3 files changed, 18 insertions, 58 deletions

diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index cbf4becd266..004c5c6aba6 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -251,23 +251,6 @@ static void *get_pages(unsigned int num)
         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. */
@@ -303,7 +286,6 @@ static void map_at(int fd, void *addr, unsigned long offset, unsigned long len)
  * 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;
 
@@ -335,19 +317,13 @@ static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr)
                 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
@@ -374,7 +350,8 @@ static unsigned long unpack_bzimage(int fd)
 
         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
@@ -1684,8 +1661,15 @@ int main(int argc, char *argv[])
         *(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. */
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 495e46a1f11..d2235db4085 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -928,18 +928,8 @@ static unsigned lguest_patch(u8 type, u16 clobber, void *ibuf,
 /*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";
@@ -1024,11 +1014,6 @@ __init void lguest_init(void *boot)
          * 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. */
diff --git a/arch/x86/lguest/i386_head.S b/arch/x86/lguest/i386_head.S
index ba4282eba5b..ebc6ac73389 100644
--- a/arch/x86/lguest/i386_head.S
+++ b/arch/x86/lguest/i386_head.S
@@ -5,11 +5,8 @@
 #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
@@ -19,19 +16,14 @@
  * 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.
@@ -47,7 +39,6 @@
         /* 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