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linux-next/include/asm-mips/stackframe.h
Maciej W. Rozycki 619b6e18fc [MIPS] R4000/R4400 daddiu erratum workaround 
This complements the generic R4000/R4400 errata workaround code and adds 
bits for the daddiu problem.  In most places it just modifies handwritten 
assembly code so that the assembler is allowed to use a temporary register 
as daddiu may now be treated as a macro that expands to a sequence of li 
and daddu.  It is the AT register or, where AT is unavailable or used 
explicitly for another purpose, an explicitly-named register is selected, 
using the .set at=<reg> feature added recently to gas.  This feature is 
only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the 
workaround remains disabled, the required version of binutils stays 
unchanged.

 Similarly, daddiu instructions put in branch delay slots in noreorder 
fragments are now taken out of them and the assembler is allowed to 
reorder them itself as possible (which it does making the whole idea of 
scheduling them into delay slots manually questionable).

 Also in the very few places where such a simple conversion was not 
possible, a handcoded longer sequence is implemented.

 Other than that there are changes to code responsible for building the 
TLB fault and page clear/copy handlers to avoid daddiu as appropriate.  
These are only effective if the erratum is verified to be present at the 
run time.

 Finally there is a trivial update to __delay(), because it uses daddiu in 
a branch delay slot.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:55 +00:00

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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, 99, 2001 Ralf Baechle
* Copyright (C) 1994, 1995, 1996 Paul M. Antoine.
* Copyright (C) 1999 Silicon Graphics, Inc.
* Copyright (C) 2007 Maciej W. Rozycki
*/
#ifndef _ASM_STACKFRAME_H
#define _ASM_STACKFRAME_H
#include <linux/threads.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/mipsregs.h>
#include <asm/asm-offsets.h>
/*
* For SMTC kernel, global IE should be left set, and interrupts
* controlled exclusively via IXMT.
*/
#ifdef CONFIG_MIPS_MT_SMTC
#define STATMASK 0x1e
#elif defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
#define STATMASK 0x3f
#else
#define STATMASK 0x1f
#endif
#ifdef CONFIG_MIPS_MT_SMTC
#include <asm/mipsmtregs.h>
#endif /* CONFIG_MIPS_MT_SMTC */
.macro SAVE_AT
.set push
.set noat
LONG_S $1, PT_R1(sp)
.set pop
.endm
.macro SAVE_TEMP
#ifdef CONFIG_CPU_HAS_SMARTMIPS
mflhxu v1
LONG_S v1, PT_LO(sp)
mflhxu v1
LONG_S v1, PT_HI(sp)
mflhxu v1
LONG_S v1, PT_ACX(sp)
#else
mfhi v1
LONG_S v1, PT_HI(sp)
mflo v1
LONG_S v1, PT_LO(sp)
#endif
#ifdef CONFIG_32BIT
LONG_S $8, PT_R8(sp)
LONG_S $9, PT_R9(sp)
#endif
LONG_S $10, PT_R10(sp)
LONG_S $11, PT_R11(sp)
LONG_S $12, PT_R12(sp)
LONG_S $13, PT_R13(sp)
LONG_S $14, PT_R14(sp)
LONG_S $15, PT_R15(sp)
LONG_S $24, PT_R24(sp)
.endm
.macro SAVE_STATIC
LONG_S $16, PT_R16(sp)
LONG_S $17, PT_R17(sp)
LONG_S $18, PT_R18(sp)
LONG_S $19, PT_R19(sp)
LONG_S $20, PT_R20(sp)
LONG_S $21, PT_R21(sp)
LONG_S $22, PT_R22(sp)
LONG_S $23, PT_R23(sp)
LONG_S $30, PT_R30(sp)
.endm
#ifdef CONFIG_SMP
#ifdef CONFIG_MIPS_MT_SMTC
#define PTEBASE_SHIFT 19 /* TCBIND */
#else
#define PTEBASE_SHIFT 23 /* CONTEXT */
#endif
.macro get_saved_sp /* SMP variation */
#ifdef CONFIG_MIPS_MT_SMTC
mfc0 k0, CP0_TCBIND
#else
MFC0 k0, CP0_CONTEXT
#endif
#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
lui k1, %hi(kernelsp)
#else
lui k1, %highest(kernelsp)
daddiu k1, %higher(kernelsp)
dsll k1, 16
daddiu k1, %hi(kernelsp)
dsll k1, 16
#endif
LONG_SRL k0, PTEBASE_SHIFT
LONG_ADDU k1, k0
LONG_L k1, %lo(kernelsp)(k1)
.endm
.macro set_saved_sp stackp temp temp2
#ifdef CONFIG_MIPS_MT_SMTC
mfc0 \temp, CP0_TCBIND
#else
MFC0 \temp, CP0_CONTEXT
#endif
LONG_SRL \temp, PTEBASE_SHIFT
LONG_S \stackp, kernelsp(\temp)
.endm
#else
.macro get_saved_sp /* Uniprocessor variation */
#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
lui k1, %hi(kernelsp)
#else
lui k1, %highest(kernelsp)
daddiu k1, %higher(kernelsp)
dsll k1, k1, 16
daddiu k1, %hi(kernelsp)
dsll k1, k1, 16
#endif
LONG_L k1, %lo(kernelsp)(k1)
.endm
.macro set_saved_sp stackp temp temp2
LONG_S \stackp, kernelsp
.endm
#endif
.macro SAVE_SOME
.set push
.set noat
.set reorder
mfc0 k0, CP0_STATUS
sll k0, 3 /* extract cu0 bit */
.set noreorder
bltz k0, 8f
move k1, sp
.set reorder
/* Called from user mode, new stack. */
get_saved_sp
#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
8: move k0, sp
PTR_SUBU sp, k1, PT_SIZE
#else
.set at=k0
8: PTR_SUBU k1, PT_SIZE
.set noat
move k0, sp
move sp, k1
#endif
LONG_S k0, PT_R29(sp)
LONG_S $3, PT_R3(sp)
/*
* You might think that you don't need to save $0,
* but the FPU emulator and gdb remote debug stub
* need it to operate correctly
*/
LONG_S $0, PT_R0(sp)
mfc0 v1, CP0_STATUS
LONG_S $2, PT_R2(sp)
LONG_S v1, PT_STATUS(sp)
#ifdef CONFIG_MIPS_MT_SMTC
/*
* Ideally, these instructions would be shuffled in
* to cover the pipeline delay.
*/
.set mips32
mfc0 v1, CP0_TCSTATUS
.set mips0
LONG_S v1, PT_TCSTATUS(sp)
#endif /* CONFIG_MIPS_MT_SMTC */
LONG_S $4, PT_R4(sp)
mfc0 v1, CP0_CAUSE
LONG_S $5, PT_R5(sp)
LONG_S v1, PT_CAUSE(sp)
LONG_S $6, PT_R6(sp)
MFC0 v1, CP0_EPC
LONG_S $7, PT_R7(sp)
#ifdef CONFIG_64BIT
LONG_S $8, PT_R8(sp)
LONG_S $9, PT_R9(sp)
#endif
LONG_S v1, PT_EPC(sp)
LONG_S $25, PT_R25(sp)
LONG_S $28, PT_R28(sp)
LONG_S $31, PT_R31(sp)
ori $28, sp, _THREAD_MASK
xori $28, _THREAD_MASK
.set pop
.endm
.macro SAVE_ALL
SAVE_SOME
SAVE_AT
SAVE_TEMP
SAVE_STATIC
.endm
.macro RESTORE_AT
.set push
.set noat
LONG_L $1, PT_R1(sp)
.set pop
.endm
.macro RESTORE_TEMP
#ifdef CONFIG_CPU_HAS_SMARTMIPS
LONG_L $24, PT_ACX(sp)
mtlhx $24
LONG_L $24, PT_HI(sp)
mtlhx $24
LONG_L $24, PT_LO(sp)
mtlhx $24
#else
LONG_L $24, PT_LO(sp)
mtlo $24
LONG_L $24, PT_HI(sp)
mthi $24
#endif
#ifdef CONFIG_32BIT
LONG_L $8, PT_R8(sp)
LONG_L $9, PT_R9(sp)
#endif
LONG_L $10, PT_R10(sp)
LONG_L $11, PT_R11(sp)
LONG_L $12, PT_R12(sp)
LONG_L $13, PT_R13(sp)
LONG_L $14, PT_R14(sp)
LONG_L $15, PT_R15(sp)
LONG_L $24, PT_R24(sp)
.endm
.macro RESTORE_STATIC
LONG_L $16, PT_R16(sp)
LONG_L $17, PT_R17(sp)
LONG_L $18, PT_R18(sp)
LONG_L $19, PT_R19(sp)
LONG_L $20, PT_R20(sp)
LONG_L $21, PT_R21(sp)
LONG_L $22, PT_R22(sp)
LONG_L $23, PT_R23(sp)
LONG_L $30, PT_R30(sp)
.endm
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
.macro RESTORE_SOME
.set push
.set reorder
.set noat
mfc0 a0, CP0_STATUS
li v1, 0xff00
ori a0, STATMASK
xori a0, STATMASK
mtc0 a0, CP0_STATUS
and a0, v1
LONG_L v0, PT_STATUS(sp)
nor v1, $0, v1
and v0, v1
or v0, a0
mtc0 v0, CP0_STATUS
LONG_L $31, PT_R31(sp)
LONG_L $28, PT_R28(sp)
LONG_L $25, PT_R25(sp)
LONG_L $7, PT_R7(sp)
LONG_L $6, PT_R6(sp)
LONG_L $5, PT_R5(sp)
LONG_L $4, PT_R4(sp)
LONG_L $3, PT_R3(sp)
LONG_L $2, PT_R2(sp)
.set pop
.endm
.macro RESTORE_SP_AND_RET
.set push
.set noreorder
LONG_L k0, PT_EPC(sp)
LONG_L sp, PT_R29(sp)
jr k0
rfe
.set pop
.endm
#else
.macro RESTORE_SOME
.set push
.set reorder
.set noat
#ifdef CONFIG_MIPS_MT_SMTC
.set mips32r2
/*
* This may not really be necessary if ints are already
* inhibited here.
*/
mfc0 v0, CP0_TCSTATUS
ori v0, TCSTATUS_IXMT
mtc0 v0, CP0_TCSTATUS
_ehb
DMT 5 # dmt a1
jal mips_ihb
#endif /* CONFIG_MIPS_MT_SMTC */
mfc0 a0, CP0_STATUS
ori a0, STATMASK
xori a0, STATMASK
mtc0 a0, CP0_STATUS
li v1, 0xff00
and a0, v1
LONG_L v0, PT_STATUS(sp)
nor v1, $0, v1
and v0, v1
or v0, a0
mtc0 v0, CP0_STATUS
#ifdef CONFIG_MIPS_MT_SMTC
/*
* Only after EXL/ERL have been restored to status can we
* restore TCStatus.IXMT.
*/
LONG_L v1, PT_TCSTATUS(sp)
_ehb
mfc0 v0, CP0_TCSTATUS
andi v1, TCSTATUS_IXMT
/* We know that TCStatua.IXMT should be set from above */
xori v0, v0, TCSTATUS_IXMT
or v0, v0, v1
mtc0 v0, CP0_TCSTATUS
_ehb
andi a1, a1, VPECONTROL_TE
beqz a1, 1f
emt
1:
.set mips0
#endif /* CONFIG_MIPS_MT_SMTC */
LONG_L v1, PT_EPC(sp)
MTC0 v1, CP0_EPC
LONG_L $31, PT_R31(sp)
LONG_L $28, PT_R28(sp)
LONG_L $25, PT_R25(sp)
#ifdef CONFIG_64BIT
LONG_L $8, PT_R8(sp)
LONG_L $9, PT_R9(sp)
#endif
LONG_L $7, PT_R7(sp)
LONG_L $6, PT_R6(sp)
LONG_L $5, PT_R5(sp)
LONG_L $4, PT_R4(sp)
LONG_L $3, PT_R3(sp)
LONG_L $2, PT_R2(sp)
.set pop
.endm
.macro RESTORE_SP_AND_RET
LONG_L sp, PT_R29(sp)
.set mips3
eret
.set mips0
.endm
#endif
.macro RESTORE_SP
LONG_L sp, PT_R29(sp)
.endm
.macro RESTORE_ALL
RESTORE_TEMP
RESTORE_STATIC
RESTORE_AT
RESTORE_SOME
RESTORE_SP
.endm
.macro RESTORE_ALL_AND_RET
RESTORE_TEMP
RESTORE_STATIC
RESTORE_AT
RESTORE_SOME
RESTORE_SP_AND_RET
.endm
/*
* Move to kernel mode and disable interrupts.
* Set cp0 enable bit as sign that we're running on the kernel stack
*/
.macro CLI
#if !defined(CONFIG_MIPS_MT_SMTC)
mfc0 t0, CP0_STATUS
li t1, ST0_CU0 | STATMASK
or t0, t1
xori t0, STATMASK
mtc0 t0, CP0_STATUS
#else /* CONFIG_MIPS_MT_SMTC */
/*
* For SMTC, we need to set privilege
* and disable interrupts only for the
* current TC, using the TCStatus register.
*/
mfc0 t0, CP0_TCSTATUS
/* Fortunately CU 0 is in the same place in both registers */
/* Set TCU0, TMX, TKSU (for later inversion) and IXMT */
li t1, ST0_CU0 | 0x08001c00
or t0, t1
/* Clear TKSU, leave IXMT */
xori t0, 0x00001800
mtc0 t0, CP0_TCSTATUS
_ehb
/* We need to leave the global IE bit set, but clear EXL...*/
mfc0 t0, CP0_STATUS
ori t0, ST0_EXL | ST0_ERL
xori t0, ST0_EXL | ST0_ERL
mtc0 t0, CP0_STATUS
#endif /* CONFIG_MIPS_MT_SMTC */
irq_disable_hazard
.endm
/*
* Move to kernel mode and enable interrupts.
* Set cp0 enable bit as sign that we're running on the kernel stack
*/
.macro STI
#if !defined(CONFIG_MIPS_MT_SMTC)
mfc0 t0, CP0_STATUS
li t1, ST0_CU0 | STATMASK
or t0, t1
xori t0, STATMASK & ~1
mtc0 t0, CP0_STATUS
#else /* CONFIG_MIPS_MT_SMTC */
/*
* For SMTC, we need to set privilege
* and enable interrupts only for the
* current TC, using the TCStatus register.
*/
_ehb
mfc0 t0, CP0_TCSTATUS
/* Fortunately CU 0 is in the same place in both registers */
/* Set TCU0, TKSU (for later inversion) and IXMT */
li t1, ST0_CU0 | 0x08001c00
or t0, t1
/* Clear TKSU *and* IXMT */
xori t0, 0x00001c00
mtc0 t0, CP0_TCSTATUS
_ehb
/* We need to leave the global IE bit set, but clear EXL...*/
mfc0 t0, CP0_STATUS
ori t0, ST0_EXL
xori t0, ST0_EXL
mtc0 t0, CP0_STATUS
/* irq_enable_hazard below should expand to EHB for 24K/34K cpus */
#endif /* CONFIG_MIPS_MT_SMTC */
irq_enable_hazard
.endm
/*
* Just move to kernel mode and leave interrupts as they are. Note
* for the R3000 this means copying the previous enable from IEp.
* Set cp0 enable bit as sign that we're running on the kernel stack
*/
.macro KMODE
#ifdef CONFIG_MIPS_MT_SMTC
/*
* This gets baroque in SMTC. We want to
* protect the non-atomic clearing of EXL
* with DMT/EMT, but we don't want to take
* an interrupt while DMT is still in effect.
*/
/* KMODE gets invoked from both reorder and noreorder code */
.set push
.set mips32r2
.set noreorder
mfc0 v0, CP0_TCSTATUS
andi v1, v0, TCSTATUS_IXMT
ori v0, TCSTATUS_IXMT
mtc0 v0, CP0_TCSTATUS
_ehb
DMT 2 # dmt v0
/*
* We don't know a priori if ra is "live"
*/
move t0, ra
jal mips_ihb
nop /* delay slot */
move ra, t0
#endif /* CONFIG_MIPS_MT_SMTC */
mfc0 t0, CP0_STATUS
li t1, ST0_CU0 | (STATMASK & ~1)
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
andi t2, t0, ST0_IEP
srl t2, 2
or t0, t2
#endif
or t0, t1
xori t0, STATMASK & ~1
mtc0 t0, CP0_STATUS
#ifdef CONFIG_MIPS_MT_SMTC
_ehb
andi v0, v0, VPECONTROL_TE
beqz v0, 2f
nop /* delay slot */
emt
2:
mfc0 v0, CP0_TCSTATUS
/* Clear IXMT, then OR in previous value */
ori v0, TCSTATUS_IXMT
xori v0, TCSTATUS_IXMT
or v0, v1, v0
mtc0 v0, CP0_TCSTATUS
/*
* irq_disable_hazard below should expand to EHB
* on 24K/34K CPUS
*/
.set pop
#endif /* CONFIG_MIPS_MT_SMTC */
irq_disable_hazard
.endm
#endif /* _ASM_STACKFRAME_H */
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