linux.git/arch/riscv/kernel, branch v6.13

riscv: use local label names instead of global ones in assembly

2025-01-08T18:46:14+00:00

Local labels should be prefix by '.L' or they'll be exported in the
symbol table. Additionally, this messes up the backtrace by displaying
an incorrect symbol:

  ...
  [   12.751810] [] _copy_from_user+0x28/0xc2
  [   12.752035] [] handle_misaligned_load+0x1ca/0x2fc
  [   12.752310] [] do_trap_load_misaligned+0x24/0xee
  [   12.752596] [] _new_vmalloc_restore_context_a0+0xc2/0xce

After:
  ...
  [   10.243916] [] _copy_from_user+0x28/0xc2
  [   10.244026] [] handle_misaligned_load+0x1ca/0x2fc
  [   10.244150] [] do_trap_load_misaligned+0x24/0xee
  [   10.244268] [] handle_exception+0x146/0x152

Signed-off-by: Clément Léger 
Reviewed-by: Alexandre Ghiti 
Fixes: 503638e0babf3 ("riscv: Stop emitting preventive sfence.vma for new vmalloc mappings")
Link: https://lore.kernel.org/r/20250103141814.508865-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: stacktrace: fix backtracing through exceptions

2025-01-08T18:45:49+00:00

Prior to commit 5d5fc33ce58e ("riscv: Improve exception and system call
latency"), backtrace through exception worked since ra was filled with
ret_from_exception symbol address and the stacktrace code checked 'pc' to
be equal to that symbol. Now that handle_exception uses regular 'call'
instructions, this isn't working anymore and backtrace stops at
handle_exception(). Since there are multiple call site to C code in the
exception handling path, rather than checking multiple potential return
addresses, add a new symbol at the end of exception handling and check pc
to be in that range.

Fixes: 5d5fc33ce58e ("riscv: Improve exception and system call latency")
Signed-off-by: Clément Léger 
Tested-by: Alexandre Ghiti 
Reviewed-by: Alexandre Ghiti 
Link: https://lore.kernel.org/r/20241209155714.1239665-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: kprobes: Fix incorrect address calculation

2025-01-08T18:39:39+00:00

p->ainsn.api.insn is a pointer to u32, therefore arithmetic operations are
multiplied by four. This is clearly undesirable for this case.

Cast it to (void *) first before any calculation.

Below is a sample before/after. The dumped memory is two kprobe slots, the
first slot has

  - c.addiw a0, 0x1c (0x7125)
  - ebreak           (0x00100073)

and the second slot has:

  - c.addiw a0, -4   (0x7135)
  - ebreak           (0x00100073)

Before this patch:

(gdb) x/16xh 0xff20000000135000
0xff20000000135000:	0x7125	0x0000	0x0000	0x0000	0x7135	0x0010	0x0000	0x0000
0xff20000000135010:	0x0073	0x0010	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000

After this patch:

(gdb) x/16xh 0xff20000000125000
0xff20000000125000:	0x7125	0x0073	0x0010	0x0000	0x7135	0x0073	0x0010	0x0000
0xff20000000125010:	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000

Fixes: b1756750a397 ("riscv: kprobes: Use patch_text_nosync() for insn slots")
Signed-off-by: Nam Cao 
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti 
Link: https://lore.kernel.org/r/20241119111056.2554419-1-namcao@linutronix.de
Signed-off-by: Palmer Dabbelt

riscv: Fix sleeping in invalid context in die()

2025-01-08T18:23:17+00:00

die() can be called in exception handler, and therefore cannot sleep.
However, die() takes spinlock_t which can sleep with PREEMPT_RT enabled.
That causes the following warning:

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 285, name: mutex
preempt_count: 110001, expected: 0
RCU nest depth: 0, expected: 0
CPU: 0 UID: 0 PID: 285 Comm: mutex Not tainted 6.12.0-rc7-00022-ge19049cf7d56-dirty #234
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
    dump_backtrace+0x1c/0x24
    show_stack+0x2c/0x38
    dump_stack_lvl+0x5a/0x72
    dump_stack+0x14/0x1c
    __might_resched+0x130/0x13a
    rt_spin_lock+0x2a/0x5c
    die+0x24/0x112
    do_trap_insn_illegal+0xa0/0xea
    _new_vmalloc_restore_context_a0+0xcc/0xd8
Oops - illegal instruction [#1]

Switch to use raw_spinlock_t, which does not sleep even with PREEMPT_RT
enabled.

Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code")
Signed-off-by: Nam Cao 
Cc: stable@vger.kernel.org
Reviewed-by: Sebastian Andrzej Siewior 
Link: https://lore.kernel.org/r/20241118091333.1185288-1-namcao@linutronix.de
Signed-off-by: Palmer Dabbelt

riscv: module: remove relocation_head rel_entry member allocation

2025-01-08T18:22:52+00:00

relocation_head's list_head member, rel_entry, doesn't need to be
allocated, its storage can just be part of the allocated relocation_head.
Remove the pointer which allows to get rid of the allocation as well as
an existing memory leak found by Kai Zhang using kmemleak.

Fixes: 8fd6c5142395 ("riscv: Add remaining module relocations")
Reported-by: Kai Zhang 
Signed-off-by: Clément Léger 
Reviewed-by: Andrew Jones 
Reviewed-by: Charlie Jenkins 
Tested-by: Charlie Jenkins 
Link: https://lore.kernel.org/r/20241128081636.3620468-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: Fix wrong usage of __pa() on a fixmap address

2024-12-11T19:43:44+00:00

riscv uses fixmap addresses to map the dtb so we can't use __pa() which
is reserved for linear mapping addresses.

Fixes: b2473a359763 ("of/fdt: add dt_phys arg to early_init_dt_scan and early_init_dt_verify")
Signed-off-by: Alexandre Ghiti 
Link: https://lore.kernel.org/r/20241209074508.53037-1-alexghiti@rivosinc.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt

riscv: Fixup boot failure when CONFIG_DEBUG_RT_MUTEXES=y

2024-12-11T19:43:39+00:00

When CONFIG_DEBUG_RT_MUTEXES=y, mutex_lock->rt_mutex_try_acquire
would change from rt_mutex_cmpxchg_acquire to
rt_mutex_slowtrylock():
	raw_spin_lock_irqsave(&lock->wait_lock, flags);
	ret = __rt_mutex_slowtrylock(lock);
	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);

Because queued_spin_#ops to ticket_#ops is changed one by one by
jump_label, raw_spin_lock/unlock would cause a deadlock during the
changing.

That means in arch/riscv/kernel/jump_label.c:
1.
arch_jump_label_transform_queue() ->
mutex_lock(&text_mutex); +-> raw_spin_lock  -> queued_spin_lock
			 |-> raw_spin_unlock -> queued_spin_unlock
patch_insn_write -> change the raw_spin_lock to ticket_lock
mutex_unlock(&text_mutex);
...

2. /* Dirty the lock value */
arch_jump_label_transform_queue() ->
mutex_lock(&text_mutex); +-> raw_spin_lock -> *ticket_lock*
                         |-> raw_spin_unlock -> *queued_spin_unlock*
			  /* BUG: ticket_lock with queued_spin_unlock */
patch_insn_write  ->  change the raw_spin_unlock to ticket_unlock
mutex_unlock(&text_mutex);
...

3. /* Dead lock */
arch_jump_label_transform_queue() ->
mutex_lock(&text_mutex); +-> raw_spin_lock -> ticket_lock /* deadlock! */
                         |-> raw_spin_unlock -> ticket_unlock
patch_insn_write -> change other raw_spin_#op -> ticket_#op
mutex_unlock(&text_mutex);

So, the solution is to disable mutex usage of
arch_jump_label_transform_queue() during early_boot_irqs_disabled, just
like we have done for stop_machine.

Reported-by: Conor Dooley 
Signed-off-by: Guo Ren 
Signed-off-by: Guo Ren 
Fixes: ab83647fadae ("riscv: Add qspinlock support")
Link: https://lore.kernel.org/linux-riscv/CAJF2gTQwYTGinBmCSgVUoPv0_q4EPt_+WiyfUA1HViAKgUzxAg@mail.gmail.com/T/#mf488e6347817fca03bb93a7d34df33d8615b3775
Cc: Palmer Dabbelt 
Cc: Alexandre Ghiti 
Tested-by: Conor Dooley 
Reviewed-by: Alexandre Ghiti 
Tested-by: Alexandre Ghiti 
Tested-by: Nam Cao 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20241130153310.3349484-1-guoren@kernel.org
Signed-off-by: Palmer Dabbelt

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2024-11-30T22:51:08+00:00

Pull more kvm updates from Paolo Bonzini:

 - ARM fixes

 - RISC-V Svade and Svadu (accessed and dirty bit) extension support for
   host and guest

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: riscv: selftests: Add Svade and Svadu Extension to get-reg-list test
  RISC-V: KVM: Add Svade and Svadu Extensions Support for Guest/VM
  dt-bindings: riscv: Add Svade and Svadu Entries
  RISC-V: Add Svade and Svadu Extensions Support
  KVM: arm64: Use MDCR_EL2.HPME to evaluate overflow of hyp counters
  KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status
  KVM: arm64: Mark set_sysreg_masks() as inline to avoid build failure
  KVM: arm64: vgic-its: Add stronger type-checking to the ITS entry sizes
  KVM: arm64: vgic: Kill VGIC_MAX_PRIVATE definition
  KVM: arm64: vgic: Make vgic_get_irq() more robust
  KVM: arm64: vgic-v3: Sanitise guest writes to GICR_INVLPIR

Merge tag 'riscv-for-linus-6.13-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2024-11-27T19:19:09+00:00

Pull RISC-v updates from Palmer Dabbelt:

 - Support for pointer masking in userspace

 - Support for probing vector misaligned access performance

 - Support for qspinlock on systems with Zacas and Zabha

* tag 'riscv-for-linus-6.13-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (38 commits)
  RISC-V: Remove unnecessary include from compat.h
  riscv: Fix default misaligned access trap
  riscv: Add qspinlock support
  dt-bindings: riscv: Add Ziccrse ISA extension description
  riscv: Add ISA extension parsing for Ziccrse
  asm-generic: ticket-lock: Add separate ticket-lock.h
  asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock
  riscv: Implement xchg8/16() using Zabha
  riscv: Implement arch_cmpxchg128() using Zacas
  riscv: Improve zacas fully-ordered cmpxchg()
  riscv: Implement cmpxchg8/16() using Zabha
  dt-bindings: riscv: Add Zabha ISA extension description
  riscv: Implement cmpxchg32/64() using Zacas
  riscv: Do not fail to build on byte/halfword operations with Zawrs
  riscv: Move cpufeature.h macros into their own header
  KVM: riscv: selftests: Add Smnpm and Ssnpm to get-reg-list test
  RISC-V: KVM: Allow Smnpm and Ssnpm extensions for guests
  riscv: hwprobe: Export the Supm ISA extension
  riscv: selftests: Add a pointer masking test
  riscv: Allow ptrace control of the tagged address ABI
  ...

Merge tag 'kvm-riscv-6.13-2' of https://github.com/kvm-riscv/linux into HEAD

2024-11-27T17:00:28+00:00

KVM/riscv changes for 6.13 part #2

- Svade and Svadu extension support for Host and Guest/VM