linux-stable.git/arch/mips/kernel/traps.c, branch v4.2.4

MIPS: show_stack: Fix stack trace with EVA

2015-08-03T07:25:17+00:00

The show_stack() function deals exclusively with kernel contexts, but if
it gets called in user context with EVA enabled, show_stacktrace() will
attempt to access the stack using EVA accesses, which will either read
other user mapped data, or more likely cause an exception which will be
handled by __get_user().

This is easily reproduced using SysRq t to show all task states, which
results in the following stack dump output:

 Stack : (Bad stack address)

Fix by setting the current user access mode to kernel around the call to
show_stacktrace(). This causes __get_user() to use normal loads to read
the kernel stack.

Now we get the correct output, like this:

 Stack : 00000000 80168960 00000000 004a0000 00000000 00000000 8060016c 1f3abd0c
           1f172cd8 8056f09c 7ff1e450 8014fc3c 00000001 806dd0b0 0000001d 00000002
           1f17c6a0 1f17c804 1f17c6a0 8066f6e0 00000000 0000000a 00000000 00000000
           00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
           00000000 00000000 00000000 00000000 00000000 0110e800 1f3abd6c 1f17c6a0
           ...

Signed-off-by: James Hogan 
Cc: Markos Chandras 
Cc: Leonid Yegoshin 
Cc: linux-mips@linux-mips.org
Cc:  # 3.15+
Patchwork: https://patchwork.linux-mips.org/patch/10778/
Signed-off-by: Ralf Baechle

MIPS: do_mcheck: Fix kernel code dump with EVA

2015-08-03T07:25:14+00:00

If a machine check exception is raised in kernel mode, user context,
with EVA enabled, then the do_mcheck handler will attempt to read the
code around the EPC using EVA load instructions, i.e. as if the reads
were from user mode. This will either read random user data if the
process has anything mapped at the same address, or it will cause an
exception which is handled by __get_user, resulting in this output:

 Code: (Bad address in epc)

Fix by setting the current user access mode to kernel if the saved
register context indicates the exception was taken in kernel mode. This
causes __get_user to use normal loads to read the kernel code.

Signed-off-by: James Hogan 
Cc: Markos Chandras 
Cc: Leonid Yegoshin 
Cc: linux-mips@linux-mips.org
Cc:  # 3.15+
Patchwork: https://patchwork.linux-mips.org/patch/10777/
Signed-off-by: Ralf Baechle

MIPS: kernel: traps: Fix broken indentation

2015-07-09T09:09:47+00:00

Fix broken indentation caused by the SMTC removal
commit b633648c5ad3cfbda0b3daea50d2135d44899259
("MIPS: MT: Remove SMTC support")

Signed-off-by: Markos Chandras 
Fixes: b633648c5ad3c ("MIPS: MT: Remove SMTC support")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10581/
Signed-off-by: Ralf Baechle

MIPS: Get rid of 'kgdb_early_setup' cruft.

2015-06-21T19:54:10+00:00

Commit 854700115ecf ([MIPS] kgdb: add arch support for the kernel's kgdb core)
added the 'kgdb_early_setup' flag to avoid  calling trap_init() and init_IRQ()
the second time, however the code that called these functions earlier,  from
kgdb_arch_init(), had been already removed by that  time,  so the flag never
served any useful purpose. Remove the related code along with ugly #ifdef'ery
at last.

[ralf@linux-mips.org: Folded in Guenter Roeck's fix.]

Signed-off-by: Sergei Shtylyov 
Patchwork: https://patchwork.linux-mips.org/patch/10501/
Signed-off-by: Guenter Roeck 
Patchwork: https://patchwork.linux-mips.org/patch/10533/
Signed-off-by: Ralf Baechle

MIPS: traps: print Exception Code in __show_regs()

2015-06-21T19:52:26+00:00

Print Exception Code when printing the Cause register.

Signed-off-by: Petri Gynther 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9998/
Signed-off-by: Ralf Baechle

MIPS: traps: remove extra Tainted: line from __show_regs() output

2015-05-12T21:50:33+00:00

__show_regs() calls show_regs_print_info(), which already outputs
the Tainted: information. So, no need to output it twice.

Signed-off-by: Petri Gynther 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9997/
Signed-off-by: Ralf Baechle

Merge tag 'cpumask-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-04-20T17:19:03+00:00

Pull final removal of deprecated cpus_* cpumask functions from Rusty Russell:
 "This is the final removal (after several years!) of the obsolete
  cpus_* functions, prompted by their mis-use in staging.

  With these function removed, all cpu functions should only iterate to
  nr_cpu_ids, so we finally only allocate that many bits when cpumasks
  are allocated offstack"

* tag 'cpumask-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (25 commits)
  cpumask: remove __first_cpu / __next_cpu
  cpumask: resurrect CPU_MASK_CPU0
  linux/cpumask.h: add typechecking to cpumask_test_cpu
  cpumask: only allocate nr_cpumask_bits.
  Fix weird uses of num_online_cpus().
  cpumask: remove deprecated functions.
  mips: fix obsolete cpumask_of_cpu usage.
  x86: fix more deprecated cpu function usage.
  ia64: remove deprecated cpus_ usage.
  powerpc: fix deprecated CPU_MASK_CPU0 usage.
  CPU_MASK_ALL/CPU_MASK_NONE: remove from deprecated region.
  staging/lustre/o2iblnd: Don't use cpus_weight
  staging/lustre/libcfs: replace deprecated cpus_ calls with cpumask_
  staging/lustre/ptlrpc: Do not use deprecated cpus_* functions
  blackfin: fix up obsolete cpu function usage.
  parisc: fix up obsolete cpu function usage.
  tile: fix up obsolete cpu function usage.
  arm64: fix up obsolete cpu function usage.
  mips: fix up obsolete cpu function usage.
  x86: fix up obsolete cpu function usage.
  ...

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2015-04-17T19:50:54+00:00

Pull MIPS updates from Ralf Baechle:
 "This is the main pull request for MIPS for Linux 4.1.  Most
  noteworthy:

   - Add more Octeon-optimized crypto functions
   - Octeon crypto preemption and locking fixes
   - Little endian support for Octeon
   - Use correct CSR to soft reset Octeons
   - Support LEDs on the Octeon-based DSR-1000N
   - Fix PCI interrupt mapping for the Octeon-based DSR-1000N
   - Mark prom_free_prom_memory() as __init for a number of systems
   - Support for Imagination's Pistachio SOC.  This includes arch and
     CLK bits.  I'd like to merge pinctrl bits later
   - Improve parallelism of csum_partial for certain pipelines
   - Organize DTB files in subdirs like other architectures
   - Implement read_sched_clock for all MIPS platforms other than
     Octeon
   - Massive series of 38 fixes and cleanups for the FPU emulator /
     kernel
   - Further FPU remulator work to support new features.  This sits on a
     separate branch which also has been pulled into the 4.1 KVM branch
   - Clean up and fixes for the SEAD3 eval board; remove unused file
   - Various updates for Netlogic platforms
   - A number of small updates for Loongson 3 platforms
   - Increase the memory limit for ATH79 platforms to 256MB
   - A fair number of fixes and updates for BCM47xx platforms
   - Finish the implementation of XPA support
   - MIPS FDC support.  No, not floppy controller but Fast Debug Channel :)
   - Detect the R16000 used in SGI legacy platforms
   - Fix Kconfig dependencies for the SSB bus support"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (265 commits)
  MIPS: Makefile: Fix MIPS ASE detection code
  MIPS: asm: elf: Set O32 default FPU flags
  MIPS: BCM47XX: Fix detecting Microsoft MN-700 & Asus WL500G
  MIPS: Kconfig: Disable SMP/CPS for 64-bit
  MIPS: Hibernate: flush TLB entries earlier
  MIPS: smp-cps: cpu_set FPU mask if FPU present
  MIPS: lose_fpu(): Disable FPU when MSA enabled
  MIPS: ralink: add missing symbol for RALINK_ILL_ACC
  MIPS: ralink: Fix bad config symbol in PCI makefile.
  SSB: fix Kconfig dependencies
  MIPS: Malta: Detect and fix bad memsize values
  Revert "MIPS: Avoid pipeline stalls on some MIPS32R2 cores."
  MIPS: Octeon: Delete override of cpu_has_mips_r2_exec_hazard.
  MIPS: Fix cpu_has_mips_r2_exec_hazard.
  MIPS: kernel: entry.S: Set correct ISA level for mips_ihb
  MIPS: asm: spinlock: Fix addiu instruction for R10000_LLSC_WAR case
  MIPS: r4kcache: Use correct base register for MIPS R6 cache flushes
  MIPS: Kconfig: Fix typo for the r2-to-r6 emulator kernel parameter
  MIPS: unaligned: Fix regular load/store instruction emulation for EVA
  MIPS: unaligned: Surround load/store macros in do {} while statements
  ...

MIPS: Set `si_code' for SIGFPE signals sent from emulation too

2015-04-07T23:10:19+00:00

Rework `process_fpemu_return' and move IEEE 754 exception interpretation
there, from `do_fpe'.  Record the cause bits set in FCSR before they are
cleared and pass them through to `process_fpemu_return' so as to set
`si_code' correctly too for SIGFPE signals sent from emulation rather
than those issued by hardware with the FPE processor exception only.

For simplicity `mipsr2_decoder' assumes `*fcr31' has been preinitialised
and only sets it to anything if an FPU instruction has been emulated,
which in turn is the only case SIGFPE can be issued for here.

Signed-off-by: Maciej W. Rozycki 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9705/
Signed-off-by: Ralf Baechle

MIPS: Always clear FCSR cause bits after emulation

2015-04-07T23:10:17+00:00

Clear any FCSR cause bits recorded in the saved FPU context after
emulation in all cases rather than in `do_fpe' only, so that any
unmasked IEEE 754 exception left from emulation does not cause a fatal
kernel-mode FPE hardware exception with the CTC1 instruction used by the
kernel to subsequently restore FCSR hardware from the saved FPU context.

Signed-off-by: Maciej W. Rozycki 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9704/
Signed-off-by: Ralf Baechle