From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Michael Roth <michael.roth@amd.com>
Subject: [PATCH v2 08/16] x86/compressed: efi-mixed: simplify IDT/GDT preserve/restore
Date: Wed, 21 Sep 2022 16:54:14 +0200 [thread overview]
Message-ID: <20220921145422.437618-9-ardb@kernel.org> (raw)
In-Reply-To: <20220921145422.437618-1-ardb@kernel.org>
Tweak the asm and remove some redundant instructions. While at it,
fix the associated comment for style and correctness.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/boot/compressed/efi_mixed.S | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)
diff --git a/arch/x86/boot/compressed/efi_mixed.S b/arch/x86/boot/compressed/efi_mixed.S
index 838514f7685a..e5b8f1d2310c 100644
--- a/arch/x86/boot/compressed/efi_mixed.S
+++ b/arch/x86/boot/compressed/efi_mixed.S
@@ -96,24 +96,20 @@ SYM_FUNC_START(__efi64_thunk)
leaq 0x20(%rsp), %rbx
sgdt (%rbx)
-
- addq $16, %rbx
- sidt (%rbx)
+ sidt 16(%rbx)
leaq 1f(%rip), %rbp
/*
- * Switch to IDT and GDT with 32-bit segments. This is the firmware GDT
- * and IDT that was installed when the kernel started executing. The
- * pointers were saved by the efi32_entry() routine below.
+ * Switch to IDT and GDT with 32-bit segments. These are the firmware
+ * GDT and IDT that were installed when the kernel started executing.
+ * The pointers were saved by the efi32_entry() routine below.
*
* Pass the saved DS selector to the 32-bit code, and use far return to
* restore the saved CS selector.
*/
- leaq efi32_boot_idt(%rip), %rax
- lidt (%rax)
- leaq efi32_boot_gdt(%rip), %rax
- lgdt (%rax)
+ lidt efi32_boot_idt(%rip)
+ lgdt efi32_boot_gdt(%rip)
movzwl efi32_boot_ds(%rip), %edx
movzwq efi32_boot_cs(%rip), %rax
@@ -187,9 +183,7 @@ SYM_FUNC_START_LOCAL(efi_enter32)
*/
cli
- lidtl (%ebx)
- subl $16, %ebx
-
+ lidtl 16(%ebx)
lgdtl (%ebx)
movl %cr4, %eax
--
2.35.1
next prev parent reply other threads:[~2022-09-21 14:55 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 14:54 [PATCH v2 00/16] x86: head_64.S spring cleaning Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 01/16] x86/compressed: efi-mixed: rename efi_thunk_64.S to efi-mixed.S Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 02/16] x86/compressed: efi-mixed: move 32-bit entrypoint code into .text section Ard Biesheuvel
2022-10-06 10:42 ` Borislav Petkov
2022-10-06 10:56 ` Ard Biesheuvel
2022-10-06 11:13 ` Borislav Petkov
2022-10-06 11:19 ` Ard Biesheuvel
2022-10-06 12:27 ` Ard Biesheuvel
2022-10-07 8:56 ` Borislav Petkov
2022-09-21 14:54 ` [PATCH v2 03/16] x86/compressed: efi-mixed: move bootargs parsing out of 32-bit startup code Ard Biesheuvel
2022-10-06 11:03 ` Borislav Petkov
2022-10-06 11:29 ` Ard Biesheuvel
2022-10-07 9:30 ` Borislav Petkov
2022-09-21 14:54 ` [PATCH v2 04/16] x86/compressed: efi-mixed: move efi32_pe_entry into .text section Ard Biesheuvel
2022-11-17 15:57 ` Borislav Petkov
2022-11-17 16:06 ` Ard Biesheuvel
2022-11-17 17:08 ` Borislav Petkov
2022-09-21 14:54 ` [PATCH v2 05/16] x86/compressed: efi-mixed: move efi32_entry out of head_64.S Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 06/16] x86/compressed: efi-mixed: move efi32_pe_entry() " Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 07/16] x86/compressed: efi: merge multiple definitions of image_offset into one Ard Biesheuvel
2022-09-21 14:54 ` Ard Biesheuvel [this message]
2022-09-21 14:54 ` [PATCH v2 09/16] x86/compressed: avoid touching ECX in startup32_set_idt_entry() Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 10/16] x86/compressed: pull global variable ref up into startup32_load_idt() Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 11/16] x86/compressed: move startup32_load_idt() into .text section Ard Biesheuvel
2022-11-18 16:44 ` Borislav Petkov
2022-09-21 14:54 ` [PATCH v2 12/16] x86/compressed: move startup32_load_idt() out of head_64.S Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 13/16] x86/compressed: move startup32_check_sev_cbit() into .text Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 14/16] x86/compressed: move startup32_check_sev_cbit() out of head_64.S Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 15/16] x86/compressed: adhere to calling convention in get_sev_encryption_bit() Ard Biesheuvel
2022-09-21 14:54 ` [PATCH v2 16/16] x86/compressed: only build mem_encrypt.S if AMD_MEM_ENCRYPT=y Ard Biesheuvel
2022-11-18 18:26 ` [PATCH v2 00/16] x86: head_64.S spring cleaning Borislav Petkov
2022-11-18 23:31 ` Ard Biesheuvel
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