linux.git/arch/openrisc/kernel, branch v6.14 Linux kernel source tree openrisc: Add support for restartable sequences 2025-01-14T17:17:16+00:00 Stafford Horne shorne@gmail.com 2024-12-12T12:33:56+00:00 ca46ebffc2d2b243cc213d444e2a440489ecd4bc Implement support for restartable sequences on OpenRISC by doing: - Select HAVE_RSEQ in Kconfig - Call rseq_syscall() on return to userspace when CONFIG_DEBUG_RSEQ is enabled. - Call rseq_signal_deliver() to fixup the pre-signal stack frame when a signal is delivered on top of a restartable sequence critical section Cc: Michael Jeanson <mjeanson@efficios.com> Signed-off-by: Stafford Horne <shorne@gmail.com> 
Implement support for restartable sequences on OpenRISC by doing:
 - Select HAVE_RSEQ in Kconfig
 - Call rseq_syscall() on return to userspace when CONFIG_DEBUG_RSEQ
   is enabled.
 - Call rseq_signal_deliver() to fixup the pre-signal stack frame when a
   signal is delivered on top of a restartable sequence critical section

Cc: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>
openrisc: Add HAVE_REGS_AND_STACK_ACCESS_API support 2025-01-14T17:17:15+00:00 Michael Jeanson mjeanson@efficios.com 2024-12-10T19:58:12+00:00 7ce8716e2769dc08eccdf2b9385db6b0346d2f0d Support for HAVE_REGS_AND_STACK_ACCESS_API needed for restartable sequences. The implementation has been copied from riscv and tested with the restartable sequences self tests. Note, pt-regs members are 'long' on openrisc which require casts for the api, someday we should try to update these to be 'unsigned long' as that's what they really are. Signed-off-by: Michael Jeanson <mjeanson@efficios.com> [stafford: Updated commit message] Signed-off-by: Stafford Horne <shorne@gmail.com> 
Support for HAVE_REGS_AND_STACK_ACCESS_API needed for restartable
sequences.

The implementation has been copied from riscv and tested with the
restartable sequences self tests.

Note, pt-regs members are 'long' on openrisc which require casts for the
api, someday we should try to update these to be 'unsigned long' as
that's what they really are.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
[stafford: Updated commit message]
Signed-off-by: Stafford Horne <shorne@gmail.com>
openrisc: Fix misalignments in head.S 2024-12-10T12:04:19+00:00 Geert Uytterhoeven geert+renesas@glider.be 2024-12-05T13:04:26+00:00 c8f8d4344d50d72181207ee73175bba567c25f58 Align all line continuations and (sub)section headers in a consistent way. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Stafford Horne <shorne@gmail.com> 
Align all line continuations and (sub)section headers in a consistent
way.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stafford Horne <shorne@gmail.com>
openrisc: place exception table at the head of vmlinux 2024-12-10T12:04:19+00:00 Masahiro Yamada masahiroy@kernel.org 2024-12-02T06:28:22+00:00 a412f04070e52e6d6b5f6f964b9d9644de16bb81 Since commit 0043ecea2399 ("vmlinux.lds.h: Adjust symbol ordering in text output section"), the exception table in arch/openrisc/kernel/head.S is no longer positioned at the very beginning of the kernel image, which causes a boot failure. Currently, the exception table resides in the regular .text section. Previously, it was placed at the head by relying on the linker receiving arch/openrisc/kernel/head.o as the first object. However, this behavior has changed because sections like .text.{asan,unknown,unlikely,hot} now precede the regular .text section. The .head.text section is intended for entry points requiring special placement. However, in OpenRISC, this section has been misused: instead of the entry points, it contains boot code meant to be discarded after booting. This feature is typically handled by the .init.text section. This commit addresses the issue by replacing the current __HEAD marker with __INIT and re-annotating the entry points with __HEAD. Additionally, it adds __REF to entry.S to suppress the following modpost warning: WARNING: modpost: vmlinux: section mismatch in reference: _tng_kernel_start+0x70 (section: .text) -> _start (section: .init.text) Fixes: 0043ecea2399 ("vmlinux.lds.h: Adjust symbol ordering in text output section") Reported-by: Guenter Roeck <linux@roeck-us.net> Closes: https://lore.kernel.org/all/5e032233-5b65-4ad5-ac50-d2eb6c00171c@roeck-us.net/#t Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Rong Xu <xur@google.com> Signed-off-by: Stafford Horne <shorne@gmail.com> 
Since commit 0043ecea2399 ("vmlinux.lds.h: Adjust symbol ordering in
text output section"), the exception table in arch/openrisc/kernel/head.S
is no longer positioned at the very beginning of the kernel image, which
causes a boot failure.

Currently, the exception table resides in the regular .text section.
Previously, it was placed at the head by relying on the linker receiving
arch/openrisc/kernel/head.o as the first object. However, this behavior
has changed because sections like .text.{asan,unknown,unlikely,hot} now
precede the regular .text section.

The .head.text section is intended for entry points requiring special
placement. However, in OpenRISC, this section has been misused: instead
of the entry points, it contains boot code meant to be discarded after
booting. This feature is typically handled by the .init.text section.

This commit addresses the issue by replacing the current __HEAD marker
with __INIT and re-annotating the entry points with __HEAD. Additionally,
it adds __REF to entry.S to suppress the following modpost warning:

  WARNING: modpost: vmlinux: section mismatch in reference: _tng_kernel_start+0x70 (section: .text) -> _start (section: .init.text)

Fixes: 0043ecea2399 ("vmlinux.lds.h: Adjust symbol ordering in text output section")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/all/5e032233-5b65-4ad5-ac50-d2eb6c00171c@roeck-us.net/#t
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Rong Xu <xur@google.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>
of/fdt: add dt_phys arg to early_init_dt_scan and early_init_dt_verify 2024-10-29T20:32:45+00:00 Usama Arif usamaarif642@gmail.com 2024-10-23T17:14:26+00:00 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 <leitao@debian.org> Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Usama Arif <usamaarif642@gmail.com> 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) <robh@kernel.org> 
 __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 <leitao@debian.org>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
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) <robh@kernel.org>
openrisc: convert to generic syscall table 2024-07-10T12:23:38+00:00 Arnd Bergmann arnd@arndb.de 2024-04-23T21:14:14+00:00 77122bf9e3dfd927de4bf4a75b6297f928313e7e The uapi/asm/unistd_32.h and asm/syscall_table_32.h headers can now be generated from scripts/syscall.tbl, which makes this consistent with the other architectures that have their own syscall.tbl. openrisc has one extra system call that gets added to scripts/syscall.tbl. The time32, stat64, rlimit and renameat entries in the syscall_abis_32 line are for system calls that were part of the generic ABI when arch/nios2 got added but are no longer enabled by default for new architectures. Both the user visible side of asm/unistd.h and the internal syscall table in the kernel should have the same effective contents after this. When asm/syscalls.h is included in kernel/fork.c for the purpose of type checking, the redirection macros cause problems. Move these so only the references get redirected. Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
The uapi/asm/unistd_32.h and asm/syscall_table_32.h headers can now be
generated from scripts/syscall.tbl, which makes this consistent with
the other architectures that have their own syscall.tbl.

openrisc has one extra system call that gets added to scripts/syscall.tbl.

The time32, stat64, rlimit and renameat entries in the syscall_abis_32
line are for system calls that were part of the generic ABI when
arch/nios2 got added but are no longer enabled by default for new
architectures.

Both the user visible side of asm/unistd.h and the internal syscall
table in the kernel should have the same effective contents after this.

When asm/syscalls.h is included in kernel/fork.c for the purpose of
type checking, the redirection macros cause problems.  Move these so
only the references get redirected.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
openrisc: Move FPU state out of pt_regs 2024-04-15T14:20:39+00:00 Stafford Horne shorne@gmail.com 2024-03-30T14:56:39+00:00 4dc70e1aadfadf968676d983587c6f5d455aba85 My original, naive, FPU support patch had the FPCSR register stored during both the *mode switch* and *context switch*. This is wasteful. Also, the original patches did not save the FPU state when handling signals during the system call fast path. We fix this by moving the FPCSR state to thread_struct in task_struct. We also introduce new helper functions save_fpu and restore_fpu which can be used to sync the FPU with thread_struct. These functions are now called when needed: - Setting up and restoring sigcontext when handling signals - Before and after __switch_to during context switches - When handling FPU exceptions - When reading and writing FPU register sets In the future we can further optimize this by doing lazy FPU save and restore. For example, FPU sync is not needed when switching to and from kernel threads (x86 does this). FPU save and restore does not need to be done two times if we have both rescheduling and signal work to do. However, since OpenRISC FPU state is a single register, I leave these optimizations for future consideration. Signed-off-by: Stafford Horne <shorne@gmail.com> 
My original, naive, FPU support patch had the FPCSR register stored
during both the *mode switch* and *context switch*.  This is wasteful.

Also, the original patches did not save the FPU state when handling
signals during the system call fast path.

We fix this by moving the FPCSR state to thread_struct in task_struct.
We also introduce new helper functions save_fpu and restore_fpu which
can be used to sync the FPU with thread_struct.  These functions are now
called when needed:

 - Setting up and restoring sigcontext when handling signals
 - Before and after __switch_to during context switches
 - When handling FPU exceptions
 - When reading and writing FPU register sets

In the future we can further optimize this by doing lazy FPU save and
restore.  For example, FPU sync is not needed when switching to and from
kernel threads (x86 does this).  FPU save and restore does not need to
be done two times if we have both rescheduling and signal work to do.
However, since OpenRISC FPU state is a single register, I leave these
optimizations for future consideration.

Signed-off-by: Stafford Horne <shorne@gmail.com>
openrisc: Add FPU config 2024-04-15T14:20:39+00:00 Stafford Horne shorne@gmail.com 2024-03-30T14:54:51+00:00 1f33446d0efb101eafad92daf08f711f60daae1a Allow disabling FPU related code sequences to save space. Signed-off-by: Stafford Horne <shorne@gmail.com> 
Allow disabling FPU related code sequences to save space.

Signed-off-by: Stafford Horne <shorne@gmail.com>
openrisc: traps: Don't send signals to kernel mode threads 2024-04-15T14:20:39+00:00 Stafford Horne shorne@gmail.com 2024-03-30T14:42:49+00:00 c88cfb5cea5f8f9868ef02cc9ce9183a26dcf20f OpenRISC exception handling sends signals to user processes on floating point exceptions and trap instructions (for debugging) among others. There is a bug where the trap handling logic may send signals to kernel threads, we should not send these signals to kernel threads, if that happens we treat it as an error. This patch adds conditions to die if the kernel receives these exceptions in kernel mode code. Fixes: 27267655c531 ("openrisc: Support floating point user api") Signed-off-by: Stafford Horne <shorne@gmail.com> 
OpenRISC exception handling sends signals to user processes on floating
point exceptions and trap instructions (for debugging) among others.
There is a bug where the trap handling logic may send signals to kernel
threads, we should not send these signals to kernel threads, if that
happens we treat it as an error.

This patch adds conditions to die if the kernel receives these
exceptions in kernel mode code.

Fixes: 27267655c531 ("openrisc: Support floating point user api")
Signed-off-by: Stafford Horne <shorne@gmail.com>
openrisc: traps: Remove calls to show_registers before die 2024-04-15T14:20:39+00:00 Stafford Horne shorne@gmail.com 2024-04-11T17:42:50+00:00 ee7e551d28aa03664ead6b45154e20644a2f1040 The die function calls show_registers unconditionally. Remove calls to show_registers before calling die to avoid printing all registers and stack status two times during a crash. This was found when testing kernel trap and floating point exception handling. Signed-off-by: Stafford Horne <shorne@gmail.com> 
The die function calls show_registers unconditionally.  Remove calls to
show_registers before calling die to avoid printing all registers and
stack status two times during a crash.

This was found when testing kernel trap and floating point exception
handling.

Signed-off-by: Stafford Horne <shorne@gmail.com>