linux-stable.git/arch/um/kernel, branch linux-6.11.y

um: Always dump trace for specified task in show_stack

2024-12-05T12:54:27+00:00

[ Upstream commit 0f659ff362eac69777c4c191b7e5ccb19d76c67d ]

Currently, show_stack() always dumps the trace of the current task.
However, it should dump the trace of the specified task if one is
provided. Otherwise, things like running "echo t > sysrq-trigger"
won't work as expected.

Fixes: 970e51feaddb ("um: Add support for CONFIG_STACKTRACE")
Signed-off-by: Tiwei Bie 
Link: https://patch.msgid.link/20241106103933.1132365-1-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg 
Signed-off-by: Sasha Levin

um: Fix the return value of elf_core_copy_task_fpregs

2024-12-05T12:54:26+00:00

[ Upstream commit 865e3845eeaa21e9a62abc1361644e67124f1ec0 ]

This function is expected to return a boolean value, which should be
true on success and false on failure.

Fixes: d1254b12c93e ("uml: fix x86_64 core dump crash")
Signed-off-by: Tiwei Bie 
Link: https://patch.msgid.link/20240913023302.130300-1-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg 
Signed-off-by: Sasha Levin

um: Fix potential integer overflow during physmem setup

2024-12-05T12:54:26+00:00

[ Upstream commit a98b7761f697e590ed5d610d87fa12be66f23419 ]

This issue happens when the real map size is greater than LONG_MAX,
which can be easily triggered on UML/i386.

Fixes: fe205bdd1321 ("um: Print minimum physical memory requirement")
Signed-off-by: Tiwei Bie 
Link: https://patch.msgid.link/20240916045950.508910-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg 
Signed-off-by: Sasha Levin

of/fdt: add dt_phys arg to early_init_dt_scan and early_init_dt_verify

2024-12-05T12:53:03+00:00

[ Upstream commit b2473a359763e27567993e7d8f37de82f57a0829 ]

 __pa() is only intended to be used for linear map addresses and using
it for initial_boot_params which is in fixmap for arm64 will give an
incorrect value. Hence save the physical address when it is known at
boot time when calling early_init_dt_scan for arm64 and use it at kexec
time instead of converting the virtual address using __pa().

Note that arm64 doesn't need the FDT region reserved in the DT as the
kernel explicitly reserves the passed in FDT. Therefore, only a debug
warning is fixed with this change.

Reported-by: Breno Leitao 
Suggested-by: Mark Rutland 
Signed-off-by: Usama Arif 
Fixes: ac10be5cdbfa ("arm64: Use common of_kexec_alloc_and_setup_fdt()")
Link: https://lore.kernel.org/r/20241023171426.452688-1-usamaarif642@gmail.com
Signed-off-by: Rob Herring (Arm) 
Signed-off-by: Sasha Levin

um: register power-off handler

2024-07-04T10:03:20+00:00

Otherwise we always get

 reboot: Power off not available: System halted instead

which is really quite pointless.

Link: https://patch.msgid.link/20240703173839.fcbb538c6686.I3d333f4773cff93c4337c4d128ee0b1b501b3dfa@changeid
Acked-By: Anton Ivanov 
Signed-off-by: Johannes Berg

um: Enable preemption in UML

2024-07-03T15:10:43+00:00

Since userspace state is saved in the MM process, kernel using
FPU still doesn't really need to do anything, so this really
is as simple as enabling preemption. The irq critical section
in sigio_handler() needs preempt_disable()/preempt_enable().

Signed-off-by: Anton Ivanov 
Link: https://patch.msgid.link/20240702102549.d2fcea450854.I12f5a53d80ec1e425e66ef272b1e95cb523b608e@changeid
[rebase, remove FPU save/restore, fix x86/um Makefile,
 rewrite commit message]
Signed-off-by: Johannes Berg

um: refactor TLB update handling

2024-07-03T15:09:50+00:00

Conceptually, we want the memory mappings to always be up to date and
represent whatever is in the TLB. To ensure that, we need to sync them
over in the userspace case and for the kernel we need to process the
mappings.

The kernel will call flush_tlb_* if page table entries that were valid
before become invalid. Unfortunately, this is not the case if entries
are added.

As such, change both flush_tlb_* and set_ptes to track the memory range
that has to be synchronized. For the kernel, we need to execute a
flush_tlb_kern_* immediately but we can wait for the first page fault in
case of set_ptes. For userspace in contrast we only store that a range
of memory needs to be synced and do so whenever we switch to that
process.

Signed-off-by: Benjamin Berg 
Link: https://patch.msgid.link/20240703134536.1161108-13-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg

um: simplify and consolidate TLB updates

2024-07-03T15:09:50+00:00

The HVC update was mostly used to compress consecutive calls into one.
This is mostly relevant for userspace where it is already handled by the
syscall stub code.

Simplify the whole logic and consolidate it for both kernel and
userspace. This does remove the sequential syscall compression for the
kernel, however that shouldn't be the main factor in most runs.

Signed-off-by: Benjamin Berg 
Link: https://patch.msgid.link/20240703134536.1161108-12-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg

um: remove force_flush_all from fork_handler

2024-07-03T15:09:50+00:00

There should be no need for this. It may be that this used to work
around another issue where after a clone the MM was in a bad state.

Signed-off-by: Benjamin Berg 
Link: https://patch.msgid.link/20240703134536.1161108-11-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg

um: Do not flush MM in flush_thread

2024-07-03T15:09:49+00:00

There should be no need to flush the memory in flush_thread. Doing this
likely worked around some issue where memory was still incorrectly
mapped when creating or cloning an MM.

With the removal of the special clone path, that isn't relevant anymore.
However, add the flush into MM initialization so that any new userspace
MM is guaranteed to be clean.

Signed-off-by: Benjamin Berg 
Link: https://patch.msgid.link/20240703134536.1161108-10-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg