linux.git/arch/mips/kernel, branch v6.1.82

MIPS: reserve exception vector space ONLY ONCE

2024-03-01T12:26:26+00:00

[ Upstream commit abcabb9e30a1f9a69c76776f8abffc31c377b542 ]

"cpu_probe" is called both by BP and APs, but reserving exception vector
(like 0x0-0x1000) called by "cpu_probe" need once and calling on APs is
too late since memblock is unavailable at that time.

So, reserve exception vector ONLY by BP.

Suggested-by: Thomas Bogendoerfer 
Signed-off-by: Huang Pei 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

mips: Call lose_fpu(0) before initializing fcr31 in mips_set_personality_nan

2024-02-01T00:17:12+00:00

commit 59be5c35850171e307ca5d3d703ee9ff4096b948 upstream.

If we still own the FPU after initializing fcr31, when we are preempted
the dirty value in the FPU will be read out and stored into fcr31,
clobbering our setting.  This can cause an improper floating-point
environment after execve().  For example:

    zsh% cat measure.c
    #include 
    int main() { return fetestexcept(FE_INEXACT); }
    zsh% cc measure.c -o measure -lm
    zsh% echo $((1.0/3)) # raising FE_INEXACT
    0.33333333333333331
    zsh% while ./measure; do ; done
    (stopped in seconds)

Call lose_fpu(0) before setting fcr31 to prevent this.

Closes: https://lore.kernel.org/linux-mips/7a6aa1bbdbbe2e63ae96ff163fab0349f58f1b9e.camel@xry111.site/
Fixes: 9b26616c8d9d ("MIPS: Respect the ISA level in FCSR handling")
Cc: stable@vger.kernel.org
Signed-off-by: Xi Ruoyao 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman

mips: Fix incorrect max_low_pfn adjustment

2024-01-25T23:27:45+00:00

[ Upstream commit 0f5cc249ff73552d3bd864e62f85841dafaa107d ]

max_low_pfn variable is incorrectly adjusted if the kernel is built with
high memory support and the later is detected in a running system, so the
memory which actually can be directly mapped is getting into the highmem
zone. See the ZONE_NORMAL range on my MIPS32r5 system:

> Zone ranges:
>   DMA      [mem 0x0000000000000000-0x0000000000ffffff]
>   Normal   [mem 0x0000000001000000-0x0000000007ffffff]
>   HighMem  [mem 0x0000000008000000-0x000000020fffffff]

while the zones are supposed to look as follows:

> Zone ranges:
>   DMA      [mem 0x0000000000000000-0x0000000000ffffff]
>   Normal   [mem 0x0000000001000000-0x000000001fffffff]
>   HighMem  [mem 0x0000000020000000-0x000000020fffffff]

Even though the physical memory within the range [0x08000000;0x20000000]
belongs to MMIO on our system, we don't really want it to be considered as
high memory since on MIPS32 that range still can be directly mapped.

Note there might be other problems caused by the max_low_pfn variable
misconfiguration. For instance high_memory variable is initialize with
virtual address corresponding to the max_low_pfn PFN, and by design it
must define the upper bound on direct map memory, then end of the normal
zone. That in its turn potentially may cause problems in accessing the
memory by means of the /dev/mem and /dev/kmem devices.

Let's fix the discovered misconfiguration then. It turns out the commit
a94e4f24ec83 ("MIPS: init: Drop boot_mem_map") didn't introduce the
max_low_pfn adjustment quite correct. If the kernel is built with high
memory support and the system is equipped with high memory, the
max_low_pfn variable will need to be initialized with PFN of the most
upper directly reachable memory address so the zone normal would be
correctly setup. On MIPS that PFN corresponds to PFN_DOWN(HIGHMEM_START).
If the system is built with no high memory support and one is detected in
the running system, we'll just need to adjust the max_pfn variable to
discard the found high memory from the system and leave the max_low_pfn as
is, since the later will be less than PFN_DOWN(HIGHMEM_START) anyway by
design of the for_each_memblock() loop performed a bit early in the
bootmem_init() method.

Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map")
Signed-off-by: Serge Semin 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

mips/smp: Call rcutree_report_cpu_starting() earlier

2024-01-25T23:27:39+00:00

commit 55702ec9603ebeffb15e6f7b113623fe1d8872f4 upstream.

rcutree_report_cpu_starting() must be called before
clockevents_register_device() to avoid the following lockdep splat triggered by
calling list_add() when CONFIG_PROVE_RCU_LIST=y:

  WARNING: suspicious RCU usage
  ...
  -----------------------------
  kernel/locking/lockdep.c:3680 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 1, debug_locks = 1
  no locks held by swapper/1/0.
  ...
  Call Trace:
  [] show_stack+0x64/0x158
  [] dump_stack_lvl+0x90/0xc4
  [] __lock_acquire+0x1404/0x2940
  [] lock_acquire+0x14c/0x448
  [] _raw_spin_lock_irqsave+0x50/0x88
  [] clockevents_register_device+0x60/0x1e8
  [] r4k_clockevent_init+0x220/0x3a0
  [] start_secondary+0x50/0x3b8

raw_smp_processor_id() is required in order to avoid calling into lockdep
before RCU has declared the CPU to be watched for readers.

See also commit 29368e093921 ("x86/smpboot:  Move rcu_cpu_starting() earlier"),
commit de5d9dae150c ("s390/smp: move rcu_cpu_starting() earlier") and commit
99f070b62322 ("powerpc/smp: Call rcu_cpu_starting() earlier").

Signed-off-by: Stefan Wiehler 
Reviewed-by: Huacai Chen 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman

MIPS: kernel: Clear FPU states when setting up kernel threads

2023-12-13T17:39:28+00:00

commit a58a173444a68412bb08849bd81c679395f20ca0 upstream.

io_uring sets up the io worker kernel thread via a syscall out of an
user space prrocess. This process might have used FPU and since
copy_thread() didn't clear FPU states for kernel threads a BUG()
is triggered for using FPU inside kernel. Move code around
to always clear FPU state for user and kernel threads.

Cc: stable@vger.kernel.org
Reported-by: Aurelien Jarno 
Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1055021
Suggested-by: Jiaxun Yang 
Reviewed-by: Jiaxun Yang 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman

mips/cpu: Switch to arch_cpu_finalize_init()

2023-08-08T18:03:47+00:00

commit 7f066a22fe353a827a402ee2835e81f045b1574d upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20230613224545.312438573@linutronix.de
Signed-off-by: Daniel Sneddon 
Signed-off-by: Greg Kroah-Hartman

MIPS: Loongson: Fix cpu_probe_loongson() again

2023-07-23T11:49:33+00:00

commit 65fee014dc41a774bcd94896f3fb380bc39d8dda upstream.

Commit 7db5e9e9e5e6c10d7d ("MIPS: loongson64: fix FTLB configuration")
move decode_configs() from the beginning of cpu_probe_loongson() to the
end in order to fix FTLB configuration. However, it breaks the CPUCFG
decoding because decode_configs() use "c->options = xxxx" rather than
"c->options |= xxxx", all information get from CPUCFG by decode_cpucfg()
is lost.

This causes error when creating a KVM guest on Loongson-3A4000:
Exception Code: 4 not handled @ PC: 0000000087ad5981, inst: 0xcb7a1898 BadVaddr: 0x0 Status: 0x0

Fix this by moving the c->cputype setting to the beginning and moving
decode_configs() after that.

Fixes: 7db5e9e9e5e6c10d7d ("MIPS: loongson64: fix FTLB configuration")
Cc: stable@vger.kernel.org
Cc: Huang Pei 
Signed-off-by: Huacai Chen 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman

mips: Move initrd_start check after initrd address sanitisation.

2023-06-21T14:00:53+00:00

[ Upstream commit 4897a898a216058dec55e5e5902534e6e224fcdf ]

PAGE_OFFSET is technically a virtual address so when checking the value of
initrd_start against it we should make sure that it has been sanitised from
the values passed by the bootloader. Without this change, even with a bootloader
that passes correct addresses for an initrd, we are failing to load it on MT7621
boards, for example.

Signed-off-by: Liviu Dudau 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

MIPS: Restore Au1300 support

2023-06-21T14:00:53+00:00

[ Upstream commit f2041708dee30a3425f680265c337acd28293782 ]

The Au1300, at least the one I have to test, uses the NetLogic vendor
ID, but commit 95b8a5e0111a ("MIPS: Remove NETLOGIC support") also
dropped Au1300 detection.  Restore Au1300 detection.

Tested on DB1300 with Au1380 chip.

Signed-off-by: Manuel Lauss 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Sasha Levin

MIPS: Define RUNTIME_DISCARD_EXIT in LD script

2023-04-26T12:28:42+00:00

commit 6dcbd0a69c84a8ae7a442840a8cf6b1379dc8f16 upstream.

MIPS's exit sections are discarded at runtime as well.

Fixes link error:
`.exit.text' referenced in section `__jump_table' of fs/fuse/inode.o:
defined in discarded section `.exit.text' of fs/fuse/inode.o

Fixes: 99cb0d917ffa ("arch: fix broken BuildID for arm64 and riscv")
Reported-by: "kernelci.org bot" 
Signed-off-by: Jiaxun Yang 
Signed-off-by: Thomas Bogendoerfer 
Signed-off-by: Greg Kroah-Hartman