linux-toradex.git/arch/x86/kernel/cpu/common.c, branch v4.4.85

x86/cpu: Fix bootup crashes by sanitizing the argument of the 'clearcpuid=' command-line option

2017-01-19T19:17:21+00:00

commit dd853fd216d1485ed3045ff772079cc8689a9a4a upstream.

A negative number can be specified in the cmdline which will be used as
setup_clear_cpu_cap() argument. With that we can clear/set some bit in
memory predceeding boot_cpu_data/cpu_caps_cleared which may cause kernel
to misbehave. This patch adds lower bound check to setup_disablecpuid().

Boris Petkov reproduced a crash:

  [    1.234575] BUG: unable to handle kernel paging request at ffffffff858bd540
  [    1.236535] IP: memcpy_erms+0x6/0x10

Signed-off-by: Lukasz Odzioba 
Acked-by: Borislav Petkov 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: andi.kleen@intel.com
Cc: bp@alien8.de
Cc: dave.hansen@linux.intel.com
Cc: luto@kernel.org
Cc: slaoub@gmail.com
Fixes: ac72e7888a61 ("x86: add generic clearcpuid=... option")
Link: http://lkml.kernel.org/r/1482933340-11857-1-git-send-email-lukasz.odzioba@intel.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/boot: Initialize FPU and X86_FEATURE_ALWAYS even if we don't have CPUID

2016-10-07T13:23:40+00:00

commit 05fb3c199bb09f5b85de56cc3ede194ac95c5e1f upstream.

Otherwise arch_task_struct_size == 0 and we die.  While we're at it,
set X86_FEATURE_ALWAYS, too.

Reported-by: David Saggiorato 
Tested-by: David Saggiorato 
Signed-off-by: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: aaeb5c01c5b ("x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86")
Link: http://lkml.kernel.org/r/8de723afbf0811071185039f9088733188b606c9.1475103911.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/cpu: Fix SMAP check in PVOPS environments

2015-11-19T10:07:49+00:00

There appears to be no formal statement of what pv_irq_ops.save_fl() is
supposed to return precisely.  Native returns the full flags, while lguest and
Xen only return the Interrupt Flag, and both have comments by the
implementations stating that only the Interrupt Flag is looked at.  This may
have been true when initially implemented, but no longer is.

To make matters worse, the Xen PVOP leaves the upper bits undefined, making
the BUG_ON() undefined behaviour.  Experimentally, this now trips for 32bit PV
guests on Broadwell hardware.  The BUG_ON() is consistent for an individual
build, but not consistent for all builds.  It has also been a sitting timebomb
since SMAP support was introduced.

Use native_save_fl() instead, which will obtain an accurate view of the AC
flag.

Signed-off-by: Andrew Cooper 
Reviewed-by: David Vrabel 
Tested-by: Rusty Russell 
Cc: Rusty Russell 
Cc: Konrad Rzeszutek Wilk 
Cc: Boris Ostrovsky 
Cc: 
Cc: Xen-devel 
CC: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1433323874-6927-1-git-send-email-andrew.cooper3@citrix.com
Signed-off-by: Thomas Gleixner

x86/cpu: Add CLZERO detection

2015-11-01T10:26:23+00:00

AMD Fam17h processors introduce support for the CLZERO
instruction. It zeroes out the 64 byte cache line specified in
RAX.

Add the bit here to allow /proc/cpuinfo to list the feature.

Boris: we're adding this as a separate ->x86_capability leaf
because CPUID_80000008_EBX is going to contain more feature bits
and it will fill out with time.

Signed-off-by: Wan Zongshun 
Signed-off-by: Aravind Gopalakrishnan 
[ Wrap code in patch form, fix comments. ]
Signed-off-by: Borislav Petkov 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Huang Rui 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Link: http://lkml.kernel.org/r/1446207099-24948-4-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar

x86/cpu: Print family/model/stepping in hex

2015-09-13T07:30:07+00:00

924e101a7ab6 ("x86/debug: Dump family, model, stepping of the
boot CPU") had its good intentions to dump the exact F/M/S as an
aid during debugging sessions but its output can be ambiguous.
Fix that:

-smpboot: CPU0: Intel Core Processor (Broadwell) (fam: 06, model: 47, stepping: 02)
+smpboot: CPU0: Intel Core Processor (Broadwell) (family: 0x6, model: 0x47, stepping: 0x2)

Also, spell out "family".

Signed-off-by: Borislav Petkov 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1441914927-32037-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar

Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-09-01T16:41:03+00:00

Pull x86 cpu updates from Ingo Molnar:
 "Two changes: a suspend/resume quirk and a new CPUID bit definition"

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpufeature: Add feature bit for Intel's Silicon Debug CPUID bit
  x86/cpu: Restore MSR_IA32_ENERGY_PERF_BIAS after resume

x86/asm/msr: Make wrmsrl() a function

2015-08-23T11:25:38+00:00

As of cf991de2f614 ("x86/asm/msr: Make wrmsrl_safe() a
function"), wrmsrl_safe is a function, but wrmsrl is still a
macro.  The wrmsrl macro performs invalid shifts if the value
argument is 32 bits. This makes it unnecessarily awkward to
write code that puts an unsigned long into an MSR.

To make this work, syscall_init needs tweaking to stop passing
a function pointer to wrmsrl.

Signed-off-by: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Willy Tarreau 
Link: http://lkml.kernel.org/r/690f0c629a1085d054e2d1ef3da073cfb3f7db92.1437678821.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86/ldt: Make modify_ldt synchronous

2015-07-31T08:23:23+00:00

modify_ldt() has questionable locking and does not synchronize
threads.  Improve it: redesign the locking and synchronize all
threads' LDTs using an IPI on all modifications.

This will dramatically slow down modify_ldt in multithreaded
programs, but there shouldn't be any multithreaded programs that
care about modify_ldt's performance in the first place.

This fixes some fallout from the CVE-2015-5157 fixes.

Signed-off-by: Andy Lutomirski 
Reviewed-by: Borislav Petkov 
Cc: Andrew Cooper 
Cc: Andy Lutomirski 
Cc: Boris Ostrovsky 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Jan Beulich 
Cc: Konrad Rzeszutek Wilk 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Sasha Levin 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: security@kernel.org 
Cc: 
Cc: xen-devel 
Link: http://lkml.kernel.org/r/4c6978476782160600471bd865b318db34c7b628.1438291540.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86/cpu: Restore MSR_IA32_ENERGY_PERF_BIAS after resume

2015-07-21T05:51:38+00:00

MSR_IA32_ENERGY_PERF_BIAS is lost after suspend/resume:

	x86_energy_perf_policy -r before

	cpu0: 0x0000000000000006
	cpu1: 0x0000000000000006
	cpu2: 0x0000000000000006
	cpu3: 0x0000000000000006
	cpu4: 0x0000000000000006
	cpu5: 0x0000000000000006
	cpu6: 0x0000000000000006
	cpu7: 0x0000000000000006

	after

	cpu0: 0x0000000000000000
	cpu1: 0x0000000000000006
	cpu2: 0x0000000000000006
	cpu3: 0x0000000000000006
	cpu4: 0x0000000000000006
	cpu5: 0x0000000000000006
	cpu6: 0x0000000000000006
	cpu7: 0x0000000000000006

Resulting in inconsistent energy policy settings across CPUs.

This register is set via init_intel() at bootup. During resume,
the secondary CPUs are brought online again and init_intel() is
callled which re-initializes the register. The boot CPU however
never reinitializes the register.

Add a syscore callback to reinitialize the register for the boot CPU.

Signed-off-by: Laura Abbott 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1437428878-4105-1-git-send-email-labbott@fedoraproject.org
Signed-off-by: Ingo Molnar

x86/fpu: Fix FPU related boot regression when CPUID masking BIOS feature is enabled

2015-06-30T05:22:10+00:00

Mike Galbraith reported:

  " My i7-4790 box is having one hell of a time with this merge
    window, dead in the water.

    BIOS setting "Limit CPUID Maximum" upsets new fpu code
    mightily. "

It turns out that Linux does a double workaround here, as per:

  066941bd4eeb ("x86: unmask CPUID levels on Intel CPUs")

it undoes the BIOS workaround - but as a side effect the CPUID
state is not completely constant during early init anymore,
and the new FPU init code did not take this into account.

So what happened is that the xstate init code did not have full
CPUID available, which broke subsequent attempts to use xstate
features.

Fix this by ordering the early FPU init code to after we've
stabilized the CPUID state.

Reported-bisected-and-tested-by: Mike Galbraith 
Cc: Andrew Morton 
Cc: Borislav Petkov 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20150627082514.GA10894@gmail.com
Signed-off-by: Ingo Molnar