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/*
* Creation Date: <2001/01/30 00:22:35 samuel>
* Time-stamp: <2001/06/24 14:48:02 samuel>
*
* <entry.S>
*
* Emulator/mac switching
*
* Copyright (C) 2001 Samuel Rydh (samuel@ibrium.se)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation
*
*/
#include "multiplexer.h"
/* Short note about DEC. Due to the kernel implementation of the DEC
* exception handler (and get_time_of_day) in the 2.3/2.4 kernel, we
* must try to maintain coherency between DEC and TB. In any case,
* we must NEVER let DEC tick faster than TB, or get_time_of_day will
* occasionally return bogus values (the result is usually
* misbehaving X).
*/
/************************************************************************/
/* Mac Entry */
/************************************************************************/
.macro ENTRY_TEST i n
.if \n-\i
lwz r4,ST_ENTRY_MAGIC+\i*4(r1)
cmpw r7,r4
lwz r5,ST_KVARS_PH+\i*4(r1)
beq+ 66f
ENTRY_TEST (\i+1),\n
.endif
.endm
.macro B_ISMOL label
ENTRY_TEST 0,MAX_NUM_SESSIONS
b 67f
66:
cmpwi cr1,r5,0
mr r1,r5
beq- cr1,67f
b \label
67:
.endm
////////////////////////////////////////////////////////////////////
// mac_entry_test
//
// mac_mode: r4,r5 = MOL_ENTRY_RX_MAGIC
// r6 = call_kernel return point (if initializing)
// r7 = session magic
mac_entry_test:
cmpwi cr0,r4,MOL_ENTRY_R4_MAGIC // MOL switch magic.
cmpwi cr1,r5,MOL_ENTRY_R5_MAGIC // Also gives us a couple of extra regs.
crand eq,eq,cr1*4+eq
SET_SESSION_TABLE r1
beq+ 1f
cmpwi cr0,r4,MOL_INITIALIZE_R4_MAGIC
cmpwi cr1,r5,MOL_INITIALIZE_R5_MAGIC
crand eq,eq,cr1*4+eq
bne+ 2f
B_ISMOL mac_entry_initialize // M: r4,r5
b 3f
1:
B_ISMOL mac_entry // M: r4,r5
b 3f
2:
mtcr r3 // Restore registers
mfsprg1 r1
mfsprg0 r3
b continue_trap_0x700
3: // XXX FIXME
b 2b
//////////////////////////////////////////////////////////
// mac_entry_initialize
//
// Run once in order to store certain things (segment
// registers and NIP)
//
// r6 emulator return point after 'call_kernel'
//
// Safe to modify: r0-r12, lr, ctr
mac_entry_initialize:
// Save emulator return point (skip over illegal inst)
mfsrr0 r5
addi r5,r5,4
stw r5,K_EMULATOR_NIP(r1) // This sets the return point once and for all
stw r2,K_EMULATOR_TOC(r1) // r2==TOC (not on linux though)
stw r6,K_EMULATOR_KCALL_NIP(r1) // Return point after 'call_kernel'
mfsrr1 r6
mfsprg1 r3
stw r6,K_EMULATOR_MSR(r1) // we want to return through mac_exit
stw r3,K_EMULATOR_STACK(r1)
lwz r3,xFLAG_BITS(r1) // Best to initialize the flag bits
mtcr r3
#if 0 // DEBUG DEBUG DEBUG
crset FBIT_CheckFlags
crset FBIT_RecalcDecInt
#endif
addi r3,r1,K_EMULATOR_SR // Save segment registers
SAVE_SEGMENT_REGS r3, /**/ r4,r5
SAVE_IBATS K_IBAT0U_SAVE, /**/ r3 // And save linux BAT registers
SAVE_DBATS K_DBAT0U_SAVE, /**/ r3
bl initialize_spr_table
bl initialize_msr_sr_table
bl _msr_altered // ALERT: modifies srr1. Reloads segment registers(!)
addi r3,r1,K_EMULATOR_SR
LOAD_SEGMENT_REGS r3, /**/ r4,r5
li r3,RVEC_EXIT
b exit_
//////////////////////////////////////////////////////////
// mac_entry
//
// sprg1 emulator stack
// srr1 emulator msr
// r13-r31 mac gprs
// fr14-fr31 mac fp registers
// fr0-fr12 mac fp registers (see xFPU_STATE)
//
// This function gives the 'mac' the control over the
// processor.
mac_entry:
TRACE(0x1111, "mac_entry")
// Save emulator registers (r1,msr) and restore flag bits
mfsprg1 r3
lwz r4,xFLAG_BITS(r1)
stw r3,K_EMULATOR_STACK(r1)
mfsrr1 r6
mtcr r4
stw r6,K_EMULATOR_MSR(r1) // The MSR_FP/MSR_VEC bits are of interest...
// Setup mac-environment
lwz r0,xNIP(r1) // Set NIP
lwz r2,x_MSR(r1) // The FPU bit should always be disabled here...
mtsrr0 r0 // srr0 is used by prepare_splitmode
rlwinm r2,r2,0,7,5 // We always clear MSR_VEC
stw r2,x_MSR(r1) // (enabling MSR_VEC is relatively cheap)
mtsrr1 r2
bl set_mac_context // M: r0,r2-r12,XER
bl set_mol_dec
RESTORE_MIDDLE_REGS // Loads r6-r12, ctr, xer
b exception_return // Loads r0-r5, lr, cr
// All returns to mac-mode goes through this function
exception_return:
lwz r3,K_RELOAD_SR(r1) // Do we need to reload segment registers & dbat0?
cmpwi r3,0
bnel- reload_sr // M: r3-r5
bt FBIT_CheckFlags,check_flags // M: r0,r2-r5
1: lwz r2,xLINK(r1)
lwz r0,xCR(r1)
mtlr r2
lwz r3,xGPR3(r1)
lwz r4,xGPR4(r1)
mfcr r2 // Save flag bits
lwz r5,xGPR5(r1)
stw r2,xFLAG_BITS(r1)
mtcr r0
lwz r2,xGPR2(r1)
lwz r0,xGPR0(r1)
lwz r1,xGPR1(r1)
rfi
// May modify r0,r2-r5. The call order is important.
check_flags:
// btl FBIT_Exception, throw_exception
// btl FBIT_MsrModified, msr_modified
btl FBIT_RecalcDecInt, recalc_int_stamp // M: r0,r2-r5
crclr FBIT_CheckFlags
b 1b
throw_exception:
blr
msr_modified:
blr
/************************************************************************/
/* Exit Mac-Mode Paths */
/************************************************************************/
// THESE ARE _ALL_ THE POSSIBLE EXIT PATHS. KEEP IT THAT WAY
// OR HAVE A *VERY GOOD* REASON TO INTRODUCE A NEW ONE.
/////////////////////////////////////////////////////////
// fixup_fpu
//
// Save fpscr and fpr13 and clear the MSR_FP bit.
// Restore the emulator fpscr value.
//
// modifies: r7,r8 (turns on MSR_FP if FP is set in x_MSR)
fixup_fpu:
lwz r7,xFPU_STATE(r1)
cmpwi r7,FPU_STATE_IN_USE // Are we the owner of the FPU?
bnelr
lwz r7,x_MSR(r1)
rlwinm r8,r7,0,19,17 // Clear MSR_FP bit
stw r8,x_MSR(r1)
mfmsr r7 // Temporary enable FPU in order to
ori r8,r7,MSR_FP // save fpscr and fpr13
mtmsr r8
isync
stfd fr13,xFPR13(r1)
mffs fr13
stfd fr13,xFPSCR-4(r1)
li r7,FPU_STATE_DIRTY
lfd fr13,xEMULATOR_FPSCR-4(r1) // We must restore FPSCR before since the emulator might
mtfsf 0xff,fr13 // use the FPU at any time, for instance in a signal handler.
stw r7,xFPU_STATE(r1) // Go to FPU_STATE_DIRTY
blr
////////////////////////////////////////////////////////
// PREPARE_ERET
//
// M: r0-r2, r9-r11 (r1 is modified)
.macro PREP_ERET nip_variable
btl FBIT_MolDecLoaded, set_kernel_dec // M: r0,r2,r9-r11
lwz r10,\nip_variable(r1)
mfcr r9
lwz r11,K_EMULATOR_MSR(r1)
mtsrr0 r10
lwz r2,K_EMULATOR_TOC(r1)
stw r9,xFLAG_BITS(r1)
lwz r1,K_EMULATOR_STACK(r1)
mtsrr1 r11
.endm
////////////////////////////////////////////////////////
// mac_exit (return to emulator)
// r3 RVEC return code
//
// On stack: nip, ctr, lr, xer, r0-r12
// In registers: r13-r31
mac_exit:
TRACE(0x2220, "mac_exit")
bl fixup_fpu // M: r7,r8
bl set_emulator_context // M: r0,r2,r7-r11,XER
exit_:
PREP_ERET K_EMULATOR_NIP // M: r0-r2,r9-r11
rfi
////////////////////////////////////////////////////////
// take_exception (take a linux exception)
//
// On stack: nip, ctr, lr, xer, r0-r12
// In registers: r13-r31
take_exception:
TRACE(0x2221, "take_exception")
mflr r12
bl fixup_fpu // M: r7,r8
bl set_emulator_context // M: r0,r2,r7-r11,XER
PREP_ERET K_EMULATOR_NIP // M: r0-r2,r9-r11
mtlr r12
li r3,RVEC_NOP
blr
//////////////////////////////////////////////////////////////
// call_kernel (call mol kernel routine)
// r3 kernel routine
// r4..r6 args
//
// On stack: nip, ctr, lr, xer, r0-r12
// In registers: r13-r31
call_kernel_save:
bl save_middle_regs // saves r6-r11, nip, ctr, xer
call_kernel:
bl fixup_fpu // M: r7,r8
bl set_emulator_context // M: r0,r2,r7-r11,XER
TRACE(0x2222, "call_kernel")
lwz r8,K_KERNEL_VARS(r1) // r8 = kvars (lvptr)
PREP_ERET K_EMULATOR_KCALL_NIP // M: r0-r2,r9-r11
li r0,__NR_multiplexer
mr r7,r3
li r3,fCallKernelFunc // r4,r5,r6 args, r7=function, r8=kvars
b continue_trap_0xc00 // fake a syscall
/************************************************************************/
/* Set Mac/Emulator Context */
/************************************************************************/
//////////////////////////////////////////////////////////////
// set_mac_context [r0,r2-r12, ctr, --->XER<---]
//
// - load segr 0-15 with mac context
// - clear BATs
//
// Currently unmodified r8-r12, ctr
set_mac_context:
li r4,0 // segment registers are soon up to date
lwz r3,K_PREPARE_SPLITMODE(r1)
stw r4,K_RELOAD_SR(r1)
cmpwi r3,0
beq+ 1f
mflr r2
bl prepare_splitmode // mod. r0,r3-r5
mtlr r2
1:
// Save and setup SPRG2 (magic) and SPRG3 (mol stack)
mfsprg2 r6
mfsprg3 r7
stw r6,K_EMULATOR_SPRG2(r1)
stw r7,K_EMULATOR_SPRG3(r1)
li r2,MOL_SPRG2_MAGIC
mtsprg3 r1
mtsprg2 r2
// Load segment registers
lwz r3,K_CUR_SR_BASE(r1)
LOAD_SEGMENT_REGS r3, /**/ r4,r5
li r4,0
mtspr IBAT0U,r4
mtspr IBAT1U,r4
mtspr IBAT2U,r4
mtspr IBAT3U,r4
lwz r3,K_DBAT0L(r1)
lwz r5,K_DBAT0U(r1)
mtspr DBAT0L,r3
mtspr DBAT0U,r5
mtspr DBAT1U,r4
mtspr DBAT2U,r4
mtspr DBAT3U,r4
blr
///////////////////////////////////////////////////////////////
// set_emulator_context [r0,r2,r7-r11,cr, --->XER<---]
//
// - load segr 0-15 with emulator context
// - restore BATs
// - restore DEC register
set_emulator_context:
lwz r0,K_EMULATOR_SPRG2(r1)
lwz r2,K_EMULATOR_SPRG3(r1)
mtsprg2 r0
mtsprg3 r2
// Restore segment registers
addi r8,r1,K_EMULATOR_SR
LOAD_SEGMENT_REGS r8, /**/ r2,r10
// BATS, r11 = linux DEC
lwz r7,K_IBAT0U_SAVE(r1)
mtspr IBAT0U,r7
lwz r2,K_IBAT1U_SAVE(r1)
mtspr IBAT1U,r2
lwz r7,K_IBAT2U_SAVE(r1)
mtspr IBAT2U,r7
lwz r2,K_IBAT3U_SAVE(r1)
mtspr IBAT3U,r2
lwz r7,K_DBAT0U_SAVE(r1)
mtspr DBAT0U,r7
lwz r7,K_DBAT0L_SAVE(r1) // must also restore lower bat...
mtspr DBAT0L,r7
lwz r2,K_DBAT1U_SAVE(r1)
mtspr DBAT1U,r2
lwz r7,K_DBAT2U_SAVE(r1)
mtspr DBAT2U,r7
lwz r2,K_DBAT3U_SAVE(r1)
mtspr DBAT3U,r2
blr
/************************************************************************/
/* Reload Segment Registers */
/************************************************************************/
//////////////////////////////////////////////////////////////
// reload_sr
//
// - loads segr 0-15 with mac context [modifies r3-r5]
// - reloads DBAT0 (used for splitmode)
//
// Modifies: r3-r5
reload_sr:
li r3,0 // segment registers are soon up to date
stw r3,K_RELOAD_SR(r1)
lwz r4,K_CUR_SR_BASE(r1)
LOAD_SEGMENT_REGS r4, /**/ r3,r5
lwz r3,K_DBAT0L(r1) // reload DBAT0
lwz r4,K_DBAT0U(r1)
mtspr DBAT0L,r3
mtspr DBAT0U,r4
blr
|
