1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __SPARC_SWITCH_TO_H
3 #define __SPARC_SWITCH_TO_H
4
5 #include <asm/smp.h>
6
7 extern struct thread_info *current_set[NR_CPUS];
8
9 /*
10 * Flush windows so that the VM switch which follows
11 * would not pull the stack from under us.
12 *
13 * SWITCH_ENTER and SWITCH_DO_LAZY_FPU do not work yet (e.g. SMP does not work)
14 * XXX WTF is the above comment? Found in late teen 2.4.x.
15 */
16 #ifdef CONFIG_SMP
17 #define SWITCH_ENTER(prv) \
18 do { \
19 if (test_tsk_thread_flag(prv, TIF_USEDFPU)) { \
20 put_psr(get_psr() | PSR_EF); \
21 fpsave(&(prv)->thread.float_regs[0], &(prv)->thread.fsr, \
22 &(prv)->thread.fpqueue[0], &(prv)->thread.fpqdepth); \
23 clear_tsk_thread_flag(prv, TIF_USEDFPU); \
24 (prv)->thread.kregs->psr &= ~PSR_EF; \
25 } \
26 } while(0)
27
28 #define SWITCH_DO_LAZY_FPU(next) /* */
29 #else
30 #define SWITCH_ENTER(prv) /* */
31 #define SWITCH_DO_LAZY_FPU(nxt) \
32 do { \
33 if (last_task_used_math != (nxt)) \
34 (nxt)->thread.kregs->psr&=~PSR_EF; \
35 } while(0)
36 #endif
37
38 #define prepare_arch_switch(next) do { \
39 __asm__ __volatile__( \
40 ".globl\tflush_patch_switch\nflush_patch_switch:\n\t" \
41 "save %sp, -0x40, %sp; save %sp, -0x40, %sp; save %sp, -0x40, %sp\n\t" \
42 "save %sp, -0x40, %sp; save %sp, -0x40, %sp; save %sp, -0x40, %sp\n\t" \
43 "save %sp, -0x40, %sp\n\t" \
44 "restore; restore; restore; restore; restore; restore; restore"); \
45 } while(0)
46
47 /* Much care has gone into this code, do not touch it.
48 *
49 * We need to loadup regs l0/l1 for the newly forked child
50 * case because the trap return path relies on those registers
51 * holding certain values, gcc is told that they are clobbered.
52 * Gcc needs registers for 3 values in and 1 value out, so we
53 * clobber every non-fixed-usage register besides l2/l3/o4/o5. -DaveM
54 *
55 * Hey Dave, that do not touch sign is too much of an incentive
56 * - Anton & Pete
57 */
58 #define switch_to(prev, next, last) do { \
59 SWITCH_ENTER(prev); \
60 SWITCH_DO_LAZY_FPU(next); \
61 cpumask_set_cpu(smp_processor_id(), mm_cpumask(next->active_mm)); \
62 __asm__ __volatile__( \
63 "sethi %%hi(here - 0x8), %%o7\n\t" \
64 "mov %%g6, %%g3\n\t" \
65 "or %%o7, %%lo(here - 0x8), %%o7\n\t" \
66 "rd %%psr, %%g4\n\t" \
67 "std %%sp, [%%g6 + %4]\n\t" \
68 "rd %%wim, %%g5\n\t" \
69 "wr %%g4, 0x20, %%psr\n\t" \
70 "nop\n\t" \
71 "std %%g4, [%%g6 + %3]\n\t" \
72 "ldd [%2 + %3], %%g4\n\t" \
73 "mov %2, %%g6\n\t" \
74 ".globl patchme_store_new_current\n" \
75 "patchme_store_new_current:\n\t" \
76 "st %2, [%1]\n\t" \
77 "wr %%g4, 0x20, %%psr\n\t" \
78 "nop\n\t" \
79 "nop\n\t" \
80 "nop\n\t" /* LEON needs all 3 nops: load to %sp depends on CWP. */ \
81 "ldd [%%g6 + %4], %%sp\n\t" \
82 "wr %%g5, 0x0, %%wim\n\t" \
83 "ldd [%%sp + 0x00], %%l0\n\t" \
84 "ldd [%%sp + 0x38], %%i6\n\t" \
85 "wr %%g4, 0x0, %%psr\n\t" \
86 "nop\n\t" \
87 "nop\n\t" \
88 "jmpl %%o7 + 0x8, %%g0\n\t" \
89 " ld [%%g3 + %5], %0\n\t" \
90 "here:\n" \
91 : "=&r" (last) \
92 : "r" (&(current_set[hard_smp_processor_id()])), \
93 "r" (task_thread_info(next)), \
94 "i" (TI_KPSR), \
95 "i" (TI_KSP), \
96 "i" (TI_TASK) \
97 : "g1", "g2", "g3", "g4", "g5", "g7", \
98 "l0", "l1", "l3", "l4", "l5", "l6", "l7", \
99 "i0", "i1", "i2", "i3", "i4", "i5", \
100 "o0", "o1", "o2", "o3", "o7"); \
101 } while(0)
102
103 void fpsave(unsigned long *fpregs, unsigned long *fsr,
104 void *fpqueue, unsigned long *fpqdepth);
105 void synchronize_user_stack(void);
106
107 #endif /* __SPARC_SWITCH_TO_H */