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Patch "x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier" has been added to the 4.9-stable tree

PATCH [email protected] 1 participant 1 message Jan 15, 2018

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This is a note to let you know that I've just added the patch titled

    x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     x86-mm-32-move-setup_clear_cpu_cap-x86_feature_pcid-earlier.patch

and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From b8b7abaed7a49b350f8ba659ddc264b04931d581 Mon Sep 17 00:00:00 2001

From: Andy Lutomirski <[email protected]>
Date: Sun, 17 Sep 2017 09:03:50 -0700
Subject: x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier

From: Andy Lutomirski <[email protected]>

commit b8b7abaed7a49b350f8ba659ddc264b04931d581 upstream.

Otherwise we might have the PCID feature bit set during cpu_init().

This is just for robustness. I haven't seen any actual bugs here.

---
 arch/x86/kernel/cpu/bugs.c   |    8 --------
 arch/x86/kernel/cpu/common.c |    8 ++++++++
 2 files changed, 8 insertions(+), 8 deletions(-)
arch/x86/kernel/cpu/bugs.c +0 -8
@@ -22,14 +22,6 @@
 
 void __init check_bugs(void)
 {
-#ifdef CONFIG_X86_32
-	/*
-	 * Regardless of whether PCID is enumerated, the SDM says
-	 * that it can't be enabled in 32-bit mode.
-	 */
-	setup_clear_cpu_cap(X86_FEATURE_PCID);
-#endif
-
 	identify_boot_cpu();
 
 	if (!IS_ENABLED(CONFIG_SMP)) {
arch/x86/kernel/cpu/common.c +8 -0
@@ -890,6 +890,14 @@ static void __init early_identify_cpu(st
 	setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
 
 	fpu__init_system(c);
+
+#ifdef CONFIG_X86_32
+	/*
+	 * Regardless of whether PCID is enumerated, the SDM says
+	 * that it can't be enabled in 32-bit mode.
+	 */
+	setup_clear_cpu_cap(X86_FEATURE_PCID);
+#endif
 }
 
 void __init early_cpu_init(void)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/x86-asm-use-register-variable-to-get-stack-pointer-value.patch queue-4.9/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.9/x86-cpufeatures-make-cpu-bugs-sticky.patch queue-4.9/x86-documentation-add-pti-description.patch queue-4.9/x86-cpu-factor-out-application-of-forced-cpu-caps.patch queue-4.9/selftests-x86-add-test_vsyscall.patch queue-4.9/x86-cpu-merge-bugs.c-and-bugs_64.c.patch queue-4.9/x86-mm-32-move-setup_clear_cpu_cap-x86_feature_pcid-earlier.patch queue-4.9/x86-alternatives-fix-optimize_nops-checking.patch