernel/i387.c | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index ab6a2e8028ae..528557470ddb 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -22,7 +22,15 @@ /* * Were we in an interrupt that interrupted kernel mode? * - * We can do a kernel_fpu_begin/end() pair *ONLY* if that + * For now, on xsave platforms we will return interrupted + * kernel FPU as not-idle. TBD: As we use non-lazy FPU restore + * for xsave platforms, ideally we can change the return value + * to something like __thread_has_fpu(current). But we need to + * be careful of doing __thread_clear_has_fpu() before saving + * the FPU etc for supporting nested uses etc. For now, take + * the simple route! + * + * On others, we can do a kernel_fpu_begin/end() pair *ONLY* if that * pair does nothing at all: the thread must not have fpu (so * that we don't try to save the FPU state), and TS must * be set (so that the clts/stts pair does nothing that is @@ -30,6 +38,9 @@ */ static inline bool interrupted_kernel_fpu_idle(void) { + if (use_xsave()) + return 0; + return !__thread_has_fpu(current) && (read_cr0() & X86_CR0_TS); } @@ -73,7 +84,7 @@ void kernel_fpu_begin(void) __save_init_fpu(me); __thread_clear_has_fpu(me); /* We do 'stts()' in kernel_fpu_end() */ - } else { + } else if (!use_xsave()) { this_cpu_write(fpu_owner_task, NULL); clts(); } @@ -82,7 +93,10 @@ EXPORT_SYMBOL(kernel_fpu_begin); void kernel_fpu_end(void) { - stts(); + if (use_xsave()) + math_state_restore(); + else + stts(); preempt_enable(); } EXPORT_SYMBOL(kernel_fpu_end); |