random: vDSO: avoid call to memset() when zeroing reserved parameter

After a recent change in LLVM [1], builds with the random vDSO
implementation, such as PowerPC and RISC-V, fail when checking the

random: vDSO: avoid call to memset() when zeroing reserved parameter

After a recent change in LLVM [1], builds with the random vDSO
implementation, such as PowerPC and RISC-V, fail when checking the vDSO:

arch/powerpc/kernel/vdso/vdso32.so.dbg: dynamic relocations are not supported
arch/riscv/kernel/vdso/vdso.so.dbg: dynamic relocations are not supported

memset() is now generated when zeroing params->reserved for some builds
because LLVM has an optimization (now run in more instances) that can
recognize at compile time when it is assigning a static value to a
contiguous area of memory and turn that into a call to memset(). Both
clang and GCC assume memset() is always available [2].

Clang has an internal fiddly hook, -max-store-memset, which we can set
to a high number, to disable generating out of line memset calls [3].
Similarly, GCC has -finline-stringops=memset to do the same [4], should
this issue ever hit future version of GCC. While these options wouldn't
make sense for normal kernel code, it is fine for the extremely limited
and intentionally compact vDSO code.

Link: https://github.com/llvm/llvm-project/commit/90cebef1411617fc3eedd359bdf00cb44b1c2439 [1]
Link: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Standards.html#index-ffreestanding [2]
Link: https://github.com/llvm/llvm-project/commit/b28eeb28bea39148738dc375e8a97072a1907e64 [3]
Link: https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-finline-stringops [4]
Closes: https://github.com/ClangBuiltLinux/linux/issues/2183
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

show more ...

riscv: vdso: Simplify cflags remove logic

Listing all flags for each object file is tedious and error-prone.

Replace it with a simpler solution.

Link: https://lore.kernel.org/all/20260630135316-f2

riscv: vdso: Simplify cflags remove logic

Listing all flags for each object file is tedious and error-prone.

Replace it with a simpler solution.

Link: https://lore.kernel.org/all/20260630135316-f26f0e0f-c08c-4d4d-9963-10f9985a7689@linutronix.de/
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20260701-riscv-vdso-lto-v1-2-89db0cd82077@linutronix.de
Signed-off-by: Paul Walmsley <pjw@kernel.org>

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riscv: vdso: Do not use LTO for the vDSO

With LTO enabled the compiler assumes that the vDSO functions are not
used and optimizes them away completely. Currently this happens to
__vdso_clock_getres(

riscv: vdso: Do not use LTO for the vDSO

With LTO enabled the compiler assumes that the vDSO functions are not
used and optimizes them away completely. Currently this happens to
__vdso_clock_getres(), __vdso_clock_gettime(), __vdso_getrandom(),
__vdso_gettimeofday() and __vdso_riscv_hwprobe().

Disable LTO for the vDSO, as these functions are hand-optimized anyways.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202606301855.WvkSC4kD-lkp@intel.com/
Fixes: 021d23428bdb ("RISC-V: build: Allow LTO to be selected")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20260701-riscv-vdso-lto-v1-1-89db0cd82077@linutronix.de
Signed-off-by: Paul Walmsley <pjw@kernel.org>

show more ...

arch/riscv: add dual vdso creation logic and select vdso based on hw

Shadow stack instructions are taken from the Zimop ISA extension,
which is mandated on RVA23. Any userspace with shadow stack
ins

arch/riscv: add dual vdso creation logic and select vdso based on hw

Shadow stack instructions are taken from the Zimop ISA extension,
which is mandated on RVA23. Any userspace with shadow stack
instructions in it will fault on hardware that doesn't have support
for Zimop. Thus, a shadow stack-enabled userspace can't be run on
hardware that doesn't support Zimop.

It's not known how Linux userspace providers will respond to this kind
of binary fragmentation. In order to keep kernel portable across
different hardware, 'arch/riscv/kernel/vdso_cfi' is created which has
Makefile logic to compile 'arch/riscv/kernel/vdso' sources with CFI
flags, and 'arch/riscv/kernel/vdso.c' is modified to select the
appropriate vdso depending on whether the underlying CPU implements
the Zimop extension. Since the offset of vdso symbols will change due
to having two different vdso binaries, there is added logic to include
a new generated vdso offset header and dynamically select the offset
(like for rt_sigreturn).

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Acked-by: Charles Mirabile <cmirabil@redhat.com>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-24-b55691eacf4f@rivosinc.com
[pjw@kernel.org: cleaned up patch description]
Signed-off-by: Paul Walmsley <pjw@kernel.org>

show more ...

arch/riscv: compile vdso with landing pad and shadow stack note

User mode tasks compiled with Zicfilp may call indirectly into the
vdso (like hwprobe indirect calls). Add support for compiling landi

arch/riscv: compile vdso with landing pad and shadow stack note

User mode tasks compiled with Zicfilp may call indirectly into the
vdso (like hwprobe indirect calls). Add support for compiling landing
pads into the vdso. Landing pad instructions in the vdso will be
no-ops for tasks which have not enabled landing pads. Furthermore, add
support for the C sources of the vdso to be compiled with shadow stack
and landing pads enabled as well.

Landing pad and shadow stack instructions are emitted only when the
VDSO_CFI cflags option is defined during compile.

Signed-off-by: Jim Shu <jim.shu@sifive.com>
Reviewed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-23-b55691eacf4f@rivosinc.com
[pjw@kernel.org: cleaned up patch description, issues reported by checkpatch]
Signed-off-by: Paul Walmsley <pjw@kernel.org>

show more ...

Merge tag 'riscv-mw2-6.16-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/alexghiti/linux into for-next

riscv patches for 6.16-rc1, part 2

* Performance improvements
- Add support for

Merge tag 'riscv-mw2-6.16-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/alexghiti/linux into for-next

riscv patches for 6.16-rc1, part 2

* Performance improvements
- Add support for vdso getrandom
- Implement raid6 calculations using vectors
- Introduce svinval tlb invalidation

* Cleanup
- A bunch of deduplication of the macros we use for manipulating instructions

* Misc
- Introduce a kunit test for kprobes
- Add support for mseal as riscv fits the requirements (thanks to Lorenzo for making sure of that :))

[Palmer: There was a rebase between part 1 and part 2, so I've had to do
some more git surgery here... at least two rounds of surgery...]

* alex-pr-2: (866 commits)
RISC-V: vDSO: Wire up getrandom() vDSO implementation
riscv: enable mseal sysmap for RV64
raid6: Add RISC-V SIMD syndrome and recovery calculations
riscv: mm: Add support for Svinval extension
riscv: Add kprobes KUnit test
riscv: kprobes: Remove duplication of RV_EXTRACT_ITYPE_IMM
riscv: kprobes: Remove duplication of RV_EXTRACT_UTYPE_IMM
riscv: kprobes: Remove duplication of RV_EXTRACT_RD_REG
riscv: kprobes: Remove duplication of RVC_EXTRACT_BTYPE_IMM
riscv: kprobes: Remove duplication of RVC_EXTRACT_C2_RS1_REG
riscv: kproves: Remove duplication of RVC_EXTRACT_JTYPE_IMM
riscv: kprobes: Remove duplication of RV_EXTRACT_BTYPE_IMM
riscv: kprobes: Remove duplication of RV_EXTRACT_RS1_REG
riscv: kprobes: Remove duplication of RV_EXTRACT_JTYPE_IMM
riscv: kprobes: Move branch_funct3 to insn.h
riscv: kprobes: Move branch_rs2_idx to insn.h
Linux 6.15-rc6
Input: xpad - fix xpad_device sorting
Input: xpad - add support for several more controllers
Input: xpad - fix Share button on Xbox One controllers
...

show more ...

RISC-V: vDSO: Wire up getrandom() vDSO implementation

Hook up the generic vDSO implementation to the generic vDSO getrandom
implementation by providing the required __arch_chacha20_blocks_nostack
an

RISC-V: vDSO: Wire up getrandom() vDSO implementation

Hook up the generic vDSO implementation to the generic vDSO getrandom
implementation by providing the required __arch_chacha20_blocks_nostack
and getrandom_syscall implementations. Also wire up the selftests.

The benchmark result:

vdso: 25000000 times in 2.466341333 seconds
libc: 25000000 times in 41.447720005 seconds
syscall: 25000000 times in 41.043926672 seconds

vdso: 25000000 x 256 times in 162.286219353 seconds
libc: 25000000 x 256 times in 2953.855018685 seconds
syscall: 25000000 x 256 times in 2796.268546000 seconds

[ alex: - Fix dynamic relocation
- Squash Nathan's fix https://lore.kernel.org/all/20250423-riscv-fix-compat_vdso-lld-v2-1-b7bbbc244501@kernel.org/
- Add comment from Loongarch ]

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Link: https://lore.kernel.org/r/20250411024600.16045-1-xry111@xry111.site
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

show more ...

Revert "RISC-V: vDSO: Wire up getrandom() vDSO implementation"

This has been on -next for a bit, but it's broken and there's already a
v2. So I'm reverting it to avoid more rebasing.

This reverts

Revert "RISC-V: vDSO: Wire up getrandom() vDSO implementation"

This has been on -next for a bit, but it's broken and there's already a
v2. So I'm reverting it to avoid more rebasing.

This reverts commit 89079520cef65d6da1e864eab4464effe5396e23.

Link: https://lore.kernel.org/r/20250602173315.20228-1-palmer@dabbelt.com
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

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riscv: vDSO: Remove --hash-style=both

When RISC-V borned, DT_GNU_HASH had already became the de-facto
standard so DT_HASH is just wasting storage space. Remove the explicit
--hash-style=both settin

riscv: vDSO: Remove --hash-style=both

When RISC-V borned, DT_GNU_HASH had already became the de-facto
standard so DT_HASH is just wasting storage space. Remove the explicit
--hash-style=both setting and rely on the distro toolchain default,
which is most likely "gnu" (i.e. generating only DT_GNU_HASH, no
DT_HASH).

Following the logic of commit 48f6430505c0
("arm64/vdso: Remove --hash-style=sysv").

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Link: https://lore.kernel.org/r/20250224112042.60282-2-xry111@xry111.site
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

show more ...

RISC-V: vDSO: Wire up getrandom() vDSO implementation

Hook up the generic vDSO implementation to the generic vDSO getrandom
implementation by providing the required __arch_chacha20_blocks_nostack
an

RISC-V: vDSO: Wire up getrandom() vDSO implementation

Hook up the generic vDSO implementation to the generic vDSO getrandom
implementation by providing the required __arch_chacha20_blocks_nostack
and getrandom_syscall implementations. Also wire up the selftests.

The benchmark result:

vdso: 25000000 times in 2.466341333 seconds
libc: 25000000 times in 41.447720005 seconds
syscall: 25000000 times in 41.043926672 seconds

vdso: 25000000 x 256 times in 162.286219353 seconds
libc: 25000000 x 256 times in 2953.855018685 seconds
syscall: 25000000 x 256 times in 2796.268546000 seconds

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Link: https://lore.kernel.org/r/20250411024600.16045-1-xry111@xry111.site
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

show more ...

vdso: Rename included Makefile

As the Makefile is included into other Makefiles it can not be used to
define objects to be built from the current source directory.
However the generic datastore will

vdso: Rename included Makefile

As the Makefile is included into other Makefiles it can not be used to
define objects to be built from the current source directory.
However the generic datastore will introduce such a local source file.
Rename the included Makefile so it is clear how it is to be used and to
make room for a regular Makefile in lib/vdso/.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-4-13a4669dfc8c@linutronix.de

show more ...

riscv: Check that vdso does not contain any dynamic relocations

Like other architectures, use the common cmd_vdso_check to make sure of
that.

Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by

riscv: Check that vdso does not contain any dynamic relocations

Like other architectures, use the common cmd_vdso_check to make sure of
that.

Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by: Vladimir Isaev <vladimir.isaev@syntacore.com>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20241016083625.136311-3-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

show more ...

riscv: vdso: Prevent the compiler from inserting calls to memset()

The compiler is smart enough to insert a call to memset() in
riscv_vdso_get_cpus(), which generates a dynamic relocation.

So preve

riscv: vdso: Prevent the compiler from inserting calls to memset()

The compiler is smart enough to insert a call to memset() in
riscv_vdso_get_cpus(), which generates a dynamic relocation.

So prevent this by using -fno-builtin option.

Fixes: e2c0cdfba7f6 ("RISC-V: User-facing API")
Cc: stable@vger.kernel.org
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20241016083625.136311-2-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

show more ...

riscv: vdso: do not strip debugging info for vdso.so.dbg

The vdso.so.dbg is a debug version of vdso and could be used for debugging
purpose. For example, perf-annotate requires debugging info to sho

riscv: vdso: do not strip debugging info for vdso.so.dbg

The vdso.so.dbg is a debug version of vdso and could be used for debugging
purpose. For example, perf-annotate requires debugging info to show source
lines. So let's keep its debugging info.

Signed-off-by: Changbin Du <changbin.du@huawei.com>
Reviewed-by: Cyril Bur <cyrilbur@tenstorrent.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240611040947.3024710-1-changbin.du@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

show more ...

Makefile: remove redundant tool coverage variables

Now Kbuild provides reasonable defaults for objtool, sanitizers, and
profilers.

Remove redundant variables.

Note:

This commit changes the covera

Makefile: remove redundant tool coverage variables

Now Kbuild provides reasonable defaults for objtool, sanitizers, and
profilers.

Remove redundant variables.

Note:

This commit changes the coverage for some objects:

- include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
- include arch/sparc/vdso/vdso-image-*.o into UBSAN
- include arch/sparc/vdso/vma.o into UBSAN
- include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vma.o into GCOV, KCOV
- include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV

I believe these are positive effects because all of them are kernel
space objects.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Roberto Sassu <roberto.sassu@huawei.com>

show more ...

kbuild: use $(src) instead of $(srctree)/$(src) for source directory

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention withou

kbuild: use $(src) instead of $(srctree)/$(src) for source directory

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:

src := $(obj)

When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.

This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.

To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.

Going forward, the variables used in Makefiles will have the following
meanings:

$(obj) - directory in the object tree
$(src) - directory in the source tree (changed by this commit)
$(objtree) - the top of the kernel object tree
$(srctree) - the top of the kernel source tree

Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

show more ...

riscv: hwprobe: do not produce frtace relocation

Such relocation causes crash of android linker similar to one
described in commit e05d57dcb8c7
("riscv: Fixup __vdso_gettimeofday broke dynamic ftrac

riscv: hwprobe: do not produce frtace relocation

Such relocation causes crash of android linker similar to one
described in commit e05d57dcb8c7
("riscv: Fixup __vdso_gettimeofday broke dynamic ftrace").

Looks like this relocation is added by CONFIG_DYNAMIC_FTRACE which is
disabled in the default android kernel.

Before:

readelf -rW arch/riscv/kernel/vdso/vdso.so:

Relocation section '.rela.dyn' at offset 0xd00 contains 1 entry:
Offset Info Type
0000000000000d20 0000000000000003 R_RISCV_RELATIVE

objdump:
0000000000000c86 <__vdso_riscv_hwprobe@@LINUX_4.15>:
c86: 0001 nop
c88: 0001 nop
c8a: 0001 nop
c8c: 0001 nop
c8e: e211 bnez a2,c92 <__vdso_riscv_hwprobe...

After:
readelf -rW arch/riscv/kernel/vdso/vdso.so:

There are no relocations in this file.

objdump:
0000000000000c86 <__vdso_riscv_hwprobe@@LINUX_4.15>:
c86: e211 bnez a2,c8a <__vdso_riscv_hwprobe...
c88: c6b9 beqz a3,cd6 <__vdso_riscv_hwprobe...
c8a: e739 bnez a4,cd8 <__vdso_riscv_hwprobe...
c8c: ffffd797 auipc a5,0xffffd

Also disable SCS since it also should not be available in vdso.

Fixes: aa5af0aa90ba ("RISC-V: Add hwprobe vDSO function and data")
Signed-off-by: Roman Artemev <roman.artemev@syntacore.com>
Signed-off-by: Vladimir Isaev <vladimir.isaev@syntacore.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20240313085843.17661-1-vladimir.isaev@syntacore.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

show more ...

Merge tag 'riscv-for-linus-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

- Support for cbo.zero in userspace

- Support for CBOs o

Merge tag 'riscv-for-linus-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

- Support for cbo.zero in userspace

- Support for CBOs on ACPI-based systems

- A handful of improvements for the T-Head cache flushing ops

- Support for software shadow call stacks

- Various cleanups and fixes

* tag 'riscv-for-linus-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (31 commits)
RISC-V: hwprobe: Fix vDSO SIGSEGV
riscv: configs: defconfig: Enable configs required for RZ/Five SoC
riscv: errata: prefix T-Head mnemonics with th.
riscv: put interrupt entries into .irqentry.text
riscv: mm: Update the comment of CONFIG_PAGE_OFFSET
riscv: Using TOOLCHAIN_HAS_ZIHINTPAUSE marco replace zihintpause
riscv/mm: Fix the comment for swap pte format
RISC-V: clarify the QEMU workaround in ISA parser
riscv: correct pt_level name via pgtable_l5/4_enabled
RISC-V: Provide pgtable_l5_enabled on rv32
clocksource: timer-riscv: Increase rating of clock_event_device for Sstc
clocksource: timer-riscv: Don't enable/disable timer interrupt
lkdtm: Fix CFI_BACKWARD on RISC-V
riscv: Use separate IRQ shadow call stacks
riscv: Implement Shadow Call Stack
riscv: Move global pointer loading to a macro
riscv: Deduplicate IRQ stack switching
riscv: VMAP_STACK overflow detection thread-safe
RISC-V: cacheflush: Initialize CBO variables on ACPI systems
RISC-V: ACPI: RHCT: Add function to get CBO block sizes
...

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kbuild: unify vdso_install rules

Currently, there is no standard implementation for vdso_install,
leading to various issues:

1. Code duplication

Many architectures duplicate similar code just

kbuild: unify vdso_install rules

Currently, there is no standard implementation for vdso_install,
leading to various issues:

1. Code duplication

Many architectures duplicate similar code just for copying files
to the install destination.

Some architectures (arm, sparc, x86) create build-id symlinks,
introducing more code duplication.

2. Unintended updates of in-tree build artifacts

The vdso_install rule depends on the vdso files to install.
It may update in-tree build artifacts. This can be problematic,
as explained in commit 19514fc665ff ("arm, kbuild: make
"make install" not depend on vmlinux").

3. Broken code in some architectures

Makefile code is often copied from one architecture to another
without proper adaptation.

'make vdso_install' for parisc does not work.

'make vdso_install' for s390 installs vdso64, but not vdso32.

To address these problems, this commit introduces a generic vdso_install
rule.

Architectures that support vdso_install need to define vdso-install-y
in arch/*/Makefile. vdso-install-y lists the files to install.

For example, arch/x86/Makefile looks like this:

vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg
vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg
vdso-install-$(CONFIG_X86_32) += arch/x86/entry/vdso/vdso32.so.dbg
vdso-install-$(CONFIG_IA32_EMULATION) += arch/x86/entry/vdso/vdso32.so.dbg

These files will be installed to $(MODLIB)/vdso/ with the .dbg suffix,
if exists, stripped away.

vdso-install-y can optionally take the second field after the colon
separator. This is needed because some architectures install a vdso
file as a different base name.

The following is a snippet from arch/arm64/Makefile.

vdso-install-$(CONFIG_COMPAT_VDSO) += arch/arm64/kernel/vdso32/vdso.so.dbg:vdso32.so

This will rename vdso.so.dbg to vdso32.so during installation. If such
architectures change their implementation so that the base names match,
this workaround will go away.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sven Schnelle <svens@linux.ibm.com> # s390
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Guo Ren <guoren@kernel.org>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

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riscv: Implement Shadow Call Stack

Implement CONFIG_SHADOW_CALL_STACK for RISC-V. When enabled, the
compiler injects instructions to all non-leaf C functions to
store the return address to the shado

riscv: Implement Shadow Call Stack

Implement CONFIG_SHADOW_CALL_STACK for RISC-V. When enabled, the
compiler injects instructions to all non-leaf C functions to
store the return address to the shadow stack and unconditionally
load it again before returning, which makes it harder to corrupt
the return address through a stack overflow, for example.

The active shadow call stack pointer is stored in the gp
register, which makes SCS incompatible with gp relaxation. Use
--no-relax-gp to ensure gp relaxation is disabled and disable
global pointer loading. Add SCS pointers to struct thread_info,
implement SCS initialization, and task switching

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20230927224757.1154247-12-samitolvanen@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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Merge tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

- Support for runtime detection of the Svnapot extension

Merge tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

- Support for runtime detection of the Svnapot extension

- Support for Zicboz when clearing pages

- We've moved to GENERIC_ENTRY

- Support for !MMU on rv32 systems

- The linear region is now mapped via huge pages

- Support for building relocatable kernels

- Support for the hwprobe interface

- Various fixes and cleanups throughout the tree

* tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (57 commits)
RISC-V: hwprobe: Explicity check for -1 in vdso init
RISC-V: hwprobe: There can only be one first
riscv: Allow to downgrade paging mode from the command line
dt-bindings: riscv: add sv57 mmu-type
RISC-V: hwprobe: Remove __init on probe_vendor_features()
riscv: Use --emit-relocs in order to move .rela.dyn in init
riscv: Check relocations at compile time
powerpc: Move script to check relocations at compile time in scripts/
riscv: Introduce CONFIG_RELOCATABLE
riscv: Move .rela.dyn outside of init to avoid empty relocations
riscv: Prepare EFI header for relocatable kernels
riscv: Unconditionnally select KASAN_VMALLOC if KASAN
riscv: Fix ptdump when KASAN is enabled
riscv: Fix EFI stub usage of KASAN instrumented strcmp function
riscv: Move DTB_EARLY_BASE_VA to the kernel address space
riscv: Rework kasan population functions
riscv: Split early and final KASAN population functions
riscv: Use PUD/P4D/PGD pages for the linear mapping
riscv: Move the linear mapping creation in its own function
riscv: Get rid of riscv_pfn_base variable
...

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RISC-V: Add hwprobe vDSO function and data

Add a vDSO function __vdso_riscv_hwprobe, which can sit in front of the
riscv_hwprobe syscall and answer common queries. We stash a copy of
static answers

RISC-V: Add hwprobe vDSO function and data

Add a vDSO function __vdso_riscv_hwprobe, which can sit in front of the
riscv_hwprobe syscall and answer common queries. We stash a copy of
static answers for the "all CPUs" case in the vDSO data page. This data
is private to the vDSO, so we can decide later to change what's stored
there or under what conditions we defer to the syscall. Currently all
data can be discovered at boot, so the vDSO function answers all queries
when the cpumask is set to the "all CPUs" hint.

There's also a boolean in the data that lets the vDSO function know that
all CPUs are the same. In that case, the vDSO will also answer queries
for arbitrary CPU masks in addition to the "all CPUs" hint.

Signed-off-by: Evan Green <evan@rivosinc.com>
Link: https://lore.kernel.org/r/20230407231103.2622178-7-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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vdso: Improve cmd_vdso_check to check all dynamic relocations

The actual intention is that no dynamic relocation exists in the VDSO. For
this the VDSO build validates that the resulting .so file doe

vdso: Improve cmd_vdso_check to check all dynamic relocations

The actual intention is that no dynamic relocation exists in the VDSO. For
this the VDSO build validates that the resulting .so file does not have any
relocations which are specified via $(ARCH_REL_TYPE_ABS) per architecture,
which is fragile as e.g. ARM64 lacks an entry for R_AARCH64_RELATIVE. Aside
of that ARCH_REL_TYPE_ABS is a misnomer as it checks for relative
relocations too.

However, some GNU ld ports produce unneeded R_*_NONE relocation entries. If
a port fails to determine the exact .rel[a].dyn size, the trailing zeros
become R_*_NONE relocations. E.g. ld's powerpc port recently fixed
https://sourceware.org/bugzilla/show_bug.cgi?id=29540). R_*_NONE are
generally a no-op in the dynamic loaders. So just ignore them.

Remove the ARCH_REL_TYPE_ABS defines and just validate that the resulting
.so file does not contain any R_* relocation entries except R_*_NONE.

Signed-off-by: Fangrui Song <maskray@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> # for aarch64
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> # for vDSO, aarch64
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://lore.kernel.org/r/20230310190750.3323802-1-maskray@google.com

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riscv: vdso: fix section overlapping under some conditions

lkp reported a build error, I tried the config and can reproduce
build error as below:

VDSOLD arch/riscv/kernel/vdso/vdso.so.dbg
ld.lld

riscv: vdso: fix section overlapping under some conditions

lkp reported a build error, I tried the config and can reproduce
build error as below:

VDSOLD arch/riscv/kernel/vdso/vdso.so.dbg
ld.lld: error: section .note file range overlaps with .text
>>> .note range is [0x7C8, 0x803]
>>> .text range is [0x800, 0x1993]

ld.lld: error: section .text file range overlaps with .dynamic
>>> .text range is [0x800, 0x1993]
>>> .dynamic range is [0x808, 0x937]

ld.lld: error: section .note virtual address range overlaps with .text
>>> .note range is [0x7C8, 0x803]
>>> .text range is [0x800, 0x1993]

Fix it by setting DISABLE_BRANCH_PROFILING which will disable branch
tracing for vdso, thus avoid useless _ftrace_annotated_branch section
and _ftrace_branch section. Although we can also fix it by removing
the hardcoded .text begin address, but I think that's another story
and should be put into another patch.

Link: https://lore.kernel.org/lkml/202210122123.Cc4FPShJ-lkp@intel.com/#r
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://lore.kernel.org/r/20221102170254.1925-1-jszhang@kernel.org
Fixes: ad5d1122b82f ("riscv: use vDSO common flow to reduce the latency of the time-related functions")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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RISC-V: vdso: Do not add missing symbols to version section in linker script

Recently, ld.lld moved from '--undefined-version' to
'--no-undefined-version' as the default, which breaks the compat vDS

RISC-V: vdso: Do not add missing symbols to version section in linker script

Recently, ld.lld moved from '--undefined-version' to
'--no-undefined-version' as the default, which breaks the compat vDSO
build:

ld.lld: error: version script assignment of 'LINUX_4.15' to symbol '__vdso_gettimeofday' failed: symbol not defined
ld.lld: error: version script assignment of 'LINUX_4.15' to symbol '__vdso_clock_gettime' failed: symbol not defined
ld.lld: error: version script assignment of 'LINUX_4.15' to symbol '__vdso_clock_getres' failed: symbol not defined

These symbols are not present in the compat vDSO or the regular vDSO for
32-bit but they are unconditionally included in the version section of
the linker script, which is prohibited with '--no-undefined-version'.

Fix this issue by only including the symbols that are actually exported
in the version section of the linker script.

Link: https://github.com/ClangBuiltLinux/linux/issues/1756
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221108171324.3377226-1-nathan@kernel.org/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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