/* * 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 #include #include #include #include #include #include #include #include #include /* * 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) /* * 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. */ msa_save_all 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 #ifdef CONFIG_MIPS_MT_SMTC /* Read-modify-writes of Status must be atomic on a VPE */ mfc0 t2, CP0_TCSTATUS ori t1, t2, TCSTATUS_IXMT mtc0 t1, CP0_TCSTATUS andi t2, t2, TCSTATUS_IXMT _ehb DMT 8 # dmt t0 move t1,ra jal mips_ihb move ra,t1 #endif /* CONFIG_MIPS_MT_SMTC */ 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 #ifdef CONFIG_MIPS_MT_SMTC _ehb andi t0, t0, VPECONTROL_TE beqz t0, 1f emt 1: mfc0 t1, CP0_TCSTATUS xori t1, t1, TCSTATUS_IXMT or t1, t1, t2 mtc0 t1, CP0_TCSTATUS _ehb #endif /* CONFIG_MIPS_MT_SMTC */ move v0, a0 jr ra END(resume) /* * Save a thread's fp context. */ LEAF(_save_fp) #if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) 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) 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) #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. * * We initialize fcr31 to rounding to nearest, no exceptions. */ #define FPU_DEFAULT 0x00000000 LEAF(_init_fpu) #ifdef CONFIG_MIPS_MT_SMTC /* Rather than manipulate per-VPE Status, set per-TC bit in TCStatus */ mfc0 t0, CP0_TCSTATUS /* Bit position is the same for Status, TCStatus */ li t1, ST0_CU1 or t0, t1 mtc0 t0, CP0_TCSTATUS #else /* Normal MIPS CU1 enable */ mfc0 t0, CP0_STATUS li t1, ST0_CU1 or t0, t1 mtc0 t0, CP0_STATUS #endif /* CONFIG_MIPS_MT_SMTC */ enable_fpu_hazard li t1, FPU_DEFAULT ctc1 t1, 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 #ifdef CONFIG_CPU_MIPS32_R2 .set push .set mips64r2 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 */ #else .set mips3 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)