[tip:x86/urgent] x86, efi stub: Add .reloc section back into image
From: tip-bot for Jordan Justen
Date: Thu Jun 07 2012 - 14:38:04 EST
Commit-ID: 743628e868c5992354fc80b4d1e9a6143da1c0e6
Gitweb: http://git.kernel.org/tip/743628e868c5992354fc80b4d1e9a6143da1c0e6
Author: Jordan Justen <jordan.l.justen@xxxxxxxxx>
AuthorDate: Thu, 7 Jun 2012 09:05:21 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Thu, 7 Jun 2012 09:52:33 -0700
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@xxxxxxxxxxx>
Signed-off-by: Jordan Justen <jordan.l.justen@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1339085121-12760-1-git-send-email-jordan.l.justen@xxxxxxxxx
Tested-by: Lee G Rosenbaum <lee.g.rosenbaum@xxxxxxxxx>
Tested-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>
Cc: Matt Fleming <matt.fleming@xxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
---
arch/x86/boot/header.S | 42 ++++++++---
arch/x86/boot/tools/build.c | 172 +++++++++++++++++++++++++++----------------
2 files changed, 140 insertions(+), 74 deletions(-)
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 8bbea6a..efe5acf 100644
--- 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 3f61f6e..4b8e165 100644
--- 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)
--
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