linux-efi.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ardb@kernel.org>,
	linux-kernel@vger.kernel.org,
	Arvind Sankar <nivedita@alum.mit.edu>
Subject: [PATCH 25/25] efi/libstub/x86: avoid globals to store context during mixed mode calls
Date: Tue, 24 Dec 2019 16:10:25 +0100	[thread overview]
Message-ID: <20191224151025.32482-26-ardb@kernel.org> (raw)
In-Reply-To: <20191224151025.32482-1-ardb@kernel.org>

Instead of storing the return address in a global variable when calling
a 32-bit EFI service from the 64-bit stub, avoid the indirection via
efi_exit32, and take the return address from the stack.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/x86/boot/compressed/efi_thunk_64.S | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/arch/x86/boot/compressed/efi_thunk_64.S b/arch/x86/boot/compressed/efi_thunk_64.S
index 593913692d16..6d95eb6b8912 100644
--- a/arch/x86/boot/compressed/efi_thunk_64.S
+++ b/arch/x86/boot/compressed/efi_thunk_64.S
@@ -10,7 +10,7 @@
  * needs to be able to service interrupts.
  *
  * On the plus side, we don't have to worry about mangling 64-bit
- * addresses into 32-bits because we're executing with an identify
+ * addresses into 32-bits because we're executing with an identity
  * mapped pagetable and haven't transitioned to 64-bit virtual addresses
  * yet.
  */
@@ -28,7 +28,7 @@ SYM_FUNC_START(efi64_thunk)
 	push	%rbx
 
 	subq	$8, %rsp
-	leaq	efi_exit32(%rip), %rax
+	leaq	1f(%rip), %rax
 	movl	%eax, 4(%rsp)
 	leaq	efi_gdt64(%rip), %rax
 	movl	%eax, (%rsp)
@@ -55,9 +55,6 @@ SYM_FUNC_START(efi64_thunk)
 
 	sgdt	save_gdt(%rip)
 
-	leaq	1f(%rip), %rbx
-	movq	%rbx, func_rt_ptr(%rip)
-
 	/*
 	 * Switch to gdt with 32-bit segments. This is the firmware GDT
 	 * that was installed when the kernel started executing. This
@@ -72,6 +69,7 @@ SYM_FUNC_START(efi64_thunk)
 	lretq
 
 1:	addq	$32, %rsp
+	movq	%rdi, %rax
 
 	lgdt	save_gdt(%rip)
 
@@ -99,13 +97,6 @@ SYM_FUNC_START(efi64_thunk)
 	ret
 SYM_FUNC_END(efi64_thunk)
 
-SYM_FUNC_START_LOCAL(efi_exit32)
-	movq	func_rt_ptr(%rip), %rax
-	push	%rax
-	mov	%rdi, %rax
-	ret
-SYM_FUNC_END(efi_exit32)
-
 	.code32
 /*
  * EFI service pointer must be in %edi.
@@ -186,8 +177,6 @@ SYM_DATA_START_LOCAL(save_gdt)
 	.quad	0
 SYM_DATA_END(save_gdt)
 
-SYM_DATA_LOCAL(func_rt_ptr, .quad 0)
-
 SYM_DATA_START(efi_gdt64)
 	.word	efi_gdt64_end - efi_gdt64
 	.long	0			/* Filled out by user */
-- 
2.20.1


  parent reply	other threads:[~2019-12-24 15:11 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-24 15:10 [GIT PULL 00/25] EFI updates for v5.6 Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 01/25] efi/gop: Remove bogus packed attribute from GOP structures Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 02/25] efi/gop: Remove unused typedef Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 03/25] efi/gop: Convert GOP structures to typedef and cleanup some types Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 04/25] efi/gop: Unify 32/64-bit functions Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 05/25] efi/libstub: remove unused __efi_call_early() macro Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 06/25] efi/x86: rename efi_is_native() to efi_is_mixed() Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 07/25] efi/libstub: use a helper to iterate over a EFI handle array Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 08/25] efi/libstub: extend native protocol definitions with mixed_mode aliases Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 09/25] efi/libstub: distinguish between native/mixed not 32/64 bit Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 10/25] efi/libstub: drop explicit 32/64-bit protocol definitions Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 11/25] efi/libstub: use stricter typing for firmware function pointers Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 12/25] efi/libstub: annotate firmware routines as __efiapi Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 13/25] efi/libstub/x86: avoid thunking for native firmware calls Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 14/25] efi/libstub: avoid protocol wrapper for file I/O routines Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 15/25] efi/libstub: get rid of 'sys_table_arg' macro parameter Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 16/25] efi/libstub: unify the efi_char16_printk implementations Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 17/25] efi/libstub/x86: drop __efi_early() export and efi_config struct Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 18/25] efi/libstub: drop sys_table_arg from printk routines Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 19/25] efi/libstub: remove 'sys_table_arg' from all function prototypes Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 20/25] efi/libstub/x86: work around page freeing issue in mixed mode Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 21/25] efi/libstub: drop protocol argument from efi_call_proto() macro Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 22/25] efi/libstub: drop 'table' argument from efi_table_attr() macro Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 23/25] efi/libstub: rename efi_call_early/_runtime macros to be more intuitive Ard Biesheuvel
2019-12-24 15:10 ` [PATCH 24/25] efi/libstub: tidy up types and names of global cmdline variables Ard Biesheuvel
2019-12-24 15:10 ` Ard Biesheuvel [this message]
2019-12-25  9:50 ` [GIT PULL 00/25] EFI updates for v5.6 Ingo Molnar

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191224151025.32482-26-ardb@kernel.org \
    --to=ardb@kernel.org \
    --cc=linux-efi@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=nivedita@alum.mit.edu \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).