linux-stable.git/arch/nds32/kernel, branch linux-5.0.y

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57+00:00

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds

Merge tag 'nds32-for-linus-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux

2018-12-29T17:37:03+00:00

Pull nds32 updates from Greentime Hu:

 - Perf support

 - Power management support

 - FPU support

 - Hardware prefetcher support

 - Build error fixed

 - Performance enhancement

* tag 'nds32-for-linus-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux:
  nds32: support hardware prefetcher
  nds32: Fix the items of hwcap_str ordering issue.
  math-emu/soft-fp.h: (_FP_ROUND_ZERO) cast 0 to void to fix warning
  math-emu/op-2.h: Use statement expressions to prevent negative constant shift
  nds32: support denormalized result through FP emulator
  nds32: Support FP emulation
  nds32: nds32 FPU port
  nds32: Remove duplicated include from pm.c
  nds32: Power management for nds32
  nds32: Add document for NDS32 PMU.
  nds32: Add perf call-graph support.
  nds32: Perf porting
  nds32: Fix bug in bitfield.h
  nds32: Fix gcc 8.0 compiler option incompatible.
  nds32: Fill all TLB entries with kernel image mapping
  nds32: Remove the redundant assignment

nds32: function_graph: Simplify with function_graph_enter()

2018-11-28T01:30:43+00:00

The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().

Have nds32 use the new code, and remove the shadow stack management as well as
having to set up the trace structure.

This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.

Cc: Greentime Hu 
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

nds32: support hardware prefetcher

2018-11-22T10:13:51+00:00

We add a config for user to enable or disable this feature.
It can be used to control the hardware prefetch function.

Signed-off-by: Nylon Chen 
Acked-by: Greentime Hu 
Signed-off-by: Greentime Hu

nds32: Fix the items of hwcap_str ordering issue.

2018-11-22T10:13:51+00:00

The hwcap_str should be set in a correct order according to HWCAP_xx.
We also add the missing "fpu_dp" to it.

Signed-off-by: Nylon Chen 
Acked-by: Greentime Hu 
Signed-off-by: Greentime Hu

nds32: support denormalized result through FP emulator

2018-11-22T10:13:27+00:00

Currently, the nds32 FPU dose not support the arithmetic of denormalized
number. When the nds32 FPU finds the result of the instruction is a
denormlized number, the nds32 FPU considers it to be an underflow condition
and rounds the result to an appropriate number. It may causes some loss
of precision. This commit proposes a solution to re-execute the
instruction by the FPU emulator to enhance the precision. To transfer
calculations from user space to kernel space, this feature will enable
the underflow exception trap by default. Enabling this feature may cause
some side effects:
  1. Performance loss due to extra FPU exception
  2. Need another scheme to control real underflow trap
       A new parameter, UDF_trap, which is belong to FPU context is used
     to control underflow trap.

User can configure this feature via CONFIG_SUPPORT_DENORMAL_ARITHMETIC

Signed-off-by: Vincent Chen 
Acked-by: Greentime Hu 
Signed-off-by: Greentime Hu

nds32: Support FP emulation

2018-11-22T10:13:21+00:00

The Andes FPU coprocessor does not support denormalized number handling.
According to the specification, FPU generates a denorm input exception
that requires the kernel to deal with this instrution operation when it
encounters denormalized operands. Hence an nds32 FPU ISA emulator in the
kernel is required to meet requirement.

Signed-off-by: Vincent Chen 
Signed-off-by: Nickhu 
Acked-by: Greentime Hu 
Signed-off-by: Greentime Hu

nds32: nds32 FPU port

2018-11-22T10:13:13+00:00

This patch set contains basic components for supporting the nds32 FPU,
such as exception handlers and context switch for FPU registers. By
default, the lazy FPU scheme is supported and the user can configure it via
CONFIG_LZAY_FPU.

Signed-off-by: Vincent Chen 
Acked-by: Greentime Hu 
Signed-off-by: Greentime Hu

nds32: Remove duplicated include from pm.c

2018-11-06T10:01:41+00:00

Remove duplicated include.

Signed-off-by: YueHaibing 
Acked-by: Pavel Machek 
Acked-by: Greentime Hu 
Signed-off-by: Greentime Hu

nds32: Power management for nds32

2018-11-06T10:01:41+00:00

There are three sleep states in nds32:
	suspend to idle,
	suspend to standby,
	suspend to ram

In suspend to ram, we use the 'standby' instruction to emulate
power management device to hang the system util wakeup source
send wakeup events to break the loop.

First, we push the general purpose registers and system registers
to stack. Second, we translate stack pointer to physical address
and store to memory to save the stack pointer. Third, after write
back and invalid the cache we hang in 'standby' intruction.
When wakeup source trigger wake up events, the loop will be break
and resume the system.

Signed-off-by: Nick Hu 
Acked-by: Pavel Machek 
Acked-by: Greentime Hu 
Signed-off-by: Greentime Hu