linux.git/arch/parisc/kernel, branch v6.9

parisc/unaligned: Rewrite 64-bit inline assembly of emulate_ldd()

2024-02-27T21:51:44+00:00

Convert to use real temp variables instead of clobbering processor
registers. This aligns the 64-bit inline assembly code with the 32-bit
assembly code which was rewritten with commit 427c1073a2a1
("parisc/unaligned: Rewrite 32-bit inline assembly of emulate_ldd()").

While at it, fix comment in 32-bit rewrite code. Temporary variables are
now used for both 32-bit and 64-bit code, so move their declarations
to the function header.

No functional change intended.

Signed-off-by: Guenter Roeck 
Cc: stable@vger.kernel.org # v6.0+
Signed-off-by: Helge Deller

parisc: make parisc_bus_type const

2024-02-27T21:51:44+00:00

Since commit d492cc2573a0 ("driver core: device.h: make struct
bus_type a const *"), the driver core can properly handle constant
struct bus_type, move the parisc_bus_type variable to be a constant
structure as well, placing it into read-only memory which can not be
modified at runtime.

Cc: Greg Kroah-Hartman 
Suggested-by: Greg Kroah-Hartman 
Signed-off-by: Ricardo B. Marliere 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Helge Deller

parisc: Show kernel unaligned memory accesses

2024-02-27T21:51:44+00:00

Warn if some kernel function triggers unaligned memory accesses.

Signed-off-by: Helge Deller

parisc: Use irq_enter_rcu() to fix warning at kernel/context_tracking.c:367

2024-02-27T21:51:44+00:00

Use irq*_rcu() functions to fix this kernel warning:

 WARNING: CPU: 0 PID: 0 at kernel/context_tracking.c:367 ct_irq_enter+0xa0/0xd0
 Modules linked in:
 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.7.0-rc3-64bit+ #1037
 Hardware name: 9000/785/C3700

 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000412cd758 00000000412cd75c
  IIR: 03ffe01f    ISR: 0000000000000000  IOR: 0000000043c20c20
  CPU:        0   CR30: 0000000041caa000 CR31: 0000000000000000
  ORIG_R28: 0000000000000005
  IAOQ[0]: ct_irq_enter+0xa0/0xd0
  IAOQ[1]: ct_irq_enter+0xa4/0xd0
  RP(r2): irq_enter+0x34/0x68
 Backtrace:
  [<000000004034a3ec>] irq_enter+0x34/0x68
  [<000000004030dc48>] do_cpu_irq_mask+0xc0/0x450
  [<0000000040303070>] intr_return+0x0/0xc

Signed-off-by: Helge Deller

parisc: Fix stack unwinder

2024-02-19T20:55:22+00:00

Debugging shows a large number of unaligned access traps in the unwinder
code. Code analysis reveals a number of issues with this code:

- handle_interruption is passed twice through
  dereference_kernel_function_descriptor()
- ret_from_kernel_thread, syscall_exit, intr_return,
  _switch_to_ret, and _call_on_stack are passed through
  dereference_kernel_function_descriptor() even though they are
  not declared as function pointers.

To fix the problems, drop one of the calls to
dereference_kernel_function_descriptor() for handle_interruption,
and compare the other pointers directly.

Fixes: 6414b30b39f9 ("parisc: unwind: Avoid missing prototype warning for handle_interruption()")
Fixes: 8e0ba125c2bf ("parisc/unwind: fix unwinder when CONFIG_64BIT is enabled")
Cc: Helge Deller 
Cc: Sven Schnelle 
Cc: John David Anglin 
Cc: Charlie Jenkins 
Cc: David Laight 
Signed-off-by: Guenter Roeck 
Signed-off-by: Helge Deller

parisc/ftrace: add missing CONFIG_DYNAMIC_FTRACE check

2024-02-16T19:18:03+00:00

Fixes a bug revealed by -Wmissing-prototypes when
CONFIG_FUNCTION_GRAPH_TRACER is enabled but not CONFIG_DYNAMIC_FTRACE:

 arch/parisc/kernel/ftrace.c:82:5: error: no previous prototype for 'ftrace_enable_ftrace_graph_caller' [-Werror=missing-prototypes]
    82 | int ftrace_enable_ftrace_graph_caller(void)
       |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 arch/parisc/kernel/ftrace.c:88:5: error: no previous prototype for 'ftrace_disable_ftrace_graph_caller' [-Werror=missing-prototypes]
    88 | int ftrace_disable_ftrace_graph_caller(void)
       |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Max Kellermann 
Signed-off-by: Helge Deller

Revert "parisc: Only list existing CPUs in cpu_possible_mask"

2024-02-06T23:13:21+00:00

This reverts commit 0921244f6f4f0d05698b953fe632a99b38907226.

It broke CPU hotplugging because it modifies the __cpu_possible_mask
after bootup, so that it will be different than nr_cpu_ids, which
then effictively breaks the workqueue setup code and triggers crashes
when shutting down CPUs at runtime.

Guenter was the first who noticed the wrong values in __cpu_possible_mask,
since the cpumask Kunit tests were failig.

Reverting this commit fixes both issues, but sadly brings back this
uncritical runtime warning:
register_cpu_capacity_sysctl: too early to get CPU4 device!

Signed-off-by: Helge Deller 
Reported-by: Guenter Roeck 
Link: https://lkml.org/lkml/2024/2/4/146
Link: https://lore.kernel.org/lkml/Zb0mbHlIud_bqftx@slm.duckdns.org/t/
Cc: stable@vger.kernel.org # 6.0+

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: Drop unneeded semicolon in parse_tree_node()

2024-01-28T08:49:47+00:00

Reported-by: kernel test robot 
Signed-off-by: Helge Deller 
Closes: https://lore.kernel.org/oe-kbuild-all/202401222059.Wli6OGT0-lkp@intel.com/