Some architectures, such as RISC-V, use the ELF e_flags field to encode
ABI-specific information (e.g., ISA extensions, fpu support). Debuggers
like GDB rely on these flags in core dumps to correctly interpret
optional register sets. If the flags are missing or incorrect, GDB may
warn and ignore valid data, for example:
warning: Unexpected size of section '.reg2/213' in core file.
This can prevent access to fpu or other architecture-specific registers
even when they were dumped.
Save the e_flags field during ELF binary loading (in load_elf_binary())
into the mm_struct, and later retrieve it during core dump generation
(in fill_note_info()). Kconfig option CONFIG_ARCH_HAS_ELF_CORE_EFLAGS
is introduced for architectures that require this behaviour.
Signed-off-by: Svetlana Parfenova <svetlana.parfenova@syntacore.com>
Link: https://lore.kernel.org/r/20250901135350.619485-1-svetlana.parfenova@syntacore.com
Signed-off-by: Kees Cook <kees@kernel.org>
Add support for enabling and using the binfmt_elf_fdpic program loader
on RISC-V platforms. The most important change is to setup registers
during program load to pass the mapping addresses to the new process.
One of the interesting features of the elf-fdpic loader is that it
also allows appropriately compiled ELF format binaries to be loaded on
nommu systems. Appropriate being those compiled with -pie.
Signed-off-by: Greg Ungerer <gerg@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230711130754.481209-3-gerg@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Pull xtensa updates from Max Filippov:
- add support for FDPIC and static PIE executable formats for noMMU
* tag 'xtensa-20221010' of https://github.com/jcmvbkbc/linux-xtensa:
xtensa: add FDPIC and static PIE support for noMMU
xtensa: clean up ELF_PLAT_INIT macro
In commit 19e8b701e2 ("a.out: Stop building a.out/osf1 support on
alpha and m68k") the last users of a.out were disabled.
As nothing has turned up to cause this change to be reverted, let's
remove the code implementing a.out support as well.
There may be userspace users of the uapi bits left so the uapi
headers have been left untouched.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Arnd Bergmann <arnd@arndb.de> # arm defconfigs
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/871qrx3hq3.fsf@email.froward.int.ebiederm.org
Define ELFOSABI_XTENSA_FDPIC and use it as an OSABI tag in the ELF
header to distinguish FDPIC ELF files from regular ELF files.
Define ELF_FDPIC_PLAT_INIT and put executable map, interpreter map and
executable dynamic section addresses into registers a4..a6.
Update start_thread macro to preserve register values in the current
register window.
Add definitions for PTRACE_GETFDPIC, PTRACE_GETFDPIC_EXEC and
PTRACE_GETFDPIC_INTERP.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Pull m68knommu updates from Greg Ungerer:
"A collection of changes to add elf-fdpic loader support for m68k.
Also a collection of various fixes. They include typo corrections,
undefined symbol compilation fixes, removal of the ISA_DMA_API support
and removal of unused code.
Summary:
- correctly set up ZERO_PAGE pointer
- drop ISA_DMA_API support
- fix comment typos
- fixes for undefined symbols
- remove unused code and variables
- elf-fdpic loader support for m68k"
* tag 'm68knommu-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
m68knommu: fix 68000 CPU link with no platform selected
m68k: removed unused "mach_get_ss"
m68knommu: fix undefined reference to `mach_get_rtc_pll'
m68knommu: fix undefined reference to `_init_sp'
m68knommu: allow elf_fdpic loader to be selected
m68knommu: add definitions to support elf_fdpic program loader
m68knommu: implement minimal regset support
m68knommu: use asm-generic/mmu.h for nommu setups
m68k: fix typos in comments
m68k: coldfire: drop ISA_DMA_API support
m68knommu: set ZERO_PAGE() to the allocated zeroed page
The m68k architecture code is capable of supporting the binfmt_elf_fdpic
loader, so allow it to be configured. It is restricted to nommu
configurations at this time due to the MMU context structures/code not
supporting everything elf_fdpic needs when MMU is enabled.
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Pull execve updates from Kees Cook:
"Execve and binfmt updates.
Eric and I have stepped up to be the active maintainers of this area,
so here's our first collection. The bulk of the work was in coredump
handling fixes; additional details are noted below:
- Handle unusual AT_PHDR offsets (Akira Kawata)
- Fix initial mapping size when PT_LOADs are not ordered (Alexey
Dobriyan)
- Move more code under CONFIG_COREDUMP (Alexey Dobriyan)
- Fix missing mmap_lock in file_files_note (Eric W. Biederman)
- Remove a.out support for alpha and m68k (Eric W. Biederman)
- Include first pages of non-exec ELF libraries in coredump (Jann
Horn)
- Don't write past end of notes for regset gap in coredump (Rick
Edgecombe)
- Comment clean-ups (Tom Rix)
- Force single empty string when argv is empty (Kees Cook)
- Add NULL argv selftest (Kees Cook)
- Properly redefine PT_GNU_* in terms of PT_LOOS (Kees Cook)
- MAINTAINERS: Update execve entry with tree (Kees Cook)
- Introduce initial KUnit testing for binfmt_elf (Kees Cook)"
* tag 'execve-v5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
binfmt_elf: Don't write past end of notes for regset gap
a.out: Stop building a.out/osf1 support on alpha and m68k
coredump: Don't compile flat_core_dump when coredumps are disabled
coredump: Use the vma snapshot in fill_files_note
coredump/elf: Pass coredump_params into fill_note_info
coredump: Remove the WARN_ON in dump_vma_snapshot
coredump: Snapshot the vmas in do_coredump
coredump: Move definition of struct coredump_params into coredump.h
binfmt_elf: Introduce KUnit test
ELF: Properly redefine PT_GNU_* in terms of PT_LOOS
MAINTAINERS: Update execve entry with more details
exec: cleanup comments
fs/binfmt_elf: Refactor load_elf_binary function
fs/binfmt_elf: Fix AT_PHDR for unusual ELF files
binfmt: move more stuff undef CONFIG_COREDUMP
selftests/exec: Test for empty string on NULL argv
exec: Force single empty string when argv is empty
coredump: Also dump first pages of non-executable ELF libraries
ELF: fix overflow in total mapping size calculation
Commit 2217b98262 ("binfmt_flat: revert "binfmt_flat: don't offset
the data start"") restored offsetting the start of the data section by
a number of words defined by MAX_SHARED_LIBS. As a result, since
MAX_SHARED_LIBS is never 0, a gap between the text and data sections
always exists. For architectures which cannot support a such gap
between the text and data sections (e.g. riscv nommu), flat binary
programs cannot be executed.
To allow an architecture to request no data start offset to allow for
contiguous text and data sections for binaries flagged with
FLAT_FLAG_RAM, introduce the new config option
CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET. Using this new option, the
macro DATA_START_OFFSET_WORDS is conditionally defined in binfmt_flat.c
to MAX_SHARED_LIBS for architectures tolerating or needing the data
start offset (CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET disabled case)
and to 0 when CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET is enabled.
DATA_START_OFFSET_WORDS is used in load_flat_file() to calculate the
data section length and start position.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Pull ELF compat updates from Al Viro:
"Sanitizing ELF compat support, especially for triarch architectures:
- X32 handling cleaned up
- MIPS64 uses compat_binfmt_elf.c both for O32 and N32 now
- Kconfig side of things regularized
Eventually I hope to have compat_binfmt_elf.c killed, with both native
and compat built from fs/binfmt_elf.c, with -DELF_BITS={64,32} passed
by kbuild, but that's a separate story - not included here"
* 'work.elf-compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
get rid of COMPAT_ELF_EXEC_PAGESIZE
compat_binfmt_elf: don't bother with undef of ELF_ARCH
Kconfig: regularize selection of CONFIG_BINFMT_ELF
mips compat: switch to compat_binfmt_elf.c
mips: don't bother with ELF_CORE_EFLAGS
mips compat: don't bother with ELF_ET_DYN_BASE
mips: KVM_GUEST makes no sense for 64bit builds...
mips: kill unused definitions in binfmt_elf[on]32.c
mips binfmt_elf*32.c: use elfcore-compat.h
x32: make X32, !IA32_EMULATION setups able to execute x32 binaries
[amd64] clean PRSTATUS_SIZE/SET_PR_FPVALID up properly
elf_prstatus: collect the common part (everything before pr_reg) into a struct
binfmt_elf: partially sanitize PRSTATUS_SIZE and SET_PR_FPVALID
The c6x architecture was added to the kernel in 2011 at a time when
running Linux on DSPs was widely seen as the logical evolution.
It appears the trend has gone back to running Linux on Arm based SoCs
with DSP, using a better supported software ecosystem, and having better
real-time behavior for the DSP code. An example of this is TI's own
Keystone2 platform.
The upstream kernel port appears to no longer have any users. Mark
Salter remained avaialable to review patches, but mentioned that
he no longer has access to working hardware himself. Without any
users, it's best to just remove the code completely to reduce the
work for cross-architecture code changes.
Many thanks to Mark for maintaining the code for the past ten years.
Link: https://lore.kernel.org/lkml/41dc7795afda9f776d8cd0d3075f776cf586e97c.camel@redhat.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
with mips converted to use of fs/config_binfmt_elf.c, there's no
need to keep selects of that thing all over arch/* - we can simply
turn into def_bool y if COMPAT && BINFMT_ELF (in fs/Kconfig.binfmt)
and get rid of all selects.
Several architectures got those selects wrong (e.g. you could
end up with sparc64 sans BINFMT_ELF, with select violating
dependencies, etc.)
Randy Dunlap has spotted some of those; IMO this is simpler than
his fix, but it depends upon the stuff that would need to be
backported, so we might end up using his variant for -stable.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.
This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.
There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'
In order to convert all of them to 1 tab + 'help', I ran the
following commend:
$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull arch/sh updates from Rich Felker:
"Fix for arch/sh build regression with newer binutils, removal of SH5,
fixes for module exports, and misc cleanup"
* tag 'sh-for-5.8' of git://git.libc.org/linux-sh:
sh: remove sh5 support
sh: add missing EXPORT_SYMBOL() for __delay
sh: Convert ins[bwl]/outs[bwl] macros to inline functions
sh: Convert iounmap() macros to inline functions
sh: Add missing DECLARE_EXPORT() for __ashiftrt_r4_xx
sh: configs: Cleanup old Kconfig IO scheduler options
arch/sh: vmlinux.scr
sh: Replace CONFIG_MTD_M25P80 with CONFIG_MTD_SPI_NOR in sh7757lcr_defconfig
sh: sh4a: Bring back tmu3_device early device
Pull documentation updates from Jonathan Corbet:
"A fair amount of stuff this time around, dominated by yet another
massive set from Mauro toward the completion of the RST conversion. I
*really* hope we are getting close to the end of this. Meanwhile,
those patches reach pretty far afield to update document references
around the tree; there should be no actual code changes there. There
will be, alas, more of the usual trivial merge conflicts.
Beyond that we have more translations, improvements to the sphinx
scripting, a number of additions to the sysctl documentation, and lots
of fixes"
* tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits)
Documentation: fixes to the maintainer-entry-profile template
zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst
tracing: Fix events.rst section numbering
docs: acpi: fix old http link and improve document format
docs: filesystems: add info about efivars content
Documentation: LSM: Correct the basic LSM description
mailmap: change email for Ricardo Ribalda
docs: sysctl/kernel: document unaligned controls
Documentation: admin-guide: update bug-hunting.rst
docs: sysctl/kernel: document ngroups_max
nvdimm: fixes to maintainter-entry-profile
Documentation/features: Correct RISC-V kprobes support entry
Documentation/features: Refresh the arch support status files
Revert "docs: sysctl/kernel: document ngroups_max"
docs: move locking-specific documents to locking/
docs: move digsig docs to the security book
docs: move the kref doc into the core-api book
docs: add IRQ documentation at the core-api book
docs: debugging-via-ohci1394.txt: add it to the core-api book
docs: fix references for ipmi.rst file
...
sh5 never became a product and has probably never really worked.
Remove it by recursively deleting all associated Kconfig options
and all corresponding files.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rich Felker <dalias@libc.org>
An arch may want to tweak the mmap prot flags for an
ELFexecutable's initial mappings. For example, arm64 is going to
need to add PROT_BTI for executable pages in an ELF process whose
executable is marked as using Branch Target Identification (an
ARMv8.5-A control flow integrity feature).
So that this can be done in a generic way, add a hook
arch_elf_adjust_prot() to modify the prot flags as desired: arches
can select CONFIG_HAVE_ELF_PROT and implement their own backend
where necessary.
By default, leave the prot flags unchanged.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
No need to carry the extra code around, given that systems using flat
binaries are generally very resource constrained.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Svetlana ParfenovaandKees Cook
Greg UngererandPalmer Dabbelt
Linus Torvalds
Eric W. BiedermanandKees Cook
Max Filippov
Greg Ungerer
Catalin MarinasandWill Deacon
David HildenbrandandMatt Turner
Damien Le MoalandGreg Ungerer
Arnd Bergmann
Al Viro
Masahiro Yamada
Mauro Carvalho ChehabandJonathan Corbet
Dave MartinandCatalin Marinas
Christoph HellwigandGreg Ungerer