From: Ard Biesheuvel <ardb+git@google.com>
To: linux-kernel@vger.kernel.org
Cc: Ard Biesheuvel <ardb@kernel.org>,
Kevin Loughlin <kevinloughlin@google.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Dionna Glaze <dionnaglaze@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Justin Stitt <justinstitt@google.com>,
Kees Cook <keescook@chromium.org>,
Brian Gerst <brgerst@gmail.com>,
linux-arch@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH v3 09/19] x86/head64: Simplify GDT/IDT initialization code
Date: Mon, 29 Jan 2024 19:05:12 +0100 [thread overview]
Message-ID: <20240129180502.4069817-30-ardb+git@google.com> (raw)
In-Reply-To: <20240129180502.4069817-21-ardb+git@google.com>
From: Ard Biesheuvel <ardb@kernel.org>
There used to be two separate code paths for programming the IDT early:
one that was called via the 1:1 mapping, and one via the kernel virtual
mapping, where the former used explicit pointer fixups to obtain 1:1
mapped addresses.
That distinction is now gone so the GDT/IDT init code can be unified and
simplified accordingly.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/kernel/head64.c | 57 +++++++-------------
1 file changed, 18 insertions(+), 39 deletions(-)
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index a4a380494703..58c58c66dec9 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -59,21 +59,12 @@ EXPORT_SYMBOL(vmemmap_base);
/*
* GDT used on the boot CPU before switching to virtual addresses.
*/
-static struct desc_struct startup_gdt[GDT_ENTRIES] __initdata = {
+static struct desc_struct startup_gdt[GDT_ENTRIES] __initconst = {
[GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32, 0, 0xfffff),
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64, 0, 0xfffff),
[GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA64, 0, 0xfffff),
};
-/*
- * Address needs to be set at runtime because it references the startup_gdt
- * while the kernel still uses a direct mapping.
- */
-static struct desc_ptr startup_gdt_descr __initdata = {
- .size = sizeof(startup_gdt)-1,
- .address = 0,
-};
-
#define __va_symbol(sym) ({ \
unsigned long __v; \
asm("movq $" __stringify(sym) ", %0":"=r"(__v)); \
@@ -517,47 +508,32 @@ void __init __noreturn x86_64_start_reservations(char *real_mode_data)
*/
static gate_desc bringup_idt_table[NUM_EXCEPTION_VECTORS] __page_aligned_data;
-static struct desc_ptr bringup_idt_descr = {
- .size = (NUM_EXCEPTION_VECTORS * sizeof(gate_desc)) - 1,
- .address = 0, /* Set at runtime */
-};
-
-static void set_bringup_idt_handler(gate_desc *idt, int n, void *handler)
-{
-#ifdef CONFIG_AMD_MEM_ENCRYPT
- struct idt_data data;
- gate_desc desc;
-
- init_idt_data(&data, n, handler);
- idt_init_desc(&desc, &data);
- native_write_idt_entry(idt, n, &desc);
-#endif
-}
-
-/* This runs while still in the direct mapping */
-static void __head startup_64_load_idt(void)
+static void early_load_idt(void (*handler)(void))
{
gate_desc *idt = bringup_idt_table;
+ struct desc_ptr bringup_idt_descr;
+
+ if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
+ struct idt_data data;
+ gate_desc desc;
- if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
/* VMM Communication Exception */
- set_bringup_idt_handler(idt, X86_TRAP_VC, vc_no_ghcb);
+ init_idt_data(&data, X86_TRAP_VC, handler);
+ idt_init_desc(&desc, &data);
+ native_write_idt_entry(idt, X86_TRAP_VC, &desc);
+ }
bringup_idt_descr.address = (unsigned long)idt;
+ bringup_idt_descr.size = sizeof(bringup_idt_table);
native_load_idt(&bringup_idt_descr);
}
-/* This is used when running on kernel addresses */
void early_setup_idt(void)
{
- /* VMM Communication Exception */
- if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
+ if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
setup_ghcb();
- set_bringup_idt_handler(bringup_idt_table, X86_TRAP_VC, vc_boot_ghcb);
- }
- bringup_idt_descr.address = (unsigned long)bringup_idt_table;
- native_load_idt(&bringup_idt_descr);
+ early_load_idt(vc_boot_ghcb);
}
/*
@@ -565,8 +541,11 @@ void early_setup_idt(void)
*/
void __head startup_64_setup_env(void)
{
+ struct desc_ptr startup_gdt_descr;
+
/* Load GDT */
startup_gdt_descr.address = (unsigned long)startup_gdt;
+ startup_gdt_descr.size = sizeof(startup_gdt) - 1;
native_load_gdt(&startup_gdt_descr);
/* New GDT is live - reload data segment registers */
@@ -574,5 +553,5 @@ void __head startup_64_setup_env(void)
"movl %%eax, %%ss\n"
"movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory");
- startup_64_load_idt();
+ early_load_idt(vc_no_ghcb);
}
--
2.43.0.429.g432eaa2c6b-goog
next prev parent reply other threads:[~2024-01-29 18:05 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-29 18:05 [PATCH v3 00/19] x86: Confine early 1:1 mapped startup code Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 01/19] efi/libstub: Add generic support for parsing mem_encrypt= Ard Biesheuvel
2024-01-31 7:31 ` Borislav Petkov
2024-02-01 16:23 ` Kevin Loughlin
2024-02-01 16:28 ` Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 02/19] x86/boot: Move mem_encrypt= parsing to the decompressor Ard Biesheuvel
2024-01-31 8:35 ` Borislav Petkov
2024-01-31 9:12 ` Ard Biesheuvel
2024-01-31 9:29 ` Borislav Petkov
2024-01-31 9:59 ` Ard Biesheuvel
2024-02-01 14:17 ` Tom Lendacky
2024-02-01 16:15 ` Ard Biesheuvel
2024-02-02 16:35 ` [PATCH] x86/Kconfig: Remove CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT Borislav Petkov
2024-02-02 16:47 ` Ard Biesheuvel
2024-02-03 10:50 ` [tip: x86/sev] " tip-bot2 for Borislav Petkov (AMD)
2024-01-29 18:05 ` [PATCH v3 03/19] x86/startup_64: Drop long return to initial_code pointer Ard Biesheuvel
2024-01-31 13:44 ` Borislav Petkov
2024-01-31 13:57 ` Ard Biesheuvel
2024-01-31 14:07 ` Ard Biesheuvel
2024-01-31 16:29 ` Borislav Petkov
2024-01-31 18:14 ` [tip: x86/boot] " tip-bot2 for Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 04/19] x86/startup_64: Simplify calculation of initial page table address Ard Biesheuvel
2024-02-05 10:40 ` Borislav Petkov
2024-01-29 18:05 ` [PATCH v3 05/19] x86/startup_64: Simplify CR4 handling in startup code Ard Biesheuvel
2024-02-06 18:21 ` Borislav Petkov
2024-02-07 10:38 ` Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 06/19] x86/startup_64: Drop global variables keeping track of LA57 state Ard Biesheuvel
2024-02-07 13:29 ` Borislav Petkov
2024-02-09 13:55 ` Ard Biesheuvel
2024-02-10 10:40 ` Borislav Petkov
2024-02-11 22:36 ` Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 07/19] x86/startup_64: Simplify virtual switch on primary boot Ard Biesheuvel
2024-02-07 14:50 ` Borislav Petkov
2024-01-29 18:05 ` [PATCH v3 08/19] x86/head64: Replace pointer fixups with PIE codegen Ard Biesheuvel
2024-02-12 10:29 ` Borislav Petkov
2024-02-12 11:52 ` Ard Biesheuvel
2024-02-12 14:18 ` Borislav Petkov
2024-01-29 18:05 ` Ard Biesheuvel [this message]
2024-02-12 14:37 ` [PATCH v3 09/19] x86/head64: Simplify GDT/IDT initialization code Borislav Petkov
2024-02-12 15:23 ` Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 10/19] asm-generic: Add special .pi.text section for position independent code Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 11/19] x86: Move return_thunk to __pitext section Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 12/19] x86/head64: Move early startup code into __pitext Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 13/19] modpost: Warn about calls from __pitext into other text sections Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 14/19] x86/coco: Make cc_set_mask() static inline Ard Biesheuvel
2024-01-30 23:16 ` Kevin Loughlin
2024-01-30 23:36 ` Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 15/19] x86/sev: Make all code reachable from 1:1 mapping __pitext Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 16/19] x86/sev: Avoid WARN() in early code Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 17/19] x86/sev: Use PIC codegen for early SEV startup code Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 18/19] x86/sev: Drop inline asm LEA instructions for RIP-relative references Ard Biesheuvel
2024-01-29 18:05 ` [PATCH v3 19/19] x86/startup_64: Don't bother setting up GS before the kernel is mapped Ard Biesheuvel
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