Thanks for your quick reply. On Wed, Feb 24, 2010 at 1:00 PM, richardvo...@gmail.com <richardvo...@gmail.com> wrote: > On Wed, Feb 24, 2010 at 12:57 AM, Swapnil Pimpale > <swapnil.p...@gmail.com> wrote: >> Hi all, >> >> I am a final year engineering student and I am doing my project in >> GRUB-1.97~beta4 and Linux Kernel 2.6.24.7. >> >> I am working on Intel Core 2 Duo architecture. I want to boot a >> separate kernel on the second core. >> As of now, I have brought up the halted AP from the GRUB by sending >> IPIs in the INIT-SIPI-SIPI sequence. I have also allocated a 4KB page >> below 1MB and asked the AP to jump to that address. >> >> I am trying to put the BSP in while(1) loop and I want the AP to >> switch from real to protected mode and then jump to start of kernel. >> But whenever I do a jump to 1MB the system reboots. > > Remember that the RAM physical address space is shared between both > processors. You'll need to tell Linux not to touch the second core > and not to touch the memory used by your second OS. I think you can > accomplish both of these goals using the right kernel command line. > Then you'll have to divide up other hardware, like PCI devices, so > that only one OS accesses any given device. For example, the second > OS won't be able to use a hard disk connected to a SATA controller > visible to the first one. Especially the second kernel needs to be > written not to address the PCI bus controller(s), including > enumeration of bus devices. > > If you can't partition the hardware like this then you'll need a > hypervisor, which uses protected mode to intercept and virtualize > attempted hardware access from the other OS. > I have considered these issues in the design. >> I am using the following code as the trampoline code for the AP. >> >> Can someone please let me know what is wrong in the following code. > > Probably you've stomped on a shared resource being used by the first > processor. Even if you run an infinite while loop on the first core, > it can still execute interrupt service routines installed by grub (or > by the second kernel, if not careful about interrupt-processor masks) > which would access grub global data structures. If you overwrite > anything you may end up with a protection fault or invalid instruction > exception, both of which would probably vector back to BIOS startup > code. > Ok, I will think in this direction. I just wanted to verify whether the code in the trampoline.S is correct or not. >> Awaiting your reply, >> >> Thanks, >> Swapnil Pimpale >> >> ----- trampoline.S ----- >> /* Tell GAS to generate 16-bit instructions so that this code works >> in real mode. */ >> >> #include <grub/symbol.h> >> #include <grub/i386/pc/memory.h> >> >> >> .align 4096 >> .code16 >> FUNCTION(TRAMPOLINE_CODE) >> initial: >> >> mov %cs, %ax >> mov %ax, %ds >> cli >> >> lidtl idtdesc - initial >> lgdtl gdtdesc - initial >> >> mov $0x9e00, %bx // 9e00 is the cs >> shl $4, %ebx >> movl $(gdt - initial + 8), %eax >> movl %ebx, %eax >> >> mov $0x10, %bx >> xor %ecx, %ecx >> mov $0xb800, %cx // address of video RAM in %cx >> shl $4, %ecx >> mov $0x0744, %dx // for printing D >> xor %eax, %eax >> pushw %ax >> mov $0x08, %ax >> pushw %ax >> xor %eax, %eax >> mov $0x9e00, %ax >> shl $4, %eax >> add protcseg - initial, %eax >> pushl %eax >> >> xor %eax, %eax >> movl %cr0, %eax // turn on the PE bit >> orl $0x1, %eax >> movl %eax, %cr0 >> >> jmp l1 >> >> l1: >> >> mov %bx, %ds >> mov %dx, (%ecx) // Print D >> add $2, %ecx >> add $1, %dx >> >> ADDR32 ljmpl $0x8,$((protcseg - initial) + (0x9e00 << 4)) >> >> .align 256 >> .code32 >> protcseg: >> >> l3: >> mov %dx, (%ecx) >> >> movw %bx, %es >> movw %bx, %fs >> movw %bx, %gs >> movw %bx, %ss >> >> l4: >> // The following is the code used by /loader/i386/linux.c for entering Linux >> mov $0x8c000, %esi >> xor %ebx, %ebx >> mov $0x8c000, %eax >> jmp *0x214(%eax) // System reboots here >> >> l5: >> jmp l5 >> >> >> .p2align 2 >> gdt: >> .word 0, 0 >> .byte 0, 0, 0, 0 >> >> .word 0xFFFF, 0 >> .byte 0, 0x9A, 0xCF, 0 >> >> .word 0xFFFF, 0 >> .byte 0, 0x92, 0xCF, 0 >> >> .word 0xFFFF, 0 >> .byte 0, 0x9E, 0, 0 >> >> .word 0xFFFF, 0 >> .byte 0, 0x92, 0, 0 >> >> gdtdesc: >> .word 0x27 >> .long gdt >> >> idtdesc: >> .word 0 >> .long 0 >> FUNCTION(TRAMPOLINE_END) >> >> >> _______________________________________________ >> Grub-devel mailing list >> Grub-devel@gnu.org >> http://lists.gnu.org/mailman/listinfo/grub-devel >> > > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > http://lists.gnu.org/mailman/listinfo/grub-devel >
_______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel
