From: Joerg Roedel <jroedel@suse.de>
Date: Mon, 7 Sep 2020 15:15:14 +0200
Subject: x86/boot/compressed/64: Add IDT Infrastructure
Git-commit: 64e682638eb51070ba6044535b250aad43c5564e
Patch-mainline: v5.10-rc1
References: jsc#SLE-14337
Add code needed to setup an IDT in the early pre-decompression
boot-code. The IDT is loaded first in startup_64, which is after
EfiExitBootServices() has been called, and later reloaded when the
kernel image has been relocated to the end of the decompression area.
This allows to setup different IDT handlers before and after the
relocation.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-14-joro@8bytes.org
---
arch/x86/boot/compressed/Makefile | 1
arch/x86/boot/compressed/head_64.S | 25 ++++++++++
arch/x86/boot/compressed/idt_64.c | 44 ++++++++++++++++++
arch/x86/boot/compressed/idt_handlers_64.S | 70 +++++++++++++++++++++++++++++
arch/x86/boot/compressed/misc.h | 5 ++
arch/x86/include/asm/desc_defs.h | 3 +
6 files changed, 148 insertions(+)
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -81,6 +81,7 @@ vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $
vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr.o
ifdef CONFIG_X86_64
vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr_64.o
+ vmlinux-objs-y += $(obj)/idt_64.o $(obj)/idt_handlers_64.o
vmlinux-objs-y += $(obj)/mem_encrypt.o
vmlinux-objs-y += $(obj)/pgtable_64.o
endif
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -33,6 +33,7 @@
#include <asm/processor-flags.h>
#include <asm/asm-offsets.h>
#include <asm/bootparam.h>
+#include <asm/desc_defs.h>
#include "pgtable.h"
/*
@@ -405,6 +406,10 @@ ENTRY(startup_64)
.Lon_kernel_cs:
+ pushq %rsi
+ call load_stage1_idt
+ popq %rsi
+
/*
* paging_prepare() sets up the trampoline and checks if we need to
* enable 5-level paging.
@@ -531,6 +536,13 @@ relocated:
lgdt gdt64(%rip)
/*
+ * Load stage2 IDT
+ */
+ pushq %rsi
+ call load_stage2_idt
+ popq %rsi
+
+/*
* Do the extraction, and jump to the new kernel..
*/
pushq %rsi /* Save the real mode argument */
@@ -683,6 +695,19 @@ SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt
SYM_DATA(image_offset, .long 0)
#endif
+ .globl boot_idt_desc
+boot_idt_desc:
+ .word boot_idt_end - boot_idt - 1
+ .quad 0
+ .balign 8
+ .globl boot_idt
+boot_idt:
+ .rept BOOT_IDT_ENTRIES
+ .quad 0
+ .quad 0
+ .endr
+boot_idt_end:
+
#ifdef CONFIG_EFI_MIXED
SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0)
SYM_DATA(efi_is64, .byte 1)
--- /dev/null
+++ b/arch/x86/boot/compressed/idt_64.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <asm/trap_pf.h>
+#include <asm/segment.h>
+#include <asm/trapnr.h>
+#include "misc.h"
+
+static void set_idt_entry(int vector, void (*handler)(void))
+{
+ unsigned long address = (unsigned long)handler;
+ gate_desc entry;
+
+ memset(&entry, 0, sizeof(entry));
+
+ entry.offset_low = (u16)(address & 0xffff);
+ entry.segment = __KERNEL_CS;
+ entry.bits.type = GATE_TRAP;
+ entry.bits.p = 1;
+ entry.offset_middle = (u16)((address >> 16) & 0xffff);
+ entry.offset_high = (u32)(address >> 32);
+
+ memcpy(&boot_idt[vector], &entry, sizeof(entry));
+}
+
+/* Have this here so we don't need to include <asm/desc.h> */
+static void load_boot_idt(const struct desc_ptr *dtr)
+{
+ asm volatile("lidt %0"::"m" (*dtr));
+}
+
+/* Setup IDT before kernel jumping to .Lrelocated */
+void load_stage1_idt(void)
+{
+ boot_idt_desc.address = (unsigned long)boot_idt;
+
+ load_boot_idt(&boot_idt_desc);
+}
+
+/* Setup IDT after kernel jumping to .Lrelocated */
+void load_stage2_idt(void)
+{
+ boot_idt_desc.address = (unsigned long)boot_idt;
+
+ load_boot_idt(&boot_idt_desc);
+}
--- /dev/null
+++ b/arch/x86/boot/compressed/idt_handlers_64.S
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Early IDT handler entry points
+ *
+ * Copyright (C) 2019 SUSE
+ *
+ * Author: Joerg Roedel <jroedel@suse.de>
+ */
+
+#include <asm/segment.h>
+
+/* For ORIG_RAX */
+#include "../../entry/calling.h"
+
+.macro EXCEPTION_HANDLER name function error_code=0
+SYM_FUNC_START(\name)
+
+ /* Build pt_regs */
+ .if \error_code == 0
+ pushq $0
+ .endif
+
+ pushq %rdi
+ pushq %rsi
+ pushq %rdx
+ pushq %rcx
+ pushq %rax
+ pushq %r8
+ pushq %r9
+ pushq %r10
+ pushq %r11
+ pushq %rbx
+ pushq %rbp
+ pushq %r12
+ pushq %r13
+ pushq %r14
+ pushq %r15
+
+ /* Call handler with pt_regs */
+ movq %rsp, %rdi
+ /* Error code is second parameter */
+ movq ORIG_RAX(%rsp), %rsi
+ call \function
+
+ /* Restore regs */
+ popq %r15
+ popq %r14
+ popq %r13
+ popq %r12
+ popq %rbp
+ popq %rbx
+ popq %r11
+ popq %r10
+ popq %r9
+ popq %r8
+ popq %rax
+ popq %rcx
+ popq %rdx
+ popq %rsi
+ popq %rdi
+
+ /* Remove error code and return */
+ addq $8, %rsp
+
+ iretq
+SYM_FUNC_END(\name)
+ .endm
+
+ .text
+ .code64
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -23,6 +23,7 @@
#include <asm/page.h>
#include <asm/boot.h>
#include <asm/bootparam.h>
+#include <asm/desc_defs.h>
#define BOOT_CTYPE_H
#include <linux/acpi.h>
@@ -133,4 +134,8 @@ int count_immovable_mem_regions(void);
static inline int count_immovable_mem_regions(void) { return 0; }
#endif
+/* idt_64.c */
+extern gate_desc boot_idt[BOOT_IDT_ENTRIES];
+extern struct desc_ptr boot_idt_desc;
+
#endif /* BOOT_COMPRESSED_MISC_H */
--- a/arch/x86/include/asm/desc_defs.h
+++ b/arch/x86/include/asm/desc_defs.h
@@ -109,6 +109,9 @@ struct desc_ptr {
#endif /* !__ASSEMBLY__ */
+/* Boot IDT definitions */
+#define BOOT_IDT_ENTRIES 32
+
/* Access rights as returned by LAR */
#define AR_TYPE_RODATA (0 * (1 << 9))
#define AR_TYPE_RWDATA (1 * (1 << 9))