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| author |   Max Filippov <jcmvbkbc@gmail.com> | 2021-05-01 15:32:58 -0700 |
|---|---|---|
| committer | Max Filippov <jcmvbkbc@gmail.com> | 2021-10-18 22:19:35 -0700 |
| commit | 0b5372570b1f3fcb35255d28e707846e613c27f2 (patch) | |
| tree | 7f38b947b50ad051903ec2d251fb51f3c62bc706 /arch/xtensa/kernel/process.c | |
| parent | xtensa: definitions for call0 ABI (diff) | |
| download | linux-dev-0b5372570b1f3fcb35255d28e707846e613c27f2.tar.xz linux-dev-0b5372570b1f3fcb35255d28e707846e613c27f2.zip | |
xtensa: implement call0 ABI support in assembly
Replace hardcoded register and opcode names with ABI-agnostic macros.
Add register save/restore code where necessary. Conditionalize windowed
only or call0 only code. Add stack initialization matching _switch_to
epilogue to copy_thread.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa/kernel/process.c')
| -rw-r--r-- | arch/xtensa/kernel/process.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index 060165340612..de6eb9ddea44 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -211,11 +211,18 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn, struct thread_info *ti; #endif +#if defined(__XTENSA_WINDOWED_ABI__) /* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */ SPILL_SLOT(childregs, 1) = (unsigned long)childregs; SPILL_SLOT(childregs, 0) = 0; p->thread.sp = (unsigned long)childregs; +#elif defined(__XTENSA_CALL0_ABI__) + /* Reserve 16 bytes for the _switch_to stack frame. */ + p->thread.sp = (unsigned long)childregs - 16; +#else +#error Unsupported Xtensa ABI +#endif if (!(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { struct pt_regs *regs = current_pt_regs(); @@ -272,11 +279,25 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn, p->thread.ra = MAKE_RA_FOR_CALL( (unsigned long)ret_from_kernel_thread, 1); - /* pass parameters to ret_from_kernel_thread: - * a2 = thread_fn, a3 = thread_fn arg + /* pass parameters to ret_from_kernel_thread: */ +#if defined(__XTENSA_WINDOWED_ABI__) + /* + * a2 = thread_fn, a3 = thread_fn arg. + * Window underflow will load registers from the + * spill slots on the stack on return from _switch_to. */ - SPILL_SLOT(childregs, 3) = thread_fn_arg; SPILL_SLOT(childregs, 2) = usp_thread_fn; + SPILL_SLOT(childregs, 3) = thread_fn_arg; +#elif defined(__XTENSA_CALL0_ABI__) + /* + * a12 = thread_fn, a13 = thread_fn arg. + * _switch_to epilogue will load registers from the stack. + */ + ((unsigned long *)p->thread.sp)[0] = usp_thread_fn; + ((unsigned long *)p->thread.sp)[1] = thread_fn_arg; +#else +#error Unsupported Xtensa ABI +#endif /* Childregs are only used when we're going to userspace * in which case start_thread will set them up. |