Release 4.14 arch/sparc/include/asm/switch_to_32.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __SPARC_SWITCH_TO_H
#define __SPARC_SWITCH_TO_H
#include <asm/smp.h>
extern struct thread_info *current_set[NR_CPUS];
/*
* Flush windows so that the VM switch which follows
* would not pull the stack from under us.
*
* SWITCH_ENTER and SWITCH_DO_LAZY_FPU do not work yet (e.g. SMP does not work)
* XXX WTF is the above comment? Found in late teen 2.4.x.
*/
#ifdef CONFIG_SMP
#define SWITCH_ENTER(prv) \
do { \
if (test_tsk_thread_flag(prv, TIF_USEDFPU)) { \
put_psr(get_psr() | PSR_EF); \
fpsave(&(prv)->thread.float_regs[0], &(prv)->thread.fsr, \
&(prv)->thread.fpqueue[0], &(prv)->thread.fpqdepth); \
clear_tsk_thread_flag(prv, TIF_USEDFPU); \
(prv)->thread.kregs->psr &= ~PSR_EF; \
} \
} while(0)
#define SWITCH_DO_LAZY_FPU(next)
/* */
#else
#define SWITCH_ENTER(prv)
/* */
#define SWITCH_DO_LAZY_FPU(nxt) \
do { \
if (last_task_used_math != (nxt)) \
(nxt)->thread.kregs->psr&=~PSR_EF; \
} while(0)
#endif
#define prepare_arch_switch(next) do { \
__asm__ __volatile__( \
".globl\tflush_patch_switch\nflush_patch_switch:\n\t" \
"save %sp, -0x40, %sp; save %sp, -0x40, %sp; save %sp, -0x40, %sp\n\t" \
"save %sp, -0x40, %sp; save %sp, -0x40, %sp; save %sp, -0x40, %sp\n\t" \
"save %sp, -0x40, %sp\n\t" \
"restore; restore; restore; restore; restore; restore; restore"); \
} while(0)
/* Much care has gone into this code, do not touch it.
*
* We need to loadup regs l0/l1 for the newly forked child
* case because the trap return path relies on those registers
* holding certain values, gcc is told that they are clobbered.
* Gcc needs registers for 3 values in and 1 value out, so we
* clobber every non-fixed-usage register besides l2/l3/o4/o5. -DaveM
*
* Hey Dave, that do not touch sign is too much of an incentive
* - Anton & Pete
*/
#define switch_to(prev, next, last) do { \
SWITCH_ENTER(prev); \
SWITCH_DO_LAZY_FPU(next); \
cpumask_set_cpu(smp_processor_id(), mm_cpumask(next->active_mm)); \
__asm__ __volatile__( \
"sethi %%hi(here - 0x8), %%o7\n\t" \
"mov %%g6, %%g3\n\t" \
"or %%o7, %%lo(here - 0x8), %%o7\n\t" \
"rd %%psr, %%g4\n\t" \
"std %%sp, [%%g6 + %4]\n\t" \
"rd %%wim, %%g5\n\t" \
"wr %%g4, 0x20, %%psr\n\t" \
"nop\n\t" \
"std %%g4, [%%g6 + %3]\n\t" \
"ldd [%2 + %3], %%g4\n\t" \
"mov %2, %%g6\n\t" \
".globl patchme_store_new_current\n" \
"patchme_store_new_current:\n\t" \
"st %2, [%1]\n\t" \
"wr %%g4, 0x20, %%psr\n\t" \
"nop\n\t" \
"nop\n\t" \
"nop\n\t" /* LEON needs all 3 nops: load to %sp depends on CWP. */ \
"ldd [%%g6 + %4], %%sp\n\t" \
"wr %%g5, 0x0, %%wim\n\t" \
"ldd [%%sp + 0x00], %%l0\n\t" \
"ldd [%%sp + 0x38], %%i6\n\t" \
"wr %%g4, 0x0, %%psr\n\t" \
"nop\n\t" \
"nop\n\t" \
"jmpl %%o7 + 0x8, %%g0\n\t" \
" ld [%%g3 + %5], %0\n\t" \
"here:\n" \
: "=&r" (last) \
: "r" (&(current_set[hard_smp_processor_id()])), \
"r" (task_thread_info(next)), \
"i" (TI_KPSR), \
"i" (TI_KSP), \
"i" (TI_TASK) \
: "g1", "g2", "g3", "g4", "g5", "g7", \
"l0", "l1", "l3", "l4", "l5", "l6", "l7", \
"i0", "i1", "i2", "i3", "i4", "i5", \
"o0", "o1", "o2", "o3", "o7"); \
} while(0)
void fpsave(unsigned long *fpregs, unsigned long *fsr,
void *fpqueue, unsigned long *fpqdepth);
void synchronize_user_stack(void);
#endif /* __SPARC_SWITCH_TO_H */
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