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%3Ba=su...

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@vger.kernel.org know about it.

From 0c2a3913d6f50503f7c59d83a6219e39508cc898 Mon Sep 17 00:00:00 2001

From: Andi Kleen ak@linux.intel.com Date: Fri, 13 Oct 2017 14:56:43 -0700 Subject: x86/fpu: Parse clearcpuid= as early XSAVE argument

From: Andi Kleen ak@linux.intel.com

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@linux.intel.com Reviewed-by: Thomas Gleixner tglx@linutronix.de Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Link: http://lkml.kernel.org/r/20171013215645.23166-4-andi@firstfloor.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- 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@linux.intel.com 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