[PATCH 4.9 03/76] x86/power/32: Move SYSENTER MSR restoration to fix_processor_context() - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bpetkov@suse.de>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Pavel Machek <pavel@ucw.cz>,
	Peter Zijlstra <peterz@infradead.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Zhang Rui <rui.zhang@intel.com>, Ingo Molnar <mingo@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 03/76] x86/power/32: Move SYSENTER MSR restoration to fix_processor_context()
Date: Mon, 15 Apr 2019 20:43:27 +0200	[thread overview]
Message-ID: <20190415183708.371743815@linuxfoundation.org> (raw)
In-Reply-To: <20190415183707.712011689@linuxfoundation.org>

[ Upstream commit 896c80bef4d3b357814a476663158aaf669d0fb3 ]

x86_64 restores system call MSRs in fix_processor_context(), and
x86_32 restored them along with segment registers.  The 64-bit
variant makes more sense, so move the 32-bit code to match the
64-bit code.

No side effects are expected to runtime behavior.

Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Link: http://lkml.kernel.org/r/65158f8d7ee64dd6bbc6c1c83b3b34aaa854e3ae.1513286253.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/power/cpu.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index ec923a1cdaf0..2335e8beb0cf 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -174,6 +174,9 @@ static void fix_processor_context(void)
 	write_gdt_entry(desc, GDT_ENTRY_TSS, &tss, DESC_TSS);
 
 	syscall_init();				/* This sets MSR_*STAR and related */
+#else
+	if (boot_cpu_has(X86_FEATURE_SEP))
+		enable_sep_cpu();
 #endif
 	load_TR_desc();				/* This does ltr */
 	load_mm_ldt(current->active_mm);	/* This does lldt */
@@ -233,12 +236,6 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
 	loadsegment(fs, ctxt->fs);
 	loadsegment(gs, ctxt->gs);
 	loadsegment(ss, ctxt->ss);
-
-	/*
-	 * sysenter MSRs
-	 */
-	if (boot_cpu_has(X86_FEATURE_SEP))
-		enable_sep_cpu();
 #else
 /* CONFIG_X86_64 */
 	asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds));
-- 
2.19.1



