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>,
Brian Gerst <brgerst@gmail.com>,
linux-arch@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH v2 09/17] x86: Move return_thunk to __pitext section
Date: Thu, 25 Jan 2024 12:28:28 +0100 [thread overview]
Message-ID: <20240125112818.2016733-28-ardb+git@google.com> (raw)
In-Reply-To: <20240125112818.2016733-19-ardb+git@google.com>
From: Ard Biesheuvel <ardb@kernel.org>
The x86 return thunk will function correctly even when it is called via
a different virtual mapping than the one it was linked at, so it can
safely be moved to .pi.text. This allows other code in that section to
call it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/kernel/vmlinux.lds.S | 2 +-
arch/x86/lib/retpoline.S | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index a349dbfc6d5a..77262e804250 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -134,7 +134,7 @@ SECTIONS
SOFTIRQENTRY_TEXT
#ifdef CONFIG_RETPOLINE
*(.text..__x86.indirect_thunk)
- *(.text..__x86.return_thunk)
+ *(.pi.text..__x86.return_thunk)
#endif
STATIC_CALL_TEXT
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index 7b2589877d06..003b35445bbb 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -136,7 +136,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array)
* relocations for same-section JMPs and that breaks the returns
* detection logic in apply_returns() and in objtool.
*/
- .section .text..__x86.return_thunk
+ .section .pi.text..__x86.return_thunk, "ax"
#ifdef CONFIG_CPU_SRSO
--
2.43.0.429.g432eaa2c6b-goog
next prev parent reply other threads:[~2024-01-25 11:32 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-25 11:28 [PATCH v2 00/17] x86: Confine early 1:1 mapped startup code Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 01/17] x86/startup_64: Drop long return to initial_code pointer Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 02/17] x86/startup_64: Simplify calculation of initial page table address Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 03/17] x86/startup_64: Simplify CR4 handling in startup code Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 04/17] x86/startup_64: Drop global variables to keep track of LA57 state Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 05/17] x86/startup_64: Simplify virtual switch on primary boot Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 06/17] x86/head64: Replace pointer fixups with PIE codegen Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 07/17] x86/head64: Simplify GDT/IDT initialization code Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 08/17] asm-generic: Add special .pi.text section for position independent code Ard Biesheuvel
2024-01-25 11:28 ` Ard Biesheuvel [this message]
2024-01-25 11:28 ` [PATCH v2 10/17] x86/head64: Move early startup code into __pitext Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 11/17] modpost: Warn about calls from __pitext into other text sections Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 12/17] x86/coco: Make cc_set_mask() static inline Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 13/17] x86/sev: Make all code reachable from 1:1 mapping __pitext Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 14/17] x86/sev: Avoid WARN() in early code Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 15/17] x86/sev: Use PIC codegen for early SEV startup code Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 16/17] x86/sev: Drop inline asm LEA instructions for RIP-relative references Ard Biesheuvel
2024-01-25 20:46 ` Kevin Loughlin
2024-01-25 23:24 ` Ard Biesheuvel
2024-01-25 11:28 ` [PATCH v2 17/17] x86/startup_64: Don't bother setting up GS before the kernel is mapped Ard Biesheuvel
2024-01-25 22:23 ` [PATCH v2 00/17] x86: Confine early 1:1 mapped startup code Nathan Chancellor
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