linux-kernel - [tip:x86/urgent] x86/power/32: Move SYSENTER MSR restoration to fix_processor

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Date:   Fri, 15 Dec 2017 06:38:07 -0800
From:   tip-bot for Andy Lutomirski <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     jpoimboe@...hat.com, mingo@...nel.org, peterz@...radead.org,
        luto@...nel.org, pavel@....cz, jarkko.nikula@...ux.intel.com,
        torvalds@...ux-foundation.org, tglx@...utronix.de,
        rui.zhang@...el.com, rjw@...ysocki.net, rafael.j.wysocki@...el.com,
        linux-kernel@...r.kernel.org, bpetkov@...e.de, hpa@...or.com
Subject: [tip:x86/urgent] x86/power/32: Move SYSENTER MSR restoration to
 fix_processor_context()

Commit-ID:  896c80bef4d3b357814a476663158aaf669d0fb3
Gitweb:     https://git.kernel.org/tip/896c80bef4d3b357814a476663158aaf669d0fb3
Author:     Andy Lutomirski <luto@...nel.org>
AuthorDate: Thu, 14 Dec 2017 13:19:06 -0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 15 Dec 2017 12:18:29 +0100

x86/power/32: Move SYSENTER MSR restoration to fix_processor_context()

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@...ux.intel.com>
Signed-off-by: Andy Lutomirski <luto@...nel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Acked-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Borislav Petkov <bpetkov@...e.de>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Pavel Machek <pavel@....cz>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rafael J. Wysocki <rjw@...ysocki.net>
Cc: Zhang Rui <rui.zhang@...el.com>
Link: http://lkml.kernel.org/r/65158f8d7ee64dd6bbc6c1c83b3b34aaa854e3ae.1513286253.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.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 472bc8c..033c61e 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 */
@@ -237,12 +240,6 @@ 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));