diff mbox series

[14/22] x86: mp: Park CPUs before running the OS

Message ID 20200522022326.238388-11-sjg@chromium.org
State Superseded
Delegated to: Bin Meng
Headers show
Series x86: Enhance MTRR functionality to support multiple CPUs | expand

Commit Message

Simon Glass May 22, 2020, 2:23 a.m. UTC 
With the new MP features the CPUs are no-longer parked when the OS is run.
Fix this by calling a special function to park them, just before the OS is
started.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

 arch/x86/cpu/cpu.c        |  5 +++++
 arch/x86/cpu/mp_init.c    | 18 ++++++++++++++++++
 arch/x86/include/asm/mp.h | 17 +++++++++++++++++
 3 files changed, 40 insertions(+)

Comments

Wolfgang Wallner June 10, 2020, 1:27 p.m. UTC | #1 
Hi Simon,

-----"Simon Glass" <sjg@chromium.org> schrieb: -----
> Betreff: [PATCH 14/22] x86: mp: Park CPUs before running the OS
> 
> With the new MP features the CPUs are no-longer parked when the OS is run.
> Fix this by calling a special function to park them, just before the OS is
> started.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
> 
>  arch/x86/cpu/cpu.c        |  5 +++++
>  arch/x86/cpu/mp_init.c    | 18 ++++++++++++++++++
>  arch/x86/include/asm/mp.h | 17 +++++++++++++++++
>  3 files changed, 40 insertions(+)
> 
 
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
diff mbox series

Patch

diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
index d0720fb7fb5..baa7dae172e 100644
--- a/arch/x86/cpu/cpu.c
+++ b/arch/x86/cpu/cpu.c
@@ -66,6 +66,11 @@  static const char *const x86_vendor_name[] = {
 
 int __weak x86_cleanup_before_linux(void)
 {
+	int ret;
+
+	ret = mp_park_aps();
+	if (ret)
+		return log_msg_ret("park", ret);
 	bootstage_stash((void *)CONFIG_BOOTSTAGE_STASH_ADDR,
 			CONFIG_BOOTSTAGE_STASH_SIZE);
 
diff --git a/arch/x86/cpu/mp_init.c b/arch/x86/cpu/mp_init.c
index 9f97dc7a9ba..a16be28647a 100644
--- a/arch/x86/cpu/mp_init.c
+++ b/arch/x86/cpu/mp_init.c
@@ -609,6 +609,24 @@  int mp_run_on_cpus(int cpu_select, mp_run_func func, void *arg)
 	return 0;
 }
 
+static void park_this_cpu(void *unused)
+{
+	stop_this_cpu();
+}
+
+int mp_park_aps(void)
+{
+	unsigned long start;
+	int ret;
+
+	start = get_timer(0);
+	ret = mp_run_on_cpus(MP_SELECT_APS, park_this_cpu, NULL);
+	if (ret)
+		return ret;
+
+	return get_timer(start);
+}
+
 int mp_init(void)
 {
 	int num_aps, num_cpus;
diff --git a/arch/x86/include/asm/mp.h b/arch/x86/include/asm/mp.h
index 0272b3c0b6a..38961ca44b3 100644
--- a/arch/x86/include/asm/mp.h
+++ b/arch/x86/include/asm/mp.h
@@ -106,6 +106,15 @@  typedef void (*mp_run_func)(void *arg);
  * @return 0 on success, -ve on error
  */
 int mp_run_on_cpus(int cpu_select, mp_run_func func, void *arg);
+
+/**
+ * mp_park_aps() - Park the APs ready for the OS
+ *
+ * This halts all CPUs except the main one, ready for the OS to use them
+ *
+ * @return 0 on success, -ve on error
+ */
+int mp_park_aps(void);
 #else
 static inline int mp_run_on_cpus(int cpu_select, mp_run_func func, void *arg)
 {
@@ -114,6 +123,14 @@  static inline int mp_run_on_cpus(int cpu_select, mp_run_func func, void *arg)
 
 	return 0;
 }
+
+static inline int mp_park_aps(void)
+{
+	/* No APs to park */
+
+	return 0;
+}
+
 #endif
 
 #endif /* _X86_MP_H_ */