linux.git/arch/powerpc/kernel/traps.c, branch v6.15

powerpc: Rely on generic printing of preemption model

2025-03-17T10:23:39+00:00

After the first printk in __die() there is show_regs() ->
show_regs_print_info() which prints the current
preemption model.

Remove the preempion model from the arch code.

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Christophe Leroy 
Reviewed-by: Shrikanth Hegde 
Link: https://lore.kernel.org/r/20250314160810.2373416-6-bigeasy@linutronix.de

powerpc/traps: Use backlight power constants

2024-08-07T12:48:26+00:00

Replace FB_BLANK_ constants with their counterparts from the
backlight subsystem. The values are identical, so there's no
change in functionality or semantics.

traps.c already includes backlight.h where the BACKLIGHT
constants are defined.

Signed-off-by: Thomas Zimmermann 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240731130720.1148872-2-tzimmermann@suse.de

powerpc: Remove core support for 40x

2024-06-28T12:28:47+00:00

Now that 40x platforms have gone, remove support
for 40x in the core of powerpc arch.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240628121201.130802-4-mpe@ellerman.id.au

powerpc: Use user_mode() macro when possible

2024-02-22T10:55:33+00:00

There is a nice macro to check user mode.

Use it instead of open coding anding with MSR_PR to increase
readability and avoid having to comment what that anding is for.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/fbf74887dcf1f1ba9e1680fc3247cbb581b00662.1708078228.git.christophe.leroy@csgroup.eu

powerpc: Fix build error due to is_valid_bugaddr()

2023-12-01T10:15:33+00:00

With CONFIG_GENERIC_BUG=n the build fails with:

  arch/powerpc/kernel/traps.c:1442:5: error: no previous prototype for ‘is_valid_bugaddr’ [-Werror=missing-prototypes]
  1442 | int is_valid_bugaddr(unsigned long addr)
       |     ^~~~~~~~~~~~~~~~

The prototype is only defined, and the function is only needed, when
CONFIG_GENERIC_BUG=y, so move the implementation under that.

Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20231130114433.3053544-2-mpe@ellerman.id.au

powerpc: Remove extern from function implementations

2023-10-19T06:12:47+00:00

Sparse reports several function implementations annotated with extern.
This is clearly incorrect, likely just copied from an actual extern
declaration in another file.

Fix the sparse warnings by removing extern.

Signed-off-by: Benjamin Gray 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20231011053711.93427-6-bgray@linux.ibm.com

Merge branch fixes into next

2023-10-18T11:26:42+00:00

Merge our fixes branch to bring in commits that are prerequisities for further
development or would cause conflicts.

powerpc: Only define __parse_fpscr() when required

2023-10-10T10:46:32+00:00

Clang 17 reports:

arch/powerpc/kernel/traps.c:1167:19: error: unused function '__parse_fpscr' [-Werror,-Wunused-function]

__parse_fpscr() is called from two sites. First call is guarded
by #ifdef CONFIG_PPC_FPU_REGS

Second call is guarded by CONFIG_MATH_EMULATION which selects
CONFIG_PPC_FPU_REGS.

So only define __parse_fpscr() when CONFIG_PPC_FPU_REGS is defined.

Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202309210327.WkqSd5Bq-lkp@intel.com/
Fixes: b6254ced4da6 ("powerpc/signal: Don't manage floating point regs when no FPU")
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/5de2998c57f3983563b27b39228ea9a7229d4110.1695385984.git.christophe.leroy@csgroup.eu

powerpc/dexcr: Move HASHCHK trap handler

2023-09-18T02:23:48+00:00

Syzkaller reported a sleep in atomic context bug relating to the HASHCHK
handler logic:

  BUG: sleeping function called from invalid context at arch/powerpc/kernel/traps.c:1518
  in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 25040, name: syz-executor
  preempt_count: 0, expected: 0
  RCU nest depth: 0, expected: 0
  no locks held by syz-executor/25040.
  irq event stamp: 34
  hardirqs last  enabled at (33): [] prep_irq_for_enabled_exit arch/powerpc/kernel/interrupt.c:56 [inline]
  hardirqs last  enabled at (33): [] interrupt_exit_user_prepare_main+0x148/0x600 arch/powerpc/kernel/interrupt.c:230
  hardirqs last disabled at (34): [] interrupt_enter_prepare+0x144/0x4f0 arch/powerpc/include/asm/interrupt.h:176
  softirqs last  enabled at (0): [] copy_process+0x16e4/0x4750 kernel/fork.c:2436
  softirqs last disabled at (0): [<0000000000000000>] 0x0
  CPU: 15 PID: 25040 Comm: syz-executor Not tainted 6.5.0-rc5-00001-g3ccdff6bb06d #3
  Hardware name: IBM,9105-22A POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1040.00 (NL1040_021) hv:phyp pSeries
  Call Trace:
  [c0000000a8247ce0] [c00000000032b0e4] __might_resched+0x3b4/0x400 kernel/sched/core.c:10189
  [c0000000a8247d80] [c0000000008c7dc8] __might_fault+0xa8/0x170 mm/memory.c:5853
  [c0000000a8247dc0] [c00000000004160c] do_program_check+0x32c/0xb20 arch/powerpc/kernel/traps.c:1518
  [c0000000a8247e50] [c000000000009b2c] program_check_common_virt+0x3bc/0x3c0

To determine if a trap was caused by a HASHCHK instruction, we inspect
the user instruction that triggered the trap. However this may sleep
if the page needs to be faulted in (get_user_instr() reaches
__get_user(), which calls might_fault() and triggers the bug message).

Move the HASHCHK handler logic to after we allow IRQs, which is fine
because we are only interested in HASHCHK if it's a user space trap.

Fixes: 5bcba4e6c13f ("powerpc/dexcr: Handle hashchk exception")
Signed-off-by: Benjamin Gray 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230915034604.45393-1-bgray@linux.ibm.com

powerpc/4xx: Remove WatchdogHandler() to fix no previous prototype error

2023-08-18T07:03:14+00:00

Building ppc40x_defconfig throws the following error:

  CC      arch/powerpc/kernel/traps.o
arch/powerpc/kernel/traps.c:2232:29: warning: no previous prototype for 'WatchdogHandler' [-Wmissing-prototypes]
 2232 | void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
      |                             ^~~~~~~~~~~~~~~

This function was imported by commit 14cf11af6cf6 ("powerpc: Merge
enough to start building in arch/powerpc.") as a weak function but
never defined and/or called outside traps.c

As it has only one caller fold it inside its caller and remove it.

Signed-off-by: Christophe Leroy 
Reviewed-by: Arnd Bergmann 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/38fe1078eb403eef74dc8f29387636fd7ecdf43c.1692276041.git.christophe.leroy@csgroup.eu