From bd399063976c6c7a09beb4730ed1d93cadbcc739 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Mon, 7 Nov 2011 18:05:32 +0530 Subject: x86, microcode: Fix the failure path of microcode update driver init code The microcode update driver's initialization code does not handle failures correctly. This patch fixes this issue. Signed-off-by: Jan Beulich Signed-off-by: Srivatsa S. Bhat Link: http://lkml.kernel.org/r/20111107123530.12164.31227.stgit@srivatsabhat.in.ibm.com Link: http://lkml.kernel.org/r/4ED8E2270200007800065120@nat28.tlf.novell.com Signed-off-by: Borislav Petkov --- arch/x86/kernel/microcode_core.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c index f2d2a664e797..9d46f5e43b51 100644 --- a/arch/x86/kernel/microcode_core.c +++ b/arch/x86/kernel/microcode_core.c @@ -256,7 +256,7 @@ static int __init microcode_dev_init(void) return 0; } -static void microcode_dev_exit(void) +static void __exit microcode_dev_exit(void) { misc_deregister(µcode_dev); } @@ -519,10 +519,8 @@ static int __init microcode_init(void) microcode_pdev = platform_device_register_simple("microcode", -1, NULL, 0); - if (IS_ERR(microcode_pdev)) { - microcode_dev_exit(); + if (IS_ERR(microcode_pdev)) return PTR_ERR(microcode_pdev); - } get_online_cpus(); mutex_lock(µcode_mutex); @@ -532,14 +530,12 @@ static int __init microcode_init(void) mutex_unlock(µcode_mutex); put_online_cpus(); - if (error) { - platform_device_unregister(microcode_pdev); - return error; - } + if (error) + goto out_pdev; error = microcode_dev_init(); if (error) - return error; + goto out_sysdev_driver; register_syscore_ops(&mc_syscore_ops); register_hotcpu_notifier(&mc_cpu_notifier); @@ -548,6 +544,20 @@ static int __init microcode_init(void) " , Peter Oruba\n"); return 0; + +out_sysdev_driver: + get_online_cpus(); + mutex_lock(µcode_mutex); + + sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver); + + mutex_unlock(µcode_mutex); + put_online_cpus(); + +out_pdev: + platform_device_unregister(microcode_pdev); + return error; + } module_init(microcode_init); -- cgit v1.2.3-59-g8ed1b From ce37defc0f6673f5ca2c92ed5cfcaf290ae7dd16 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 5 Dec 2011 14:28:37 +0100 Subject: x86: Document rdmsr_safe restrictions Recently, I got bitten by using rdmsr_safe too early in the boot process. Document its shortcomings for future reference. Link: http://lkml.kernel.org/r/4ED5B70F.606@lwfinger.net Signed-off-by: Borislav Petkov --- arch/x86/include/asm/msr.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 084ef95274cd..95203d40ffdd 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -169,7 +169,14 @@ static inline int wrmsr_safe(unsigned msr, unsigned low, unsigned high) return native_write_msr_safe(msr, low, high); } -/* rdmsr with exception handling */ +/* + * rdmsr with exception handling. + * + * Please note that the exception handling works only after we've + * switched to the "smart" #GP handler in trap_init() which knows about + * exception tables - using this macro earlier than that causes machine + * hangs on boxes which do not implement the @msr in the first argument. + */ #define rdmsr_safe(msr, p1, p2) \ ({ \ int __err; \ -- cgit v1.2.3-59-g8ed1b