linux-stable.git/arch/mips/kernel, branch v3.16.4

MIPS: mcount: Adjust stack pointer for static trace in MIPS32

2014-10-05T20:41:02+00:00

commit 8a574cfa2652545eb95595d38ac2a0bb501af0ae upstream.

Every mcount() call in the MIPS 32-bit kernel is done as follows:

[...]
move at, ra
jal _mcount
addiu sp, sp, -8
[...]

but upon returning from the mcount() function, the stack pointer
is not adjusted properly. This is explained in details in 58b69401c797
(MIPS: Function tracer: Fix broken function tracing).

Commit ad8c396936e3 ("MIPS: Unbreak function tracer for 64-bit kernel.)
fixed the stack manipulation for 64-bit but it didn't fix it completely
for MIPS32.

Signed-off-by: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7792/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: CPS: Initialize EVA before bringing up VPEs from secondary cores

2014-09-17T16:22:04+00:00

commit 6521d9a436a62e83ce57d6be6e5484e1098c1380 upstream.

The CPS code is doing several memory loads when configuring the VPEs
from secondary cores, so the segmentation control registers must be
initialized in time otherwise the kernel will crash with strange
TLB exceptions.

Reviewed-by: Paul Burton 
Signed-off-by: Markos Chandras 
Patchwork: http://patchwork.linux-mips.org/patch/7424/
Signed-off-by: James Hogan 
Signed-off-by: Greg Kroah-Hartman

MIPS: scall64-o32: Fix indirect syscall detection

2014-09-17T16:22:03+00:00

commit 5245689900804604fdc349c8d9b8985b0e401ae2 upstream.

Commit 4c21b8fd8f14 (MIPS: seccomp: Handle indirect system calls (o32))
added indirect syscall detection for O32 processes running on MIPS64
but it did not work as expected. The reason is the the scall64-o32
implementation differs compared to scall32-o32. In the former, the v0
(syscall number) register contains the absolute syscall number
(4000 + X) whereas in the latter it contains the relative syscall
number (X). Fix the code to avoid doing an extra addition, and load
the v0 register directly to the first argument for syscall_trace_enter.
Moreover, set the .reorder assembler option in order to have better
control on this part of the assembly code.

Signed-off-by: Markos Chandras 
Patchwork: http://patchwork.linux-mips.org/patch/7481/
Signed-off-by: James Hogan 
Signed-off-by: Greg Kroah-Hartman

MIPS: asm/reg.h: Make 32- and 64-bit definitions available at the same time

2014-09-17T16:22:03+00:00

commit bcec7c8da6b092b1ff3327fd83c2193adb12f684 upstream.

Get rid of the WANT_COMPAT_REG_H test and instead define both the 32-
and 64-bit register offset definitions at the same time with
MIPS{32,64}_ prefixes, then define the existing EF_* names to the
correct definitions for the kernel's bitness.

This patch is a prerequisite of the following bug fix patch.

Signed-off-by: Alex Smith 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7451/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: Remove BUG_ON(!is_fpu_owner()) in do_ade()

2014-09-17T16:22:03+00:00

commit 2e5767a27337812f6850b3fa362419e2f085e5c3 upstream.

In do_ade(), is_fpu_owner() isn't preempt-safe. For example, when an
unaligned ldc1 is executed, do_cpu() is called and then FPU will be
enabled (and TIF_USEDFPU will be set for the current process). Then,
do_ade() is called because the access is unaligned.  If the current
process is preempted at this time, TIF_USEDFPU will be cleard.  So when
the process is scheduled again, BUG_ON(!is_fpu_owner()) is triggered.

This small program can trigger this BUG in a preemptible kernel:

int main (int argc, char *argv[])
{
        double u64[2];

        while (1) {
                asm volatile (
                        ".set push \n\t"
                        ".set noreorder \n\t"
                        "ldc1 $f3, 4(%0) \n\t"
                        ".set pop \n\t"
                        ::"r"(u64):
                );
        }

        return 0;
}

V2: Remove the BUG_ON() unconditionally due to Paul's suggestion.

Signed-off-by: Huacai Chen 
Signed-off-by: Jie Chen 
Signed-off-by: Rui Wang 
Cc: John Crispin 
Cc: Steven J. Hill 
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang 
Cc: Zhangjin Wu 
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: Prevent user from setting FCSR cause bits

2014-09-17T16:22:02+00:00

commit b1442d39fac2fcfbe6a4814979020e993ca59c9e upstream.

If one or more matching FCSR cause & enable bits are set in saved thread
context then when that context is restored the kernel will take an FP
exception. This is of course undesirable and considered an oops, leading
to the kernel writing a backtrace to the console and potentially
rebooting depending upon the configuration. Thus the kernel avoids this
situation by clearing the cause bits of the FCSR register when handling
FP exceptions and after emulating FP instructions.

However the kernel does not prevent userland from setting arbitrary FCSR
cause & enable bits via ptrace, using either the PTRACE_POKEUSR or
PTRACE_SETFPREGS requests. This means userland can trivially cause the
kernel to oops on any system with an FPU. Prevent this from happening
by clearing the cause bits when writing to the saved FCSR context via
ptrace.

This problem appears to exist at least back to the beginning of the git
era in the PTRACE_POKEUSR case.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Cc: Paul Burton 
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7438/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: smp-mt: Fix link error when PROC_FS=n

2014-09-17T16:22:02+00:00

commit 7d907fa1c6ccb64c7f64cc7d3dcc7f6fe30a67b4 upstream.

Commit d6d3c9afaab4 (MIPS: MT: proc: Add support for printing VPE and TC
ids) causes a link error when CONFIG_PROC_FS=n:

arch/mips/built-in.o: In function `proc_cpuinfo_notifier_init':
smp-mt.c: undefined reference to `register_proc_cpuinfo_notifier'

This is fixed by adding an ifdef around the procfs handling code
in smp-mt.c.

Signed-off-by: James Hogan 
Reported-by: Markos Chandras 
Reviewed-by: Markos Chandras 
Cc: Ralf Baechle 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7244/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: ptrace: Avoid smp_processor_id() when retrieving FPU IR

2014-09-17T16:22:02+00:00

commit 656ff9bef08c19a6471b49528dacb4cbbeb1e537 upstream.

Whenever ptrace attempts to retrieve the FPU implementation register it
accesses it through current_cpu_data, which calls smp_processor_id().
Since the code may execute with preemption enabled, this can trigger
a warning. Fix this by using boot_cpu_data to get the IR instead.

Signed-off-by: Alex Smith 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7449/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: ptrace: Change GP regset to use correct core dump register layout

2014-09-17T16:22:01+00:00

commit c23b3d1a53119849dc3c23c417124deb067aa33d upstream.

Commit 6a9c001b7ec3 ("MIPS: Switch ELF core dumper to use regsets.")
switched the core dumper to use regsets, however the GP regset code
simply makes a direct copy of the kernel's pt_regs, which does not
match the original core dump register layout as defined in asm/reg.h.
Furthermore, the definition of pt_regs can vary with certain Kconfig
variables, therefore the GP regset can never be relied upon to return
registers in the same layout.

Therefore, this patch changes the GP regset to match the original core
dump layout. The layout differs for 32- and 64-bit processes, so
separate implementations of the get/set functions are added for the
32- and 64-bit regsets.

Signed-off-by: Alex Smith 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7452/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: ptrace: Test correct task's flags in task_user_regset_view()

2014-09-17T16:22:01+00:00

commit 65768a1a92cb12cbba87588927cf597a65d560aa upstream.

task_user_regset_view() should test for TIF_32BIT_REGS in the flags of
the specified task, not of the current task.

Signed-off-by: Alex Smith 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7450/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman