cbfstool: autocreate trampoline

Add the code necessary to create the linux trampoline blob.
Don't enforce this for the in-coreboot build or use objcopy
to produce linux_trampoline.o as it is a bit trickier to get
all the details right than I had hoped:
 - you have to know the elf architecture of the host machine
 - you might have to have more tools (xxd, perl, etc) installed

Change-Id: I9b7877c58d90f9fb21d16e0061a31e19fffa2470
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: https://review.coreboot.org/12505
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

3 files changed, 159 insertions, 160 deletions

diff --git a/util/cbfstool/Makefile b/util/cbfstool/Makefile
index 085a19a481..b595297c8d 100644
--- a/util/cbfstool/Makefile
+++ b/util/cbfstool/Makefile
@@ -4,6 +4,7 @@ objutil ?= $(top)/util
 CONFIG_FMD_GENPARSER := y
 
 HOSTCC ?= $(CC)
+OBJCOPY ?= objcopy
 
 .PHONY: all
 all: $(objutil)/cbfstool/cbfstool \
@@ -17,6 +18,18 @@ clean:
 	$(RM) $(objutil)/cbfstool/fmaptool $(fmapobj)
 	$(RM) $(objutil)/cbfstool/rmodtool $(rmodobj)
 
+linux_trampoline.c: linux_trampoline.S
+	rm -f linux_trampoline.c
+	$(CC) -m32 -o linux_trampoline linux_trampoline.S -ffreestanding -nostdlib -nostdinc -Wl,--defsym=_start=0
+	$(OBJCOPY) -Obinary -j .data linux_trampoline trampoline
+	echo "/* This file is automatically generated. Do not manually change */" > trampoline.c
+	xxd -c 16 -i trampoline >> trampoline.c
+	perl -pi -e 's,unsigned int.*$$,,g;s,unsigned char,const unsigned char,g' trampoline.c
+	echo "const void * const trampoline_start = &trampoline;" >> trampoline.c
+	echo "const unsigned long trampoline_size = sizeof trampoline;" >> trampoline.c
+	mv trampoline.c linux_trampoline.c
+	rm linux_trampoline trampoline
+
 .SILENT:
 
 include Makefile.inc
diff --git a/util/cbfstool/linux_trampoline.S b/util/cbfstool/linux_trampoline.S
new file mode 100644
index 0000000000..65819e948b
--- /dev/null
+++ b/util/cbfstool/linux_trampoline.S
@@ -0,0 +1,133 @@
+/*
+ * linux_trampoline
+ *
+ * Copyright (C) 2013 Patrick Georgi <patrick@georgi-clan.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+/* NOTE: THIS CODE MUST REMAIN POSITION INDEPENDENT
+ *       IT SHOULDN'T USE THE STACK
+ *       AND IN GENERAL EXPECT NOTHING BUT RAM TO WORK
+ */
+.code32
+.data
+
+#include "linux_trampoline.h"
+#define HEADER_SIG 0x4f49424c // LBIO little endian
+#define CB_TAG_FORWARD 0x11
+#define CB_TAG_MEMORY 0x1
+#define CB_TAG_FRAMEBUFFER 0x12
+
+#define E820_NR_OFFSET 0x1e8
+#define LINUX_ENTRY_OFFSET 0x214
+#define E820_OFFSET 0x2d0
+
+.trampoline_start:
+
+cld
+xor %edx, %edx
+mov $0, %ecx
+
+.headerSearch:
+mov $0x10000, %ebx
+add %ecx, %ebx
+mov (%ecx), %eax
+cmp $HEADER_SIG, %eax
+je .headerSearchDone // found the header
+add $16, %ecx
+cmp %ecx, %ebx
+jne .headerSearch
+
+.headerSearchDone:
+cmp %ecx, %ebx // reached the end == not found anything?
+je 2f // give up
+
+// we assume the checksum is okay, no test
+mov 4(%ecx), %ebx
+add %ecx, %ebx // ebx = cb_header + header_bytes
+mov 20(%ecx), %ecx // ecx = table_entries
+
+.tableScan:
+cmp $CB_TAG_FORWARD, (%ebx)
+jne .testMemory
+
+/* forward tag: assume 32bit pointer */
+mov 8(%ebx), %ecx
+jmp .headerSearch
+
+.testMemory:
+cmp $CB_TAG_MEMORY, (%ebx)
+jne .testFramebuffer
+
+/* memory tag: copy e820 map and entry count. also determine alt_mem_k */
+mov 4(%ebx), %eax
+sub $8, %eax
+shr $2, %eax /* eax = number of dwords of e820 data */
+cmp $(32 * 5), %eax /* linux wants at most 32 entries of 5 dwords */
+jng 1f
+mov $(32 * 5), %eax /* only copy 32 entries */
+1:
+mov %eax, %esi
+mov $5, %edi
+div %edi
+mov %eax, (LINUX_PARAM_LOC + E820_NR_OFFSET)
+mov %esi, %eax
+xchg %eax, %ecx
+lea 8(%ebx), %esi /* e820 data source */
+mov $(LINUX_PARAM_LOC + E820_OFFSET), %edi
+rep movsl
+xchg %eax, %ecx
+jmp .endScan
+
+.testFramebuffer:
+cmp $CB_TAG_FRAMEBUFFER, (%ebx)
+jne .endScan
+/* TODO: handle framebuffer tag */
+
+.endScan:
+add 4(%ebx), %ebx
+dec %ecx
+jnz .tableScan
+
+/* Setup basic code and data segment selectors for Linux
+**
+** Flat code segment descriptor:
+**   selector: 0x10
+**   base    : 0x00000000
+**   limit   : 0xFFFFFFFF
+**   type    : code, execute, read
+**
+** Flat data segment descriptor:
+**   selector: 0x18
+**   base    : 0x00000000
+**   limit   : 0xFFFFFFFF
+**   type    : data, read/write
+**
+** Use TRAMPOLINE_ENTRY_LOC as a scratchpad.
+*/
+mov  $TRAMPOLINE_ENTRY_LOC, %eax
+sgdt (%eax)
+mov  2(%eax), %ebx
+movl  $0x0000ffff, 16(%ebx)
+movl  $0x00cf9b00, 20(%ebx)
+movl  $0x0000ffff, 24(%ebx)
+movl  $0x00cf9300, 28(%ebx)
+
+/* finally: jump to kernel */
+mov $LINUX_PARAM_LOC, %esi
+jmp *(LINUX_PARAM_LOC + LINUX_ENTRY_OFFSET)
+
+
+2:
+hlt
+jmp 2b
+
+.trampoline_end:
diff --git a/util/cbfstool/linux_trampoline.c b/util/cbfstool/linux_trampoline.c
index aacf4111c1..c5956d651d 100644
--- a/util/cbfstool/linux_trampoline.c
+++ b/util/cbfstool/linux_trampoline.c
@@ -1,164 +1,17 @@
-/*
- * linux_trampoline
- *
- * Copyright (C) 2013 Patrick Georgi <patrick@georgi-clan.de>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
-#if 0
-/* NOTE: THIS CODE MUST REMAIN POSITION INDEPENDENT
- *       IT SHOULDN'T USE THE STACK
- *       AND IN GENERAL EXPECT NOTHING BUT RAM TO WORK
- */
-.code32
-.data
-
-#include "linux_trampoline.h"
-#define HEADER_SIG 0x4f49424c // LBIO little endian
-#define CB_TAG_FORWARD 0x11
-#define CB_TAG_MEMORY 0x1
-#define CB_TAG_FRAMEBUFFER 0x12
-
-#define E820_NR_OFFSET 0x1e8
-#define LINUX_ENTRY_OFFSET 0x214
-#define E820_OFFSET 0x2d0
-
-.trampoline_start:
-
-cld
-xor %edx, %edx
-mov $0, %ecx
-
-.headerSearch:
-mov $0x10000, %ebx
-add %ecx, %ebx
-mov (%ecx), %eax
-cmp $HEADER_SIG, %eax
-je .headerSearchDone // found the header
-add $16, %ecx
-cmp %ecx, %ebx
-jne .headerSearch
-
-.headerSearchDone:
-cmp %ecx, %ebx // reached the end == not found anything?
-je 2f // give up
-
-// we assume the checksum is okay, no test
-mov 4(%ecx), %ebx
-add %ecx, %ebx // ebx = cb_header + header_bytes
-mov 20(%ecx), %ecx // ecx = table_entries
-
-.tableScan:
-cmp $CB_TAG_FORWARD, (%ebx)
-jne .testMemory
-
-/* forward tag: assume 32bit pointer */
-mov 8(%ebx), %ecx
-jmp .headerSearch
-
-.testMemory:
-cmp $CB_TAG_MEMORY, (%ebx)
-jne .testFramebuffer
-
-/* memory tag: copy e820 map and entry count. also determine alt_mem_k */
-mov 4(%ebx), %eax
-sub $8, %eax
-shr $2, %eax /* eax = number of dwords of e820 data */
-cmp $(32 * 5), %eax /* linux wants at most 32 entries of 5 dwords */
-jng 1f
-mov $(32 * 5), %eax /* only copy 32 entries */
-1:
-mov %eax, %esi
-mov $5, %edi
-div %edi
-mov %eax, (LINUX_PARAM_LOC + E820_NR_OFFSET)
-mov %esi, %eax
-xchg %eax, %ecx
-lea 8(%ebx), %esi /* e820 data source */
-mov $(LINUX_PARAM_LOC + E820_OFFSET), %edi
-rep movsl
-xchg %eax, %ecx
-jmp .endScan
-
-.testFramebuffer:
-cmp $CB_TAG_FRAMEBUFFER, (%ebx)
-jne .endScan
-/* TODO: handle framebuffer tag */
-
-.endScan:
-add 4(%ebx), %ebx
-dec %ecx
-jnz .tableScan
-
-/* Setup basic code and data segment selectors for Linux
-**
-** Flat code segment descriptor:
-**   selector: 0x10
-**   base    : 0x00000000
-**   limit   : 0xFFFFFFFF
-**   type    : code, execute, read
-**
-** Flat data segment descriptor:
-**   selector: 0x18
-**   base    : 0x00000000
-**   limit   : 0xFFFFFFFF
-**   type    : data, read/write
-**
-** Use TRAMPOLINE_ENTRY_LOC as a scratchpad.
-*/
-mov  $TRAMPOLINE_ENTRY_LOC, %eax
-sgdt (%eax)
-mov  2(%eax), %ebx
-movl  $0x0000ffff, 16(%ebx)
-movl  $0x00cf9b00, 20(%ebx)
-movl  $0x0000ffff, 24(%ebx)
-movl  $0x00cf9300, 28(%ebx)
-
-/* finally: jump to kernel */
-mov $LINUX_PARAM_LOC, %esi
-jmp *(LINUX_PARAM_LOC + LINUX_ENTRY_OFFSET)
-
-
-2:
-hlt
-jmp 2b
-
-.trampoline_end:
-
-.global trampoline_start, trampoline_size
-trampoline_start:
-.long .trampoline_start
-trampoline_size:
-.long .trampoline_end - .trampoline_start
-#endif
-
-/* The code above is hand-crafted to fit various contraints.
- * To simplify porting, the below matches the above.
- * When changing any code in here, compile the above as a .S
- * file, objcopy it to binary and paste the result below (minus
- * the last 8 bytes which are trampoline_start and trampoline_size).
- */
+/* This file is automatically generated. Do not manually change */
 const unsigned char trampoline[] = {
-0xfc, 0x31, 0xd2, 0xb9, 0x00, 0x00, 0x00, 0x00, 0xbb, 0x00, 0x00, 0x01, 0x00, 0x01, 0xcb, 0x8b,
-0x01, 0x3d, 0x4c, 0x42, 0x49, 0x4f, 0x74, 0x07, 0x83, 0xc1, 0x10, 0x39, 0xcb, 0x75, 0xe9, 0x39,
-0xcb, 0x0f, 0x84, 0x85, 0x00, 0x00, 0x00, 0x8b, 0x59, 0x04, 0x01, 0xcb, 0x8b, 0x49, 0x14, 0x83,
-0x3b, 0x11, 0x75, 0x05, 0x8b, 0x4b, 0x08, 0xeb, 0xcf, 0x83, 0x3b, 0x01, 0x75, 0x33, 0x8b, 0x43,
-0x04, 0x83, 0xe8, 0x08, 0xc1, 0xe8, 0x02, 0x3d, 0xa0, 0x00, 0x00, 0x00, 0x7e, 0x05, 0xb8, 0xa0,
-0x00, 0x00, 0x00, 0x89, 0xc6, 0xbf, 0x05, 0x00, 0x00, 0x00, 0xf7, 0xf7, 0xa3, 0xe8, 0x01, 0x09,
-0x00, 0x89, 0xf0, 0x91, 0x8d, 0x73, 0x08, 0xbf, 0xd0, 0x02, 0x09, 0x00, 0xf3, 0xa5, 0x91, 0xeb,
-0x05, 0x83, 0x3b, 0x12, 0x75, 0x00, 0x03, 0x5b, 0x04, 0x49, 0x75, 0xb3, 0xb8, 0x00, 0x00, 0x04,
-0x00, 0x0f, 0x01, 0x00, 0x8b, 0x58, 0x02, 0xc7, 0x43, 0x10, 0xff, 0xff, 0x00, 0x00, 0xc7, 0x43,
-0x14, 0x00, 0x9b, 0xcf, 0x00, 0xc7, 0x43, 0x18, 0xff, 0xff, 0x00, 0x00, 0xc7, 0x43, 0x1c, 0x00,
-0x93, 0xcf, 0x00, 0xbe, 0x00, 0x00, 0x09, 0x00, 0xff, 0x25, 0x14, 0x02, 0x09, 0x00, 0xf4, 0xeb,
-0xfd
+  0xfc, 0x31, 0xd2, 0xb9, 0x00, 0x00, 0x00, 0x00, 0xbb, 0x00, 0x00, 0x01, 0x00, 0x01, 0xcb, 0x8b,
+  0x01, 0x3d, 0x4c, 0x42, 0x49, 0x4f, 0x74, 0x07, 0x83, 0xc1, 0x10, 0x39, 0xcb, 0x75, 0xe9, 0x39,
+  0xcb, 0x0f, 0x84, 0x87, 0x00, 0x00, 0x00, 0x8b, 0x59, 0x04, 0x01, 0xcb, 0x8b, 0x49, 0x14, 0x83,
+  0x3b, 0x11, 0x75, 0x05, 0x8b, 0x4b, 0x08, 0xeb, 0xcf, 0x83, 0x3b, 0x01, 0x75, 0x33, 0x8b, 0x43,
+  0x04, 0x83, 0xe8, 0x08, 0xc1, 0xe8, 0x02, 0x3d, 0xa0, 0x00, 0x00, 0x00, 0x7e, 0x05, 0xb8, 0xa0,
+  0x00, 0x00, 0x00, 0x89, 0xc6, 0xbf, 0x05, 0x00, 0x00, 0x00, 0xf7, 0xf7, 0xa3, 0xe8, 0x01, 0x09,
+  0x00, 0x89, 0xf0, 0x91, 0x8d, 0x73, 0x08, 0xbf, 0xd0, 0x02, 0x09, 0x00, 0xf3, 0xa5, 0x91, 0xeb,
+  0x05, 0x83, 0x3b, 0x12, 0x75, 0x00, 0x03, 0x5b, 0x04, 0x49, 0x75, 0xb3, 0xb8, 0x00, 0x00, 0x04,
+  0x00, 0x0f, 0x01, 0x00, 0x8b, 0x58, 0x02, 0xc7, 0x43, 0x10, 0xff, 0xff, 0x00, 0x00, 0xc7, 0x43,
+  0x14, 0x00, 0x9b, 0xcf, 0x00, 0xc7, 0x43, 0x18, 0xff, 0xff, 0x00, 0x00, 0xc7, 0x43, 0x1c, 0x00,
+  0x93, 0xcf, 0x00, 0xbe, 0x00, 0x00, 0x09, 0x00, 0xff, 0x25, 0x14, 0x02, 0x09, 0x00, 0xf4, 0xeb,
+  0xfd
 };
 
 const void * const trampoline_start = &trampoline;