1 // SPDX-License-Identifier: GPL-2.0
15  * struct emuframe - The 'emulation' frame structure
32  * - Actually emulating all instructions isn't feasible. We would need to
33  *   be able to handle instructions from all revisions of the MIPS ISA,
34  *   all ASEs & all vendor instruction set extensions. This would be a
40  * - We must execute the instruction within user context. If we were to
45  * - We used to place the frame on the users stack, but this requires
47  *   per-process page is now used instead.
49  * - The instruction in @emul may be something entirely invalid for a
57  * - The user may generate a fake struct emuframe if they wish, invoking
77 	mm_context_t *mm_ctx = &current->mm->context;  in alloc_emuframe()
80 retry:  in alloc_emuframe()
81 	spin_lock(&mm_ctx->bd_emupage_lock);  in alloc_emuframe()
84 	if (!mm_ctx->bd_emupage_allocmap) {  in alloc_emuframe()
85 		mm_ctx->bd_emupage_allocmap = bitmap_zalloc(emupage_frame_count,  in alloc_emuframe()
87 		if (!mm_ctx->bd_emupage_allocmap) {  in alloc_emuframe()
94 	idx = bitmap_find_free_region(mm_ctx->bd_emupage_allocmap,  in alloc_emuframe()
102 		 * However the worst case is that we repeat all this and end up  in alloc_emuframe()
105 		spin_unlock(&mm_ctx->bd_emupage_lock);  in alloc_emuframe()
106 		if (!wait_event_killable(mm_ctx->bd_emupage_queue,  in alloc_emuframe()
107 			!bitmap_full(mm_ctx->bd_emupage_allocmap,  in alloc_emuframe()
109 			goto retry;  in alloc_emuframe()
111 		/* Received a fatal signal - just give in */  in alloc_emuframe()
116 	pr_debug("allocate emuframe %d to %d\n", idx, current->pid);  in alloc_emuframe()
118 	spin_unlock(&mm_ctx->bd_emupage_lock);  in alloc_emuframe()
124 	mm_context_t *mm_ctx = &mm->context;  in free_emuframe()
126 	spin_lock(&mm_ctx->bd_emupage_lock);  in free_emuframe()
128 	pr_debug("free emuframe %d from %d\n", idx, current->pid);  in free_emuframe()
129 	bitmap_clear(mm_ctx->bd_emupage_allocmap, idx, 1);  in free_emuframe()
132 	wake_up(&mm_ctx->bd_emupage_queue);  in free_emuframe()
134 	spin_unlock(&mm_ctx->bd_emupage_lock);  in free_emuframe()
141 	if (regs->cp0_epc < base)  in within_emuframe()
143 	if (regs->cp0_epc >= (base + PAGE_SIZE))  in within_emuframe()
154 	fr_idx = atomic_xchg(&tsk->thread.bd_emu_frame, BD_EMUFRAME_NONE);  in dsemul_thread_cleanup()
163 	if (tsk->mm)  in dsemul_thread_cleanup()
164 		free_emuframe(fr_idx, tsk->mm);  in dsemul_thread_cleanup()
180 	fr_idx = atomic_read(&current->thread.bd_emu_frame);  in dsemul_thread_rollback()
190 	 * of the emupage - we'll free the allocated frame anyway.  in dsemul_thread_rollback()
192 	if (msk_isa16_mode(regs->cp0_epc) == (unsigned long)&fr->emul)  in dsemul_thread_rollback()
193 		regs->cp0_epc = current->thread.bd_emu_branch_pc;  in dsemul_thread_rollback()
194 	else if (msk_isa16_mode(regs->cp0_epc) == (unsigned long)&fr->badinst)  in dsemul_thread_rollback()
195 		regs->cp0_epc = current->thread.bd_emu_cont_pc;  in dsemul_thread_rollback()
197 	atomic_set(&current->thread.bd_emu_frame, BD_EMUFRAME_NONE);  in dsemul_thread_rollback()
198 	free_emuframe(fr_idx, current->mm);  in dsemul_thread_rollback()
204 	mm_context_t *mm_ctx = &mm->context;  in dsemul_mm_cleanup()
206 	bitmap_free(mm_ctx->bd_emupage_allocmap);  in dsemul_mm_cleanup()
212 	int isa16 = get_isa16_mode(regs->cp0_epc);  in mips_dsemul()
220 		return -1;  in mips_dsemul()
228 			return -1;  in mips_dsemul()
236 			v = regs->cp0_epc & ~3;  in mips_dsemul()
238 			regs->regs[rs] = (long)v;  in mips_dsemul()
239 			return -1;  in mips_dsemul()
243 	pr_debug("dsemul 0x%08lx cont at 0x%08lx\n", regs->cp0_epc, cont_pc);  in mips_dsemul()
246 	fr_idx = atomic_read(&current->thread.bd_emu_frame);  in mips_dsemul()
276 		MIPS_FPU_EMU_INC_STATS(errors);  in mips_dsemul()
277 		free_emuframe(fr_idx, current->mm);  in mips_dsemul()
282 	current->thread.bd_emu_branch_pc = branch_pc;  in mips_dsemul()
283 	current->thread.bd_emu_cont_pc = cont_pc;  in mips_dsemul()
284 	atomic_set(&current->thread.bd_emu_frame, fr_idx);  in mips_dsemul()
287 	regs->cp0_epc = fr_uaddr | isa16;  in mips_dsemul()
296 		MIPS_FPU_EMU_INC_STATS(errors);  in do_dsemulret()
300 	/* Set EPC to return to post-branch instruction */  in do_dsemulret()
301 	xcp->cp0_epc = current->thread.bd_emu_cont_pc;  in do_dsemulret()
302 	pr_debug("dsemulret to 0x%08lx\n", xcp->cp0_epc);  in do_dsemulret()