linux-kernel - [PATCH] Fix resume on x86-32 machines

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Message-ID: <20171210213804.GA4660@amd>
Date:   Sun, 10 Dec 2017 22:38:05 +0100
From:   Pavel Machek <pavel@....cz>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Zhang Rui <rui.zhang@...el.com>,
        Andrew Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        the arch/x86 maintainers <x86@...nel.org>
Subject: [PATCH] Fix resume on x86-32 machines


After 4.15-rc2, suspend stopped working on Thinkpad X60. 5b06bbc
(unintentionally?) reordered stuff with respect to
fix_processor_context() on 32-bit and 64-bit. We undo that change on
32-bit.

While we are at it, fix a comment.

Signed-off-by: Pavel Machek <pavel@....cz>
Fixes: 5b06bbcfc2c621da3009da8decb7511500c293ed

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 5191de1..af7b613 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -216,8 +216,8 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
 	write_cr0(ctxt->cr0);
 
 	/*
-	 * now restore the descriptor tables to their proper values
-	 * ltr is done i fix_processor_context().
+	 * Now restore the descriptor tables to their proper values
+	 * ltr is done in fix_processor_context().
 	 */
 #ifdef CONFIG_X86_32
 	load_idt(&ctxt->idt);
@@ -235,13 +235,11 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
 	wrmsrl(MSR_GS_BASE, ctxt->gs_base);
 #endif
 
-	fix_processor_context();
-
+#ifdef CONFIG_X86_32
 	/*
-	 * Restore segment registers.  This happens after restoring the GDT
-	 * and LDT, which happen in fix_processor_context().
+	 * Restore segment registers.
 	 */
-#ifdef CONFIG_X86_32
+
 	loadsegment(es, ctxt->es);
 	loadsegment(fs, ctxt->fs);
 	loadsegment(gs, ctxt->gs);
@@ -252,8 +250,17 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
 	 */
 	if (boot_cpu_has(X86_FEATURE_SEP))
 		enable_sep_cpu();
+
+	fix_processor_context();
 #else
 /* CONFIG_X86_64 */
+	/*
+	 * Restore segment registers.  This happens after restoring the GDT
+	 * and LDT, which happen in fix_processor_context().
+	 */
+	
+	fix_processor_context();
+
 	asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds));
 	asm volatile ("movw %0, %%es" :: "r" (ctxt->es));
 	asm volatile ("movw %0, %%fs" :: "r" (ctxt->fs));


-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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