Especially the irq_ts_save() function is pretty bloaty, generating
over a dozen instructions, so uninline them.
Even though the API is used rarely, the space savings are measurable:
text data bss dec hex filename
13331995 2572920 1634304 17539219 10ba093 vmlinux.before
13331739 2572920 1634304 17538963 10b9f93 vmlinux.after
( This also allows the removal of an include file inclusion from fpu/api.h,
speeding up the kernel build slightly. )
Reviewed-by: Borislav Petkov <b...@alien8.de>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
arch/x86/include/asm/fpu/api.h | 27 ++-------------------------
arch/x86/kernel/fpu/core.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 32 insertions(+), 25 deletions(-)
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index 0c713455fc63..62035cc1d961 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -10,8 +10,6 @@
#ifndef _ASM_X86_FPU_API_H
#define _ASM_X86_FPU_API_H
-#include <linux/hardirq.h>
-
/*
* Careful: __kernel_fpu_begin/end() must be called with preempt disabled
* and they don't touch the preempt state on their own.
@@ -35,28 +33,7 @@ extern bool irq_fpu_usable(void);
* in interrupt context interacting wrongly with other user/kernel fpu usage,
we
* should use them only in the context of irq_ts_save/restore()
*/
-static inline int irq_ts_save(void)
-{
- /*
- * If in process context and not atomic, we can take a spurious DNA
fault.
- * Otherwise, doing clts() in process context requires disabling
preemption
- * or some heavy lifting like kernel_fpu_begin()
- */
- if (!in_atomic())
- return 0;
-
- if (read_cr0() & X86_CR0_TS) {
- clts();
- return 1;
- }
-
- return 0;
-}
-
-static inline void irq_ts_restore(int TS_state)
-{
- if (TS_state)
- stts();
-}
+extern int irq_ts_save(void);
+extern void irq_ts_restore(int TS_state);
#endif /* _ASM_X86_FPU_API_H */
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 15fd714b6a83..34a4e1032424 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -6,6 +6,7 @@
* Gareth Hughes <gar...@valinux.com>, May 2000
*/
#include <asm/fpu/internal.h>
+#include <linux/hardirq.h>
/*
* Track whether the kernel is using the FPU state
@@ -140,6 +141,35 @@ void kernel_fpu_end(void)
}
EXPORT_SYMBOL_GPL(kernel_fpu_end);
+/*
+ * CR0::TS save/restore functions:
+ */
+int irq_ts_save(void)
+{
+ /*
+ * If in process context and not atomic, we can take a spurious DNA
fault.
+ * Otherwise, doing clts() in process context requires disabling
preemption
+ * or some heavy lifting like kernel_fpu_begin()
+ */
+ if (!in_atomic())
+ return 0;
+
+ if (read_cr0() & X86_CR0_TS) {
+ clts();
+ return 1;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(irq_ts_save);
+
+void irq_ts_restore(int TS_state)
+{
+ if (TS_state)
+ stts();
+}
+EXPORT_SYMBOL_GPL(irq_ts_restore);
+
static void __save_fpu(struct fpu *fpu)
{
if (use_xsave()) {
--
2.1.0
--
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