Rename 'eva_entry' to 'platform_eva_init' as required by the new
'eva_init' macro in the eva.h header. Since this macro is now used
in a platform dependent way, it must not depend on its caller so move
the t1 register initialization inside this macro. Also set the .reorder
assembler option in case the caller may have previously set .noreorder.
This may allow a few assembler optimizations. Finally include missing
headers and document the register usage for this macro.
Reviewed-by: NPaul Burton <paul.burton@imgtec.com>
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>
Patchwork: http://patchwork.linux-mips.org/patch/7423/Signed-off-by: NJames Hogan <james.hogan@imgtec.com>

Generic code may need to perform certain operations when EVA is
enabled, for example, configure the segmentation registers during
boot. In order to avoid using more CONFIG_EVA ifdefs in the arch code,
such functions will be added in this header instead.
Initially this header contains a macro which will be used by generic
code later on during VPEs configuration on secondary cores.
All it does is to call the platform specific EVA init code in case
EVA is enabled.
Reviewed-by: NPaul Burton <paul.burton@imgtec.com>
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>
Patchwork: http://patchwork.linux-mips.org/patch/7422/Signed-off-by: NJames Hogan <james.hogan@imgtec.com>

Commit 4c21b8fd (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: NMarkos Chandras <markos.chandras@imgtec.com>
Patchwork: http://patchwork.linux-mips.org/patch/7481/
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>

On MIPS64, O32 processes set both TIF_32BIT_ADDR and
TIF_32BIT_REGS so the previous condition treated O32 applications
as N32 when evaluating seccomp filters. Fix the condition to check
both TIF_32BIT_{REGS, ADDR} for the N32 AUDIT flag.
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>
Patchwork: http://patchwork.linux-mips.org/patch/7480/
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>

In preemptible kernel, only TIF_USEDFPU flag is reliable to distinguish
whether _init_fpu()/_restore_fp() is needed. Because the value of the
CP0_Status.CU1 isn't changed during preemption.

V2: Fix coding style.
Signed-off-by: NHuacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/7515/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The nlm_xlp_defconfig build fails with

./arch/mips/include/asm/mach-netlogic/topology.h:15:0:
			error: "topology_core_id" redefined [-Werror]
In file included from include/linux/smp.h:59:0,
	[ ...]
                 from arch/mips/mm/dma-default.c:12:
./arch/mips/include/asm/smp.h:41:0:
			note: this is the location of the previous definition

and similar errors.

This is caused by commit bda4584c ("MIPS: Support CPU topology files
in sysfs") which adds the defines to arch/mips/include/asm/smp.h.

Remove the defines from arch/mips/include/asm/mach-netlogic/topology.h
as no longer necessary.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7513/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Multicore MIPSes without I/D hardware coherency suffered from a race
condition in the page fault handler. The page table entry was
published before any pending lazy D-cache flush was committed, hence
it allowed execution of stale page cache data by other VPEs in the
system.

To make the cache handling safe we need to perform flushing already in
the set_pte_at function. MIPSes without coherent I-caches can get a
small increase in flushes due to the unavailability of the execute
flag in set_pte_at.

[ralf@linux-mips.org: outlining set_pte_at() saves a good k in a test
build, so I moved its definition from pgtable.h to cache.c.]
Signed-off-by: NLars Persson <larper@axis.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7511/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Using kstrtol to parse the "{e,}memsize" variables was wrong because this
parses signed long numbers. In case of '{e,}memsize' >= 2G, the top bit
is set, resulting to -ERANGE errors and possibly random system memory
boundaries. We fix this by replacing "kstrtol" with "kstrtoul".
We also improve the code to check the kstrtoul return value and
print a warning if an error was returned.
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # v3.15+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7543/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Enable PSC0 (I2C/SPI) clock and leave PSC1 (Audio) alone.  This patch
restores functionality to both Audio and I2C/SPI.
Signed-off-by: NManuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7544/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This adds some code based on code from the Broadcom GPL tar to fix the
reboot problems on BCM4705/BCM4785. I tried rebooting my device for ~10
times and have never seen a problem. This reverts the changes in the
previous commit and adds the real fix as suggested by Rafał.

Setting bit 22 in Reg 22, sel 4 puts the BIU (Bus Interface Unit) into
async mode.

The previous commit was 316cad5c [MIPS:
BCM47XX: make reboot more relaiable]
Signed-off-by: NHauke Mehrtens <hauke@hauke-m.de>
Cc: jogo@openwrt.org
Cc: zajec5@gmail.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7545/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7537/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Add common declaration to get rid of following sparse warning: "symbol
'plat_irq_dispatch' was not declared. Should it be static?"
Signed-off-by: NSergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Linux MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7539/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Remove unused argument to make the plat_irq_dispatch() function
declaration similar to the realization of other platforms.
Signed-off-by: NSergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Linux MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7538/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

In RT kernel, I ran into the following calltrace, so PMU interrupts cannot
be threaded

in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/0
INFO: lockdep is turned off.
Call Trace:
[<ffffffff8088595c>] dump_stack+0x1c/0x50
[<ffffffff801a958c>] __might_sleep+0x13c/0x148
[<ffffffff80891c54>] rt_spin_lock+0x3c/0xb0
[<ffffffff801ad29c>] __wake_up+0x3c/0x80
[<ffffffff80243ba4>] perf_event_wakeup+0x8c/0xf8
[<ffffffff80243c50>] perf_pending_event+0x40/0x78
[<ffffffff8023d88c>] irq_work_run+0x74/0xc0
[<ffffffff80152640>] mipsxx_pmu_handle_shared_irq+0x110/0x228
[<ffffffff8015276c>] mipsxx_pmu_handle_irq+0x14/0x30
[<ffffffff801ffda4>] handle_irq_event_percpu+0xbc/0x470
[<ffffffff80204478>] handle_percpu_irq+0x98/0xc8
[<ffffffff801ff284>] generic_handle_irq+0x4c/0x68
[<ffffffff8089748c>] do_IRQ+0x2c/0x48
[<ffffffff80105864>] plat_irq_dispatch+0x64/0xd0

[ralf@linux-mips.org: I don't see why based on this register dump the
handler should be marked IRQF_NO_THREAD - but the handler is manipulating
per-CPU resources so we don't want it to be rescheduled to another CPU.]
Signed-off-by: NYang Wei <Wei.Yang@windriver.com>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: mingo@redhat.com
Cc: acme@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7506/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Since there is not indirection page in crash type, so the vaule of the head
field of kimage structure is not equal to the address of indirection page but
IND_DONE. so we have to set kexec_indirection_page variable to the address of
the head field of image structure.

[ralf@linux-mips.org: Don't add pointless empty line, fix trailing
whitespace damage.]
Signed-off-by: NYang Wei <Wei.Yang@windriver.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7499/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Load purgatory code in RAM and relocate it based on the location.
Relocation code has been inspired by module relocation code and purgatory
relocation code in kexec-tools.

Also compute the checksums of loaded kexec segments and store them in
purgatory.

Arch independent code provides this functionality so that arch dependent
bootloaders can make use of it.

Helper functions are provided to get/set symbol values in purgatory which
are used by bootloaders later to set things like stack and entry point of
second kernel etc.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use sigsp() instead of the open coded variant.
Signed-off-by: NRichard Weinberger <richard@nod.at>

Use the more generic functions get_signal() signal_setup_done()
for signal delivery.
Signed-off-by: NRichard Weinberger <richard@nod.at>

clean up names related to socket filtering and bpf in the following way:
- everything that deals with sockets keeps 'sk_*' prefix
- everything that is pure BPF is changed to 'bpf_*' prefix

split 'struct sk_filter' into
struct sk_filter {
	atomic_t        refcnt;
	struct rcu_head rcu;
	struct bpf_prog *prog;
};
and
struct bpf_prog {
        u32                     jited:1,
                                len:31;
        struct sock_fprog_kern  *orig_prog;
        unsigned int            (*bpf_func)(const struct sk_buff *skb,
                                            const struct bpf_insn *filter);
        union {
                struct sock_filter      insns[0];
                struct bpf_insn         insnsi[0];
                struct work_struct      work;
        };
};
so that 'struct bpf_prog' can be used independent of sockets and cleans up
'unattached' bpf use cases

split SK_RUN_FILTER macro into:
    SK_RUN_FILTER to be used with 'struct sk_filter *' and
    BPF_PROG_RUN to be used with 'struct bpf_prog *'

__sk_filter_release(struct sk_filter *) gains
__bpf_prog_release(struct bpf_prog *) helper function

also perform related renames for the functions that work
with 'struct bpf_prog *', since they're on the same lines:

sk_filter_size -> bpf_prog_size
sk_filter_select_runtime -> bpf_prog_select_runtime
sk_filter_free -> bpf_prog_free
sk_unattached_filter_create -> bpf_prog_create
sk_unattached_filter_destroy -> bpf_prog_destroy
sk_store_orig_filter -> bpf_prog_store_orig_filter
sk_release_orig_filter -> bpf_release_orig_filter
__sk_migrate_filter -> bpf_migrate_filter
__sk_prepare_filter -> bpf_prepare_filter

API for attaching classic BPF to a socket stays the same:
sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *)
and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program
which is used by sockets, tun, af_packet

API for 'unattached' BPF programs becomes:
bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *)
and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program
which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix checkpatch warning:
WARNING: debugfs_remove(NULL) is safe this check is probably not required
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Acked-by: NLars-Peter Clausen <lars@metafoo.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7225/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Fix checkpatch warning:
WARNING: debugfs_remove_recursive(NULL) is safe this check is probably not required
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Acked-by: NDavid Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7224/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This patch implements the stack protector code in MIPS compressed boot
phase based on the same code added to arm in commit
8779657d "stackprotector: Introduce
CONFIG_CC_STACKPROTECTOR_STRONG" by Kees Cook <keescook@chromium.org>
Signed-off-by: NBen Chan <benchan@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
Reviewed-by: NKees Cook <keescook@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7175/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The MIPS_CONF4_FTLBSETS_SHIFT define is cut and pasted twice so we can
remove the second define.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: John Crispin <blogic@openwrt.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: kernel-janitors@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7063/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

BONITO_PCIMEMBASECFG_ADDRMASK was cut and pasted twice so we can delete
the second define.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: kernel-janitors@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7062/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Initialise the MAARs such that speculation is enabled for all physical
addresses outside of the I/O region.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7333/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Add initialisation for Memory Accessibility Attribute Registers. Generic
code cannot know the platform-specific requirements with regards to
speculative accesses, so it simply calls a platform_maar_init function
which platforms with MAARs are expected to implement by calling the
provided write_maar_pair function & returning the number of MAAR pairs
used. A weak default implementation will simply use no MAAR pairs. Any
present but unused MAAR pairs are then marked invalid, effectively
disabling them.

The end result of this patch is that MAARs are all marked invalid, until
platforms implement the platform_maar_init function.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7331/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Detect the presence of MAAR using the MRP bit in Config5, and record
that presence using a CPU option bit. A cpu_has_maar macro will then
allow code to conditionalise upon the presence of MAARs.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7330/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Add accessor macros for the Memory Accessibility Attribute Registers
(MAARs), the bits contained within the MAARs & the Config5.MRP bit
indicating their presence. The only current use of the MAARs is to
enable speculative accesses to regions of memory. Besides the potential
performance benefits of speculative accesses, they are a requirement
for the P5600 core to handle non-128b-aligned MSA vector loads & stores
rather than generating an address error.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7329/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

In light of the commit 16f77de8 (Revert "MIPS: Save/restore MSA
context around signals") the MSA support in the kernel is incomplete.
Until the replacement for the former sigcontext changes is agreed upon
and in tree, mark MSA experimental & disable it by default.

MSA is only implemented by one CPU supported by the kernel, the P5600.
The P5600 is a 32 bit core, and thus MSA can only be used when the
experimental CONFIG_MIPS_O32_FP64_SUPPORT option is enabled. Therefore
MSA is only being used in experimental settings anyway and this change
doesn't actually make any difference beyond clarifying the state of
MSA support.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7311/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

MSA requires that Status.FR == 1, so for MIPS32 tasks MSA can only be
used if CONFIG_MIPS_O32_FP64_SUPPORT is enabled. If it is not & the
kernel is 32bit, there's no point including support for MSA.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7310/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The TIF_MSA_CTX_LIVE flag (indicating that a task has MSA context which
needs to be preserved) was being cleared in start_thread, but the
TIF_USEDMSA flag (indicating that a task has used MSA in this timeslice)
was not. In copy_thread neither flag was cleared, but both need to be.
Without clearing these flags the kernel will proceed to attempt to save
MSA context when the task is context switched out, and if the task had
not used MSA in the meantime then it will fail because MSA or the FPU
are disabled. The end result is typically:

  do_cpu invoked from kernel context![#1]:
  CPU: 0 PID: 99 Comm: sh Not tainted 3.16.0-rc4-00025-g6dc9476-dirty #88
  task: 8f23dc60 ti: 8f1d8000 task.ti: 8f1d8000
  ...
  Call Trace:
  [<8010edbc>] resume+0x5c/0x280
  [<80481e0c>] __schedule+0x370/0x800
  [<80104838>] work_resched+0x8/0x2c

Fix by consistently clearing both flags in both functions.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7309/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The MSA specification upon first read appears to suggest that it is safe
to perform vector loads & stores with arbitrary alignment. However it
leaves provision for "address-dependent exceptions"... Align the vector
context to a 16 byte boundary to ensure that the kernel cannot cause any
such exceptions.

Note that the fpu field of struct thread_struct was already at a 16 byte
boundary within the struct, the introduction of FPU_ALIGN simply makes
the requirement explicit. The only part of this impacting the generated
kernel binary is ARCH_MIN_TASKALIGN.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7308/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Preemption must be disabled throughout the process of enabling the FPU,
enabling MSA & initialising the vector registers. Without doing so it
is possible to lose the FPU or MSA whilst initialising them causing
that initialisation to fail.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7307/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The kernel relies upon MSA being disabled when a task begins running,
so that it can initialise or restore context in response to the
resulting MSA disabled exception. Previously the state of MSA following
boot was left as it was before the kernel ran, where MSA could
potentially have been enabled. Explicitly disable it during boot to
prevent any problems.

As a nice side effect the code reads a little better too.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7306/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Commit d96cc3d1 "MIPS: Add microMIPS MSA support." attempted to use
the value of a macro within an inline asm statement but instead emitted
a comment leading to the cfcmsa & ctcmsa instructions being omitted. Fix
that by passing CFC_MSA_INSN & CTC_MSA_INSN as arguments to the asm
statements.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7305/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

If a task does not execute scalar FP instructions prior to using MSA
then the flags indicating that the task has live MSA context were not
being set. The upper 64b of each vector register would then be lost
upon the tasks first context switch after using MSA.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7500/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

When a task first makes use of MSA we need to ensure that the upper
64b of the vector registers are set to some value such that no
information can be leaked to it from the previous task to use MSA
context on the CPU. The architecture formerly specified that these
bits would be cleared to 0 when a scalar FP instructions wrote to the
aliased FP registers, which would have implicitly handled this as the
kernel restored scalar FP context. However more recent versions of the
specification now state that the value of the bits in such cases is
unpredictable. Initialise them explictly to be sure, and set all the
bits to 1 rather than 0 for consistency with the least significant
64b.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7497/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The kernel depends upon MSA never being enabled when the FPU is not, a
condition which is currently violated in a few places (whilst saving
sigcontext, following mips_cpu_save). Catch all the problem cases by
disabling MSA in lose_fpu, after saving context if necessary.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7302/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Switching the vector context implicitly saves & restores the state of
the aliased scalar FP data registers, however the scalar FP control
& status register is distinct from the MSA control & status register.
In order to allow scalar FP to function correctly in programs using
MSA, the scalar CSR needs to be saved & restored along with the MSA
vector context.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7301/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>