Replace all S390_lowcore usages in arch/s390/ by get_lowcore(). Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
It has been removed in commit 2c6b96762fbd ("s390/fpu: remove TIF_FPU"),
so we should not mention TIF_FPU in the comment here anymore. Since the
remaining parts of the comment just document the obvious fact that
save_user_fpu_regs() saves the FPU state, simply remove the comment now
completely.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20240503080648.81461-1-thuth@redhat.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
KVM was the only user which modified the regs pointer in struct fpu. Remove the pointer and convert the rest of the core fpu code to directly access the save area embedded within struct fpu. Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Make the kernel fpu context preemptible. Add another fpu structure to the thread_struct, and use it to save and restore the kernel fpu context if its task uses fpu registers when it is preempted. Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Rename save_fpu_regs(), load_fpu_regs(), and struct thread_struct's fpu member to save_user_fpu_regs(), load_user_fpu_regs(), and ufpu. This way the function and variable names reflect for which context they are supposed to be used. This large and trivial conversion is a prerequisite for making the kernel fpu usage preemptible. Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The FPU state, as represented by the CIF_FPU flag reflects the FPU state of a task, not the CPU it is running on. Therefore convert the flag to a regular TIF flag. This removes the magic in switch_to() where a save_fpu_regs() call for the currently (previous) running task sets the per-cpu CIF_FPU flag, which is required to restore FPU register contents of the next task, when it returns to user space. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Instead of open-coding lfpc, sfpc, and stfpc inline assemblies at several locations, provide an fpu_* function for each instruction and use the function instead. Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Move, rename, and merge the fpu and vx header files. This way fpu header files have a consistent naming scheme (fpu*.h). Also get rid of the fpu subdirectory and move header files to asm directory, so that all fpu and vx header files can be found at the same location. Merge internal.h header file into other header files, since the internal helpers are used at many locations. so those helper functions are really not internal. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Move the switch_to() implementation to process.c and use the generic switch_to.h header file instead, like some other architectures. This addresses also the oddity that the old switch_to() implementation assigns the return value of __switch_to() to 'prev' instead of 'last', like it should. Remove also all includes of switch_to.h from C files, except process.c. Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
s390 selects ARCH_WANTS_DYNAMIC_TASK_STRUCT in order to make the size of the task structure dependent on the availability of the vector facility. This doesn't make sense anymore because since many years all machines provide the vector facility. Therefore simplify the code a bit and remove s390 support for ARCH_WANTS_DYNAMIC_TASK_STRUCT. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>