libpayload: Add x86_64 (64-bit) support

This patch introduces x86_64 (64-bit) support to the payload, building
upon the existing x86 (32-bit) architecture. Files necessary for 64-bit
compilation are now guarded by the `CONFIG_LP_ARCH_X86_64` Kconfig
option.

BUG=b:242829490
TEST=Able to verify all valid combinations between coreboot and
payload with this patch.

Payload Entry Point Behavior with below code.

+----------------+--------------------+----------------------------+
| LP_ARCH_X86_64 | Payload Entry Mode | Description                |
+----------------+--------------------+----------------------------+
| No             | 32-bit             | Direct protected mode init |
+----------------+--------------------+----------------------------+
| Yes            | 32-bit             | Protected to long mode     |
+----------------+--------------------+----------------------------+
| Yes            | 64-bit             | Long mode initialization   |
+----------------+--------------------+----------------------------+

Change-Id: I69fda47bedf1a14807b1515c4aed6e3a1d5b8585
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81968
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 221 insertions, 0 deletions

diff --git a/payloads/libpayload/arch/x86/exception_asm_64.S b/payloads/libpayload/arch/x86/exception_asm_64.S
new file mode 100644
index 0000000000..ee4e9e5b76
--- /dev/null
+++ b/payloads/libpayload/arch/x86/exception_asm_64.S
@@ -0,0 +1,221 @@
+/*
+ *
+ * Copyright 2024 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+	.align 16
+	.global exception_stack_end
+exception_stack_end:
+	.quad 0
+	.global exception_state
+exception_state:
+	.quad 0
+
+/* Some temporary variables which are used while saving exception state. */
+vector:
+	.quad 0
+error_code:
+	.quad 0
+old_rsp:
+	.quad 0
+old_rax:
+	.quad 0
+
+	.align 16
+
+/*
+ * Each exception vector has a small stub associated with it which sets aside
+ * the error code, if any, records which vector we entered from, and calls
+ * the common exception entry point. Some exceptions have error codes and some
+ * don't, so we have a macro for each type.
+ */
+
+	.macro stub num
+exception_stub_\num:
+	movq	$0, error_code
+	movq	$\num, vector
+	jmp	exception_common
+	.endm
+
+	.macro stub_err num
+exception_stub_\num:
+	pop	error_code
+	movq	$\num, vector
+	jmp	exception_common
+	.endm
+
+	.altmacro
+	.macro	user_defined_stubs from, to
+	stub	\from
+	.if	\to-\from
+	user_defined_stubs	%(from+1),\to
+	.endif
+	.endm
+
+	stub 0
+	stub 1
+	stub 2
+	stub 3
+	stub 4
+	stub 5
+	stub 6
+	stub 7
+	stub_err 8
+	stub 9
+	stub_err 10
+	stub_err 11
+	stub_err 12
+	stub_err 13
+	stub_err 14
+	stub 15
+	stub 16
+	stub_err 17
+	stub 18
+	stub 19
+	stub 20
+	stub 21
+	stub 22
+	stub 23
+	stub 24
+	stub 25
+	stub 26
+	stub 27
+	stub 28
+	stub 29
+	stub_err 30
+	stub 31
+	/* Split the macro so we avoid a stack overflow. */
+	user_defined_stubs 32, 63
+	user_defined_stubs 64, 127
+	user_defined_stubs 128, 191
+	user_defined_stubs 192, 255
+
+exception_common:
+
+	/* Return from the exception. */
+	iretl
+
+/*
+ * We need segment selectors for the IDT, so we need to know where things are
+ * in the GDT. We set one up here which is pretty standard and largely copied
+ * from coreboot.
+ */
+	.align 16
+gdt:
+	/* selgdt 0, unused */
+	.word 0x0000, 0x0000
+	.byte 0x00, 0x00, 0x00, 0x00
+
+	/* selgdt 8, unused */
+	.word 0x0000, 0x0000
+	.byte 0x00, 0x00, 0x00, 0x00
+
+	/* selgdt 0x10, flat 4GB code segment */
+	.word 0xffff, 0x0000
+	.byte 0x00, 0x9b, 0xcf, 0x00
+
+	/* selgdt 0x18, flat 4GB data segment */
+	.word 0xffff, 0x0000
+	.byte	0x00, 0x92, 0xcf, 0x00
+
+	/* selgdt 0x20, flat x64 code segment */
+	.word	0xffff, 0x0000
+	.byte	0x00, 0x9b, 0xaf, 0x00
+gdt_end:
+
+/* GDT pointer for use with lgdt */
+.global gdt_ptr
+gdt_ptr:
+	.word	gdt_end - gdt - 1
+	.quad	gdt
+
+	/*
+	 * Record the target and construct the actual entry at init time. This
+	 * is necessary because the linker doesn't want to construct the entry
+	 * for us.
+	 */
+	.macro interrupt_gate target
+	.quad \target
+	.quad \target
+	.endm
+
+	.altmacro
+	.macro	user_defined_gates from, to
+	interrupt_gate	exception_stub_\from
+	.if	\to-\from
+	user_defined_gates	%(from+1),\to
+	.endif
+	.endm
+
+	.align 16
+	.global	idt
+idt:
+	interrupt_gate exception_stub_0
+	interrupt_gate exception_stub_1
+	interrupt_gate exception_stub_2
+	interrupt_gate exception_stub_3
+	interrupt_gate exception_stub_4
+	interrupt_gate exception_stub_5
+	interrupt_gate exception_stub_6
+	interrupt_gate exception_stub_7
+	interrupt_gate exception_stub_8
+	interrupt_gate exception_stub_9
+	interrupt_gate exception_stub_10
+	interrupt_gate exception_stub_11
+	interrupt_gate exception_stub_12
+	interrupt_gate exception_stub_13
+	interrupt_gate exception_stub_14
+	interrupt_gate exception_stub_15
+	interrupt_gate exception_stub_16
+	interrupt_gate exception_stub_17
+	interrupt_gate exception_stub_18
+	interrupt_gate exception_stub_19
+	interrupt_gate exception_stub_20
+	interrupt_gate exception_stub_21
+	interrupt_gate exception_stub_22
+	interrupt_gate exception_stub_23
+	interrupt_gate exception_stub_24
+	interrupt_gate exception_stub_25
+	interrupt_gate exception_stub_26
+	interrupt_gate exception_stub_27
+	interrupt_gate exception_stub_28
+	interrupt_gate exception_stub_29
+	interrupt_gate exception_stub_30
+	interrupt_gate exception_stub_31
+	user_defined_gates 32, 63
+	user_defined_gates 64, 127
+	user_defined_gates 128, 191
+	user_defined_gates 192, 255
+idt_end:
+
+/* IDT pointer for use with lidt */
+idt_ptr:
+	.word idt_end - idt - 1
+	.quad idt
+
+	.global exception_init_asm
+exception_init_asm:
+	ret