Pull UML updates from Richard Weinberger:
- hostfs: Convert to writepages
- many cleanups: removal of dead macros, missing __init
* tag 'uml-for-linus-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
um: Remove unused asm/archparam.h header
um: Include missing headers in asm/pgtable.h
hostfs: Convert to writepages
um: rtc: use RTC time when calculating the alarm
um: Remove unused user_context function
um: Remove unused THREAD_NAME_LEN macro
um: Remove unused PGD_BOUND macro
um: Mark setup_env_path as __init
um: Mark install_fatal_handler as __init
um: Mark set_stklim as __init
um: Mark get_top_address as __init
um: Mark parse_cache_line as __init
um: Mark parse_host_cpu_flags as __init
um: Count iomem_size only once in physmem calculation
um: Remove obsolete fixmap support
um: Remove unused MODULES_LEN macro
Pull UML updates from Richard Weinberger:
- Lots of cleanups, mostly from Benjamin Berg and Tiwei Bie
- Removal of unused code
- Fix for sparse warnings
- Cleanup around stub_exe()
* tag 'uml-for-linus-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (68 commits)
hostfs: Fix the NULL vs IS_ERR() bug for __filemap_get_folio()
um: move thread info into task
um: Always dump trace for specified task in show_stack
um: vector: Do not use drvdata in release
um: net: Do not use drvdata in release
um: ubd: Do not use drvdata in release
um: ubd: Initialize ubd's disk pointer in ubd_add
um: virtio_uml: query the number of vqs if supported
um: virtio_uml: fix call_fd IRQ allocation
um: virtio_uml: send SET_MEM_TABLE message with the exact size
um: remove broken double fault detection
um: remove duplicate UM_NSEC_PER_SEC definition
um: remove file sync for stub data
um: always include kconfig.h and compiler-version.h
um: set DONTDUMP and DONTFORK flags on KASAN shadow memory
um: fix sparse warnings in signal code
um: fix sparse warnings from regset refactor
um: Remove double zero check
um: fix stub exe build with CONFIG_GCOV
um: Use os_set_pdeathsig helper in winch thread/process
...
Pull asm-generic updates from Arnd Bergmann:
"These are a number of unrelated cleanups, generally simplifying the
architecture specific header files:
- A series from Al Viro simplifies asm/vga.h, after it turns out that
most of it can be generalized.
- A series from Julian Vetter adds a common version of
memcpy_{to,from}io() and memset_io() and changes most architectures
to use that instead of their own implementation
- A series from Niklas Schnelle concludes his work to make PC style
inb()/outb() optional
- Nicolas Pitre contributes improvements for the generic do_div()
helper
- Christoph Hellwig adds a generic version of page_to_phys() and
phys_to_page(), replacing the slightly different architecture
specific definitions.
- Uwe Kleine-Koenig has a minor cleanup for ioctl definitions"
* tag 'asm-generic-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (24 commits)
empty include/asm-generic/vga.h
sparc: get rid of asm/vga.h
asm/vga.h: don't bother with scr_mem{cpy,move}v() unless we need to
vt_buffer.h: get rid of dead code in default scr_...() instances
tty: serial: export serial_8250_warn_need_ioport
lib/iomem_copy: fix kerneldoc format style
hexagon: simplify asm/io.h for !HAS_IOPORT
loongarch: Use new fallback IO memcpy/memset
csky: Use new fallback IO memcpy/memset
arm64: Use new fallback IO memcpy/memset
New implementation for IO memcpy and IO memset
watchdog: Add HAS_IOPORT dependency for SBC8360 and SBC7240
__arch_xprod64(): make __always_inline when optimizing for performance
ARM: div64: improve __arch_xprod_64()
asm-generic/div64: optimize/simplify __div64_const32()
lib/math/test_div64: add some edge cases relevant to __div64_const32()
asm-generic: add an optional pfn_valid check to page_to_phys
asm-generic: provide generic page_to_phys and phys_to_page implementations
asm-generic/io.h: Remove I/O port accessors for HAS_IOPORT=n
tty: serial: handle HAS_IOPORT dependencies
...
This selects the THREAD_INFO_IN_TASK option for UM and changes the way
that the current task is discovered. This is trivial though, as UML
already tracks the current task in cpu_tasks[] and this can be used to
retrieve it.
Also remove the signal handler code that copies the thread information
into the IRQ stack. It is obsolete now, which also means that the
mentioned race condition cannot happen anymore.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Hajime Tazaki <thehajime@gmail.com>
Link: https://patch.msgid.link/20241111102910.46512-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The show_stack function had some code to detect double faults. However,
the logic is wrong and it would e.g. trigger if a WARNING happened
inside an IRQ.
Remove it without trying to add a new logic. The current behaviour,
which will just fault repeatedly until the IRQ stack is used up and the
host kills UML, seems to be good enough.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-5-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
page_to_phys is duplicated by all architectures, and from some strange
reason placed in <asm/io.h> where it doesn't fit at all.
phys_to_page is only provided by a few architectures despite having a lot
of open coded users.
Provide generic versions in <asm-generic/memory_model.h> to make these
helpers more easily usable.
Note with this patch powerpc loses the CONFIG_DEBUG_VIRTUAL pfn_valid
check. It will be added back in a generic version later.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The PTRACE_GETREGSET API has now existed since Linux 2.6.33. The XSAVE
CPU feature should also be sufficiently common to be able to rely on it.
With this, define our internal FP state to be the hosts XSAVE data. Add
discovery for the hosts XSAVE size and place the FP registers at the end
of task_struct so that we can adjust the size at runtime.
Next we can implement the regset API on top and update the signal
handling as well as ptrace APIs to use them. Also switch coredump
creation to use the regset API and finally set HAVE_ARCH_TRACEHOOK.
This considerably improves the signal frames. Previously they might not
have contained all the registers (i386) and also did not have the
sizes and magic values set to the correct values to permit userspace to
decode the frame.
As a side effect, this will permit UML to run on hosts with newer CPU
extensions (such as AMX) that need even more register state.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241023094120.4083426-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
In time-travel mode userspace can do a lot of work without any time
passing. Unfortunately, this can result in OOM situations as the RCU
core code will never be run.
Work around this by keeping track of userspace processes that do not
yield for a lot of operations. When this happens, insert a jiffie into
the sched_clock clock to account time against the process and cause the
bookkeeping to run.
As sched_clock is used for tracing, it is useful to keep it in sync
between the different VMs. As such, try to remove added ticks again when
the actual clock ticks.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241010142537.1134685-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When a PTE is updated in the page table, the _PAGE_NEWPAGE bit will
always be set. And the corresponding page will always be mapped or
unmapped depending on whether the PTE is present or not. The check
on the _PAGE_NEWPROT bit is not really reachable. Abandoning it will
allow us to simplify the code and remove the unreachable code.
Reviewed-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011102354.1682626-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When loading the UML binary, the host kernel will place the stack at the
highest possible address. It will then map the program name and
environment variables onto the start of the stack.
As such, an easy way to figure out the host_task_size is to use the
highest pointer to an environment variable as a reference.
Ensure that this works by disabling address layout randomization and
re-executing UML in case it was enabled.
This increases the available TASK_SIZE for 64 bit UML considerably.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-9-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Using clone will not undo features that have been enabled by libc. An
example of this already happening is rseq, which could cause the kernel
to read/write memory of the userspace process. In the future the
standard library might also use mseal by default to protect itself,
which would also thwart our attempts at unmapping everything.
Solve all this by taking a step back and doing an execve into a tiny
static binary that sets up the minimal environment required for the
stub without using any standard library. That way we have a clean
execution environment that is fully under the control of UML.
Note that this changes things a bit as the FDs are not anymore shared
with the kernel. Instead, we explicitly share the FDs for the physical
memory and all existing iomem regions. Doing this is fine, as iomem
regions cannot be added at runtime.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-3-benjamin@sipsolutions.net
[use pipe() instead of pipe2(), remove unneeded close() calls]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
We do not need the extra save/restore of the FP registers when getting
the fault information. This was originally added in commit 2f56debd77
("uml: fix FP register corruption") but at that time the code was not
saving/restoring the FP registers when switching to userspace. This was
fixed in commit fbfe9c847e ("um: Save FPU registers between task
switches") and since then the auxiliary registers have not been useful.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241004233821.2130874-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
