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review.coreboot.org / coreboot / 40cb3fe94dacfba0b146aae2be9c03c0a0ddb691 / . / src / arch / x86 / assembly_entry.S
blob: 869acc84e2fcb1e3b63770c920d06c27e1b723b8 [file] [log] [blame]
Patrick Georgi11f00792020-03-04 15:10:45 +0100[diff] [blame]1/* SPDX-License-Identifier: GPL-2.0-only */
Aaron Durbine581b062015-09-03 11:29:28 -0500[diff] [blame]2
Aaron Durbinaef58652016-04-29 12:34:01 -0500[diff] [blame]3/*
Arthur Heymansc05b1a62019-11-22 21:01:30 +0100[diff] [blame]4 * This path is for stages that are post bootblock. The gdt is reloaded
5 * to accommodate platforms that are executing out of CAR. In order to
6 * continue with C code execution one needs to set stack pointer and
7 * clear .bss variables that are stage specific.
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]8 */
Felix Heldca928c62020-04-04 01:47:37 +0200[diff] [blame]9
10#if CONFIG(RESET_VECTOR_IN_RAM)
11 #define _STACK_TOP _eearlyram_stack
12#else
13 #define _STACK_TOP _ecar_stack
14#endif
15
Patrick Rudolphadcf7822020-08-27 20:50:18 +0200[diff] [blame]16#if ENV_X86_64
Patrick Rudolph29ed4f52020-07-05 08:46:55 +0200[diff] [blame]17.code64
18#else
19.code32
20#endif
21
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]22.section ".text._start", "ax", @progbits
23.global _start
24_start:
25
Hannah Williamsd3c0c0c2018-04-27 09:09:04 -0700[diff] [blame]26 /* Migrate GDT to this text segment */
Patrick Rudolphadcf7822020-08-27 20:50:18 +0200[diff] [blame]27#if ENV_X86_64
Patrick Rudolph29ed4f52020-07-05 08:46:55 +0200[diff] [blame]28 call gdt_init64
29#else
Hannah Williamsd3c0c0c2018-04-27 09:09:04 -0700[diff] [blame]30 call gdt_init
Patrick Rudolph29ed4f52020-07-05 08:46:55 +0200[diff] [blame]31#endif
Hannah Williamsd3c0c0c2018-04-27 09:09:04 -0700[diff] [blame]32
Felix Heldca928c62020-04-04 01:47:37 +0200[diff] [blame]33 /* reset stack pointer to CAR/EARLYRAM stack */
34 mov $_STACK_TOP, %esp
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]35
Kyösti Mälkki910490f2019-08-22 12:56:22 +0300[diff] [blame]36 /* clear .bss section as it is not shared */
Arthur Heymans9efb0c02020-11-30 14:03:51 +0100[diff] [blame]37#if ENV_SEPARATE_BSS
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]38 cld
39 xor %eax, %eax
Kyösti Mälkki910490f2019-08-22 12:56:22 +0300[diff] [blame]40 movl $(_ebss), %ecx
41 movl $(_bss), %edi
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]42 sub %edi, %ecx
Kyösti Mälkki5cbaba42019-08-28 20:52:37 +0300[diff] [blame]43 shrl $2, %ecx
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]44 rep stosl
Arthur Heymans9efb0c02020-11-30 14:03:51 +0100[diff] [blame]45#endif
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]46
Julius Werner21a40532020-04-21 16:03:53 -0700[diff] [blame]47#if ((ENV_SEPARATE_VERSTAGE && CONFIG(VERSTAGE_DEBUG_SPINLOOP)) \
Julius Wernercd49cce2019-03-05 16:53:33 -0800[diff] [blame]48 || (ENV_ROMSTAGE && CONFIG(ROMSTAGE_DEBUG_SPINLOOP)))
Lee Leahyd131ea32016-06-08 13:40:08 -0700[diff] [blame]49
50 /* Wait for a JTAG debugger to break in and set EBX non-zero */
51 xor %ebx, %ebx
52
53debug_spinloop:
54 cmp $0, %ebx
55 jz debug_spinloop
56#endif
57
Marshall Dawsonce9c8832017-07-07 16:09:56 -0600[diff] [blame]58 andl $0xfffffff0, %esp
Julius Wernercd49cce2019-03-05 16:53:33 -0800[diff] [blame]59#if CONFIG(IDT_IN_EVERY_STAGE)
Aaron Durbin4b032e42018-04-20 01:39:30 -0600[diff] [blame]60 call exception_init
61#endif
Harshit Sharmaa6ebe082020-07-20 00:21:05 -0700[diff] [blame]62
63#if CONFIG(ASAN_IN_ROMSTAGE)
64 call asan_init
65#endif
Marshall Dawsonce9c8832017-07-07 16:09:56 -0600[diff] [blame]66 call car_stage_entry
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]67
Aaron Durbinafec0712019-08-28 07:34:51 -0600[diff] [blame]68 /* Expect to never return. */
Andrey Petrov73f70692016-02-28 22:37:15 -0800[diff] [blame]691:
70 jmp 1b