linux-kernel - [tip: x86/entry] x86/entry: Compile entry_SYSCALL32

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Date:   Thu, 14 Sep 2023 11:27:03 -0000
From:   "tip-bot2 for Nikolay Borisov" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Nikolay Borisov <nik.borisov@...e.com>,
        Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/entry] x86/entry: Compile entry_SYSCALL32_ignore() unconditionally

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     370dcd58548a360bbf8a65b89b410d09f56bf0c6
Gitweb:        https://git.kernel.org/tip/370dcd58548a360bbf8a65b89b410d09f56bf0c6
Author:        Nikolay Borisov <nik.borisov@...e.com>
AuthorDate:    Fri, 23 Jun 2023 14:14:06 +03:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Thu, 14 Sep 2023 13:19:53 +02:00

x86/entry: Compile entry_SYSCALL32_ignore() unconditionally

To limit the IA32 exposure on 64bit kernels while keeping the
flexibility for the user to enable it when required, the compile time
enable/disable via CONFIG_IA32_EMULATION is not good enough and will
be complemented with a kernel command line option.

Right now entry_SYSCALL32_ignore() is only compiled when
CONFIG_IA32_EMULATION=n, but boot-time enable- / disablement obviously
requires it to be unconditionally available.

Remove the #ifndef CONFIG_IA32_EMULATION guard.

Signed-off-by: Nikolay Borisov <nik.borisov@...e.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/r/20230623111409.3047467-4-nik.borisov@suse.com

---
 arch/x86/entry/entry_64.S | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 3be71ac..f71664d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1511,7 +1511,6 @@ nmi_restore:
 	iretq
 SYM_CODE_END(asm_exc_nmi)
 
-#ifndef CONFIG_IA32_EMULATION
 /*
  * This handles SYSCALL from 32-bit code.  There is no way to program
  * MSRs to fully disable 32-bit SYSCALL.
@@ -1522,7 +1521,6 @@ SYM_CODE_START(entry_SYSCALL32_ignore)
 	mov	$-ENOSYS, %eax
 	sysretl
 SYM_CODE_END(entry_SYSCALL32_ignore)
-#endif
 
 .pushsection .text, "ax"
 	__FUNC_ALIGN