diff options
| -rw-r--r-- | util/cbfstool/Makefile | 13 | ||||
| -rw-r--r-- | util/cbfstool/linux_trampoline.S | 133 | ||||
| -rw-r--r-- | util/cbfstool/linux_trampoline.c | 173 |
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; |