kernel.git/arch/openrisc, branch linux-6.4.y

openrisc: Union fpcsr and oldmask in sigcontext to unbreak userspace ABI

2023-07-23T11:53:45Z

[ Upstream commit dceaafd668812115037fc13a1893d068b7b880f5 ] With commit 27267655c531 ("openrisc: Support floating point user api") I added an entry to the struct sigcontext which caused an unwanted change to the userspace ABI. To fix this we use the previously unused oldmask field space for the floating point fpcsr state. We do this with a union to restore the ABI back to the pre kernel v6.4 ABI and keep API compatibility. This does mean if there is some code somewhere that is setting oldmask in an OpenRISC specific userspace sighandler it would end up setting the floating point register status, but I think it's unlikely as oldmask was never functional before. Fixes: 27267655c531 ("openrisc: Support floating point user api") Reported-by: Szabolcs Nagy Closes: https://lore.kernel.org/openrisc/20230626213840.GA1236108@port70.net/ Signed-off-by: Stafford Horne Signed-off-by: Sasha Levin

mm: always expand the stack with the mmap write lock held

2023-07-01T11:12:40Z

commit 8d7071af890768438c14db6172cc8f9f4d04e184 upstream. This finishes the job of always holding the mmap write lock when extending the user stack vma, and removes the 'write_locked' argument from the vm helper functions again. For some cases, we just avoid expanding the stack at all: drivers and page pinning really shouldn't be extending any stacks. Let's see if any strange users really wanted that. It's worth noting that architectures that weren't converted to the new lock_mm_and_find_vma() helper function are left using the legacy "expand_stack()" function, but it has been changed to drop the mmap_lock and take it for writing while expanding the vma. This makes it fairly straightforward to convert the remaining architectures. As a result of dropping and re-taking the lock, the calling conventions for this function have also changed, since the old vma may no longer be valid. So it will now return the new vma if successful, and NULL - and the lock dropped - if the area could not be extended. Tested-by: Vegard Nossum Tested-by: John Paul Adrian Glaubitz # ia64 Tested-by: Frank Scheiner # ia64 Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

Merge tag 'locking-core-2023-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-05-05T19:56:55Z

Pull locking updates from Ingo Molnar: - Introduce local{,64}_try_cmpxchg() - a slightly more optimal primitive, which will be used in perf events ring-buffer code - Simplify/modify rwsems on PREEMPT_RT, to address writer starvation - Misc cleanups/fixes * tag 'locking-core-2023-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/atomic: Correct (cmp)xchg() instrumentation locking/x86: Define arch_try_cmpxchg_local() locking/arch: Wire up local_try_cmpxchg() locking/generic: Wire up local{,64}_try_cmpxchg() locking/atomic: Add generic try_cmpxchg{,64}_local() support locking/rwbase: Mitigate indefinite writer starvation locking/arch: Rename all internal __xchg() names to __arch_xchg()

Merge tag 'for-linus' of https://github.com/openrisc/linux

2023-05-01T18:52:32Z

Pull OpenRISC updates from Stafford Horne: "Two things for OpenRISC this cycle: - Small cleanup for device tree cpu iteration from Rob Herring - Add support for storing, restoring and accessing user space FPU state, to allow for libc to support the FPU on OpenRISC" * tag 'for-linus' of https://github.com/openrisc/linux: openrisc: Add floating point regset openrisc: Support floating point user api openrisc: Support storing and restoring fpu state openrisc: Properly store r31 to pt_regs on unhandled exceptions openrisc: Use common of_get_cpu_node() instead of open-coding

locking/arch: Rename all internal xchg() names to arch_xchg()

2023-04-29T07:08:44Z

Decrease the probability of this internal facility to be used by driver code. Signed-off-by: Andrzej Hajda Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Arnd Bergmann Reviewed-by: Andi Shyti Acked-by: Geert Uytterhoeven [m68k] Acked-by: Palmer Dabbelt [riscv] Link: https://lore.kernel.org/r/20230118154450.73842-1-andrzej.hajda@intel.com Cc: Linus Torvalds

openrisc: Add floating point regset

2023-04-26T14:08:06Z

Define REGSET_FPU to allow reading and writing the FPCSR fpu state register. This will be used primarily by debuggers like GDB. Signed-off-by: Stafford Horne

openrisc: Support floating point user api

2023-04-26T14:08:06Z

Add support for handling floating point exceptions and forwarding the SIGFPE signal to processes. Also, add fpu state to sigcontext. Signed-off-by: Stafford Horne

openrisc: Support storing and restoring fpu state

2023-04-26T14:08:06Z

OpenRISC floating point state is not so expensive to save as OpenRISC uses general purpose registers for floating point instructions. We need to save only the floating point status and control register, FPCSR. Add support to maintain the FPCSR unconditionally upon exceptions and switches. On machines that do not support FPU this will always just store 0x0 and restore is a no-op. On FPU systems this adds an additional special purpose register read/write and read/write to memory (already cached). Signed-off-by: Stafford Horne

openrisc: Properly store r31 to pt_regs on unhandled exceptions

2023-04-26T14:08:06Z

In commit 91993c8c2ed5 ("openrisc: use shadow registers to save regs on exception") the unhandled exception path was changed to do an early store of r30 instead of r31. The entry code was not updated and r31 is not getting stored to pt_regs. This patch updates the entry handler to store r31 instead of r30. We also remove some misleading commented out store r30 and r31 instructrions. I noticed this while working on adding floating point exception handling, This issue probably would never impact anything since we kill the process or Oops right away on unhandled exceptions. Fixes: 91993c8c2ed5 ("openrisc: use shadow registers to save regs on exception") Signed-off-by: Stafford Horne

openrisc: Use common of_get_cpu_node() instead of open-coding

2023-04-01T05:40:27Z

The common of_get_cpu_node() is equivalent to setup_find_cpu_node(), so use it instead. Signed-off-by: Rob Herring Signed-off-by: Stafford Horne