diff options
Diffstat (limited to 'arch/x86/lguest')
| -rw-r--r-- | arch/x86/lguest/boot.c | 7 | ||||
| -rw-r--r-- | arch/x86/lguest/i386_head.S | 41 |
2 files changed, 38 insertions, 10 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 3a06b51..090f30c 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -86,6 +86,7 @@ struct lguest_data lguest_data = { .hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF }, .noirq_start = (u32)lguest_noirq_start, .noirq_end = (u32)lguest_noirq_end, + .kernel_address = PAGE_OFFSET, .blocked_interrupts = { 1 }, /* Block timer interrupts */ .syscall_vec = SYSCALL_VECTOR, }; @@ -1033,11 +1034,7 @@ __init void lguest_init(void *boot) /*G:070 Now we've seen all the paravirt_ops, we return to * lguest_init() where the rest of the fairly chaotic boot setup - * occurs. - * - * The Host expects our first hypercall to tell it where our "struct - * lguest_data" is, so we do that first. */ - hcall(LHCALL_LGUEST_INIT, __pa(&lguest_data), 0, 0); + * occurs. */ /* The native boot code sets up initial page tables immediately after * the kernel itself, and sets init_pg_tables_end so they're not diff --git a/arch/x86/lguest/i386_head.S b/arch/x86/lguest/i386_head.S index 6d7a74f..ba4282e 100644 --- a/arch/x86/lguest/i386_head.S +++ b/arch/x86/lguest/i386_head.S @@ -1,5 +1,6 @@ #include <linux/linkage.h> #include <linux/lguest.h> +#include <asm/lguest_hcall.h> #include <asm/asm-offsets.h> #include <asm/thread_info.h> #include <asm/processor-flags.h> @@ -8,18 +9,48 @@ * looks for. The plan is that the Linux boot protocol will be extended with a * "platform type" field which will guide us here from the normal entry point, * but for the moment this suffices. The normal boot code uses %esi for the - * boot header, so we do too. We convert it to a virtual address by adding - * PAGE_OFFSET, and hand it to lguest_init() as its argument (ie. %eax). + * boot header, so we do too. + * + * WARNING: be very careful here! We're running at addresses equal to physical + * addesses (around 0), not above PAGE_OFFSET as most code expectes + * (eg. 0xC0000000). Jumps are relative, so they're OK, but we can't touch any + * data. * * The .section line puts this code in .init.text so it will be discarded after * boot. */ .section .init.text, "ax", @progbits .ascii "GenuineLguest" - /* Set up initial stack. */ - movl $(init_thread_union+THREAD_SIZE),%esp + /* Make initial hypercall now, so we can set up the pagetables. */ + movl $LHCALL_LGUEST_INIT, %eax + movl $lguest_data - __PAGE_OFFSET, %edx + int $LGUEST_TRAP_ENTRY + + /* Set up boot information pointer to hand to lguest_init(): it wants + * a virtual address. */ movl %esi, %eax addl $__PAGE_OFFSET, %eax - jmp lguest_init + + /* The Host put the toplevel pagetable in lguest_data.pgdir. The movsl + * instruction uses %esi, so we needed to save it above. */ + movl lguest_data - __PAGE_OFFSET + LGUEST_DATA_pgdir, %esi + + /* Copy first 32 entries of page directory to __PAGE_OFFSET entries. + * This means the first 128M of kernel memory will be mapped at + * PAGE_OFFSET where the kernel expects to run. This will get it far + * enough through boot to switch to its own pagetables. */ + movl $32, %ecx + movl %esi, %edi + addl $((__PAGE_OFFSET >> 22) * 4), %edi + rep + movsl + + /* Set up the initial stack so we can run C code. */ + movl $(init_thread_union+THREAD_SIZE),%esp + + + /* Jumps are relative, and we're running __PAGE_OFFSET too low at the + * moment. */ + jmp lguest_init+__PAGE_OFFSET /*G:055 We create a macro which puts the assembler code between lgstart_ and * lgend_ markers. These templates are put in the .text section: they can't be |