switch_to_32.h (3616B)
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 7extern 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 103void fpsave(unsigned long *fpregs, unsigned long *fsr, 104 void *fpqueue, unsigned long *fpqdepth); 105void synchronize_user_stack(void); 106 107#endif /* __SPARC_SWITCH_TO_H */