linux-toradex.git/tools/objtool/check.h, branch v5.10-rc2

objtool: Refactor jump table code to support other architectures

2020-09-10T15:43:13+00:00

The way to identify jump tables and retrieve all the data necessary to
handle the different execution branches is not the same on all
architectures.  In order to be able to add other architecture support,
define an arch-dependent function to process jump-tables.

Reviewed-by: Miroslav Benes 
Signed-off-by: Raphael Gault 
[J.T.: Move arm64 bits out of this patch,
       Have only one function to find the start of the jump table,
       for now assume that the jump table format will be the same as
       x86]
Signed-off-by: Julien Thierry 
Signed-off-by: Josh Poimboeuf

objtool: Make relocation in alternative handling arch dependent

2020-09-10T15:43:13+00:00

As pointed out by the comment in handle_group_alt(), support of
relocation for instructions in an alternative group depends on whether
arch specific kernel code handles it.

So, let objtool arch specific code decide whether a relocation for
the alternative section should be accepted.

Reviewed-by: Miroslav Benes 
Signed-off-by: Julien Thierry 
Signed-off-by: Josh Poimboeuf

objtool: Define 'struct orc_entry' only when needed

2020-09-01T22:19:12+00:00

Implementation of ORC requires some definitions that are currently
provided by the target architecture headers. Do not depend on these
definitions when the orc subcommand is not implemented.

This avoid requiring arches with no orc implementation to provide dummy
orc definitions.

Signed-off-by: Julien Thierry 
Reviewed-by: Miroslav Benes 
Signed-off-by: Josh Poimboeuf

x86/static_call: Add inline static call implementation for x86-64

2020-09-01T07:58:05+00:00

Add the inline static call implementation for x86-64. The generated code
is identical to the out-of-line case, except we move the trampoline into
it's own section.

Objtool uses the trampoline naming convention to detect all the call
sites. It then annotates those call sites in the .static_call_sites
section.

During boot (and module init), the call sites are patched to call
directly into the destination function.  The temporary trampoline is
then no longer used.

[peterz: merged trampolines, put trampoline in section]

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Cc: Linus Torvalds 
Link: https://lore.kernel.org/r/20200818135804.864271425@infradead.org

objtool: Rename rela to reloc

2020-06-01T14:40:58+00:00

Before supporting additional relocation types rename the relevant
types and functions from "rela" to "reloc". This work be done with
the following regex:

  sed -e 's/struct rela/struct reloc/g' \
      -e 's/\([_\*]\)rela\(s\{0,1\}\)/\1reloc\2/g' \
      -e 's/tmprela\(s\{0,1\}\)/tmpreloc\1/g' \
      -e 's/relasec/relocsec/g' \
      -e 's/rela_list/reloc_list/g' \
      -e 's/rela_hash/reloc_hash/g' \
      -e 's/add_rela/add_reloc/g' \
      -e 's/rela->/reloc->/g' \
      -e '/rela[,\.]/{ s/\([^\.>]\)rela\([\.,]\)/\1reloc\2/g ; }' \
      -e 's/rela =/reloc =/g' \
      -e 's/relas =/relocs =/g' \
      -e 's/relas\[/relocs[/g' \
      -e 's/relaname =/relocname =/g' \
      -e 's/= rela\;/= reloc\;/g' \
      -e 's/= relas\;/= relocs\;/g' \
      -e 's/= relaname\;/= relocname\;/g' \
      -e 's/, rela)/, reloc)/g' \
      -e 's/\([ @]\)rela\([ "]\)/\1reloc\2/g' \
      -e 's/ rela$/ reloc/g' \
      -e 's/, relaname/, relocname/g' \
      -e 's/sec->rela/sec->reloc/g' \
      -e 's/(\(!\{0,1\}\)rela/(\1reloc/g' \
      -i \
      arch.h \
      arch/x86/decode.c  \
      check.c \
      check.h \
      elf.c \
      elf.h \
      orc_gen.c \
      special.c

Notable exceptions which complicate the regex include gelf_*
library calls and standard/expected section names which still use
"rela" because they encode the type of relocation expected. Also, keep
"rela" in the struct because it encodes a specific type of relocation
we currently expect.

It will eventually turn into a member of an anonymous union when a
susequent patch adds implicit addend, or "rel", relocation support.

Signed-off-by: Matt Helsley 
Signed-off-by: Josh Poimboeuf

objtool: Enable compilation of objtool for all architectures

2020-05-20T14:17:28+00:00

Objtool currently only compiles for x86 architectures. This is
fine as it presently does not support tooling for other
architectures. However, we would like to be able to convert other
kernel tools to run as objtool sub commands because they too
process ELF object files. This will allow us to convert tools
such as recordmcount to use objtool's ELF code.

Since much of recordmcount's ELF code is copy-paste code to/from
a variety of other kernel tools (look at modpost for example) this
means that if we can convert recordmcount we can convert more.

We define weak definitions for subcommand entry functions and other weak
definitions for shared functions critical to building existing
subcommands. These return 127 when the command is missing which signify
tools that do not exist on all architectures.  In this case the "check"
and "orc" tools do not exist on all architectures so we only add them
for x86. Future changes adding support for "check", to arm64 for
example, can then modify the SUBCMD_CHECK variable when building for
arm64.

Objtool is not currently wired in to KConfig to be built for other
architectures because it's not needed for those architectures and
there are no commands it supports other than those for x86. As more
command support is enabled on various architectures the necessary
KConfig changes can be made (e.g. adding "STACK_VALIDATION") to
trigger building objtool.

[ jpoimboe: remove aliases, add __weak macro, add error messages ]

Cc: Julien Thierry 
Signed-off-by: Matt Helsley 
Signed-off-by: Josh Poimboeuf

objtool: Move struct objtool_file into arch-independent header

2020-05-20T13:35:20+00:00

The objtool_file structure describes the files objtool works on,
is used by the check subcommand, and the check.h header is included
by the orc subcommands so it's presently used by all subcommands.

Since the structure will be useful in all subcommands besides check,
and some subcommands may not want to include check.h to get the
definition, split the structure out into a new header meant for use
by all objtool subcommands.

Signed-off-by: Matt Helsley 
Reviewed-by: Julien Thierry 
Signed-off-by: Josh Poimboeuf

objtool: Uniquely identify alternative instruction groups

2020-04-30T18:14:31+00:00

Assign a unique identifier to every alternative instruction group in
order to be able to tell which instructions belong to what
alternative.

[peterz: extracted from a larger patch]
Signed-off-by: Alexandre Chartre 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Miroslav Benes

objtool: Implement noinstr validation

2020-04-22T08:53:50+00:00

Validate that any call out of .noinstr.text is in between
instr_begin() and instr_end() annotations.

This annotation is useful to ensure correct behaviour wrt tracing
sensitive code like entry/exit and idle code. When we run code in a
sensitive context we want a guarantee no unknown code is ran.

Since this validation relies on knowing the section of call
destination symbols, we must run it on vmlinux.o instead of on
individual object files.

Add two options:

 -d/--duplicate "duplicate validation for vmlinux"
 -l/--vmlinux "vmlinux.o validation"

Where the latter auto-detects when objname ends with "vmlinux.o" and
the former will force all validations, also those already done on
!vmlinux object files.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Miroslav Benes 
Reviewed-by: Alexandre Chartre 
Acked-by: Josh Poimboeuf 
Link: https://lkml.kernel.org/r/20200416115119.106268040@infradead.org
Signed-off-by: Ingo Molnar

objtool: Fix !CFI insn_state propagation

2020-04-22T08:53:50+00:00

Objtool keeps per instruction CFI state in struct insn_state and will
save/restore this where required. However, insn_state has grown some
!CFI state, and this must not be saved/restored (that would
loose/destroy state).

Fix this by moving the CFI specific parts of insn_state into struct
cfi_state.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Miroslav Benes 
Reviewed-by: Alexandre Chartre 
Acked-by: Josh Poimboeuf 
Link: https://lkml.kernel.org/r/20200416115119.045821071@infradead.org
Signed-off-by: Ingo Molnar