return addr;
}
-/* To find out where to start we look for the magic Guest string, which marks
- * the code we see in lguest_asm.S. This is a hack which we are currently
- * plotting to replace with the normal Linux entry point. */
-static unsigned long entry_point(const void *start, const void *end)
-{
- const void *p;
-
- /* The scan gives us the physical starting address. We boot with
- * pagetables set up with virtual and physical the same, so that's
- * OK. */
- for (p = start; p < end; p++)
- if (memcmp(p, "GenuineLguest", strlen("GenuineLguest")) == 0)
- return to_guest_phys(p + strlen("GenuineLguest"));
-
- errx(1, "Is this image a genuine lguest?");
-}
-
/* This routine is used to load the kernel or initrd. It tries mmap, but if
* that fails (Plan 9's kernel file isn't nicely aligned on page boundaries),
* it falls back to reading the memory in. */
* We return the starting address. */
static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr)
{
- void *start = (void *)-1, *end = NULL;
Elf32_Phdr phdr[ehdr->e_phnum];
unsigned int i;
verbose("Section %i: size %i addr %p\n",
i, phdr[i].p_memsz, (void *)phdr[i].p_paddr);
- /* We track the first and last address we mapped, so we can
- * tell entry_point() where to scan. */
- if (from_guest_phys(phdr[i].p_paddr) < start)
- start = from_guest_phys(phdr[i].p_paddr);
- if (from_guest_phys(phdr[i].p_paddr) + phdr[i].p_filesz > end)
- end=from_guest_phys(phdr[i].p_paddr)+phdr[i].p_filesz;
-
/* We map this section of the file at its physical address. */
map_at(elf_fd, from_guest_phys(phdr[i].p_paddr),
phdr[i].p_offset, phdr[i].p_filesz);
}
- return entry_point(start, end);
+ /* The entry point is given in the ELF header. */
+ return ehdr->e_entry;
}
/*L:160 Unfortunately the entire ELF image isn't compressed: the segments
verbose("Unpacked size %i addr %p\n", len, img);
- return entry_point(img, img + len);
+ /* The entry point for a bzImage is always the first byte */
+ return (unsigned long)img;
}
/*L:150 A bzImage, unlike an ELF file, is not meant to be loaded. You're
*(u32 *)(boot + 0x228) = 4096;
concat(boot + 4096, argv+optind+2);
- /* The guest type value of "1" tells the Guest it's under lguest. */
- *(int *)(boot + 0x23c) = 1;
+ /* Boot protocol version: 2.07 supports the fields for lguest. */
+ *(u16 *)(boot + 0x206) = 0x207;
+
+ /* The hardware_subarch value of "1" tells the Guest it's an lguest. */
+ *(u32 *)(boot + 0x23c) = 1;
+
+ /* Set bit 6 of the loadflags (aka. KEEP_SEGMENTS) so the entry path
+ * does not try to reload segment registers. */
+ *(u8 *)(boot + 0x211) |= (1 << 6);
/* We tell the kernel to initialize the Guest: this returns the open
* /dev/lguest file descriptor. */
/*G:030 Once we get to lguest_init(), we know we're a Guest. The pv_ops
* structures in the kernel provide points for (almost) every routine we have
* to override to avoid privileged instructions. */
-__init void lguest_init(void *boot)
+__init void lguest_init(void)
{
- /* Copy boot parameters first: the Launcher put the physical location
- * in %esi, and head.S converted that to a virtual address and handed
- * it to us. We use "__memcpy" because "memcpy" sometimes tries to do
- * tricky things to go faster, and we're not ready for that. */
- __memcpy(&boot_params, boot, PARAM_SIZE);
- /* The boot parameters also tell us where the command-line is: save
- * that, too. */
- __memcpy(boot_command_line, __va(boot_params.hdr.cmd_line_ptr),
- COMMAND_LINE_SIZE);
-
/* We're under lguest, paravirt is enabled, and we're running at
* privilege level 1, not 0 as normal. */
pv_info.name = "lguest";
* the normal data segment to get through booting. */
asm volatile ("mov %0, %%fs" : : "r" (__KERNEL_DS) : "memory");
- /* Clear the part of the kernel data which is expected to be zero.
- * Normally it will be anyway, but if we're loading from a bzImage with
- * CONFIG_RELOCATALE=y, the relocations will be sitting here. */
- memset(__bss_start, 0, __bss_stop - __bss_start);
-
/* The Host uses the top of the Guest's virtual address space for the
* Host<->Guest Switcher, and it tells us how much it needs in
* lguest_data.reserve_mem, set up on the LGUEST_INIT hypercall. */
#include <asm/thread_info.h>
#include <asm/processor-flags.h>
-/*G:020 This is where we begin: we have a magic signature which the launcher
- * 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.
+/*G:020 This is where we begin: head.S notes that the boot header's platform
+ * type field is "1" (lguest), so calls us here. The boot header is in %esi.
*
* WARNING: be very careful here! We're running at addresses equal to physical
* addesses (around 0), not above PAGE_OFFSET as most code expectes
* The .section line puts this code in .init.text so it will be discarded after
* boot. */
.section .init.text, "ax", @progbits
-.ascii "GenuineLguest"
+ENTRY(lguest_entry)
/* 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
-
/* The Host put the toplevel pagetable in lguest_data.pgdir. The movsl
- * instruction uses %esi, so we needed to save it above. */
+ * instruction uses %esi implicitly. */
movl lguest_data - __PAGE_OFFSET + LGUEST_DATA_pgdir, %esi
/* Copy first 32 entries of page directory to __PAGE_OFFSET entries.
/* 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
projects / linux-2.6 / commitdiff