From a858b5e50442579a73112c7c79bf6096e96de535 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Wed, 11 Feb 2015 14:54:42 +0100 Subject: [PATCH] x86/microcode/intel: Fix printing of microcode blobs in show_saved_mc() When doing echo 1 > /sys/devices/system/cpu/microcode/reload in order to reload microcode, I get: microcode: Total microcode saved: 1 BUG: using smp_processor_id() in preemptible [00000000] code: bash/2606 caller is debug_smp_processor_id+0x17/0x20 CPU: 1 PID: 2606 Comm: bash Not tainted 3.19.0-rc7+ #9 Hardware name: LENOVO 2320CTO/2320CTO, BIOS G2ET86WW (2.06 ) 11/13/2012 ffffffff81a4266d ffff8802131db808 ffffffff81666588 0000000000000007 0000000000000001 ffff8802131db838 ffffffff812e6eef ffff8802131db868 00000000000306a9 0000000000000010 0000000000000015 ffff8802131db848 Call Trace: dump_stack check_preemption_disabled debug_smp_processor_id show_saved_mc ? save_microcode.constprop.8 save_mc_for_early ? print_context_stack ? dump_trace ? __bfs ? mark_held_locks ? get_page_from_freelist ? trace_hardirqs_on_caller ? trace_hardirqs_on ? __alloc_pages_nodemask ? __get_vm_area_node ? map_vm_area ? __vmalloc_node_range ? generic_load_microcode generic_load_microcode ? microcode_fini_cpu request_microcode_fw reload_store dev_attr_store sysfs_kf_write kernfs_fop_write vfs_write ? sysret_check SyS_write system_call_fastpath microcode: CPU1: sig=0x306a9, pf=0x10, rev=0x15 microcode: mc_saved[0]: sig=0x306a9, pf=0x12, rev=0x1b, toal size=0x3000, date = 2014-05-29 because we're using smp_processor_id() in preemtible context. And we don't really need to use it there because the microcode container we're dumping is global and CPU-specific info is irrelevant. While at it, make pr_* stuff use "microcode: " prefix for easier grepping and document how to enable the DEBUG build. Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/microcode/intel_early.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/intel_early.c b/arch/x86/kernel/cpu/microcode/intel_early.c index 88a0348f455c..2f49ab4ac0ae 100644 --- a/arch/x86/kernel/cpu/microcode/intel_early.c +++ b/arch/x86/kernel/cpu/microcode/intel_early.c @@ -16,6 +16,14 @@ * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ + +/* + * This needs to be before all headers so that pr_debug in printk.h doesn't turn + * printk calls into no_printk(). + * + *#define DEBUG + */ + #include #include #include @@ -28,6 +36,9 @@ #include #include +#undef pr_fmt +#define pr_fmt(fmt) "microcode: " fmt + static unsigned long mc_saved_in_initrd[MAX_UCODE_COUNT]; static struct mc_saved_data { unsigned int mc_saved_count; @@ -397,8 +408,7 @@ static void __ref show_saved_mc(void) sig = uci.cpu_sig.sig; pf = uci.cpu_sig.pf; rev = uci.cpu_sig.rev; - pr_debug("CPU%d: sig=0x%x, pf=0x%x, rev=0x%x\n", - smp_processor_id(), sig, pf, rev); + pr_debug("CPU: sig=0x%x, pf=0x%x, rev=0x%x\n", sig, pf, rev); for (i = 0; i < mc_saved_data.mc_saved_count; i++) { struct microcode_header_intel *mc_saved_header; -- 2.20.1