linux.git/arch/arc/kernel/setup.c, branch v5.1

ARC: unaligned: relax the check for gcc supporting -mno-unaligned-access

2019-03-05T17:16:33+00:00

Without bleeding edge gcc, kernel builds were tripping everywhere.

So current gcc will generate unaligned code despite
!CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS but that is something we have to
live with.

Signed-off-by: Vineet Gupta

ARC: boot log: cut down on verbosity

2019-02-25T23:12:23+00:00

The syscall ABI has long been fixed, so no need to call that out now.

Also, there's no need to print really fine details such as norm,
barrel-shifter etc. Those are given in a Linux enabled hardware config.
So now we print just 1 line for all optional "instruction" related
hardware features

|
| ISA Extn	: atomic ll64 unalign mpy[opt 9] div_rem

vs. 2 before

|
|ISA Extn	: atomic ll64 unalign
|		: mpy[opt 9] div_rem norm barrel-shift swap minmax swape

Signed-off-by: Vineet Gupta

ARCv2: boot log: refurbish HS core/release identification

2019-02-25T23:09:44+00:00

HS core names and releases have so far been identified based solely on
IDENTIFY.ARCVER field. With the future HS releases this will not
be sufficient as same ARCVER 0x54 could be an HS38 or HS48.

So rewrite the code to use a new BCR to identify the cores properly.

Signed-off-by: Vineet Gupta

ARC: u-boot args: check that magic number is correct

2019-02-25T20:11:01+00:00

In case of devboards we really often disable bootloader and load
Linux image in memory via JTAG. Even if kernel tries to verify
uboot_tag and uboot_arg there is sill a chance that we treat some
garbage in registers as valid u-boot arguments in JTAG case.
E.g. it is enough to have '1' in r0 to treat any value in r2 as
a boot command line.

So check that magic number passed from u-boot is correct and drop
u-boot arguments otherwise. That helps to reduce the possibility
of using garbage as u-boot arguments in JTAG case.

We can safely check U-boot magic value (0x0) in linux passed via
r1 register as U-boot pass it from the beginning. So there is no
backward-compatibility issues.

Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta

ARCv2: Add explcit unaligned access support (and ability to disable too)

2019-02-25T20:10:58+00:00

As of today we enable unaligned access unconditionally on ARCv2.
Do this under a Kconfig option to allow disable it for test, benchmarking
etc. Also while at it

  - Select HAVE_EFFICIENT_UNALIGNED_ACCESS
  - Although gcc defaults to unaligned access (since GNU 2018.03), add the
    right toggles for enabling or disabling as appropriate
  - update bootlog to prints both HW feature status (exists, enabled/disabled)
    and SW status (used / not used).
  - wire up the relaxed memcpy for unaligned access

Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta 
[vgupta: squashed patches, handle gcc -mno-unaligned-access quick]

ARCv2: don't assume core 0x54 has dual issue

2019-02-21T22:53:36+00:00

The first release of core4 (0x54) was dual issue only (HS4x).
Newer releases allow hardware to be configured as single issue (HS3x)
or dual issue.

Prevent accessing a HS4x only aux register in HS3x, which otherwise
leads to illegal instruction exceptions

Signed-off-by: Vineet Gupta

ARC: enable uboot support unconditionally

2019-02-21T19:03:19+00:00

After reworking U-boot args handling code and adding paranoid
arguments check we can eliminate CONFIG_ARC_UBOOT_SUPPORT and
enable uboot support unconditionally.

For JTAG case we can assume that core registers will come up
reset value of 0 or in worst case we rely on user passing
'-on=clear_regs' to Metaware debugger.

Cc: stable@vger.kernel.org
Tested-by: Corentin LABBE 
Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta

ARC: U-boot: check arguments paranoidly

2019-02-21T19:03:18+00:00

Handle U-boot arguments paranoidly:
 * don't allow to pass unknown tag.
 * try to use external device tree blob only if corresponding tag
   (TAG_DTB) is set.
 * don't check uboot_tag if kernel build with no ARC_UBOOT_SUPPORT.

NOTE:
If U-boot args are invalid we skip them and try to use embedded device
tree blob. We can't panic on invalid U-boot args as we really pass
invalid args due to bug in U-boot code.
This happens if we don't provide external DTB to U-boot and
don't set 'bootargs' U-boot environment variable (which is default
case at least for HSDK board) In that case we will pass
{r0 = 1 (bootargs in r2); r1 = 0; r2 = 0;} to linux which is invalid.

While I'm at it refactor U-boot arguments handling code.

Cc: stable@vger.kernel.org
Tested-by: Corentin LABBE 
Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta

ARC: fix actionpoints configuration detection

2019-02-21T19:03:16+00:00

Fix reversed logic while actionpoints configuration (full/min)
detection.

Fixies: 7dd380c338f1e ("ARC: boot log: print Action point details")
Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta

ARC: boot log: print Action point details

2019-01-17T22:38:00+00:00

This now prints the number of action points {2,4,8} and {min,full}
targets supported.

Signed-off-by: Vineet Gupta