um: mark rodata read-only and implement _nofault accesses

Mark read-only data actually read-only (simple mprotect), and
to be able to test it also implement _nofault accesses. This
works by setting

um: mark rodata read-only and implement _nofault accesses

Mark read-only data actually read-only (simple mprotect), and
to be able to test it also implement _nofault accesses. This
works by setting up a new "segv_continue" pointer in current,
and then when we hit a segfault we change the signal return
context so that we continue at that address. The code using
this sets it up so that it jumps to a label and then aborts
the access that way, returning -EFAULT.

It's possible to optimize the ___backtrack_faulted() thing by
using asm goto (compiler version dependent) and/or gcc's (not
sure if clang has it) &&label extension, but at least in one
attempt I made the && caused the compiler to not load -EFAULT
into the register in case of jumping to the &&label from the
fault handler. So leave it like this for now.

Signed-off-by: Johannes Berg <[email protected]>
Co-developed-by: Benjamin Berg <[email protected]>
Signed-off-by: Benjamin Berg <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Johannes Berg <[email protected]>

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um: switch to regset API and depend on XSTATE

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 th

um: switch to regset API and depend on XSTATE

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 <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Johannes Berg <[email protected]>

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um: remove fault_catcher infrastructure

This was perhaps intended to do _nofault copies, but the
real reason is lost to history. Remove this, it's not
needed, and using longjmp() out of the middle o

um: remove fault_catcher infrastructure

This was perhaps intended to do _nofault copies, but the
real reason is lost to history. Remove this, it's not
needed, and using longjmp() out of the middle of the
signal handler with all the state it has modified is
not going to be a good idea anyway.

Link: https://patch.msgid.link/20241010224513.901c4d390b3e.Ia74742668b44603c1ca23dd36f90e964e6e7ee55@changeid
Signed-off-by: Johannes Berg <[email protected]>

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um: Remove unused fields from thread_struct

These fields are no longer used since the removal of tt mode.

Signed-off-by: Tiwei Bie <[email protected]>
Signed-off-by: Richard Weinberger <richar

um: Remove unused fields from thread_struct

These fields are no longer used since the removal of tt mode.

Signed-off-by: Tiwei Bie <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

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um: Fix the -Wmissing-prototypes warning for get_thread_reg

The get_thread_reg function is defined in the user code, and is
called by the kernel code. It should be declared in a shared header.

Fixe

um: Fix the -Wmissing-prototypes warning for get_thread_reg

The get_thread_reg function is defined in the user code, and is
called by the kernel code. It should be declared in a shared header.

Fixes: dbba7f704aa0 ("um: stop polluting the namespace with registers.h contents")
Signed-off-by: Tiwei Bie <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

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um: Drop support for hosts without SYSEMU_SINGLESTEP support

These features have existed since Linux 2.6.14 and can be considered
widely available at this point. Also drop the backward compatibility

um: Drop support for hosts without SYSEMU_SINGLESTEP support

These features have existed since Linux 2.6.14 and can be considered
widely available at this point. Also drop the backward compatibility
code for PTRACE_SETOPTIONS.

Signed-off-by: Benjamin Berg <[email protected]>

----

v2:
* Continue to define PTRACE_SYSEMU_SINGLESTEP as glibc only added it in
version 2.27.
Signed-off-by: Richard Weinberger <[email protected]>

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um: Make the definition of cpu_data more compatible

Match the x86 implementation to improve build errors.
Noticed when building allyesconfig.

e.g.
../arch/um/include/asm/processor-generic.h:94:19:

um: Make the definition of cpu_data more compatible

Match the x86 implementation to improve build errors.
Noticed when building allyesconfig.

e.g.
../arch/um/include/asm/processor-generic.h:94:19: error: called object is not a function or function pointer
94 | #define cpu_data (&boot_cpu_data)
| ~^~~~~~~~~~~~~~~
../drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_topology.c:2157:16: note: in expansion of macro ‘cpu_data’
2157 | return cpu_data(first_cpu_of_numa_node).apicid;

Signed-off-by: Peter Foley <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

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kernel: exit: cleanup release_thread()

Only x86 has own release_thread(), introduce a new weak release_thread()
function to clean empty definitions in other ARCHs.

Link: https://lkml.kernel.org/r/2

kernel: exit: cleanup release_thread()

Only x86 has own release_thread(), introduce a new weak release_thread()
function to clean empty definitions in other ARCHs.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kefeng Wang <[email protected]>
Acked-by: Guo Ren <[email protected]> [csky]
Acked-by: Russell King (Oracle) <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Brian Cain <[email protected]>
Acked-by: Michael Ellerman <[email protected]> [powerpc]
Acked-by: Stafford Horne <[email protected]> [openrisc]
Acked-by: Catalin Marinas <[email protected]> [arm64]
Acked-by: Huacai Chen <[email protected]> [LoongArch]
Cc: Alexander Gordeev <[email protected]>
Cc: Anton Ivanov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: Guo Ren <[email protected]> [csky]
Cc: Heiko Carstens <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Jonas Bonn <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Stefan Kristiansson <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Xuerui Wang <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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um: remove unused mm_copy_segments

It was already removed by commit c17c02040bf0 ("arch: remove unused
*_segments() macros/functions") but seems to have been accidentally
reintroduced by commit 0500

um: remove unused mm_copy_segments

It was already removed by commit c17c02040bf0 ("arch: remove unused
*_segments() macros/functions") but seems to have been accidentally
reintroduced by commit 0500871f21b2 ("Construct init thread stack in the
linker script rather than by union"). Remove it for good.

Signed-off-by: Tobias Klauser <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

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um: stop polluting the namespace with registers.h contents

Only one extern in there is needed in processor-generic.h, and it's
not needed anywhere else. So move it over there and get rid of
the inc

um: stop polluting the namespace with registers.h contents

Only one extern in there is needed in processor-generic.h, and it's
not needed anywhere else. So move it over there and get rid of
the include in processor-generic.h, adding includes of registers.h
to the few files that need the declarations in it.

Signed-off-by: Al Viro <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

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sched: Add wrapper for get_wchan() to keep task blocked

Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zij

sched: Add wrapper for get_wchan() to keep task blocked

Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Russell King (Oracle) <[email protected]> [arm]
Tested-by: Mark Rutland <[email protected]> [arm64]
Link: https://lkml.kernel.org/r/[email protected]

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um: Add support for host CPU flags and alignment

1. Reflect host cpu flags into the UML instance so they can
be used to select the correct implementations for xor, crypto, etc.

2. Reflect host cach

um: Add support for host CPU flags and alignment

1. Reflect host cpu flags into the UML instance so they can
be used to select the correct implementations for xor, crypto, etc.

2. Reflect host cache alignment into UML instance. This is
important when running 32 bit on a 64 bit host as 32 bit by
default aligns to 32 while the actual alignment should be 64.
Ditto for some Xeons which align at 128.

Signed-off-by: Anton Ivanov <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

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um: Add SPDX headers for files in arch/um/include

Convert files to use SPDX header. All files are licensed under the GPLv2.

Signed-off-by: Alex Dewar <[email protected]>
Signed-off-by: Richard W

um: Add SPDX headers for files in arch/um/include

Convert files to use SPDX header. All files are licensed under the GPLv2.

Signed-off-by: Alex Dewar <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

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Construct init thread stack in the linker script rather than by union

Construct the init thread stack in the linker script rather than doing it
by means of a union so that ia64's init_task.c can be

Construct init thread stack in the linker script rather than by union

Construct the init thread stack in the linker script rather than doing it
by means of a union so that ia64's init_task.c can be got rid of.

The following symbols are then made available from INIT_TASK_DATA() linker
script macro:

init_thread_union
init_stack

INIT_TASK_DATA() also expands the region to THREAD_SIZE to accommodate the
size of the init stack. init_thread_union is given its own section so that
it can be placed into the stack space in the right order. I'm assuming
that the ia64 ordering is correct and that the task_struct is first and the
thread_info second.

Signed-off-by: David Howells <[email protected]>
Tested-by: Tony Luck <[email protected]>
Tested-by: Will Deacon <[email protected]> (arm64)
Tested-by: Palmer Dabbelt <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>

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arch: remove unused *_segments() macros/functions

Some architectures define the no-op macros/functions copy_segments,
release_segments and forget_segments. These are used nowhere in the
tree, so rem

arch: remove unused *_segments() macros/functions

Some architectures define the no-op macros/functions copy_segments,
release_segments and forget_segments. These are used nowhere in the
tree, so removed them.

Signed-off-by: Tobias Klauser <[email protected]>
Acked-by: Vineet Gupta <[email protected]> [for arch/arc]
Signed-off-by: Linus Torvalds <[email protected]>

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arch: remove unused macro/function thread_saved_pc()

The only user of thread_saved_pc() in non-arch-specific code was removed
in commit 8243d5597793 ("sched/core: Remove pointless printout in
sched_

arch: remove unused macro/function thread_saved_pc()

The only user of thread_saved_pc() in non-arch-specific code was removed
in commit 8243d5597793 ("sched/core: Remove pointless printout in
sched_show_task()"). Remove the implementations as well.

Some architectures use thread_saved_pc() in their arch-specific code.
Leave their thread_saved_pc() intact.

Signed-off-by: Tobias Klauser <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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um: Remove broken SMP support

At times where UML used the TT mode to operate it had
kind of SMP support. It never got finished nor was
stable.
Let's rip out that cruft and stop confusing developers

um: Remove broken SMP support

At times where UML used the TT mode to operate it had
kind of SMP support. It never got finished nor was
stable.
Let's rip out that cruft and stop confusing developers
which do tree-wide SMP cleanups.

If someone wants SMP support UML it has do be done from scratch.

Signed-off-by: Richard Weinberger <[email protected]>

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um: Removed unused attributes from thread_struct

temp_stack and mm_count have no users and can be killed.

Signed-off-by: Richard Weinberger <[email protected]>

um: Get rid of thread_struct->saved_task

As we have a sane show_stack() now, we can drop
the ->saved_task hack.

Signed-off-by: Richard Weinberger <[email protected]>

um: Make stack trace reliable against kernel mode faults

As UML uses an alternative signal stack we cannot use
the current stack pointer for stack dumping if UML itself
dies by SIGSEGV. To bypass th

um: Make stack trace reliable against kernel mode faults

As UML uses an alternative signal stack we cannot use
the current stack pointer for stack dumping if UML itself
dies by SIGSEGV. To bypass this issue we save regs taken
from mcontext in our segv handler into thread_struct and
use these regs to obtain the stack pointer in show_stack().

Signed-off-by: Richard Weinberger <[email protected]>

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x86, um: convert to saner kernel_execve() semantics

Signed-off-by: Al Viro <[email protected]>

um: get rid of pointless include "..." where include <...> will do

Signed-off-by: Al Viro <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

um: switch to generic kernel_thread()

Signed-off-by: Al Viro <[email protected]>

um: kill thread->forking

we only use that to tell copy_thread() done by syscall from that
done by kernel_thread(). However, it's easier to do simply by
checking PF_KTHREAD in thread flags.

Merge s

um: kill thread->forking

we only use that to tell copy_thread() done by syscall from that
done by kernel_thread(). However, it's easier to do simply by
checking PF_KTHREAD in thread flags.

Merge sys_clone() guts for 32bit and 64bit, while we are at it...

Signed-off-by: Al Viro <[email protected]>

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um: kill thread->forking

we only use that to tell copy_thread() done by syscall from that
done by kernel_thread(). However, it's easier to do simply by
checking PF_KTHREAD in thread flags.

Merge s

um: kill thread->forking

we only use that to tell copy_thread() done by syscall from that
done by kernel_thread(). However, it's easier to do simply by
checking PF_KTHREAD in thread flags.

Merge sys_clone() guts for 32bit and 64bit, while we are at it...

Signed-off-by: Al Viro <[email protected]>

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