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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/mips/include/asm/switch_to.h
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/mips/include/asm/switch_to.h')
-rw-r--r--arch/mips/include/asm/switch_to.h142
1 files changed, 142 insertions, 0 deletions
diff --git a/arch/mips/include/asm/switch_to.h b/arch/mips/include/asm/switch_to.h
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+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle
+ * Copyright (C) 1996 by Paul M. Antoine
+ * Copyright (C) 1999 Silicon Graphics
+ * Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
+ * Copyright (C) 2000 MIPS Technologies, Inc.
+ */
+#ifndef _ASM_SWITCH_TO_H
+#define _ASM_SWITCH_TO_H
+
+#include <asm/cpu-features.h>
+#include <asm/watch.h>
+#include <asm/dsp.h>
+#include <asm/cop2.h>
+#include <asm/fpu.h>
+
+struct task_struct;
+
+/**
+ * resume - resume execution of a task
+ * @prev: The task previously executed.
+ * @next: The task to begin executing.
+ * @next_ti: task_thread_info(next).
+ *
+ * This function is used whilst scheduling to save the context of prev & load
+ * the context of next. Returns prev.
+ */
+extern asmlinkage struct task_struct *resume(struct task_struct *prev,
+ struct task_struct *next, struct thread_info *next_ti);
+
+extern unsigned int ll_bit;
+extern struct task_struct *ll_task;
+
+#ifdef CONFIG_MIPS_MT_FPAFF
+
+/*
+ * Handle the scheduler resume end of FPU affinity management. We do this
+ * inline to try to keep the overhead down. If we have been forced to run on
+ * a "CPU" with an FPU because of a previous high level of FP computation,
+ * but did not actually use the FPU during the most recent time-slice (CU1
+ * isn't set), we undo the restriction on cpus_mask.
+ *
+ * We're not calling set_cpus_allowed() here, because we have no need to
+ * force prompt migration - we're already switching the current CPU to a
+ * different thread.
+ */
+
+#define __mips_mt_fpaff_switch_to(prev) \
+do { \
+ struct thread_info *__prev_ti = task_thread_info(prev); \
+ \
+ if (cpu_has_fpu && \
+ test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) && \
+ (!(KSTK_STATUS(prev) & ST0_CU1))) { \
+ clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND); \
+ prev->cpus_mask = prev->thread.user_cpus_allowed; \
+ } \
+ next->thread.emulated_fp = 0; \
+} while(0)
+
+#else
+#define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0)
+#endif
+
+/*
+ * Clear LLBit during context switches on MIPSr5+ such that eretnc can be used
+ * unconditionally when returning to userland in entry.S.
+ */
+#define __clear_r5_hw_ll_bit() do { \
+ if (cpu_has_mips_r5 || cpu_has_mips_r6) \
+ write_c0_lladdr(0); \
+} while (0)
+
+#define __clear_software_ll_bit() do { \
+ if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc) \
+ ll_bit = 0; \
+} while (0)
+
+/*
+ * Check FCSR for any unmasked exceptions pending set with `ptrace',
+ * clear them and send a signal.
+ */
+#ifdef CONFIG_MIPS_FP_SUPPORT
+# define __sanitize_fcr31(next) \
+do { \
+ unsigned long fcr31 = mask_fcr31_x(next->thread.fpu.fcr31); \
+ void __user *pc; \
+ \
+ if (unlikely(fcr31)) { \
+ pc = (void __user *)task_pt_regs(next)->cp0_epc; \
+ next->thread.fpu.fcr31 &= ~fcr31; \
+ force_fcr31_sig(fcr31, pc, next); \
+ } \
+} while (0)
+#else
+# define __sanitize_fcr31(next)
+#endif
+
+/*
+ * For newly created kernel threads switch_to() will return to
+ * ret_from_kernel_thread, newly created user threads to ret_from_fork.
+ * That is, everything following resume() will be skipped for new threads.
+ * So everything that matters to new threads should be placed before resume().
+ */
+#define switch_to(prev, next, last) \
+do { \
+ __mips_mt_fpaff_switch_to(prev); \
+ lose_fpu_inatomic(1, prev); \
+ if (tsk_used_math(next)) \
+ __sanitize_fcr31(next); \
+ if (cpu_has_dsp) { \
+ __save_dsp(prev); \
+ __restore_dsp(next); \
+ } \
+ if (cop2_present) { \
+ u32 status = read_c0_status(); \
+ \
+ set_c0_status(ST0_CU2); \
+ if ((KSTK_STATUS(prev) & ST0_CU2)) { \
+ if (cop2_lazy_restore) \
+ KSTK_STATUS(prev) &= ~ST0_CU2; \
+ cop2_save(prev); \
+ } \
+ if (KSTK_STATUS(next) & ST0_CU2 && \
+ !cop2_lazy_restore) { \
+ cop2_restore(next); \
+ } \
+ write_c0_status(status); \
+ } \
+ __clear_r5_hw_ll_bit(); \
+ __clear_software_ll_bit(); \
+ if (cpu_has_userlocal) \
+ write_c0_userlocal(task_thread_info(next)->tp_value); \
+ __restore_watch(next); \
+ (last) = resume(prev, next, task_thread_info(next)); \
+} while (0)
+
+#endif /* _ASM_SWITCH_TO_H */