linux.git/tools/objtool/include, branch v6.2

Merge tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2022-12-19T13:13:33+00:00

Pull powerpc updates from Michael Ellerman:

 - Add powerpc qspinlock implementation optimised for large system
   scalability and paravirt. See the merge message for more details

 - Enable objtool to be built on powerpc to generate mcount locations

 - Use a temporary mm for code patching with the Radix MMU, so the
   writable mapping is restricted to the patching CPU

 - Add an option to build the 64-bit big-endian kernel with the ELFv2
   ABI

 - Sanitise user registers on interrupt entry on 64-bit Book3S

 - Many other small features and fixes

Thanks to Aboorva Devarajan, Angel Iglesias, Benjamin Gray, Bjorn
Helgaas, Bo Liu, Chen Lifu, Christoph Hellwig, Christophe JAILLET,
Christophe Leroy, Christopher M. Riedl, Colin Ian King, Deming Wang,
Disha Goel, Dmitry Torokhov, Finn Thain, Geert Uytterhoeven, Gustavo A.
R. Silva, Haowen Bai, Joel Stanley, Jordan Niethe, Julia Lawall, Kajol
Jain, Laurent Dufour, Li zeming, Miaoqian Lin, Michael Jeanson, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Miehlbradt, Nicholas Piggin,
Pali Rohár, Randy Dunlap, Rohan McLure, Russell Currey, Sathvika
Vasireddy, Shaomin Deng, Stephen Kitt, Stephen Rothwell, Thomas
Weißschuh, Tiezhu Yang, Uwe Kleine-König, Xie Shaowen, Xiu Jianfeng,
XueBing Chen, Yang Yingliang, Zhang Jiaming, ruanjinjie, Jessica Yu,
and Wolfram Sang.

* tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (181 commits)
  powerpc/code-patching: Fix oops with DEBUG_VM enabled
  powerpc/qspinlock: Fix 32-bit build
  powerpc/prom: Fix 32-bit build
  powerpc/rtas: mandate RTAS syscall filtering
  powerpc/rtas: define pr_fmt and convert printk call sites
  powerpc/rtas: clean up includes
  powerpc/rtas: clean up rtas_error_log_max initialization
  powerpc/pseries/eeh: use correct API for error log size
  powerpc/rtas: avoid scheduling in rtas_os_term()
  powerpc/rtas: avoid device tree lookups in rtas_os_term()
  powerpc/rtasd: use correct OF API for event scan rate
  powerpc/rtas: document rtas_call()
  powerpc/pseries: unregister VPA when hot unplugging a CPU
  powerpc/pseries: reset the RCU watchdogs after a LPM
  powerpc: Take in account addition CPU node when building kexec FDT
  powerpc: export the CPU node count
  powerpc/cpuidle: Set CPUIDLE_FLAG_POLLING for snooze state
  powerpc/dts/fsl: Fix pca954x i2c-mux node names
  cxl: Remove unnecessary cxl_pci_window_alignment()
  selftests/powerpc: Fix resource leaks
  ...

objtool/powerpc: Implement arch_pc_relative_reloc()

2022-11-23T10:26:10+00:00

Provide an implementation for arch_pc_relative_reloc(). It is needed to
pass the build once 61c6065ef7ec ("objtool: Allow !PC relative
relocations") is merged.

Signed-off-by: Michael Ellerman

objtool: Add arch specific function arch_ftrace_match()

2022-11-18T08:00:16+00:00

Add architecture specific function to look for relocation records
pointing to architecture specific symbols.

Suggested-by: Christophe Leroy 
Tested-by: Naveen N. Rao 
Reviewed-by: Naveen N. Rao 
Reviewed-by: Christophe Leroy 
Acked-by: Josh Poimboeuf 
Signed-off-by: Sathvika Vasireddy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221114175754.1131267-15-sv@linux.ibm.com

objtool: Add --mnop as an option to --mcount

2022-11-18T08:00:16+00:00

Some architectures (powerpc) may not support ftrace locations being nop'ed
out at build time. Introduce CONFIG_HAVE_OBJTOOL_NOP_MCOUNT for objtool, as
a means for architectures to enable nop'ing of ftrace locations. Add --mnop
as an option to objtool --mcount, to indicate support for the same.

Also, make sure that --mnop can be passed as an option to objtool only when
--mcount is passed.

Tested-by: Naveen N. Rao 
Reviewed-by: Naveen N. Rao 
Acked-by: Josh Poimboeuf 
Reviewed-by: Christophe Leroy 
Signed-off-by: Sathvika Vasireddy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221114175754.1131267-12-sv@linux.ibm.com

objtool: Use target file class size instead of a compiled constant

2022-11-18T08:00:16+00:00

In order to allow using objtool on cross-built kernels,
determine size of long from elf data instead of using
sizeof(long) at build time.

For the time being this covers only mcount.

[Sathvika Vasireddy: Rename variable "size" to "addrsize" and function
"elf_class_size()" to "elf_class_addrsize()", and modify
create_mcount_loc_sections() function to follow reverse christmas tree
format to order local variable declarations.]

Tested-by: Naveen N. Rao 
Reviewed-by: Naveen N. Rao 
Acked-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Christophe Leroy 
Signed-off-by: Sathvika Vasireddy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221114175754.1131267-11-sv@linux.ibm.com

objtool: Use target file endianness instead of a compiled constant

2022-11-18T08:00:15+00:00

Some architectures like powerpc support both endianness, it's
therefore not possible to fix the endianness via arch/endianness.h
because there is no easy way to get the target endianness at
build time.

Use the endianness recorded in the file objtool is working on.

Tested-by: Naveen N. Rao 
Reviewed-by: Naveen N. Rao 
Acked-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221114175754.1131267-10-sv@linux.ibm.com

objtool: Optimize elf_dirty_reloc_sym()

2022-11-05T10:28:02+00:00

When moving a symbol in the symtab its index changes and any reloc
referring that symtol-table-index will need to be rewritten too.

In order to facilitate this, objtool simply marks the whole reloc
section 'changed' which will cause the whole section to be
re-generated.

However, finding the relocs that use any given symbol is implemented
rather crudely -- a fully iteration of all sections and their relocs.
Given that some builds have over 20k sections (kallsyms etc..)
iterating all that for *each* symbol moved takes a bit of time.

Instead have each symbol keep a list of relocs that reference it.

This *vastly* improves build times for certain configs.

Reported-by: Borislav Petkov 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/Y2LlRA7x+8UsE1xf@hirez.programming.kicks-ass.net

objtool: Add --cfi to generate the .cfi_sites section

2022-11-01T12:44:10+00:00

Add the location of all __cfi_##name symbols (as generated by kCFI) to
a section such that we might re-write things at kernel boot.

Notably; boot time re-hashing and FineIBT are the intended use of
this.

Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20221027092842.568039454@infradead.org

objtool: Add option to generate prefix symbols

2022-11-01T12:44:09+00:00

When code is compiled with:

  -fpatchable-function-entry=${PADDING_BYTES},${PADDING_BYTES}

functions will have PADDING_BYTES of NOP in front of them. Unwinders
and other things that symbolize code locations will typically
attribute these bytes to the preceding function.

Given that these bytes nominally belong to the following symbol this
mis-attribution is confusing.

Inspired by the fact that CFI_CLANG emits __cfi_##name symbols to
claim these bytes, allow objtool to emit __pfx_##name symbols to do
the same.

Therefore add the objtool --prefix=N argument, to conditionally place
a __pfx_##name symbol at N bytes ahead of symbol 'name' when: all
these preceding bytes are NOP and name-N is an instruction boundary.

Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Yujie Liu 
Link: https://lkml.kernel.org/r/20221028194453.526899822@infradead.org

objtool: Avoid O(bloody terrible) behaviour -- an ode to libelf

2022-11-01T12:44:08+00:00

Due to how gelf_update_sym*() requires an Elf_Data pointer, and how
libelf keeps Elf_Data in a linked list per section,
elf_update_symbol() ends up having to iterate this list on each
update to find the correct Elf_Data for the index'ed symbol.

By allocating one Elf_Data per new symbol, the list grows per new
symbol, giving an effective O(n^2) insertion time. This is obviously
bloody terrible.

Therefore over-allocate the Elf_Data when an extention is needed.
Except it turns out libelf disregards Elf_Scn::sh_size in favour of
the sum of Elf_Data::d_size. IOW it will happily write out all the
unused space and fill it with:

  0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND

entries (aka zeros). Which obviously violates the STB_LOCAL placement
rule, and is a general pain in the backside for not being the desired
behaviour.

Manually fix-up the Elf_Data size to avoid this problem before calling
elf_update().

This significantly improves performance when adding a significant
number of symbols.

Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Yujie Liu 
Link: https://lkml.kernel.org/r/20221028194453.461658986@infradead.org