linux-stable.git/arch/mips, branch v5.3.5

mips: properly account for stack randomization and stack guard gap

2019-10-07T17:01:45+00:00

[ Upstream commit b1f61b5bde3a1f50392c97b4c8513d1b8efb1cf2 ]

This commit takes care of stack randomization and stack guard gap when
computing mmap base address and checks if the task asked for
randomization.  This fixes the problem uncovered and not fixed for arm
here: https://lkml.kernel.org/r/20170622200033.25714-1-riel@redhat.com

Link: http://lkml.kernel.org/r/20190730055113.23635-10-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti 
Acked-by: Kees Cook 
Acked-by: Paul Burton 
Reviewed-by: Luis Chamberlain 
Cc: Albert Ou 
Cc: Alexander Viro 
Cc: Catalin Marinas 
Cc: Christoph Hellwig 
Cc: Christoph Hellwig 
Cc: James Hogan 
Cc: Palmer Dabbelt 
Cc: Ralf Baechle 
Cc: Russell King 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

mips/atomic: Fix smp_mb__{before,after}_atomic()

2019-10-07T17:01:34+00:00

[ Upstream commit 42344113ba7a1ed7b5654cd5270af0d5698d8521 ]

Recent probing at the Linux Kernel Memory Model uncovered a
'surprise'. Strongly ordered architectures where the atomic RmW
primitive implies full memory ordering and
smp_mb__{before,after}_atomic() are a simple barrier() (such as MIPS
without WEAK_REORDERING_BEYOND_LLSC) fail for:

	*x = 1;
	atomic_inc(u);
	smp_mb__after_atomic();
	r0 = *y;

Because, while the atomic_inc() implies memory order, it
(surprisingly) does not provide a compiler barrier. This then allows
the compiler to re-order like so:

	atomic_inc(u);
	*x = 1;
	smp_mb__after_atomic();
	r0 = *y;

Which the CPU is then allowed to re-order (under TSO rules) like:

	atomic_inc(u);
	r0 = *y;
	*x = 1;

And this very much was not intended. Therefore strengthen the atomic
RmW ops to include a compiler barrier.

Reported-by: Andrea Parri 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Paul Burton 
Signed-off-by: Sasha Levin

mips/atomic: Fix loongson_llsc_mb() wreckage

2019-10-07T17:01:32+00:00

[ Upstream commit 1c6c1ca318585f1096d4d04bc722297c85e9fb8a ]

The comment describing the loongson_llsc_mb() reorder case doesn't
make any sense what so ever. Instruction re-ordering is not an SMP
artifact, but rather a CPU local phenomenon. Clarify the comment by
explaining that these issue cause a coherence fail.

For the branch speculation case; if futex_atomic_cmpxchg_inatomic()
needs one at the bne branch target, then surely the normal
__cmpxch_asm() implementation does too. We cannot rely on the
barriers from cmpxchg() because cmpxchg_local() is implemented with
the same macro, and branch prediction and speculation are, too, CPU
local.

Fixes: e02e07e3127d ("MIPS: Loongson: Introduce and use loongson_llsc_mb()")
Cc: Huacai Chen 
Cc: Huang Pei 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Paul Burton 
Signed-off-by: Sasha Levin

MIPS: tlbex: Explicitly cast _PAGE_NO_EXEC to a boolean

2019-10-07T17:01:29+00:00

[ Upstream commit c59ae0a1055127dd3828a88e111a0db59b254104 ]

clang warns:

arch/mips/mm/tlbex.c:634:19: error: use of logical '&&' with constant
operand [-Werror,-Wconstant-logical-operand]
        if (cpu_has_rixi && _PAGE_NO_EXEC) {
                         ^  ~~~~~~~~~~~~~
arch/mips/mm/tlbex.c:634:19: note: use '&' for a bitwise operation
        if (cpu_has_rixi && _PAGE_NO_EXEC) {
                         ^~
                         &
arch/mips/mm/tlbex.c:634:19: note: remove constant to silence this
warning
        if (cpu_has_rixi && _PAGE_NO_EXEC) {
                        ~^~~~~~~~~~~~~~~~
1 error generated.

Explicitly cast this value to a boolean so that clang understands we
intend for this to be a non-zero value.

Fixes: 00bf1c691d08 ("MIPS: tlbex: Avoid placing software PTE bits in Entry* PFN fields")
Link: https://github.com/ClangBuiltLinux/linux/issues/609
Signed-off-by: Nathan Chancellor 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Nick Desaulniers 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Signed-off-by: Sasha Levin

MIPS: Don't use bc_false uninitialized in __mm_isBranchInstr

2019-10-07T17:01:29+00:00

[ Upstream commit c2869aafe7191d366d74c55cb8a93c6d0baba317 ]

clang warns:

arch/mips/kernel/branch.c:148:8: error: variable 'bc_false' is used
uninitialized whenever switch case is taken
[-Werror,-Wsometimes-uninitialized]
                case mm_bc2t_op:
                     ^~~~~~~~~~
arch/mips/kernel/branch.c:157:8: note: uninitialized use occurs here
                        if (bc_false)
                            ^~~~~~~~
arch/mips/kernel/branch.c:149:8: error: variable 'bc_false' is used
uninitialized whenever switch case is taken
[-Werror,-Wsometimes-uninitialized]
                case mm_bc1t_op:
                     ^~~~~~~~~~
arch/mips/kernel/branch.c:157:8: note: uninitialized use occurs here
                        if (bc_false)
                            ^~~~~~~~
arch/mips/kernel/branch.c:142:4: note: variable 'bc_false' is declared
here
                        int bc_false = 0;
                        ^
2 errors generated.

When mm_bc1t_op and mm_bc2t_op are taken, the bc_false initialization
does not happen, which leads to a garbage value upon use, as illustrated
below with a small sample program.

$ mipsel-linux-gnu-gcc --version | head -n1
mipsel-linux-gnu-gcc (Debian 8.3.0-2) 8.3.0

$ clang --version | head -n1
ClangBuiltLinux clang version 9.0.0 (git://github.com/llvm/llvm-project
544315b4197034a3be8acd12cba56a75fb1f08dc) (based on LLVM 9.0.0svn)

$ cat test.c
 #include 

 static void switch_scoped(int opcode)
 {
	 switch (opcode) {
	 case 1:
	 case 2: {
		 int bc_false = 0;

		 bc_false = 4;
	 case 3:
	 case 4:
		 printf("\t* switch scoped bc_false = %d\n", bc_false);
	 }
	 }
 }

 static void function_scoped(int opcode)
 {
	 int bc_false = 0;

	 switch (opcode) {
	 case 1:
	 case 2: {
		 bc_false = 4;
	 case 3:
	 case 4:
		 printf("\t* function scoped bc_false = %d\n", bc_false);
	 }
	 }
 }

 int main(void)
 {
	 int opcode;

	 for (opcode = 1; opcode < 5; opcode++) {
		 printf("opcode = %d:\n", opcode);
		 switch_scoped(opcode);
		 function_scoped(opcode);
		 printf("\n");
	 }

	 return 0;
 }

$ mipsel-linux-gnu-gcc -std=gnu89 -static test.c && \
  qemu-mipsel a.out
opcode = 1:
        * switch scoped bc_false = 4
        * function scoped bc_false = 4

opcode = 2:
        * switch scoped bc_false = 4
        * function scoped bc_false = 4

opcode = 3:
        * switch scoped bc_false = 2147483004
        * function scoped bc_false = 0

opcode = 4:
        * switch scoped bc_false = 2147483004
        * function scoped bc_false = 0

$ clang -std=gnu89 --target=mipsel-linux-gnu -m32 -static test.c && \
  qemu-mipsel a.out
opcode = 1:
        * switch scoped bc_false = 4
        * function scoped bc_false = 4

opcode = 2:
        * switch scoped bc_false = 4
        * function scoped bc_false = 4

opcode = 3:
        * switch scoped bc_false = 2147483004
        * function scoped bc_false = 0

opcode = 4:
        * switch scoped bc_false = 2147483004
        * function scoped bc_false = 0

Move the definition up so that we get the right behavior and mark it
__maybe_unused as it will not be used when CONFIG_MIPS_FP_SUPPORT
isn't enabled.

Fixes: 6a1cc218b9cc ("MIPS: branch: Remove FP branch handling when CONFIG_MIPS_FP_SUPPORT=n")
Link: https://github.com/ClangBuiltLinux/linux/issues/603
Signed-off-by: Nathan Chancellor 
Signed-off-by: Paul Burton 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Nick Desaulniers 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Signed-off-by: Sasha Levin

MIPS: Ingenic: Disable broken BTB lookup optimization.

2019-10-07T17:01:29+00:00

[ Upstream commit 053951dda71ecb4b554a2cdbe26f5f6f9bee9dd2 ]

In order to further reduce power consumption, the XBurst core
by default attempts to avoid branch target buffer lookups by
detecting & special casing loops. This feature will cause
BogoMIPS and lpj calculate in error. Set cp0 config7 bit 4 to
disable this feature.

Signed-off-by: Zhou Yanjie 
Signed-off-by: Paul Burton 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: ralf@linux-mips.org
Cc: paul@crapouillou.net
Cc: jhogan@kernel.org
Cc: malat@debian.org
Cc: gregkh@linuxfoundation.org
Cc: tglx@linutronix.de
Cc: allison@lohutok.net
Cc: syq@debian.org
Cc: chenhc@lemote.com
Cc: jiaxun.yang@flygoat.com
Signed-off-by: Sasha Levin

Merge tag 'Wimplicit-fallthrough-5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

2019-08-22T18:26:10+00:00

Pull more fallthrough fixes from Gustavo A. R. Silva:
 "Fix fall-through warnings on arm and mips for multiple configurations"

* tag 'Wimplicit-fallthrough-5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  video: fbdev: acornfb: Mark expected switch fall-through
  scsi: libsas: sas_discover: Mark expected switch fall-through
  MIPS: Octeon: Mark expected switch fall-through
  power: supply: ab8500_charger: Mark expected switch fall-through
  watchdog: wdt285: Mark expected switch fall-through
  mtd: sa1100: Mark expected switch fall-through
  drm/sun4i: tcon: Mark expected switch fall-through
  drm/sun4i: sun6i_mipi_dsi: Mark expected switch fall-through
  ARM: riscpc: Mark expected switch fall-through
  dmaengine: fsldma: Mark expected switch fall-through

MIPS: Octeon: Mark expected switch fall-through

2019-08-21T00:43:47+00:00

Mark switch cases where we are expecting to fall through.

Fix the following warning (Building: cavium_octeon_defconfig mips):

arch/mips/include/asm/octeon/cvmx-sli-defs.h:47:6: warning: this statement
may fall through [-Wimplicit-fallthrough=]

Signed-off-by: Gustavo A. R. Silva

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2019-08-09T22:46:29+00:00

Pull kvm fixes from Paolo Bonzini:
 "Bugfixes (arm and x86) and cleanups"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  selftests: kvm: Adding config fragments
  KVM: selftests: Update gitignore file for latest changes
  kvm: remove unnecessary PageReserved check
  KVM: arm/arm64: vgic: Reevaluate level sensitive interrupts on enable
  KVM: arm: Don't write junk to CP15 registers on reset
  KVM: arm64: Don't write junk to sysregs on reset
  KVM: arm/arm64: Sync ICH_VMCR_EL2 back when about to block
  x86: kvm: remove useless calls to kvm_para_available
  KVM: no need to check return value of debugfs_create functions
  KVM: remove kvm_arch_has_vcpu_debugfs()
  KVM: Fix leak vCPU's VMCS value into other pCPU
  KVM: Check preempted_in_kernel for involuntary preemption
  KVM: LAPIC: Don't need to wakeup vCPU twice afer timer fire
  arm64: KVM: hyp: debug-sr: Mark expected switch fall-through
  KVM: arm64: Update kvm_arm_exception_class and esr_class_str for new EC
  KVM: arm: vgic-v3: Mark expected switch fall-through
  arm64: KVM: regmap: Fix unexpected switch fall-through
  KVM: arm/arm64: Introduce kvm_pmu_vcpu_init() to setup PMU counter index

Merge tag 'kvmarm-fixes-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2019-08-09T14:53:39+00:00

KVM/arm fixes for 5.3

- A bunch of switch/case fall-through annotation, fixing one actual bug
- Fix PMU reset bug
- Add missing exception class debug strings