x86, efi stub: Add .reloc section back into image

Some UEFI firmware will not load a .efi with a .reloc section
with a size of 0.

Therefore, we create a .efi image with 4 main areas and 3 sections.
1. PE/COFF file header
2. .setup section (covers all setup code following the first sector)
3. .reloc section (contains 1 dummy reloc entry, created in build.c)
4. .text section (covers the remaining kernel image)

To make room for the new .setup section data, the header
bugger_off_msg had to be shortened.

Reported-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Link: http://lkml.kernel.org/r/1339085121-12760-1-git-send-email-jordan.l.justen@intel.com
Tested-by: Lee G Rosenbaum <lee.g.rosenbaum@intel.com>
Tested-by: Henrik Rydberg <rydberg@euromail.se>
Cc: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 8bbea6aa40d9705b68e1dd9531b7c9c74d96a106..efe5acfc79c30c8ab2df32586618fa6f7c2fc88b 100644 (file)
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -94,10 +94,10 @@ bs_die:
 
        .section ".bsdata", "a"
 bugger_off_msg:
-       .ascii  "Direct booting from floppy is no longer supported.\r\n"
-       .ascii  "Please use a boot loader program instead.\r\n"
+       .ascii  "Direct floppy boot is not supported. "
+       .ascii  "Use a boot loader program instead.\r\n"
        .ascii  "\n"
-       .ascii  "Remove disk and press any key to reboot . . .\r\n"
+       .ascii  "Remove disk and press any key to reboot ...\r\n"
        .byte   0
 
 #ifdef CONFIG_EFI_STUB
@@ -111,7 +111,7 @@ coff_header:
 #else
        .word   0x8664                          # x86-64
 #endif
-       .word   2                               # nr_sections
+       .word   3                               # nr_sections
        .long   0                               # TimeDateStamp
        .long   0                               # PointerToSymbolTable
        .long   1                               # NumberOfSymbols
@@ -158,8 +158,8 @@ extra_header_fields:
 #else
        .quad   0                               # ImageBase
 #endif
-       .long   0x1000                          # SectionAlignment
-       .long   0x200                           # FileAlignment
+       .long   0x20                            # SectionAlignment
+       .long   0x20                            # FileAlignment
        .word   0                               # MajorOperatingSystemVersion
        .word   0                               # MinorOperatingSystemVersion
        .word   0                               # MajorImageVersion
@@ -200,8 +200,10 @@ extra_header_fields:
 
        # Section table
 section_table:
-       .ascii  ".text"
-       .byte   0
+       #
+       # The offset & size fields are filled in by build.c.
+       #
+       .ascii  ".setup"
        .byte   0
        .byte   0
        .long   0
@@ -217,9 +219,8 @@ section_table:
 
        #
        # The EFI application loader requires a relocation section
-       # because EFI applications must be relocatable. But since
-       # we don't need the loader to fixup any relocs for us, we
-       # just create an empty (zero-length) .reloc section header.
+       # because EFI applications must be relocatable. The .reloc
+       # offset & size fields are filled in by build.c.
        #
        .ascii  ".reloc"
        .byte   0
@@ -233,6 +234,25 @@ section_table:
        .word   0                               # NumberOfRelocations
        .word   0                               # NumberOfLineNumbers
        .long   0x42100040                      # Characteristics (section flags)
+
+       #
+       # The offset & size fields are filled in by build.c.
+       #
+       .ascii  ".text"
+       .byte   0
+       .byte   0
+       .byte   0
+       .long   0
+       .long   0x0                             # startup_{32,64}
+       .long   0                               # Size of initialized data
+                                               # on disk
+       .long   0x0                             # startup_{32,64}
+       .long   0                               # PointerToRelocations
+       .long   0                               # PointerToLineNumbers
+       .word   0                               # NumberOfRelocations
+       .word   0                               # NumberOfLineNumbers
+       .long   0x60500020                      # Characteristics (section flags)
+
 #endif /* CONFIG_EFI_STUB */
 
        # Kernel attributes; used by setup.  This is part 1 of the

diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
index 3f61f6e2b46f3ece150f20b409c1e652f3dd301b..4b8e165ee5723643dcd89619a341c7559eafe2bd 100644 (file)
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -50,6 +50,8 @@ typedef unsigned int   u32;
 u8 buf[SETUP_SECT_MAX*512];
 int is_big_kernel;
 
+#define PECOFF_RELOC_RESERVE 0x20
+
 /*----------------------------------------------------------------------*/
 
 static const u32 crctab32[] = {
@@ -133,11 +135,103 @@ static void usage(void)
        die("Usage: build setup system [> image]");
 }
 
-int main(int argc, char ** argv)
-{
 #ifdef CONFIG_EFI_STUB
-       unsigned int file_sz, pe_header;
+
+static void update_pecoff_section_header(char *section_name, u32 offset, u32 size)
+{
+       unsigned int pe_header;
+       unsigned short num_sections;
+       u8 *section;
+
+       pe_header = get_unaligned_le32(&buf[0x3c]);
+       num_sections = get_unaligned_le16(&buf[pe_header + 6]);
+
+#ifdef CONFIG_X86_32
+       section = &buf[pe_header + 0xa8];
+#else
+       section = &buf[pe_header + 0xb8];
 #endif
+
+       while (num_sections > 0) {
+               if (strncmp((char*)section, section_name, 8) == 0) {
+                       /* section header size field */
+                       put_unaligned_le32(size, section + 0x8);
+
+                       /* section header vma field */
+                       put_unaligned_le32(offset, section + 0xc);
+
+                       /* section header 'size of initialised data' field */
+                       put_unaligned_le32(size, section + 0x10);
+
+                       /* section header 'file offset' field */
+                       put_unaligned_le32(offset, section + 0x14);
+
+                       break;
+               }
+               section += 0x28;
+               num_sections--;
+       }
+}
+
+static void update_pecoff_setup_and_reloc(unsigned int size)
+{
+       u32 setup_offset = 0x200;
+       u32 reloc_offset = size - PECOFF_RELOC_RESERVE;
+       u32 setup_size = reloc_offset - setup_offset;
+
+       update_pecoff_section_header(".setup", setup_offset, setup_size);
+       update_pecoff_section_header(".reloc", reloc_offset, PECOFF_RELOC_RESERVE);
+
+       /*
+        * Modify .reloc section contents with a single entry. The
+        * relocation is applied to offset 10 of the relocation section.
+        */
+       put_unaligned_le32(reloc_offset + 10, &buf[reloc_offset]);
+       put_unaligned_le32(10, &buf[reloc_offset + 4]);
+}
+
+static void update_pecoff_text(unsigned int text_start, unsigned int file_sz)
+{
+       unsigned int pe_header;
+       unsigned int text_sz = file_sz - text_start;
+
+       pe_header = get_unaligned_le32(&buf[0x3c]);
+
+       /* Size of image */
+       put_unaligned_le32(file_sz, &buf[pe_header + 0x50]);
+
+       /*
+        * Size of code: Subtract the size of the first sector (512 bytes)
+        * which includes the header.
+        */
+       put_unaligned_le32(file_sz - 512, &buf[pe_header + 0x1c]);
+
+#ifdef CONFIG_X86_32
+       /*
+        * Address of entry point.
+        *
+        * The EFI stub entry point is +16 bytes from the start of
+        * the .text section.
+        */
+       put_unaligned_le32(text_start + 16, &buf[pe_header + 0x28]);
+#else
+       /*
+        * Address of entry point. startup_32 is at the beginning and
+        * the 64-bit entry point (startup_64) is always 512 bytes
+        * after. The EFI stub entry point is 16 bytes after that, as
+        * the first instruction allows legacy loaders to jump over
+        * the EFI stub initialisation
+        */
+       put_unaligned_le32(text_start + 528, &buf[pe_header + 0x28]);
+#endif /* CONFIG_X86_32 */
+
+       update_pecoff_section_header(".text", text_start, text_sz);
+}
+
+#endif /* CONFIG_EFI_STUB */
+
+int main(int argc, char ** argv)
+{
        unsigned int i, sz, setup_sectors;
        int c;
        u32 sys_size;
@@ -163,6 +257,12 @@ int main(int argc, char ** argv)
                die("Boot block hasn't got boot flag (0xAA55)");
        fclose(file);
 
+#ifdef CONFIG_EFI_STUB
+       /* Reserve 0x20 bytes for .reloc section */
+       memset(buf+c, 0, PECOFF_RELOC_RESERVE);
+       c += PECOFF_RELOC_RESERVE;
+#endif
+
        /* Pad unused space with zeros */
        setup_sectors = (c + 511) / 512;
        if (setup_sectors < SETUP_SECT_MIN)
@@ -170,6 +270,10 @@ int main(int argc, char ** argv)
        i = setup_sectors*512;
        memset(buf+c, 0, i-c);
 
+#ifdef CONFIG_EFI_STUB
+       update_pecoff_setup_and_reloc(i);
+#endif
+
        /* Set the default root device */
        put_unaligned_le16(DEFAULT_ROOT_DEV, &buf[508]);
 
@@ -194,66 +298,8 @@ int main(int argc, char ** argv)
        put_unaligned_le32(sys_size, &buf[0x1f4]);
 
 #ifdef CONFIG_EFI_STUB
-       file_sz = sz + i + ((sys_size * 16) - sz);
-
-       pe_header = get_unaligned_le32(&buf[0x3c]);
-
-       /* Size of image */
-       put_unaligned_le32(file_sz, &buf[pe_header + 0x50]);
-
-       /*
-        * Subtract the size of the first section (512 bytes) which
-        * includes the header and .reloc section. The remaining size
-        * is that of the .text section.
-        */
-       file_sz -= 512;
-
-       /* Size of code */
-       put_unaligned_le32(file_sz, &buf[pe_header + 0x1c]);
-
-#ifdef CONFIG_X86_32
-       /*
-        * Address of entry point.
-        *
-        * The EFI stub entry point is +16 bytes from the start of
-        * the .text section.
-        */
-       put_unaligned_le32(i + 16, &buf[pe_header + 0x28]);
-
-       /* .text size */
-       put_unaligned_le32(file_sz, &buf[pe_header + 0xb0]);
-
-       /* .text vma */
-       put_unaligned_le32(0x200, &buf[pe_header + 0xb4]);
-
-       /* .text size of initialised data */
-       put_unaligned_le32(file_sz, &buf[pe_header + 0xb8]);
-
-       /* .text file offset */
-       put_unaligned_le32(0x200, &buf[pe_header + 0xbc]);
-#else
-       /*
-        * Address of entry point. startup_32 is at the beginning and
-        * the 64-bit entry point (startup_64) is always 512 bytes
-        * after. The EFI stub entry point is 16 bytes after that, as
-        * the first instruction allows legacy loaders to jump over
-        * the EFI stub initialisation
-        */
-       put_unaligned_le32(i + 528, &buf[pe_header + 0x28]);
-
-       /* .text size */
-       put_unaligned_le32(file_sz, &buf[pe_header + 0xc0]);
-
-       /* .text vma */
-       put_unaligned_le32(0x200, &buf[pe_header + 0xc4]);
-
-       /* .text size of initialised data */
-       put_unaligned_le32(file_sz, &buf[pe_header + 0xc8]);
-
-       /* .text file offset */
-       put_unaligned_le32(0x200, &buf[pe_header + 0xcc]);
-#endif /* CONFIG_X86_32 */
-#endif /* CONFIG_EFI_STUB */
+       update_pecoff_text(setup_sectors * 512, sz + i + ((sys_size * 16) - sz));
+#endif
 
        crc = partial_crc32(buf, i, crc);
        if (fwrite(buf, 1, i, stdout) != i)