The RISC-V Vector specification states in "Appendix D: Calling
Convention for Vector State" [1] that "Executing a system call causes
all caller-saved vector registers (v0-v31, vl, vtype) and vstart to
become unspecified.". In the RISC-V kernel this is called "discarding
the vstate".
Returning from a signal handler via the rt_sigreturn() syscall, vector
discard is also performed. However, this is not an issue since the
vector state should be restored from the sigcontext, and therefore not
care about the vector discard.
The "live state" is the actual vector register in the running context,
and the "vstate" is the vector state of the task. A dirty live state,
means that the vstate and live state are not in synch.
When vectorized user_from_copy() was introduced, an bug sneaked in at
the restoration code, related to the discard of the live state.
An example when this go wrong:
1. A userland application is executing vector code
2. The application receives a signal, and the signal handler is
entered.
3. The application returns from the signal handler, using the
rt_sigreturn() syscall.
4. The live vector state is discarded upon entering the
rt_sigreturn(), and the live state is marked as "dirty", indicating
that the live state need to be synchronized with the current
vstate.
5. rt_sigreturn() restores the vstate, except the Vector registers,
from the sigcontext
6. rt_sigreturn() restores the Vector registers, from the sigcontext,
and now the vectorized user_from_copy() is used. The dirty live
state from the discard is saved to the vstate, making the vstate
corrupt.
7. rt_sigreturn() returns to the application, which crashes due to
corrupted vstate.
Note that the vectorized user_from_copy() is invoked depending on the
value of CONFIG_RISCV_ISA_V_UCOPY_THRESHOLD. Default is 768, which
means that vlen has to be larger than 128b for this bug to trigger.
The fix is simply to mark the live state as non-dirty/clean prior
performing the vstate restore.
Link: https://github.com/riscv/riscv-isa-manual/releases/download/riscv-isa-release-8abdb41-2024-03-26/unpriv-isa-asciidoc.pdf # [1]
Reported-by: Charlie Jenkins <charlie@rivosinc.com>
Reported-by: Vineet Gupta <vgupta@kernel.org>
Fixes: c2a658d419 ("riscv: lib: vectorize copy_to_user/copy_from_user")
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Andy Chiu <andy.chiu@sifive.com>
Tested-by: Vineet Gupta <vineetg@rivosinc.com>
Link: https://lore.kernel.org/r/20240403072638.567446-1-bjorn@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Andy Chiu <andy.chiu@sifive.com> says:
This series provides support running Vector in kernel mode.
Additionally, kernel-mode Vector can be configured to run without
turnning off preemption on a CONFIG_PREEMPT kernel. Along with the
suport, we add Vector optimized copy_{to,from}_user. And provide a
simple threshold to decide when to run the vectorized functions.
We decided to drop vectorized memcpy/memset/memmove for the moment due
to the concern of memory side-effect in kernel_vector_begin(). The
detailed description can be found at v9[0]
This series is composed by 4 parts:
patch 1-4: adds basic support for kernel-mode Vector
patch 5: includes vectorized copy_{to,from}_user into the kernel
patch 6: refactor context switch code in fpu [1]
patch 7-10: provides some code refactors and support for preemptible
kernel-mode Vector.
This series can be merged if we feel any part of {1~4, 5, 6, 7~10} is
mature enough.
This patch is tested on a QEMU with V and verified that booting, normal
userspace operations all work as usual with thresholds set to 0. Also,
we test by launching multiple kernel threads which continuously executes
and verifies Vector operations in the background. The module that tests
these operation is expected to be upstream later.
* b4-shazam-merge:
riscv: vector: allow kernel-mode Vector with preemption
riscv: vector: use kmem_cache to manage vector context
riscv: vector: use a mask to write vstate_ctrl
riscv: vector: do not pass task_struct into riscv_v_vstate_{save,restore}()
riscv: fpu: drop SR_SD bit checking
riscv: lib: vectorize copy_to_user/copy_from_user
riscv: sched: defer restoring Vector context for user
riscv: Add vector extension XOR implementation
riscv: vector: make Vector always available for softirq context
riscv: Add support for kernel mode vector
Link: https://lore.kernel.org/r/20240115055929.4736-1-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
riscv_v_vstate_{save,restore}() can operate only on the knowlege of
struct __riscv_v_ext_state, and struct pt_regs. Let the caller decides
which should be passed into the function. Meanwhile, the kernel-mode
Vector is going to introduce another vstate, so this also makes functions
potentially able to be reused.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20240115055929.4736-8-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
User will use its Vector registers only after the kernel really returns
to the userspace. So we can delay restoring Vector registers as long as
we are still running in kernel mode. So, add a thread flag to indicates
the need of restoring Vector and do the restore at the last
arch-specific exit-to-user hook. This save the context restoring cost
when we switch over multiple processes that run V in kernel mode. For
example, if the kernel performs a context swicth from A->B->C, and
returns to C's userspace, then there is no need to restore B's
V-register.
Besides, this also prevents us from repeatedly restoring V context when
executing kernel-mode Vector multiple times.
The cost of this is that we must disable preemption and mark vector as
busy during vstate_{save,restore}. Because then the V context will not
get restored back immediately when a trap-causing context switch happens
in the middle of vstate_{save,restore}.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20240115055929.4736-5-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The save_v_state() is technically sending a __user pointer through
__put_user() and thus is generating a sparse warning so force the
value to be "void *" to fix:
arch/riscv/kernel/signal.c:94:16: warning: incorrect type in initializer (different address spaces)
arch/riscv/kernel/signal.c:94:16: expected void *__val
arch/riscv/kernel/signal.c:94:16: got void [noderef] __user *[assigned] datap
Fixes: 8ee0b41898 ("riscv: signal: Add sigcontext save/restore for vector")
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Link: https://lore.kernel.org/r/20231123142708.261733-1-ben.dooks@codethink.co.uk
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This is really just a single patch, but since the offending fix hasn't
yet made it to my for-next I'm merging it here.
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
In the current riscv implementation, blocking syscalls like read() may
not correctly restart after being interrupted by ptrace. This problem
arises when the syscall restart process in arch_do_signal_or_restart()
is bypassed due to changes to the regs->cause register, such as an
ebreak instruction.
Steps to reproduce:
1. Interrupt the tracee process with PTRACE_SEIZE & PTRACE_INTERRUPT.
2. Backup original registers and instruction at new_pc.
3. Change pc to new_pc, and inject an instruction (like ebreak) to this
address.
4. Resume with PTRACE_CONT and wait for the process to stop again after
executing ebreak.
5. Restore original registers and instructions, and detach from the
tracee process.
6. Now the read() syscall in tracee will return -1 with errno set to
ERESTARTSYS.
Specifically, during an interrupt, the regs->cause changes from
EXC_SYSCALL to EXC_BREAKPOINT due to the injected ebreak, which is
inaccessible via ptrace so we cannot restore it. This alteration breaks
the syscall restart condition and ends the read() syscall with an
ERESTARTSYS error. According to include/linux/errno.h, it should never
be seen by user programs. X86 can avoid this issue as it checks the
syscall condition using a register (orig_ax) exposed to user space.
Arm64 handles syscall restart before calling get_signal, where it could
be paused and inspected by ptrace/debugger.
This patch adjusts the riscv implementation to arm64 style, which also
checks syscall using a kernel register (syscallno). It ensures the
syscall restart process is not bypassed when changes to the cause
register occur, providing more consistent behavior across various
architectures.
For a simplified reproduction program, feel free to visit:
https://github.com/ancientmodern/riscv-ptrace-bug-demo.
Signed-off-by: Haorong Lu <ancientmodern4@gmail.com>
Link: https://lore.kernel.org/r/20230803224458.4156006-1-ancientmodern4@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The alternative stack checking in get_sigframe introduced by the Vector
support is not needed and has a problem. It is not needed as we have
already validate it at the beginning of the function if we are already
on an altstack. If not, the size of an altstack is always validated at
its allocation stage with sigaltstack_size_valid().
Besides, we must only regard the size of an altstack if the handler of a
signal is registered with SA_ONSTACK. So, blindly checking overflow of
an altstack if sas_ss_size not equals to zero will check against wrong
signal handlers if only a subset of signals are registered with
SA_ONSTACK.
Fixes: 8ee0b41898 ("riscv: signal: Add sigcontext save/restore for vector")
Reported-by: Prashanth Swaminathan <prashanthsw@google.com>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Link: https://lore.kernel.org/r/20230822164904.21660-1-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Some extensions, such as Vector, dynamically change footprint on a
signal frame, so MINSIGSTKSZ is no longer accurate. For example, an
RV64V implementation with vlen = 512 may occupy 2K + 40 + 12 Bytes of a
signal frame with the upcoming support. And processes that do not
execute any vector instructions do not need to reserve the extra
sigframe. So we need a way to guard the allocation size of the sigframe
at process runtime according to current status of V.
Thus, provide the function sigaltstack_size_valid() to validate its size
based on current allocation status of supported extensions.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230605110724.21391-17-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The vector register belongs to the signal context. They need to be stored
and restored as entering and leaving the signal handler. According to the
V-extension specification, the maximum length of the vector registers can
be 2^16. Hence, if userspace refers to the MINSIGSTKSZ to create a
sigframe, it may not be enough. To resolve this problem, this patch refers
to the commit 94b07c1f8c
("arm64: signal: Report signal frame size to userspace via auxv") to enable
userspace to know the minimum required sigframe size through the auxiliary
vector and use it to allocate enough memory for signal context.
Note that auxv always reports size of the sigframe as if V exists for
all starting processes, whenever the kernel has CONFIG_RISCV_ISA_V. The
reason is that users usually reference this value to allocate an
alternative signal stack, and the user may use V anytime. So the user
must reserve a space for V-context in sigframe in case that the signal
handler invokes after the kernel allocating V.
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230605110724.21391-16-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This patch facilitates the existing fp-reserved words for placement of
the first extension's context header on the user's sigframe. A context
header consists of a distinct magic word and the size, including the
header itself, of an extension on the stack. Then, the frame is followed
by the context of that extension, and then a header + context body for
another extension if exists. If there is no more extension to come, then
the frame must be ended with a null context header. A special case is
rv64gc, where the kernel support no extensions requiring to expose
additional regfile to the user. In such case the kernel would place the
null context header right after the first reserved word of
__riscv_q_ext_state when saving sigframe. And the kernel would check if
all reserved words are zeros when a signal handler returns.
__riscv_q_ext_state---->| |<-__riscv_extra_ext_header
~ ~
.reserved[0]--->|0 |<- .reserved
<-------|magic |<- .hdr
| |size |_______ end of sc_fpregs
| |ext-bdy|
| ~ ~
+)size ------->|magic |<- another context header
|size |
|ext-bdy|
~ ~
|magic:0|<- null context header
|size:0 |
The vector registers will be saved in datap pointer. The datap pointer
will be allocated dynamically when the task needs in kernel space. On
the other hand, datap pointer on the sigframe will be set right after
the __riscv_v_ext_state data structure.
Co-developed-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Suggested-by: Vineet Gupta <vineetg@rivosinc.com>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Co-developed-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230605110724.21391-15-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
In order to let kernel/user locate and identify an extension context on
the existing sigframe, we are going to utilize reserved space of fp and
encode the information there. And since the sigcontext has already
preserved a space for fp context w or w/o CONFIG_FPU, we move those
reserved words checking/setting routine back into generic code.
This commit also undone an additional logical change carried by the
refactor commit 007f5c3589
("Refactor FPU code in signal setup/return procedures"). Originally we
did not restore fp context if restoring of gpr have failed. And it was
fine on the other side. In such way the kernel could keep the regfiles
intact, and potentially react at the failing point of restore.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230605110724.21391-14-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
* 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.
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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
- 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
...
In a NOMMU kernel, sigreturn trampolines are generated on the user
stack by setup_rt_frame. Currently, these trampolines are not instruction
fenced, thus their visibility to ifetch is not guaranteed.
This patch adds a flush_icache_range in setup_rt_frame to fix this
problem.
Signed-off-by: Mathis Salmen <mathis.salmen@matsal.de>
Fixes: 6bd33e1ece ("riscv: add nommu support")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230406101130.82304-1-mathis.salmen@matsal.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This patch converts riscv to use the generic entry infrastructure from
kernel/entry/*. The generic entry makes maintainers' work easier and
codes more elegant. Here are the changes:
- More clear entry.S with handle_exception and ret_from_exception
- Get rid of complex custom signal implementation
- Move syscall procedure from assembly to C, which is much more
readable.
- Connect ret_from_fork & ret_from_kernel_thread to generic entry.
- Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode
- Use the standard preemption code instead of custom
Suggested-by: Huacai Chen <chenhuacai@kernel.org>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by: Yipeng Zou <zouyipeng@huawei.com>
Tested-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Link: https://lore.kernel.org/r/20230222033021.983168-5-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The return to userspace path in entry.S may enable interrupts without the
corresponding lockdep annotation, producing a splat[0] when DEBUG_LOCKDEP
is enabled. Simply calling __trace_hardirqs_on() here gets a bit messy
due to the use of RA to point back to ret_from_exception, so just move
the whole slow-path loop into C. It's more readable and it lets us use
local_irq_{enable,disable}(), avoiding the need for manual annotations
altogether.
[0]:
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(!lockdep_hardirqs_enabled())
WARNING: CPU: 2 PID: 1 at kernel/locking/lockdep.c:5512 check_flags+0x10a/0x1e0
Modules linked in:
CPU: 2 PID: 1 Comm: init Not tainted 6.1.0-rc4-00160-gb56b6e2b4f31 #53
Hardware name: riscv-virtio,qemu (DT)
epc : check_flags+0x10a/0x1e0
ra : check_flags+0x10a/0x1e0
<snip>
status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
[<ffffffff808edb90>] lock_is_held_type+0x78/0x14e
[<ffffffff8003dae2>] __might_resched+0x26/0x22c
[<ffffffff8003dd24>] __might_sleep+0x3c/0x66
[<ffffffff80022c60>] get_signal+0x9e/0xa70
[<ffffffff800054a2>] do_notify_resume+0x6e/0x422
[<ffffffff80003c68>] ret_from_exception+0x0/0x10
irq event stamp: 44512
hardirqs last enabled at (44511): [<ffffffff808f901c>] _raw_spin_unlock_irqrestore+0x54/0x62
hardirqs last disabled at (44512): [<ffffffff80008200>] __trace_hardirqs_off+0xc/0x14
softirqs last enabled at (44472): [<ffffffff808f9fbe>] __do_softirq+0x3de/0x51e
softirqs last disabled at (44467): [<ffffffff80017760>] irq_exit+0xd6/0x104
---[ end trace 0000000000000000 ]---
possible reason: unannotated irqs-on.
Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>
Fixes: 3c46979829 ("riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT")
Link: https://lore.kernel.org/r/20221111223108.1976562-1-abrestic@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
riscv has an equivalent of arm bug fixed by 653d48b221 ("arm: fix
really nasty sigreturn bug"); if signal gets caught by an interrupt that
hits when we have the right value in a0 (-513), *and* another signal
gets delivered upon sigreturn() (e.g. included into the blocked mask for
the first signal and posted while the handler had been running), the
syscall restart logics will see regs->cause equal to EXC_SYSCALL (we are
in a syscall, after all) and a0 already restored to its original value
(-513, which happens to be -ERESTARTNOINTR) and assume that we need to
apply the usual syscall restart logics.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: e2c0cdfba7 ("RISC-V: User-facing API")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/YxJEiSq%2FCGaL6Gm9@ZenIV/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Fix the warning:
arch/riscv/kernel/signal.c:316:27: warning: no previous prototype for function 'do_notify_resume' [-Wmissing-prototypes]
asmlinkage __visible void do_notify_resume(struct pt_regs *regs,
All other functions in the file are static & none of the existing
headers stood out as an obvious location. Create signal.h to hold the
declaration.
Fixes: e2c0cdfba7 ("RISC-V: User-facing API")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220814141237.493457-4-mail@conchuod.ie
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Implement compat_setup_rt_frame for sigcontext save & restore. The
main process is the same with signal, but the rv32 pt_regs' size
is different from rv64's, so we needs convert them.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220405071314.3225832-19-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This set of changes removes tracehook.h, moves modification of all of
the ptrace fields inside of siglock to remove races, adds a missing
permission check to ptrace.c
The removal of tracehook.h is quite significant as it has been a major
source of confusion in recent years. Much of that confusion was
around task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled
making the semantics clearer).
For people who don't know tracehook.h is a vestiage of an attempt to
implement uprobes like functionality that was never fully merged, and
was later superseeded by uprobes when uprobes was merged. For many
years now we have been removing what tracehook functionaly a little
bit at a time. To the point where now anything left in tracehook.h is
some weird strange thing that is difficult to understand.
Eric W. Biederman (15):
ptrace: Move ptrace_report_syscall into ptrace.h
ptrace/arm: Rename tracehook_report_syscall report_syscall
ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
ptrace: Remove arch_syscall_{enter,exit}_tracehook
ptrace: Remove tracehook_signal_handler
task_work: Remove unnecessary include from posix_timers.h
task_work: Introduce task_work_pending
task_work: Call tracehook_notify_signal from get_signal on all architectures
task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
resume_user_mode: Move to resume_user_mode.h
tracehook: Remove tracehook.h
ptrace: Move setting/clearing ptrace_message into ptrace_stop
ptrace: Return the signal to continue with from ptrace_stop
Jann Horn (1):
ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
Yang Li (1):
ptrace: Remove duplicated include in ptrace.c
MAINTAINERS | 1 -
arch/Kconfig | 5 +-
arch/alpha/kernel/ptrace.c | 5 +-
arch/alpha/kernel/signal.c | 4 +-
arch/arc/kernel/ptrace.c | 5 +-
arch/arc/kernel/signal.c | 4 +-
arch/arm/kernel/ptrace.c | 12 +-
arch/arm/kernel/signal.c | 4 +-
arch/arm64/kernel/ptrace.c | 14 +--
arch/arm64/kernel/signal.c | 4 +-
arch/csky/kernel/ptrace.c | 5 +-
arch/csky/kernel/signal.c | 4 +-
arch/h8300/kernel/ptrace.c | 5 +-
arch/h8300/kernel/signal.c | 4 +-
arch/hexagon/kernel/process.c | 4 +-
arch/hexagon/kernel/signal.c | 1 -
arch/hexagon/kernel/traps.c | 6 +-
arch/ia64/kernel/process.c | 4 +-
arch/ia64/kernel/ptrace.c | 6 +-
arch/ia64/kernel/signal.c | 1 -
arch/m68k/kernel/ptrace.c | 5 +-
arch/m68k/kernel/signal.c | 4 +-
arch/microblaze/kernel/ptrace.c | 5 +-
arch/microblaze/kernel/signal.c | 4 +-
arch/mips/kernel/ptrace.c | 5 +-
arch/mips/kernel/signal.c | 4 +-
arch/nds32/include/asm/syscall.h | 2 +-
arch/nds32/kernel/ptrace.c | 5 +-
arch/nds32/kernel/signal.c | 4 +-
arch/nios2/kernel/ptrace.c | 5 +-
arch/nios2/kernel/signal.c | 4 +-
arch/openrisc/kernel/ptrace.c | 5 +-
arch/openrisc/kernel/signal.c | 4 +-
arch/parisc/kernel/ptrace.c | 7 +-
arch/parisc/kernel/signal.c | 4 +-
arch/powerpc/kernel/ptrace/ptrace.c | 8 +-
arch/powerpc/kernel/signal.c | 4 +-
arch/riscv/kernel/ptrace.c | 5 +-
arch/riscv/kernel/signal.c | 4 +-
arch/s390/include/asm/entry-common.h | 1 -
arch/s390/kernel/ptrace.c | 1 -
arch/s390/kernel/signal.c | 5 +-
arch/sh/kernel/ptrace_32.c | 5 +-
arch/sh/kernel/signal_32.c | 4 +-
arch/sparc/kernel/ptrace_32.c | 5 +-
arch/sparc/kernel/ptrace_64.c | 5 +-
arch/sparc/kernel/signal32.c | 1 -
arch/sparc/kernel/signal_32.c | 4 +-
arch/sparc/kernel/signal_64.c | 4 +-
arch/um/kernel/process.c | 4 +-
arch/um/kernel/ptrace.c | 5 +-
arch/x86/kernel/ptrace.c | 1 -
arch/x86/kernel/signal.c | 5 +-
arch/x86/mm/tlb.c | 1 +
arch/xtensa/kernel/ptrace.c | 5 +-
arch/xtensa/kernel/signal.c | 4 +-
block/blk-cgroup.c | 2 +-
fs/coredump.c | 1 -
fs/exec.c | 1 -
fs/io-wq.c | 6 +-
fs/io_uring.c | 11 +-
fs/proc/array.c | 1 -
fs/proc/base.c | 1 -
include/asm-generic/syscall.h | 2 +-
include/linux/entry-common.h | 47 +-------
include/linux/entry-kvm.h | 2 +-
include/linux/posix-timers.h | 1 -
include/linux/ptrace.h | 81 ++++++++++++-
include/linux/resume_user_mode.h | 64 ++++++++++
include/linux/sched/signal.h | 17 +++
include/linux/task_work.h | 5 +
include/linux/tracehook.h | 226 -----------------------------------
include/uapi/linux/ptrace.h | 2 +-
kernel/entry/common.c | 19 +--
kernel/entry/kvm.c | 9 +-
kernel/exit.c | 3 +-
kernel/livepatch/transition.c | 1 -
kernel/ptrace.c | 47 +++++---
kernel/seccomp.c | 1 -
kernel/signal.c | 62 +++++-----
kernel/task_work.c | 4 +-
kernel/time/posix-cpu-timers.c | 1 +
mm/memcontrol.c | 2 +-
security/apparmor/domain.c | 1 -
security/selinux/hooks.c | 1 -
85 files changed, 372 insertions(+), 495 deletions(-)
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Merge tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ptrace cleanups from Eric Biederman:
"This set of changes removes tracehook.h, moves modification of all of
the ptrace fields inside of siglock to remove races, adds a missing
permission check to ptrace.c
The removal of tracehook.h is quite significant as it has been a major
source of confusion in recent years. Much of that confusion was around
task_work and TIF_NOTIFY_SIGNAL (which I have now decoupled making the
semantics clearer).
For people who don't know tracehook.h is a vestiage of an attempt to
implement uprobes like functionality that was never fully merged, and
was later superseeded by uprobes when uprobes was merged. For many
years now we have been removing what tracehook functionaly a little
bit at a time. To the point where anything left in tracehook.h was
some weird strange thing that was difficult to understand"
* tag 'ptrace-cleanups-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ptrace: Remove duplicated include in ptrace.c
ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE
ptrace: Return the signal to continue with from ptrace_stop
ptrace: Move setting/clearing ptrace_message into ptrace_stop
tracehook: Remove tracehook.h
resume_user_mode: Move to resume_user_mode.h
resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume
signal: Move set_notify_signal and clear_notify_signal into sched/signal.h
task_work: Decouple TIF_NOTIFY_SIGNAL and task_work
task_work: Call tracehook_notify_signal from get_signal on all architectures
task_work: Introduce task_work_pending
task_work: Remove unnecessary include from posix_timers.h
ptrace: Remove tracehook_signal_handler
ptrace: Remove arch_syscall_{enter,exit}_tracehook
ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h
ptrace/arm: Rename tracehook_report_syscall report_syscall
ptrace: Move ptrace_report_syscall into ptrace.h
Add calls to rseq_signal_deliver() and rseq_syscall() to introduce RSEQ
support.
1. Call the rseq_signal_deliver() function to fixup on the pre-signal
frame when a signal is delivered on top of a restartable sequence
critical section.
2. Check that system calls are not invoked from within rseq critical
sections by invoking rseq_signal() from ret_from_syscall(). With
CONFIG_DEBUG_RSEQ, such behavior results in termination of the
process with SIGSEGV.
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Move set_notify_resume and tracehook_notify_resume into resume_user_mode.h.
While doing that rename tracehook_notify_resume to resume_user_mode_work.
Update all of the places that included tracehook.h for these functions to
include resume_user_mode.h instead.
Update all of the callers of tracehook_notify_resume to call
resume_user_mode_work.
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220309162454.123006-12-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The has_fpu check sits at hot code path: switch_to(). Currently, has_fpu
is a bool variable if FPU=y, switch_to() checks it each time, we can
optimize out this check by turning the has_fpu into a static key.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This patch adds support for uprobes on riscv architecture.
Just like kprobe, it support single-step and simulate instructions.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
All the callers currently do this, clean it up and move the clearing
into tracehook_notify_resume() instead.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The kernel runs in M-mode without using page tables, and thus can't run
bare metal without help from additional firmware.
Most of the patch is just stubbing out code not needed without page
tables, but there is an interesting detail in the signals implementation:
- The normal RISC-V syscall ABI only implements rt_sigreturn as VDSO
entry point, but the ELF VDSO is not supported for nommu Linux.
We instead copy the code to call the syscall onto the stack.
In addition to enabling the nommu code a new defconfig for a small
kernel image that can run in nommu mode on qemu is also provided, to run
a kernel in qemu you can use the following command line:
qemu-system-riscv64 -smp 2 -m 64 -machine virt -nographic \
-kernel arch/riscv/boot/loader \
-drive file=rootfs.ext2,format=raw,id=hd0 \
-device virtio-blk-device,drive=hd0
Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
[paul.walmsley@sifive.com: updated to apply; add CONFIG_MMU guards
around PCI_IOBASE definition to fix build issues; fixed checkpatch
issues; move the PCI_IO_* and VMEMMAP address space macros along
with the others; resolve sparse warning]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Many of the privileged CSRs exist in a supervisor and machine version
that are used very similarly. Provide versions of the CSR names and
fields that map to either the S-mode or M-mode variant depending on
a new CONFIG_RISCV_M_MODE kconfig symbol.
Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>
and Paul Walmsley <paul.walmsley@sifive.com>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de> # for drivers/clocksource, drivers/irqchip
[paul.walmsley@sifive.com: updated to apply]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Rather than adding prototypes for C functions called only by assembly
code, mark them as __visible. This avoids adding prototypes that will
never be used by the callers. Resolves the following sparse warnings:
arch/riscv/kernel/irq.c:27:29: warning: symbol 'do_IRQ' was not declared. Should it be static?
arch/riscv/kernel/ptrace.c:151:6: warning: symbol 'do_syscall_trace_enter' was not declared. Should it be static?
arch/riscv/kernel/ptrace.c:165:6: warning: symbol 'do_syscall_trace_exit' was not declared. Should it be static?
arch/riscv/kernel/signal.c:295:17: warning: symbol 'do_notify_resume' was not declared. Should it be static?
arch/riscv/kernel/traps.c:92:1: warning: symbol 'do_trap_unknown' was not declared. Should it be static?
arch/riscv/kernel/traps.c:94:1: warning: symbol 'do_trap_insn_misaligned' was not declared. Should it be static?
arch/riscv/kernel/traps.c:96:1: warning: symbol 'do_trap_insn_fault' was not declared. Should it be static?
arch/riscv/kernel/traps.c:98:1: warning: symbol 'do_trap_insn_illegal' was not declared. Should it be static?
arch/riscv/kernel/traps.c💯1: warning: symbol 'do_trap_load_misaligned' was not declared. Should it be static?
arch/riscv/kernel/traps.c:102:1: warning: symbol 'do_trap_load_fault' was not declared. Should it be static?
arch/riscv/kernel/traps.c:104:1: warning: symbol 'do_trap_store_misaligned' was not declared. Should it be static?
arch/riscv/kernel/traps.c:106:1: warning: symbol 'do_trap_store_fault' was not declared. Should it be static?
arch/riscv/kernel/traps.c:108:1: warning: symbol 'do_trap_ecall_u' was not declared. Should it be static?
arch/riscv/kernel/traps.c:110:1: warning: symbol 'do_trap_ecall_s' was not declared. Should it be static?
arch/riscv/kernel/traps.c:112:1: warning: symbol 'do_trap_ecall_m' was not declared. Should it be static?
arch/riscv/kernel/traps.c:124:17: warning: symbol 'do_trap_break' was not declared. Should it be static?
arch/riscv/kernel/smpboot.c:136:24: warning: symbol 'smp_callin' was not declared. Should it be static?
Based on a suggestion from Luc Van Oostenryck.
This version includes changes based on feedback from Christoph Hellwig
<hch@lst.de>.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de> # for do_syscall_trace_*
The __user annotations were removed from the {save,restore}_fp_state()
function signatures by commit 007f5c3589 ("Refactor FPU code in
signal setup/return procedures"), but should be present, and sparse
warns when they are not applied. Add them back in.
This change should have no functional impact.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Fixes: 007f5c3589 ("Refactor FPU code in signal setup/return procedures")
Cc: Alan Kao <alankao@andestech.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Pull force_sig() argument change from Eric Biederman:
"A source of error over the years has been that force_sig has taken a
task parameter when it is only safe to use force_sig with the current
task.
The force_sig function is built for delivering synchronous signals
such as SIGSEGV where the userspace application caused a synchronous
fault (such as a page fault) and the kernel responded with a signal.
Because the name force_sig does not make this clear, and because the
force_sig takes a task parameter the function force_sig has been
abused for sending other kinds of signals over the years. Slowly those
have been fixed when the oopses have been tracked down.
This set of changes fixes the remaining abusers of force_sig and
carefully rips out the task parameter from force_sig and friends
making this kind of error almost impossible in the future"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus
signal: Remove the signal number and task parameters from force_sig_info
signal: Factor force_sig_info_to_task out of force_sig_info
signal: Generate the siginfo in force_sig
signal: Move the computation of force into send_signal and correct it.
signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal
signal: Remove the task parameter from force_sig_fault
signal: Use force_sig_fault_to_task for the two calls that don't deliver to current
signal: Explicitly call force_sig_fault on current
signal/unicore32: Remove tsk parameter from __do_user_fault
signal/arm: Remove tsk parameter from __do_user_fault
signal/arm: Remove tsk parameter from ptrace_break
signal/nds32: Remove tsk parameter from send_sigtrap
signal/riscv: Remove tsk parameter from do_trap
signal/sh: Remove tsk parameter from force_sig_info_fault
signal/um: Remove task parameter from send_sigtrap
signal/x86: Remove task parameter from send_sigtrap
signal: Remove task parameter from force_sig_mceerr
signal: Remove task parameter from force_sig
signal: Remove task parameter from force_sigsegv
...
All of the remaining callers pass current into force_sig so
remove the task parameter to make this obvious and to make
misuse more difficult in the future.
This also makes it clear force_sig passes current into force_sig_info.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not see the file copying or write to the free
software foundation inc
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 12 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190523091651.231300438@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function of do_notify_resume called by entry.S could be entered
in loop when SIGPENDING was setted again before sret. So we must add
prevent code to make syscall restart (regs->sepc -= 0x4) or it may
re-execute unexpected instructions.
Just like in_syscall & forget_syscall used by arm.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We expect that a kernel with CONFIG_FPU=y can still support no-FPU
machines. To do so, the kernel should first examine the existence of a
FPU, then do nothing if a FPU does exist; otherwise, it should
disable/bypass all FPU-related functions.
In this patch, a new global variable, has_fpu, is created and determined
when parsing the hardware capability from device tree during booting.
This variable is used in those FPU-related functions.
Signed-off-by: Alan Kao <alankao@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Cc: Vincent Chen <vincentc@andestech.com>
Cc: Zong Li <zong@andestech.com>
Cc: Nick Hu <nickhu@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
FPU codes have been separated from common part in previous patches.
This patch add the CONFIG_FPU option and some stubs, so that a no-FPU
configuration is allowed.
Signed-off-by: Alan Kao <alankao@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Cc: Vincent Chen <vincentc@andestech.com>
Cc: Zong Li <zong@andestech.com>
Cc: Nick Hu <nickhu@andestech.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
FPU-related logic is separated from normal signal handling path in
this patch. Kernel can easily be configured to exclude those procedures
for no-FPU systems.
Signed-off-by: Alan Kao <alankao@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Cc: Vincent Chen <vincentc@andestech.com>
Cc: Zong Li <zong@andestech.com>
Cc: Nick Hu <nickhu@andestech.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This patch contains code that is in some way visible to the user:
including via system calls, the VDSO, module loading and signal
handling. It also contains some generic code that is ABI visible.
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
