Messages in this thread | | | Date | Wed, 01 Jul 2009 23:39:52 -0700 | From | Yinghai Lu <> | Subject | Re: [PATCH, v2] x86: Fix printk call in print_local_apic() |
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Ingo Molnar wrote: > * Ingo Molnar <mingo@elte.hu> wrote: > >>> - printk(KERN_DEBUG "0123456789abcdef0123456789abcdef\n" KERN_DEBUG); >>> + printk(KERN_DEBUG "0123456789abcdef0123456789abcdef\n"); >>> for (i = 0; i < 8; i++) { >>> + char bin[33]; >>> v = apic_read(base + i*0x10); >>> + >>> + /* Do we really want to print out LSB first? */ >> We definitely want MSB first - i'll flip around the order. > > in fact i dont remember ever having relied on the bitfield nature of > that printout. Since this is uncommon debug code, printing the plain > hexa value is more than enough. > > In fact we can compact it down to a single line: > > 0123456701234567012345670123456701234567012345670123456701234567 > > instead of 4 lines of bitfields. > > So i've done the patch below that looks quite a bit simpler. Mind > testing it, does it fix all the printout artifacts you've seen? > > Ingo > > ------------------> >>From ef611b322dc9a917c71f28f9498dfff0d3949779 Mon Sep 17 00:00:00 2001 > From: Ingo Molnar <mingo@elte.hu> > Date: Thu, 2 Jul 2009 08:26:20 +0200 > Subject: [PATCH] x86: Fix printk call in print_local_apic() > > Instead of this: > > [ 75.690022] <7>printing local APIC contents on CPU#0/0: > [ 75.704406] ... APIC ID: 00000000 (0) > [ 75.707905] ... APIC VERSION: 00060015 > [ 75.722551] ... APIC TASKPRI: 00000000 (00) > [ 75.725473] ... APIC PROCPRI: 00000000 > [ 75.728592] ... APIC LDR: 00000001 > [ 75.742137] ... APIC SPIV: 000001ff > [ 75.744101] ... APIC ISR field: > [ 75.746648] 0123456789abcdef0123456789abcdef > [ 75.746649] <7>00000000000000000000000000000000 > > Improve the code to be saner and simpler and just print out > the bitfield in a single line using hexa values - not as a > (rather pointless) binary bitfield. > > Partially reused Linus's initial fix for this. > > Reported-and-Tested-by: Yinghai Lu <yinghai@kernel.org> > Signed-off-by: Yinghai Lu <yinghai@kernel.org> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Andrew Morton <akpm@linux-foundation.org> > LKML-Reference: <4A4C43BC.90506@kernel.org> > Signed-off-by: Ingo Molnar <mingo@elte.hu> > --- > arch/x86/kernel/apic/io_apic.c | 25 ++++++++++--------------- > 1 files changed, 10 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c > index 4d0216f..e32e453 100644 > --- a/arch/x86/kernel/apic/io_apic.c > +++ b/arch/x86/kernel/apic/io_apic.c > @@ -1716,25 +1716,19 @@ __apicdebuginit(void) print_IO_APIC(void) > return; > } > > -__apicdebuginit(void) print_APIC_bitfield(int base) > +__apicdebuginit(void) print_APIC_(int base)
?
> { > - unsigned int v; > int i, j; > > - if (apic_verbosity == APIC_QUIET) > + if (apic_verbosity != APIC_QUIET)
is this one reversed?
> return; > > - printk(KERN_DEBUG "0123456789abcdef0123456789abcdef\n" KERN_DEBUG); > - for (i = 0; i < 8; i++) { > - v = apic_read(base + i*0x10); > - for (j = 0; j < 32; j++) { > - if (v & (1<<j)) > - printk("1"); > - else > - printk("0"); > - } > - printk("\n"); > - } > + printk(KERN_DEBUG); > + > + for (i = 0; i < 8; i++) > + printk(KERN_CONT "%08x", i, apic_read(base + i*0x10)); > + > + printk(KERN_CONT "\n"); > } > > __apicdebuginit(void) print_local_APIC(void *dummy) > @@ -1745,7 +1739,8 @@ __apicdebuginit(void) print_local_APIC(void *dummy) > if (apic_verbosity == APIC_QUIET) > return; > > - printk("\n" KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n", > + printk(KERN_DEBUG "\n"); > + printk(KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n", > smp_processor_id(), hard_smp_processor_id()); > v = apic_read(APIC_ID); > printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v, read_apic_id());
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