2023-06-23 11:25:05

by Nikolay Borisov

Subject: [PATCH v4 3/6] 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 <[email protected]>
---
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 ccce0ccd8589..7068af44008a 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1514,7 +1514,6 @@ SYM_CODE_START(asm_exc_nmi)
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.
@@ -1525,7 +1524,6 @@ SYM_CODE_START(entry_SYSCALL32_ignore)
mov $-ENOSYS, %eax
sysretl
SYM_CODE_END(entry_SYSCALL32_ignore)
-#endif

.pushsection .text, "ax"
__FUNC_ALIGN
--
2.34.1

2023-09-14 12:56:37

by tip-bot2 for Alexey Makhalov

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 <[email protected]>
AuthorDate: Fri, 23 Jun 2023 14:14:06 +03:00
Committer: Thomas Gleixner <[email protected]>
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 <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

---
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