From 3b520b238e018ef0e9d11c9115d5e7d9419c4ef9 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 7 Jul 2005 17:56:38 -0700 Subject: [PATCH] MTRR suspend/resume cleanup There has been some discuss about solving the SMP MTRR suspend/resume breakage, but I didn't find a patch for it. This is an intent for it. The basic idea is moving mtrr initializing into cpu_identify for all APs (so it works for cpu hotplug). For BP, restore_processor_state is responsible for restoring MTRR. Signed-off-by: Shaohua Li Acked-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/cpu/mtrr/main.c | 76 ++++++++++++++++++++++++++++------------ 1 file changed, 53 insertions(+), 23 deletions(-) (limited to 'arch/i386/kernel/cpu/mtrr/main.c') diff --git a/arch/i386/kernel/cpu/mtrr/main.c b/arch/i386/kernel/cpu/mtrr/main.c index d66b09e0c82..764cac64e21 100644 --- a/arch/i386/kernel/cpu/mtrr/main.c +++ b/arch/i386/kernel/cpu/mtrr/main.c @@ -332,6 +332,8 @@ int mtrr_add_page(unsigned long base, unsigned long size, error = -EINVAL; + /* No CPU hotplug when we change MTRR entries */ + lock_cpu_hotplug(); /* Search for existing MTRR */ down(&main_lock); for (i = 0; i < num_var_ranges; ++i) { @@ -372,6 +374,7 @@ int mtrr_add_page(unsigned long base, unsigned long size, error = i; out: up(&main_lock); + unlock_cpu_hotplug(); return error; } @@ -461,6 +464,8 @@ int mtrr_del_page(int reg, unsigned long base, unsigned long size) return -ENXIO; max = num_var_ranges; + /* No CPU hotplug when we change MTRR entries */ + lock_cpu_hotplug(); down(&main_lock); if (reg < 0) { /* Search for existing MTRR */ @@ -501,6 +506,7 @@ int mtrr_del_page(int reg, unsigned long base, unsigned long size) error = reg; out: up(&main_lock); + unlock_cpu_hotplug(); return error; } /** @@ -544,21 +550,9 @@ static void __init init_ifs(void) centaur_init_mtrr(); } -static void __init init_other_cpus(void) -{ - if (use_intel()) - get_mtrr_state(); - - /* bring up the other processors */ - set_mtrr(~0U,0,0,0); - - if (use_intel()) { - finalize_mtrr_state(); - mtrr_state_warn(); - } -} - - +/* The suspend/resume methods are only for CPU without MTRR. CPU using generic + * MTRR driver doesn't require this + */ struct mtrr_value { mtrr_type ltype; unsigned long lbase; @@ -611,13 +605,13 @@ static struct sysdev_driver mtrr_sysdev_driver = { /** - * mtrr_init - initialize mtrrs on the boot CPU + * mtrr_bp_init - initialize mtrrs on the boot CPU * * This needs to be called early; before any of the other CPUs are * initialized (i.e. before smp_init()). * */ -static int __init mtrr_init(void) +void __init mtrr_bp_init(void) { init_ifs(); @@ -674,12 +668,48 @@ static int __init mtrr_init(void) if (mtrr_if) { set_num_var_ranges(); init_table(); - init_other_cpus(); - - return sysdev_driver_register(&cpu_sysdev_class, - &mtrr_sysdev_driver); + if (use_intel()) + get_mtrr_state(); } - return -ENXIO; } -subsys_initcall(mtrr_init); +void mtrr_ap_init(void) +{ + unsigned long flags; + + if (!mtrr_if || !use_intel()) + return; + /* + * Ideally we should hold main_lock here to avoid mtrr entries changed, + * but this routine will be called in cpu boot time, holding the lock + * breaks it. This routine is called in two cases: 1.very earily time + * of software resume, when there absolutely isn't mtrr entry changes; + * 2.cpu hotadd time. We let mtrr_add/del_page hold cpuhotplug lock to + * prevent mtrr entry changes + */ + local_irq_save(flags); + + mtrr_if->set_all(); + + local_irq_restore(flags); +} + +static int __init mtrr_init_finialize(void) +{ + if (!mtrr_if) + return 0; + if (use_intel()) + mtrr_state_warn(); + else { + /* The CPUs haven't MTRR and seemes not support SMP. They have + * specific drivers, we use a tricky method to support + * suspend/resume for them. + * TBD: is there any system with such CPU which supports + * suspend/resume? if no, we should remove the code. + */ + sysdev_driver_register(&cpu_sysdev_class, + &mtrr_sysdev_driver); + } + return 0; +} +subsys_initcall(mtrr_init_finialize); -- cgit v1.2.3