linux.git/include/asm-generic/sections.h, branch v6.18.21

percpu: Remove __per_cpu_load

2025-02-18T09:16:00+00:00

__per_cpu_load is now always equal to __per_cpu_start.

Signed-off-by: Brian Gerst 
Signed-off-by: Ingo Molnar 
Reviewed-by: Ard Biesheuvel 
Cc: Linus Torvalds 
Link: https://lore.kernel.org/r/20250123190747.745588-15-brgerst@gmail.com

jump_label,module: Don't alloc static_key_mod for __ro_after_init keys

2024-03-22T10:18:16+00:00

When a static_key is marked ro_after_init, its state will never change
(after init), therefore jump_label_update() will never need to iterate
the entries, and thus module load won't actually need to track this --
avoiding the static_key::next write.

Therefore, mark these keys such that jump_label_add_module() might
recognise them and avoid the modification.

Use the special state: 'static_key_linked(key) && !static_key_mod(key)'
to denote such keys.

jump_label_add_module() does not exist under CONFIG_JUMP_LABEL=n, so the
newly-introduced jump_label_init_ro() can be defined as a nop for that
configuration.

[ mingo: Renamed jump_label_ro() to jump_label_init_ro() ]

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Valentin Schneider 
Signed-off-by: Ingo Molnar 
Acked-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/20240313180106.2917308-2-vschneid@redhat.com

asm-generic: sections: refactor memory_intersects

2022-08-28T21:02:45+00:00

There are two problems with the current code of memory_intersects:

First, it doesn't check whether the region (begin, end) falls inside the
region (virt, vend), that is (virt < begin && vend > end).

The second problem is if vend is equal to begin, it will return true but
this is wrong since vend (virt + size) is not the last address of the
memory region but (virt + size -1) is.  The wrong determination will
trigger the misreporting when the function check_for_illegal_area calls
memory_intersects to check if the dma region intersects with stext region.

The misreporting is as below (stext is at 0x80100000):
 WARNING: CPU: 0 PID: 77 at kernel/dma/debug.c:1073 check_for_illegal_area+0x130/0x168
 DMA-API: chipidea-usb2 e0002000.usb: device driver maps memory from kernel text or rodata [addr=800f0000] [len=65536]
 Modules linked in:
 CPU: 1 PID: 77 Comm: usb-storage Not tainted 5.19.0-yocto-standard #5
 Hardware name: Xilinx Zynq Platform
  unwind_backtrace from show_stack+0x18/0x1c
  show_stack from dump_stack_lvl+0x58/0x70
  dump_stack_lvl from __warn+0xb0/0x198
  __warn from warn_slowpath_fmt+0x80/0xb4
  warn_slowpath_fmt from check_for_illegal_area+0x130/0x168
  check_for_illegal_area from debug_dma_map_sg+0x94/0x368
  debug_dma_map_sg from __dma_map_sg_attrs+0x114/0x128
  __dma_map_sg_attrs from dma_map_sg_attrs+0x18/0x24
  dma_map_sg_attrs from usb_hcd_map_urb_for_dma+0x250/0x3b4
  usb_hcd_map_urb_for_dma from usb_hcd_submit_urb+0x194/0x214
  usb_hcd_submit_urb from usb_sg_wait+0xa4/0x118
  usb_sg_wait from usb_stor_bulk_transfer_sglist+0xa0/0xec
  usb_stor_bulk_transfer_sglist from usb_stor_bulk_srb+0x38/0x70
  usb_stor_bulk_srb from usb_stor_Bulk_transport+0x150/0x360
  usb_stor_Bulk_transport from usb_stor_invoke_transport+0x38/0x440
  usb_stor_invoke_transport from usb_stor_control_thread+0x1e0/0x238
  usb_stor_control_thread from kthread+0xf8/0x104
  kthread from ret_from_fork+0x14/0x2c

Refactor memory_intersects to fix the two problems above.

Before the 1d7db834a027e ("dma-debug: use memory_intersects()
directly"), memory_intersects is called only by printk_late_init:

printk_late_init -> init_section_intersects ->memory_intersects.

There were few places where memory_intersects was called.

When commit 1d7db834a027e ("dma-debug: use memory_intersects()
directly") was merged and CONFIG_DMA_API_DEBUG is enabled, the DMA
subsystem uses it to check for an illegal area and the calltrace above
is triggered.

[akpm@linux-foundation.org: fix nearby comment typo]
Link: https://lkml.kernel.org/r/20220819081145.948016-1-quanyang.wang@windriver.com
Fixes: 979559362516 ("asm/sections: add helpers to check for section data")
Signed-off-by: Quanyang Wang 
Cc: Ard Biesheuvel 
Cc: Arnd Bergmann 
Cc: Thierry Reding 
Cc: 
Signed-off-by: Andrew Morton

asm-generic: Refactor dereference_[kernel]_function_descriptor()

2022-02-16T12:25:11+00:00

dereference_function_descriptor() and
dereference_kernel_function_descriptor() are identical on the
three architectures implementing them.

Make them common and put them out-of-line in kernel/extable.c
which is one of the users and has similar type of functions.

Signed-off-by: Christophe Leroy 
Reviewed-by: Kees Cook 
Reviewed-by: Arnd Bergmann 
Acked-by: Helge Deller 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/449db09b2eba57f4ab05f80102a67d8675bc8bcd.1644928018.git.christophe.leroy@csgroup.eu

asm-generic: Define 'func_desc_t' to commonly describe function descriptors

2022-02-16T12:25:11+00:00

We have three architectures using function descriptors, each with its
own type and name.

Add a common typedef that can be used in generic code.

Also add a stub typedef for architecture without function descriptors,
to avoid a forest of #ifdefs.

It replaces the similar 'func_desc_t' previously defined in
arch/powerpc/kernel/module_64.c

Signed-off-by: Christophe Leroy 
Reviewed-by: Kees Cook 
Acked-by: Arnd Bergmann 
Acked-by: Helge Deller 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/f1f91b142b3c1082bdc1586ce71c9bac1e75213c.1644928018.git.christophe.leroy@csgroup.eu

asm-generic: Define CONFIG_HAVE_FUNCTION_DESCRIPTORS

2022-02-16T12:25:11+00:00

Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by a config option
named CONFIG_HAVE_FUNCTION_DESCRIPTORS and use it instead of
'dereference_function_descriptor' macro to know whether an
arch has function descriptors.

To limit churn in one of the following patches, use
an #ifdef/#else construct with empty first part
instead of an #ifndef in asm-generic/sections.h

On powerpc, make sure the config option matches the ABI used
by the compiler with a BUILD_BUG_ON() and add missing _CALL_ELF=2
when calling 'sparse' so that sparse sees the same piece of
code as GCC.

And include a helper to check whether an arch has function
descriptors or not : have_function_descriptors()

Signed-off-by: Christophe Leroy 
Reviewed-by: Kees Cook 
Reviewed-by: Nicholas Piggin 
Acked-by: Helge Deller 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/4a0f11fb0ea74a3197bc44dd7ba25e53a24fd03d.1644928018.git.christophe.leroy@csgroup.eu

Merge tag 'for-5.17/parisc-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

2022-01-11T23:42:45+00:00

Pull parisc architecture updates from Helge Deller:

 - Fix lpa and lpa_user defines (John David Anglin)

 - Fix symbol lookup of init functions with an __is_kernel() fix (Helge
   Deller)

 - Fix wrong pdc_toc_pim_11 and pdc_toc_pim_20 definitions (Helge
   Deller)

 - Add lws_atomic_xchg and lws_atomic_store syscalls (John David Anglin)

 - Rewrite light-weight syscall and futex code (John David Anglin)

 - Enable TOC (transfer of contents) feature unconditionally (Helge
   Deller)

 - Improve fault handler messages (John David Anglin)

 - Improve build process (Masahiro Yamada)

 - Reduce kernel code footprint of user access functions (Helge Deller)

 - Fix build error due to outX() macros (Bart Van Assche)

 - Ue default_groups in kobj_type in pdc_stable (Greg Kroah-Hartman)

 - Default to 16 CPUs on 32-bit kernel (Helge Deller)

* tag 'for-5.17/parisc-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Default to 16 CPUs on 32-bit kernel
  sections: Fix __is_kernel() to include init ranges
  parisc: Re-use toc_stack as hpmc_stack
  parisc: Enable TOC (transfer of contents) feature unconditionally
  parisc: io: Improve the outb(), outw() and outl() macros
  parisc: pdc_stable: use default_groups in kobj_type
  parisc: Add kgdb io_module to read chars via PDC
  parisc: Fix pdc_toc_pim_11 and pdc_toc_pim_20 definitions
  parisc: Add lws_atomic_xchg and lws_atomic_store syscalls
  parisc: Rewrite light-weight syscall and futex code
  parisc: Enhance page fault termination message
  parisc: Don't call faulthandler_disabled() in do_page_fault()
  parisc: Switch user access functions to signal errors in r29 instead of r8
  parisc: Avoid calling faulthandler_disabled() twice
  parisc: Fix lpa and lpa_user defines
  parisc: Define depi_safe macro
  parisc: decompressor: do not copy source files while building

sections: Fix __is_kernel() to include init ranges

2022-01-11T10:57:38+00:00

With CONFIG_KALLSYMS_ALL=y, the function is_ksym_addr() is used to
determine if a symbol is from inside the kernel range. For that the
given symbol address is checked if it's inside the _stext to _end range.

Although this is correct, some architectures (e.g. parisc) may have the
init area before the _stext address and as such the check in
is_ksym_addr() fails.  By extending the range check to include the init
section, __is_kernel() will now detect symbols in this range as well.

This fixes an issue on parisc where addresses of kernel functions in
init sections aren't resolved to their symbol names.

Signed-off-by: Helge Deller

sections: global data can be in .bss

2021-11-22T14:53:45+00:00

When checking an address is located in a global data section also check
for the .bss section as global variables initialized to 0 can be in
there (-fzero-initialized-in-bss).

This was found when looking at ensure_safe_net_sysctl which was failing
to detect non-init sysctl pointing to a global data section when the
data was in the .bss section.

Signed-off-by: Antoine Tenart 
Acked-by: Steven Rostedt (VMware) 
Acked-by: Arnd Bergmann 
Signed-off-by: David S. Miller

sections: provide internal __is_kernel() and __is_kernel_text() helper

2021-11-09T18:02:51+00:00

An internal __is_kernel() helper which only check the kernel address
ranges, and an internal __is_kernel_text() helper which only check text
section ranges.

Link: https://lkml.kernel.org/r/20210930071143.63410-7-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Reviewed-by: Sergey Senozhatsky 
Cc: Alexander Potapenko 
Cc: Alexei Starovoitov 
Cc: Andrey Konovalov 
Cc: Andrey Ryabinin 
Cc: Arnd Bergmann 
Cc: Benjamin Herrenschmidt 
Cc: Borislav Petkov 
Cc: Christophe Leroy 
Cc: "David S. Miller" 
Cc: Dmitry Vyukov 
Cc: Ingo Molnar 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Paul Mackerras 
Cc: Petr Mladek 
Cc: Richard Henderson 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds