>
> ----- "Yinghai" <yinghai@kernel.org> a écrit :
>
>> On Dec 23, 2010, at 1:57 AM, Florian Fainelli <ffainelli@freebox.fr>
>> wrote:
>>
>>> On Tuesday 14 December 2010 22:19:39 Florian Fainelli wrote:
>>>> From: Florian Fainelli <ffainelli@freebox.fr>
>>>>
>>>> Since 893f38d1 (x86: Use find_e820() instead of hard coded
>> trampoline
>>>> address), the trampoline base address should be provided by the
>> BIOS as an
>>>> e820 area. Some minimalistic BIOSes (like CEFDK on CE4100) may not
>> provide
>>>> any e820 area, still we should fallback to a fixed trampoline base
>> address
>>>> for SMP to work correctly.
>>
>> No e820 memmap ?
>
> Yes, the BIOS is only doing the very minimal setup to get a kernel in real-mode booting.
>
>>
>> Not sure how does it work
>>
>> Do you have boot log with debug ?
>
> I would need to produce one for you, give me a couple days to be in sync.
>
>>
>> Also recent kernel is using memblock already for finding free area.
>>
>> Thanks
>>
>>
>>
>>>>
>>>> Cc: Dirk Brandewie <dirk.brandewie@gmail.com>
>>>> Cc:
sodaville@linutronix.de
>>>> Cc: Ingo Molnar <mingo@elte.hu>
>>>> Cc: Yinghai Lu <yinghai@kernel.org>
>>>> Signed-off-by: Florian Fainelli <ffainelli@freebox.fr>
>>>
>>> Ingo, Yinghai, anything wrong with that patch? Thank you.
>>>
>>>> ---
>>>> diff --git a/arch/x86/include/asm/trampoline.h
>>>> b/arch/x86/include/asm/trampoline.h index f4500fb..908b395 100644
>>>> --- a/arch/x86/include/asm/trampoline.h
>>>> +++ b/arch/x86/include/asm/trampoline.h
>>>> @@ -16,6 +16,7 @@ extern unsigned long initial_code;
>>>> extern unsigned long initial_gs;
>>>>
>>>> #define TRAMPOLINE_SIZE roundup(trampoline_end - trampoline_data,
>>>> PAGE_SIZE) +#define TRAMPOLINE_BASE 0x6000
>>>>
>>>> extern unsigned long setup_trampoline(void);
>>>> extern void __init reserve_trampoline_memory(void);
>>>> diff --git a/arch/x86/kernel/trampoline.c
>> b/arch/x86/kernel/trampoline.c
>>>> index f1488a3..d025aae 100644
>>>> --- a/arch/x86/kernel/trampoline.c
>>>> +++ b/arch/x86/kernel/trampoline.c
>>>> @@ -21,8 +21,11 @@ void __init reserve_trampoline_memory(void)
>>>>
>>>> /* Has to be in very low memory so we can execute real-mode AP
>> code. */
>>>> mem = find_e820_area(0, 1<<20, TRAMPOLINE_SIZE, PAGE_SIZE);
>>>> - if (mem == -1L)
>>>> - panic("Cannot allocate trampoline\n");
>>>> + if (mem == -1L) {
>>>> + printk(KERN_INFO "BIOS did not provide e820 area for
>> trampoline"
>>>> + " ,using static trampoline address\n");
>>>> + mem = TRAMPOLINE_BASE;
>>>> + }
>>>>
>>>> trampoline_base = __va(mem);
>>>> reserve_early(mem, mem + TRAMPOLINE_SIZE, "TRAMPOLINE");
