From e23f22b5cb9e44da24cb8494707536211adff8d1 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:46 +0200 Subject: [PATCH] dcdbas: Make use of smp_call_on_cpu() Use smp_call_on_cpu() to raise SMI on CPU 0. Make call secure by adding get_online_cpus() to avoid e.g. suspend resume cycles in between. Signed-off-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) Cc: Douglas_Warzecha@dell.com Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akataria@vmware.com Cc: boris.ostrovsky@oracle.com Cc: chrisw@sous-sol.org Cc: david.vrabel@citrix.com Cc: hpa@zytor.com Cc: jdelvare@suse.com Cc: jeremy@goop.org Cc: linux@roeck-us.net Cc: pali.rohar@gmail.com Cc: rusty@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1472453327-19050-6-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- drivers/firmware/dcdbas.c | 51 ++++++++++++++++++++------------------- 1 file changed, 26 insertions(+), 25 deletions(-) diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c index 829eec8959f2..2fe1a130189f 100644 --- a/drivers/firmware/dcdbas.c +++ b/drivers/firmware/dcdbas.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -238,33 +239,14 @@ static ssize_t host_control_on_shutdown_store(struct device *dev, return count; } -/** - * dcdbas_smi_request: generate SMI request - * - * Called with smi_data_lock. - */ -int dcdbas_smi_request(struct smi_cmd *smi_cmd) +static int raise_smi(void *par) { - cpumask_var_t old_mask; - int ret = 0; - - if (smi_cmd->magic != SMI_CMD_MAGIC) { - dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n", - __func__); - return -EBADR; - } + struct smi_cmd *smi_cmd = par; - /* SMI requires CPU 0 */ - if (!alloc_cpumask_var(&old_mask, GFP_KERNEL)) - return -ENOMEM; - - cpumask_copy(old_mask, ¤t->cpus_allowed); - set_cpus_allowed_ptr(current, cpumask_of(0)); if (smp_processor_id() != 0) { dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n", __func__); - ret = -EBUSY; - goto out; + return -EBUSY; } /* generate SMI */ @@ -280,9 +262,28 @@ int dcdbas_smi_request(struct smi_cmd *smi_cmd) : "memory" ); -out: - set_cpus_allowed_ptr(current, old_mask); - free_cpumask_var(old_mask); + return 0; +} +/** + * dcdbas_smi_request: generate SMI request + * + * Called with smi_data_lock. + */ +int dcdbas_smi_request(struct smi_cmd *smi_cmd) +{ + int ret; + + if (smi_cmd->magic != SMI_CMD_MAGIC) { + dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n", + __func__); + return -EBADR; + } + + /* SMI requires CPU 0 */ + get_online_cpus(); + ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true); + put_online_cpus(); + return ret; } -- 2.20.1