linux.git/arch/parisc/kernel/cache.c, branch v6.8

parisc: BTLB: Fix crash when setting up BTLB at CPU bringup

2024-01-31T12:51:26+00:00

When using hotplug and bringing up a 32-bit CPU, ask the firmware about the
BTLB information to set up the static (block) TLB entries.

For that write access to the static btlb_info struct is needed, but
since it is marked __ro_after_init the kernel segfaults with missing
write permissions.

Fix the crash by dropping the __ro_after_init annotation.

Fixes: e5ef93d02d6c ("parisc: BTLB: Initialize BTLB tables at CPU startup")
Signed-off-by: Helge Deller 
Cc:  # v6.6+

parisc: Fix random data corruption from exception handler

2024-01-30T16:18:58+00:00

The current exception handler implementation, which assists when accessing
user space memory, may exhibit random data corruption if the compiler decides
to use a different register than the specified register %r29 (defined in
ASM_EXCEPTIONTABLE_REG) for the error code. If the compiler choose another
register, the fault handler will nevertheless store -EFAULT into %r29 and thus
trash whatever this register is used for.
Looking at the assembly I found that this happens sometimes in emulate_ldd().

To solve the issue, the easiest solution would be if it somehow is
possible to tell the fault handler which register is used to hold the error
code. Using %0 or %1 in the inline assembly is not posssible as it will show
up as e.g. %r29 (with the "%r" prefix), which the GNU assembler can not
convert to an integer.

This patch takes another, better and more flexible approach:
We extend the __ex_table (which is out of the execution path) by one 32-word.
In this word we tell the compiler to insert the assembler instruction
"or %r0,%r0,%reg", where %reg references the register which the compiler
choosed for the error return code.
In case of an access failure, the fault handler finds the __ex_table entry and
can examine the opcode. The used register is encoded in the lowest 5 bits, and
the fault handler can then store -EFAULT into this register.

Since we extend the __ex_table to 3 words we can't use the BUILDTIME_TABLE_SORT
config option any longer.

Signed-off-by: Helge Deller 
Cc:  # v6.0+

parisc: Check for valid stride size for cache flushes

2024-01-28T08:49:46+00:00

Report if the calculated cache stride size is zero, otherwise the cache
flushing routine will never finish and hang the machine.
This can be reproduced with a testcase in qemu, where the firmware reports
wrong cache values.

Signed-off-by: Helge Deller

parisc: BTLB: Initialize BTLB tables at CPU startup

2023-09-07T07:12:20+00:00

Initialize the BTLB entries when starting up a CPU.
Note that BTLBs are not available on 64-bit CPUs.

Signed-off-by: Helge Deller

parisc: implement the new page table range API

2023-08-24T23:20:22+00:00

Add set_ptes(), update_mmu_cache_range(), flush_dcache_folio() and
flush_icache_pages().  Change the PG_arch_1 (aka PG_dcache_dirty) flag
from being per-page to per-folio.

Link: https://lkml.kernel.org/r/20230802151406.3735276-21-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Acked-by: Mike Rapoport (IBM) 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Signed-off-by: Andrew Morton

parisc: Add cacheflush() syscall

2023-06-30T15:14:13+00:00

Signed-off-by: Helge Deller

parisc: add pte_unmap() to balance get_ptep()

2023-06-19T23:19:07+00:00

To keep balance in future, remember to pte_unmap() after a successful
get_ptep().  And act as if flush_cache_pages() really needs a map there,
to read the pfn before "unmapping", to be sure page table is not removed.

Link: https://lkml.kernel.org/r/653369-95ef-acd2-d6ea-e95f5a997493@google.com
Signed-off-by: Hugh Dickins 
Cc: Alexander Gordeev 
Cc: Alexandre Ghiti 
Cc: Aneesh Kumar K.V 
Cc: Catalin Marinas 
Cc: Christian Borntraeger 
Cc: Chris Zankel 
Cc: Claudio Imbrenda 
Cc: David Hildenbrand 
Cc: "David S. Miller" 
Cc: Geert Uytterhoeven 
Cc: Greg Ungerer 
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: John David Anglin 
Cc: John Paul Adrian Glaubitz 
Cc: Kirill A. Shutemov 
Cc: Matthew Wilcox (Oracle) 
Cc: Max Filippov 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Mike Kravetz 
Cc: Mike Rapoport (IBM) 
Cc: Palmer Dabbelt 
Cc: Peter Zijlstra 
Cc: Qi Zheng 
Cc: Russell King 
Cc: Suren Baghdasaryan 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

parisc: Fix flush_dcache_page() for usage from irq context

2023-05-24T17:03:49+00:00

Since at least kernel 6.1, flush_dcache_page() is called with IRQs
disabled, e.g. from aio_complete().

But the current implementation for flush_dcache_page() on parisc
unintentionally re-enables IRQs, which may lead to deadlocks.

Fix it by using xa_lock_irqsave() and xa_unlock_irqrestore()
for the flush_dcache_mmap_*lock() macros instead.

Cc: linux-parisc@vger.kernel.org
Cc: stable@kernel.org # 5.18+
Signed-off-by: Helge Deller

parisc: remove mmap linked list from cache handling

2022-09-27T02:46:19+00:00

Use the VMA iterator instead.

Link: https://lkml.kernel.org/r/20220906194824.2110408-33-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Liam R. Howlett 
Acked-by: Vlastimil Babka 
Reviewed-by: Davidlohr Bueso 
Tested-by: Yu Zhao 
Cc: Catalin Marinas 
Cc: David Hildenbrand 
Cc: David Howells 
Cc: SeongJae Park 
Cc: Sven Schnelle 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

Merge tag 'for-5.20/parisc-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

2022-08-05T16:58:58+00:00

Pull parisc updates from Helge Deller:
 "One real bugfix to change the io_pgetevents_time64() syscall to use
  the compat implementation when running in compat mode, otherwise the
  signed int32 parameters min_nr and nr will be incorrectly handled as
  unsigned int64 values.

  Other than that just small cleanups:

   - hardware database housekeeping and proper /proc/iomem output

   - add proper function exit code if probe functions fail

   - drop stale variables (pa_swapper_pg_lock)

   - drop unneccessary zero-initializations

   - typo fixes in comments"

* tag 'for-5.20/parisc-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  Input: gscps2 - check return value of ioremap() in gscps2_probe()
  parisc: io_pgetevents_time64() needs compat syscall in 32-bit compat mode
  parisc: Drop zero variable initialisations in mm/init.c
  parisc: Do not initialise statics to 0
  parisc: Check the return value of ioremap() in lba_driver_probe()
  parisc: Drop pa_swapper_pg_lock spinlock
  parisc: Fix comment typo in fault.c
  parisc: Fix device names in /proc/iomem
  parisc: Clean up names in hardware database