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SubjectRE: [3.9-rc1 x86] Bug in ioremap code?
Date
> Subject: Re: [3.9-rc1 x86] Bug in ioremap code?
>
> Fenghua,
>
> Could you look at this thread and see if you can see what the problem
> is?
>
> -hpa
>
> On 03/05/2013 03:46 PM, Dave Hansen wrote:
> > Not sure if it's related by 3.9-rc1 gets in to a reboot loop for me.
> I
> > assume it's triple-faulting. The last line on the console I see is:
> >
> > [ 0.085702] SMP alternatives: lockdep: fixing up alternatives
> > [ 0.086859] smpboot: Booting Node 0, Processors [ 0.086859]
> > smpboot: Booting Node 0, Processors #1 OK
> > #1 OK
> >
> > I bisected it down to the neighborhood of c47f39e. After that, I get
> > some compile errors:
> >
> >> arch/x86/built-in.o: In function `generic_load_microcode':
> >> microcode_intel.c:(.text+0x28195): undefined reference to
> `microcode_sanity_check'
> >> microcode_intel.c:(.text+0x281ab): undefined reference to
> `get_matching_microcode'
> >
> > Turning off CONFIG_MICROCODE:
> >
> > -CONFIG_MICROCODE=y
> > -CONFIG_MICROCODE_INTEL=y
> > -# CONFIG_MICROCODE_AMD is not set
> > -CONFIG_MICROCODE_OLD_INTERFACE=y
> > -CONFIG_MICROCODE_INTEL_LIB=y
> > -CONFIG_MICROCODE_INTEL_EARLY=y
> > -CONFIG_MICROCODE_EARLY=y
> > +# CONFIG_MICROCODE is not set
> >
> > lets it boot again and fixes those compile errors. This is with this
> > config:
> >
> > http://i-love.sakura.ne.jp/tmp/config-3.9-rc1
> >
> > running under a kvm guest:
> >
> > qemu-system-x86_64 -append 'earlyprintk=ttyS0,115200,keep
> > console=ttyS0,115200 nmi_watchdog=0 root=/dev/sda1 bootmem_debug'
> > -kernel vmlinuz -usbdevice tablet -vnc :1 -net user -net
> > nic,model=e1000 -hda sarge-amd64-runme-1G.img -m 10240 -smp 2
> >

Before setting page in 32-bit kernel boot, we load microcode. To access global variables in linear addr, we use __pa_symbol(). There is no problem in native. Is this a problem in 32-bit guest kernel boot?

Related code is as follows:

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 8e7f655..2f70530 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -144,6 +144,11 @@ ENTRY(startup_32)
movl %eax, pa(olpc_ofw_pgd)
#endif

+#ifdef CONFIG_MICROCODE_EARLY
+ /* Early load ucode on BSP. */
+ call load_ucode_bsp
+#endif
+
/*
* Initialize page tables. This creates a PDE and a set of page
* tables, which are located immediately beyond __brk_base. The variable @@ -299,6 +304,12 @@ ENTRY(startup_32_smp)
+void __init
+load_ucode_intel_bsp(void)
+{
+ u64 ramdisk_image, ramdisk_size;
+ unsigned long initrd_start_early, initrd_end_early;
+ struct ucode_cpu_info uci;
+#ifdef CONFIG_X86_32
+ struct boot_params *boot_params_p;
+
+ boot_params_p = (struct boot_params *)__pa_symbol(&boot_params);
+ ramdisk_image = boot_params_p->hdr.ramdisk_image;
+ ramdisk_size = boot_params_p->hdr.ramdisk_size;
+ initrd_start_early = ramdisk_image;
+ initrd_end_early = initrd_start_early + ramdisk_size;
+
+ _load_ucode_intel_bsp(
+ (struct mc_saved_data *)__pa_symbol(&mc_saved_data),
+ (unsigned long *)__pa_symbol(&mc_saved_in_initrd),
+ initrd_start_early, initrd_end_early, &uci);
+ #else


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