linux.git/arch/mips/kernel/traps.c, branch v6.8

MIPS: reserve exception vector space ONLY ONCE

2024-01-26T09:33:34+00:00

"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

Merge tag 'mips_6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

2024-01-17T19:20:50+00:00

Pull MIPS updates from Thomas Bogendoerfer:
 "Just cleanups and fixes"

* tag 'mips_6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: Alchemy: Fix an out-of-bound access in db1550_dev_setup()
  MIPS: Alchemy: Fix an out-of-bound access in db1200_dev_setup()
  MIPS: Fix typos
  MIPS: Remove unused shadow GPR support from vector irq setup
  MIPS: Allow vectored interrupt handler to reside everywhere for 64bit
  mips: Set dump-stack arch description
  mips: mm: add slab availability checking in ioremap_prot
  mips: Optimize max_mapnr init procedure
  mips: Fix max_mapnr being uninitialized on early stages
  mips: Fix incorrect max_low_pfn adjustment
  mips: dmi: Fix early remap on MIPS32
  MIPS: compressed: Use correct instruction for 64 bit code
  MIPS: SGI-IP27: hubio: fix nasid kernel-doc warning
  MAINTAINERS: Add myself as maintainer of the Ralink architecture

MIPS: Fix typos

2024-01-08T09:39:12+00:00

Fix typos, most reported by "codespell arch/mips".  Only touches comments,
no code changes.

Signed-off-by: Bjorn Helgaas 
Cc: linux-mips@vger.kernel.org
Reviewed-by: Randy Dunlap 
Signed-off-by: Thomas Bogendoerfer

MIPS: Remove unused shadow GPR support from vector irq setup

2023-12-30T14:36:25+00:00

Using shadow GPRs for vectored interrupts has never been used,
time to remove it.

Signed-off-by: Thomas Bogendoerfer

MIPS: Allow vectored interrupt handler to reside everywhere for 64bit

2023-12-30T14:36:01+00:00

Setting up vector interrupts worked only with handlers, which resided
in CKSEG0 space. This limits the kernel placement for 64bit platforms.
By patching in the offset into vi_handlers[] instead of the full
handler address, the vectored exception handler can load the
address by itself and jump to it.

Signed-off-by: Thomas Bogendoerfer 
Reviewed-by: Jiaxun Yang

mips: fix tlb_init() prototype

2023-12-11T01:21:40+00:00

There are two definitions for tlb_init(), but no global declaration:

arch/mips/mm/tlb-r4k.c:552:6: error: no previous prototype for 'tlb_init' [-Werror=missing-prototypes]
arch/mips/mm/tlb-r3k.c:244:6: error: no previous prototype for 'tlb_init' [-Werror=missing-prototypes]

Move the declaration to asm/setup.h and included it as needed.

Link: https://lkml.kernel.org/r/20231204115710.2247097-12-arnd@kernel.org
Signed-off-by: Arnd Bergmann 
Cc: Stephen Rothwell 
Cc: Thomas Bogendoerfer 
Signed-off-by: Andrew Morton

MIPS: fix fortify panic when copying asm exception handlers

2022-03-07T12:09:28+00:00

With KCFLAGS="-O3", I was able to trigger a fortify-source
memcpy() overflow panic on set_vi_srs_handler().
Although O3 level is not supported in the mainline, under some
conditions that may've happened with any optimization settings,
it's just a matter of inlining luck. The panic itself is correct,
more precisely, 50/50 false-positive and not at the same time.
From the one side, no real overflow happens. Exception handler
defined in asm just gets copied to some reserved places in the
memory.
But the reason behind is that C code refers to that exception
handler declares it as `char`, i.e. something of 1 byte length.
It's obvious that the asm function itself is way more than 1 byte,
so fortify logics thought we are going to past the symbol declared.
The standard way to refer to asm symbols from C code which is not
supposed to be called from C is to declare them as
`extern const u8[]`. This is fully correct from any point of view,
as any code itself is just a bunch of bytes (including 0 as it is
for syms like _stext/_etext/etc.), and the exact size is not known
at the moment of compilation.
Adjust the type of the except_vec_vi_*() and related variables.
Make set_handler() take `const` as a second argument to avoid
cast-away warnings and give a little more room for optimization.

Signed-off-by: Alexander Lobakin 
Signed-off-by: Thomas Bogendoerfer

exit: Add and use make_task_dead.

2021-12-13T18:04:45+00:00

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman"

MIPS: Allow modules to set board_be_handler

2021-11-09T15:07:26+00:00

After making the brcmstb_gisb driver modular with 707a4cdf86e5 ("bus:
brcmstb_gisb: Allow building as module") Guenter reported that mips
allmodconfig failed to link because board_be_handler was referenced.

Thomas indicated that if we were to continue making the brcmstb_gisb
driver modular for MIPS we would need to introduce a function that
allows setting the board_be_handler and export that function towards
modules.

This is what is being done here: board_be_handler is made static and is
now settable with a mips_set_be_handler() function which is exported.

Reported-by: Guenter Roeck 
Suggested-by: Thomas Bogendoerfer 
Fixes: 707a4cdf86e5 ("bus: brcmstb_gisb: Allow building as module")
Signed-off-by: Florian Fainelli 
Tested-by: Guenter Roeck 
Signed-off-by: Thomas Bogendoerfer

arch/mips/kernel/traps: use vma_lookup() instead of find_vma()

2021-06-29T17:53:51+00:00

Use vma_lookup() to find the VMA at a specific address.  As vma_lookup()
will return NULL if the address is not within any VMA, the start address
no longer needs to be validated.

Link: https://lkml.kernel.org/r/20210521174745.2219620-8-Liam.Howlett@Oracle.com
Signed-off-by: Liam R. Howlett 
Reviewed-by: Laurent Dufour 
Acked-by: David Hildenbrand 
Acked-by: Davidlohr Bueso 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds