This is a note to let you know that I've just added the patch titled
x86/fpu: Parse clearcpuid= as early XSAVE argument
to the 4.14-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-fpu-parse-clearcpuid-as-early-xsave-argument.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0c2a3913d6f50503f7c59d83a6219e39508cc898 Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Date: Fri, 13 Oct 2017 14:56:43 -0700
Subject: x86/fpu: Parse clearcpuid= as early XSAVE argument
From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
commit 0c2a3913d6f50503f7c59d83a6219e39508cc898 upstream.
With a followon patch we want to make clearcpuid affect the XSAVE
configuration. But xsave is currently initialized before arguments
are parsed. Move the clearcpuid= parsing into the special
early xsave argument parsing code.
Since clearcpuid= contains a = we need to keep the old __setup
around as a dummy, otherwise it would end up as a environment
variable in init's environment.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20171013215645.23166-4-andi@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/common.c | 16 +++++++---------
arch/x86/kernel/fpu/init.c | 11 +++++++++++
2 files changed, 18 insertions(+), 9 deletions(-)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1301,18 +1301,16 @@ void print_cpu_info(struct cpuinfo_x86 *
pr_cont(")\n");
}
-static __init int setup_disablecpuid(char *arg)
+/*
+ * clearcpuid= was already parsed in fpu__init_parse_early_param.
+ * But we need to keep a dummy __setup around otherwise it would
+ * show up as an environment variable for init.
+ */
+static __init int setup_clearcpuid(char *arg)
{
- int bit;
-
- if (get_option(&arg, &bit) && bit >= 0 && bit < NCAPINTS * 32)
- setup_clear_cpu_cap(bit);
- else
- return 0;
-
return 1;
}
-__setup("clearcpuid=", setup_disablecpuid);
+__setup("clearcpuid=", setup_clearcpuid);
#ifdef CONFIG_X86_64
DEFINE_PER_CPU_FIRST(union irq_stack_union,
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -249,6 +249,10 @@ static void __init fpu__init_system_ctx_
*/
static void __init fpu__init_parse_early_param(void)
{
+ char arg[32];
+ char *argptr = arg;
+ int bit;
+
if (cmdline_find_option_bool(boot_command_line, "no387"))
setup_clear_cpu_cap(X86_FEATURE_FPU);
@@ -266,6 +270,13 @@ static void __init fpu__init_parse_early
if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
+
+ if (cmdline_find_option(boot_command_line, "clearcpuid", arg,
+ sizeof(arg)) &&
+ get_option(&argptr, &bit) &&
+ bit >= 0 &&
+ bit < NCAPINTS * 32)
+ setup_clear_cpu_cap(bit);
}
/*
Patches currently in stable-queue which might be from ak@xxxxxxxxxxxxxxx are
queue-4.14/bitops-add-clear-set_bit32-to-linux-bitops.h.patch
queue-4.14/x86-fpu-remove-the-explicit-clearing-of-xsave-dependent-features.patch
queue-4.14/x86-cpuid-add-generic-table-for-cpuid-dependencies.patch
queue-4.14/x86-cpuid-prevent-out-of-bound-access-in-do_clear_cpu_cap.patch
queue-4.14/x86-fpu-parse-clearcpuid-as-early-xsave-argument.patch
queue-4.14/x86-fpu-make-xsave-check-the-base-cpuid-features-before-enabling.patch