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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/mips/kernel/r4k_switch.S
Initial import
Diffstat (limited to 'arch/mips/kernel/r4k_switch.S')
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diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S
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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, 1995, 1996, 1998, 1999, 2002, 2003 Ralf Baechle
+ * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
+ * Copyright (C) 1994, 1995, 1996, by Andreas Busse
+ * Copyright (C) 1999 Silicon Graphics, Inc.
+ * Copyright (C) 2000 MIPS Technologies, Inc.
+ * written by Carsten Langgaard, carstenl@mips.com
+ */
+#include <asm/asm.h>
+#include <asm/cachectl.h>
+#include <asm/fpregdef.h>
+#include <asm/mipsregs.h>
+#include <asm/asm-offsets.h>
+#include <asm/pgtable-bits.h>
+#include <asm/regdef.h>
+#include <asm/stackframe.h>
+#include <asm/thread_info.h>
+
+#include <asm/asmmacro.h>
+
+/* preprocessor replaces the fp in ".set fp=64" with $30 otherwise */
+#undef fp
+
+/*
+ * Offset to the current process status flags, the first 32 bytes of the
+ * stack are not used.
+ */
+#define ST_OFF (_THREAD_SIZE - 32 - PT_SIZE + PT_STATUS)
+
+#ifndef USE_ALTERNATE_RESUME_IMPL
+/*
+ * task_struct *resume(task_struct *prev, task_struct *next,
+ * struct thread_info *next_ti, s32 fp_save)
+ */
+ .align 5
+ LEAF(resume)
+ mfc0 t1, CP0_STATUS
+ LONG_S t1, THREAD_STATUS(a0)
+ cpu_save_nonscratch a0
+ LONG_S ra, THREAD_REG31(a0)
+
+ /*
+ * Check whether we need to save any FP context. FP context is saved
+ * iff the process has used the context with the scalar FPU or the MSA
+ * ASE in the current time slice, as indicated by _TIF_USEDFPU and
+ * _TIF_USEDMSA respectively. switch_to will have set fp_save
+ * accordingly to an FP_SAVE_ enum value.
+ */
+ beqz a3, 2f
+
+ /*
+ * We do. Clear the saved CU1 bit for prev, such that next time it is
+ * scheduled it will start in userland with the FPU disabled. If the
+ * task uses the FPU then it will be enabled again via the do_cpu trap.
+ * This allows us to lazily restore the FP context.
+ */
+ PTR_L t3, TASK_THREAD_INFO(a0)
+ LONG_L t0, ST_OFF(t3)
+ li t1, ~ST0_CU1
+ and t0, t0, t1
+ LONG_S t0, ST_OFF(t3)
+
+ /* Check whether we're saving scalar or vector context. */
+ bgtz a3, 1f
+
+ /* Save 128b MSA vector context + scalar FP control & status. */
+ .set push
+ SET_HARDFLOAT
+ cfc1 t1, fcr31
+ msa_save_all a0
+ .set pop /* SET_HARDFLOAT */
+
+ sw t1, THREAD_FCR31(a0)
+ b 2f
+
+1: /* Save 32b/64b scalar FP context. */
+ fpu_save_double a0 t0 t1 # c0_status passed in t0
+ # clobbers t1
+2:
+
+#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
+ PTR_LA t8, __stack_chk_guard
+ LONG_L t9, TASK_STACK_CANARY(a1)
+ LONG_S t9, 0(t8)
+#endif
+
+ /*
+ * The order of restoring the registers takes care of the race
+ * updating $28, $29 and kernelsp without disabling ints.
+ */
+ move $28, a2
+ cpu_restore_nonscratch a1
+
+ PTR_ADDU t0, $28, _THREAD_SIZE - 32
+ set_saved_sp t0, t1, t2
+ mfc0 t1, CP0_STATUS /* Do we really need this? */
+ li a3, 0xff01
+ and t1, a3
+ LONG_L a2, THREAD_STATUS(a1)
+ nor a3, $0, a3
+ and a2, a3
+ or a2, t1
+ mtc0 a2, CP0_STATUS
+ move v0, a0
+ jr ra
+ END(resume)
+
+#endif /* USE_ALTERNATE_RESUME_IMPL */
+
+/*
+ * Save a thread's fp context.
+ */
+LEAF(_save_fp)
+#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) || \
+ defined(CONFIG_CPU_MIPS32_R6)
+ mfc0 t0, CP0_STATUS
+#endif
+ fpu_save_double a0 t0 t1 # clobbers t1
+ jr ra
+ END(_save_fp)
+
+/*
+ * Restore a thread's fp context.
+ */
+LEAF(_restore_fp)
+#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) || \
+ defined(CONFIG_CPU_MIPS32_R6)
+ mfc0 t0, CP0_STATUS
+#endif
+ fpu_restore_double a0 t0 t1 # clobbers t1
+ jr ra
+ END(_restore_fp)
+
+#ifdef CONFIG_CPU_HAS_MSA
+
+/*
+ * Save a thread's MSA vector context.
+ */
+LEAF(_save_msa)
+ msa_save_all a0
+ jr ra
+ END(_save_msa)
+
+/*
+ * Restore a thread's MSA vector context.
+ */
+LEAF(_restore_msa)
+ msa_restore_all a0
+ jr ra
+ END(_restore_msa)
+
+LEAF(_init_msa_upper)
+ msa_init_all_upper
+ jr ra
+ END(_init_msa_upper)
+
+#endif
+
+/*
+ * Load the FPU with signalling NANS. This bit pattern we're using has
+ * the property that no matter whether considered as single or as double
+ * precision represents signaling NANS.
+ *
+ * The value to initialize fcr31 to comes in $a0.
+ */
+
+ .set push
+ SET_HARDFLOAT
+
+LEAF(_init_fpu)
+ mfc0 t0, CP0_STATUS
+ li t1, ST0_CU1
+ or t0, t1
+ mtc0 t0, CP0_STATUS
+ enable_fpu_hazard
+
+ ctc1 a0, fcr31
+
+ li t1, -1 # SNaN
+
+#ifdef CONFIG_64BIT
+ sll t0, t0, 5
+ bgez t0, 1f # 16 / 32 register mode?
+
+ dmtc1 t1, $f1
+ dmtc1 t1, $f3
+ dmtc1 t1, $f5
+ dmtc1 t1, $f7
+ dmtc1 t1, $f9
+ dmtc1 t1, $f11
+ dmtc1 t1, $f13
+ dmtc1 t1, $f15
+ dmtc1 t1, $f17
+ dmtc1 t1, $f19
+ dmtc1 t1, $f21
+ dmtc1 t1, $f23
+ dmtc1 t1, $f25
+ dmtc1 t1, $f27
+ dmtc1 t1, $f29
+ dmtc1 t1, $f31
+1:
+#endif
+
+#ifdef CONFIG_CPU_MIPS32
+ mtc1 t1, $f0
+ mtc1 t1, $f1
+ mtc1 t1, $f2
+ mtc1 t1, $f3
+ mtc1 t1, $f4
+ mtc1 t1, $f5
+ mtc1 t1, $f6
+ mtc1 t1, $f7
+ mtc1 t1, $f8
+ mtc1 t1, $f9
+ mtc1 t1, $f10
+ mtc1 t1, $f11
+ mtc1 t1, $f12
+ mtc1 t1, $f13
+ mtc1 t1, $f14
+ mtc1 t1, $f15
+ mtc1 t1, $f16
+ mtc1 t1, $f17
+ mtc1 t1, $f18
+ mtc1 t1, $f19
+ mtc1 t1, $f20
+ mtc1 t1, $f21
+ mtc1 t1, $f22
+ mtc1 t1, $f23
+ mtc1 t1, $f24
+ mtc1 t1, $f25
+ mtc1 t1, $f26
+ mtc1 t1, $f27
+ mtc1 t1, $f28
+ mtc1 t1, $f29
+ mtc1 t1, $f30
+ mtc1 t1, $f31
+
+#if defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_CPU_MIPS32_R6)
+ .set push
+ .set MIPS_ISA_LEVEL_RAW
+ .set fp=64
+ sll t0, t0, 5 # is Status.FR set?
+ bgez t0, 1f # no: skip setting upper 32b
+
+ mthc1 t1, $f0
+ mthc1 t1, $f1
+ mthc1 t1, $f2
+ mthc1 t1, $f3
+ mthc1 t1, $f4
+ mthc1 t1, $f5
+ mthc1 t1, $f6
+ mthc1 t1, $f7
+ mthc1 t1, $f8
+ mthc1 t1, $f9
+ mthc1 t1, $f10
+ mthc1 t1, $f11
+ mthc1 t1, $f12
+ mthc1 t1, $f13
+ mthc1 t1, $f14
+ mthc1 t1, $f15
+ mthc1 t1, $f16
+ mthc1 t1, $f17
+ mthc1 t1, $f18
+ mthc1 t1, $f19
+ mthc1 t1, $f20
+ mthc1 t1, $f21
+ mthc1 t1, $f22
+ mthc1 t1, $f23
+ mthc1 t1, $f24
+ mthc1 t1, $f25
+ mthc1 t1, $f26
+ mthc1 t1, $f27
+ mthc1 t1, $f28
+ mthc1 t1, $f29
+ mthc1 t1, $f30
+ mthc1 t1, $f31
+1: .set pop
+#endif /* CONFIG_CPU_MIPS32_R2 || CONFIG_CPU_MIPS32_R6 */
+#else
+ .set MIPS_ISA_ARCH_LEVEL_RAW
+ dmtc1 t1, $f0
+ dmtc1 t1, $f2
+ dmtc1 t1, $f4
+ dmtc1 t1, $f6
+ dmtc1 t1, $f8
+ dmtc1 t1, $f10
+ dmtc1 t1, $f12
+ dmtc1 t1, $f14
+ dmtc1 t1, $f16
+ dmtc1 t1, $f18
+ dmtc1 t1, $f20
+ dmtc1 t1, $f22
+ dmtc1 t1, $f24
+ dmtc1 t1, $f26
+ dmtc1 t1, $f28
+ dmtc1 t1, $f30
+#endif
+ jr ra
+ END(_init_fpu)
+
+ .set pop /* SET_HARDFLOAT */