Merge from Etherboot 5.4

diff --cc src/arch/i386/core/elf.c
index 40a18a1,40a18a1..fbb4032
--- 1/src/arch/i386/core/elf.c
--- 2/src/arch/i386/core/elf.c
+++ b/src/arch/i386/core/elf.c
@@@ -74,7 -74,7 +74,7 @@@ struct Elf_Bhdr *prepare_boot_params(vo
        notes.nf1.n_descsz = sizeof(notes.nf1_bootp_data);
        notes.nf1.n_type   = EB_BOOTP_DATA;
        CP(notes.nf1_name,   EB_PARAM_NOTE);
--      notes.nf1_bootp_data = virt_to_phys(BOOTP_DATA_ADDR);
++      notes.nf1_bootp_data = virt_to_phys(&bootp_data);
  
        notes.nf2.n_namesz = sizeof(EB_PARAM_NOTE);
        notes.nf2.n_descsz = sizeof(notes.nf2_header);

diff --cc src/arch/i386/core/multiboot_loader.c
index e9785f1,e9785f1..5622524
--- 1/src/arch/i386/core/multiboot_loader.c
--- 2/src/arch/i386/core/multiboot_loader.c
+++ b/src/arch/i386/core/multiboot_loader.c
@@@ -56,28 -56,28 +56,82 @@@ struct multiboot_header 
  };
  
  static struct multiboot_header *mbheader;
++static unsigned int mbimgoffset, mboffset;
++static unsigned char mbbuffer[12];
  
  static struct multiboot_info mbinfo;
  
--static void multiboot_probe(unsigned char *data, int len)
++static void multiboot_init(void)
++{
++      mbheader = NULL;
++      mbimgoffset = 0;
++      mboffset = 0;
++}
++
++/* Remember this probing function is actually different from the usual probing
++ * functions, since the Multiboot header is somewhere in the first 8KB of the
++ * image and it is byte aligned, but there is not much more known about how to
++ * find it.  In the Etherboot context the most complicated issue is that the
++ * image has to be processed block-by-block, with unknown block size and no
++ * guarantees about block alignment with respect to the image.  */
++static void multiboot_peek(unsigned char *data, int len)
  {
--    int offset;
      struct multiboot_header *h;
  
--    /* Multiboot spec requires the header to be in first 8KB of the image */
--    if (len > 8192)
--          len = 8192;
++      /* If we have already searched the first 8KB of the image or if we have
++       * already found a valid Multiboot header, skip this code.  */
++    if ((mboffset == 12) || (mbimgoffset >= 8192))
++              return;
++
++      if (mbimgoffset + len >= 8192)
++          len = 8192 - mbimgoffset;
  
--    for (offset = 0; offset < len; offset += 4) {
--          h = (struct multiboot_header *) (data + offset);
--          if (h->magic == MULTIBOOT_HEADER_MAGIC
--                          && h->magic + h->flags + h->checksum == 0) {
--                  printf("/Multiboot");
--                  mbheader = h;
--                  return;
--          }
--    }
--    mbheader = 0;
++      /* This piece of code is pretty stupid, since it always copies data, even
++       * if it is word aligned.  This shouldn't matter too much on platforms that
++       * use the Multiboot spec, since the processors are usually reasonably fast
++       * and this code is only executed for the first 8KB of the image.  Feel
++       * free to improve it, but be prepared to write quite a lot of code that
++       * deals with non-aligned data with respect to the image to load.  */
++      while (len > 0) {
++              mbimgoffset++;
++              memcpy(mbbuffer + mboffset, data, 1);
++              mboffset++;
++              data++;
++              len--;
++              if (mboffset == 4) {
++                      /* Accumulated a word into the buffer.  */
++                      h = (struct multiboot_header *)mbbuffer;
++                      if (h->magic != MULTIBOOT_HEADER_MAGIC) {
++                              /* Wrong magic, this cannot be the start of the header.  */
++                              mboffset = 0;
++                      }
++              } else if (mboffset == 12) {
++                      /* Accumulated the minimum header data into the buffer.  */
++                      h = (struct multiboot_header *)mbbuffer;
++                      if (h->magic + h->flags + h->checksum != 0) {
++                              /* Checksum error, not a valid header.  Check for a possible
++                               * header starting in the current flag/checksum field.  */
++                              if (h->flags == MULTIBOOT_HEADER_MAGIC) {
++                                      mboffset -= 4;
++                                      memmove(mbbuffer, mbbuffer + 4, mboffset);
++                              } else if (h->checksum == MULTIBOOT_HEADER_MAGIC) {
++                                      mboffset -= 8;
++                                      memmove(mbbuffer, mbbuffer + 8, mboffset);
++                              } else {
++                                      mboffset = 0;
++                              }
++                      } else {
++                          printf("Multiboot... ");
++                          mbheader = h;
++                              if ((h->flags & 0xfffc) != 0) {
++                                      printf("\nERROR: Unsupported Multiboot requirements flags\n");
++                                      longjmp(restart_etherboot, -2);
++                              }
++                              break;
++                      }
++              }
++      }
++      mbimgoffset += len;
  }
  
  static inline void multiboot_boot(unsigned long entry)
@@@ -94,7 -94,7 +148,7 @@@
         * strings of the maximum size are possible.  Note this buffer
         * can overrun if a stupid file name is chosen.  Oh well.  */
        c = cmdline;
--      for (i = 0; KERNEL_BUF[i] != 0; i++) {
++      for (i = 0; KERNEL_BUF[i] != '\0'; i++) {
                switch (KERNEL_BUF[i]) {
                case ' ':
                case '\\':
@@@ -106,6 -106,6 +160,11 @@@
                }
                *c++ = KERNEL_BUF[i];
        }
++      if (addparam != NULL) {
++              *c++ = ' ';
++              memcpy(c, addparam, addparamlen);
++              c += addparamlen;
++      }
        (void)sprintf(c, " -retaddr %#lX", virt_to_phys(xend32));
  
        mbinfo.flags = MULTIBOOT_MMAP_VALID | MULTIBOOT_MEM_VALID |MULTIBOOT_CMDLINE_VALID;
@@@ -139,5 -139,5 +198,11 @@@
        os_regs.eax = 0x2BADB002;
        os_regs.ebx = virt_to_phys(&mbinfo);
        xstart32(entry);
--      longjmp(restart_etherboot, -2);
++      /* A Multiboot kernel by default never returns - there is nothing in the
++       * specification about what happens to the boot loader after the kernel has
++       * been started.  Thus if the kernel returns it is definitely aware of the
++       * semantics involved (i.e. the "-retaddr" parameter).  Do not treat this
++       * as an error, but restart with a fresh DHCP request in order to activate
++       * the menu again in case one is used.  */
++      longjmp(restart_etherboot, 2);
  }