linux-toradex.git/arch/mips/kernel, branch v4.4.2

MIPS: CPS: drop .set mips64r2 directives

2015-12-22T11:16:32+00:00

Commit 977e043d5ea1 ("MIPS: kernel: cps-vec: Replace mips32r2 ISA level
with mips64r2") leads to .set mips64r2 directives being present in 32
bit (ie. CONFIG_32BIT=y) kernels. This is incorrect & leads to MIPS64
instructions being emitted by the assembler when expanding
pseudo-instructions. For example the "move" instruction can legitimately
be expanded to a "daddu". This causes problems when the kernel is run on
a MIPS32 CPU, as CONFIG_32BIT kernels of course often are...

Fix this by dropping the .set  directives entirely now that Kconfig
should be ensuring that kernels including this code are built with a
suitable -march= compiler flag.

Signed-off-by: Paul Burton 
Cc: Markos Chandras 
Cc: James Hogan 
Cc:  # 3.16+
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10869/
Signed-off-by: Ralf Baechle

MIPS: uaccess: Take EVA into account in [__]clear_user

2015-12-22T10:58:43+00:00

__clear_user() (and clear_user() which uses it), always access the user
mode address space, which results in EVA store instructions when EVA is
enabled even if the current user address limit is KERNEL_DS.

Fix this by adding a new symbol __bzero_kernel for the normal kernel
address space bzero in EVA mode, and call that from __clear_user() if
eva_kernel_access().

Signed-off-by: James Hogan 
Cc: Markos Chandras 
Cc: Paul Burton 
Cc: Leonid Yegoshin 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10844/
Signed-off-by: Ralf Baechle

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

2015-11-15T17:10:53+00:00

Pull MIPS updates from Ralf Baechle:
 "These are the highlists of the main MIPS pull request for 4.4:

   - Add latencytop support
   - Support appended DTBs
   - VDSO support and initially use it for gettimeofday.
   - Drop the .MIPS.abiflags and ELF NOTE sections from vmlinux
   - Support for the 5KE, an internal test core.
   - Switch all MIPS platfroms to libata drivers.
   - Improved support, cleanups for ralink and Lantiq platforms.
   - Support for the new xilfpga platform.
   - A number of DTB improvments for BMIPS.
   - Improved support for CM and CPS.
   - Minor JZ4740 and BCM47xx enhancements"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (120 commits)
  MIPS: idle: add case for CPU_5KE
  MIPS: Octeon: Support APPENDED_DTB
  MIPS: vmlinux: create a section for appended DTB
  MIPS: Clean up compat_siginfo_t
  MIPS: Fix PAGE_MASK definition
  MIPS: BMIPS: Enable GZIP ramdisk and timed printks
  MIPS: Add xilfpga defconfig
  MIPS: xilfpga: Add mipsfpga platform code
  MIPS: xilfpga: Add xilfpga device tree files.
  dt-bindings: MIPS: Document xilfpga bindings and boot style
  MIPS: Make MIPS_CMDLINE_DTB default
  MIPS: Make the kernel arguments from dtb available
  MIPS: Use USE_OF as the guard for appended dtb
  MIPS: BCM63XX: Use pr_* instead of printk
  MIPS: Loongson: Cleanup CONFIG_LOONGSON_SUSPEND.
  MIPS: lantiq: Disable xbar fpi burst mode
  MIPS: lantiq: Force the crossbar to big endian
  MIPS: lantiq: Initialize the USB core on boot
  MIPS: lantiq: Return correct value for fpi clock on ar9
  MIPS: ralink: Add missing clock on rt305x
  ...

Merge branch '4.3-fixes' into mips-for-linux-next

2015-11-12T10:36:03+00:00

MIPS: idle: add case for CPU_5KE

2015-11-12T10:35:48+00:00

While the 5KE processors have never been taped out, they exists though
a CP0.PRId and experimental RTLs or QEMU implementations. Add a case
entry in the idle code, as they can use the standard idle loop like the
5K processors.

Signed-off-by: Aurelien Jarno 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11099/
Signed-off-by: Ralf Baechle

MIPS: vmlinux: create a section for appended DTB

2015-11-12T10:35:48+00:00

For bootloaders that support booting only ELF kernels and load only ELF
segments to memory there is no easy way to supply DTB without kernel
recompilation. For that purpose, create a section called .appended_dtb
that can be later updated with board-specific DTB using binutils e.g. at
kernel installation time.

Signed-off-by: Aaro Koskinen 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11114/
Signed-off-by: Ralf Baechle

MIPS: Make the kernel arguments from dtb available

2015-11-11T07:38:34+00:00

Similar to how arm allows using selecting between bootloader arguments,
dtb arguments and both, allow to select them on mips. But since we have
less control over the place of the dtb do not modify it but instead use
the boot_command_line for merging them.

The default is "use bootloader arguments" to keep the current behaviour
as default.

Signed-off-by: Jonas Gorski 
Cc: linux-mips@linux-mips.org
Cc: Kevin Cernekee 
Cc: Florian Fainelli 
Cc: Zubair Lutfullah Kakakhel 
Cc: James Hogan 
Cc: John Crispin 
Cc: Ganesan Ramalingam 
Cc: Jayachandran C 
Cc: Andrew Bresticker 
Cc: James Hartley 
Patchwork: https://patchwork.linux-mips.org/patch/11284/
Signed-off-by: Ralf Baechle

MIPS: Add LATENCYTOP support

2015-11-11T07:36:46+00:00

Add LATENCYTOP support for MIPS. Tested on OCTEON.

Signed-off-by: Aaro Koskinen 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11353/
Signed-off-by: Ralf Baechle

MIPS: VDSO: Add implementations of gettimeofday() and clock_gettime()

2015-11-11T07:36:41+00:00

Add user-mode implementations of gettimeofday() and clock_gettime() to
the VDSO. This is currently usable with 2 clocksources: the CP0 count
register, which is accessible to user-mode via RDHWR on R2 and later
cores, or the MIPS Global Interrupt Controller (GIC) timer, which
provides a "user-mode visible" section containing a mirror of its
counter registers. This section must be mapped into user memory, which
is done below the VDSO data page.

When a supported clocksource is not in use, the VDSO functions will
return -ENOSYS, which causes libc to fall back on the standard syscall
path.

When support for neither of these clocksources is compiled into the
kernel at all, the VDSO still provides clock_gettime(), as the coarse
realtime/monotonic clocks can still be implemented. However,
gettimeofday() is not provided in this case as nothing can be done
without a suitable clocksource. This causes the symbol lookup to fail
in libc and it will then always use the standard syscall path.

This patch includes a workaround for a bug in QEMU which results in
RDHWR on the CP0 count register always returning a constant (incorrect)
value. A fix for this has been submitted, and the workaround can be
removed after the fix has been in stable releases for a reasonable
amount of time.

A simple performance test which calls gettimeofday() 1000 times in a
loop and calculates the average execution time gives the following
results on a Malta + I6400 (running at 20MHz):

 - Syscall:    ~31000 ns
 - VDSO (GIC): ~15000 ns
 - VDSO (CP0): ~9500 ns

[markos.chandras@imgtec.com:
- Minor code re-arrangements in order for mappings to be made
in the order they appear to the process' address space.
- Move do_{monotonic, realtime} outside of the MIPS_CLOCK_VSYSCALL ifdef
- Use gic_get_usm_range so we can do the GIC mapping in the
arch/mips/kernel/vdso instead of the GIC irqchip driver]

Signed-off-by: Alex Smith 
Signed-off-by: Markos Chandras 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11338/
Signed-off-by: Ralf Baechle

MIPS: Initial implementation of a VDSO

2015-11-11T07:36:36+00:00

Add an initial implementation of a proper (i.e. an ELF shared library)
VDSO. With this commit it does not export any symbols, it only replaces
the current signal return trampoline page. A later commit will add user
implementations of gettimeofday()/clock_gettime().

To support both new toolchains and old ones which don't generate ABI
flags section, we define its content manually and then use a tool
(genvdso) to patch up the section to have the correct name and type.
genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the
kernel, and generates a C file containing a "struct mips_vdso_image"
containing both the VDSO data and these offsets. This C file is
compiled into the kernel.

On 64-bit kernels we require a different VDSO for each supported ABI,
so we may build up to 3 different VDSOs. The VDSO to use is selected by
the mips_abi structure.

A kernel/user shared data page is created and mapped below the VDSO
image. This is currently empty, but will be used by the user time
function implementations which are added later.

[markos.chandras@imgtec.com:
- Add more comments
- Move abi detection in genvdso.h since it's the get_symbol function
that needs it.
- Add an R6 specific way to calculate the base address of VDSO in order
to avoid the branch instruction which affects performance.
- Do not patch .gnu.attributes since it's not needed for dynamic linking.
- Simplify Makefile a little bit.
- checkpatch fixes
- Restrict VDSO support for binutils < 2.25 for pre-R6
- Include atomic64.h for O32 variant on MIPS64]

Signed-off-by: Alex Smith 
Signed-off-by: Markos Chandras 
Cc: Matthew Fortune 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11337/
Signed-off-by: Ralf Baechle