From patchwork Mon Jul 6 03:37:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Glass X-Patchwork-Id: 240769 List-Id: U-Boot discussion From: sjg at chromium.org (Simon Glass) Date: Sun, 5 Jul 2020 21:37:30 -0600 Subject: [PATCH v3 14/25] x86: mp: Park CPUs before running the OS In-Reply-To: <20200706033741.2169374-1-sjg@chromium.org> References: <20200706033741.2169374-1-sjg@chromium.org> Message-ID: <20200706033741.2169374-13-sjg@chromium.org> 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 Reviewed-by: Wolfgang Wallner --- Changes in v3: - Update the comment for mp_park_aps() 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(+) diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c index d0720fb7fb..baa7dae172 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 bcb7513084..0bf325ae88 100644 --- a/arch/x86/cpu/mp_init.c +++ b/arch/x86/cpu/mp_init.c @@ -651,6 +651,24 @@ 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 3f1d70663d..4acce55b8c 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 time taken to park the APs on success (in microseconds), -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_ */