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linux/arch/mips/kernel/genex.S
Kevin D. Kissell 0db34215c7 [MIPS] SMTC: Interrupt mask backstop hack 
To support multiple TC microthreads acting as "CPUs" within a VPE,
VPE-wide interrupt mask bits must be specially manipulated during
interrupt handling. To support legacy drivers and interrupt controller
management code, SMTC has a "backstop" to track and if necessary restore
the interrupt mask. This has some performance impact on interrupt service
overhead. Disable it only if you know what you are doing.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-07-12 17:41:17 +01:00

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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 - 2000, 2001, 2003 Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2001 MIPS Technologies, Inc.
* Copyright (C) 2002 Maciej W. Rozycki
*/
#include <linux/init.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/cacheops.h>
#include <asm/irqflags.h>
#include <asm/regdef.h>
#include <asm/fpregdef.h>
#include <asm/mipsregs.h>
#include <asm/stackframe.h>
#include <asm/war.h>
#include <asm/page.h>
#define PANIC_PIC(msg) \
.set push; \
.set reorder; \
PTR_LA a0,8f; \
.set noat; \
PTR_LA AT, panic; \
jr AT; \
9: b 9b; \
.set pop; \
TEXT(msg)
__INIT
NESTED(except_vec0_generic, 0, sp)
PANIC_PIC("Exception vector 0 called")
END(except_vec0_generic)
NESTED(except_vec1_generic, 0, sp)
PANIC_PIC("Exception vector 1 called")
END(except_vec1_generic)
/*
* General exception vector for all other CPUs.
*
* Be careful when changing this, it has to be at most 128 bytes
* to fit into space reserved for the exception handler.
*/
NESTED(except_vec3_generic, 0, sp)
.set push
.set noat
#if R5432_CP0_INTERRUPT_WAR
mfc0 k0, CP0_INDEX
#endif
mfc0 k1, CP0_CAUSE
andi k1, k1, 0x7c
#ifdef CONFIG_64BIT
dsll k1, k1, 1
#endif
PTR_L k0, exception_handlers(k1)
jr k0
.set pop
END(except_vec3_generic)
/*
* General exception handler for CPUs with virtual coherency exception.
*
* Be careful when changing this, it has to be at most 256 (as a special
* exception) bytes to fit into space reserved for the exception handler.
*/
NESTED(except_vec3_r4000, 0, sp)
.set push
.set mips3
.set noat
mfc0 k1, CP0_CAUSE
li k0, 31<<2
andi k1, k1, 0x7c
.set push
.set noreorder
.set nomacro
beq k1, k0, handle_vced
li k0, 14<<2
beq k1, k0, handle_vcei
#ifdef CONFIG_64BIT
dsll k1, k1, 1
#endif
.set pop
PTR_L k0, exception_handlers(k1)
jr k0
/*
* Big shit, we now may have two dirty primary cache lines for the same
* physical address. We can safely invalidate the line pointed to by
* c0_badvaddr because after return from this exception handler the
* load / store will be re-executed.
*/
handle_vced:
MFC0 k0, CP0_BADVADDR
li k1, -4 # Is this ...
and k0, k1 # ... really needed?
mtc0 zero, CP0_TAGLO
cache Index_Store_Tag_D, (k0)
cache Hit_Writeback_Inv_SD, (k0)
#ifdef CONFIG_PROC_FS
PTR_LA k0, vced_count
lw k1, (k0)
addiu k1, 1
sw k1, (k0)
#endif
eret
handle_vcei:
MFC0 k0, CP0_BADVADDR
cache Hit_Writeback_Inv_SD, (k0) # also cleans pi
#ifdef CONFIG_PROC_FS
PTR_LA k0, vcei_count
lw k1, (k0)
addiu k1, 1
sw k1, (k0)
#endif
eret
.set pop
END(except_vec3_r4000)
__FINIT
.align 5
NESTED(handle_int, PT_SIZE, sp)
#ifdef CONFIG_TRACE_IRQFLAGS
/*
* Check to see if the interrupted code has just disabled
* interrupts and ignore this interrupt for now if so.
*
* local_irq_disable() disables interrupts and then calls
* trace_hardirqs_off() to track the state. If an interrupt is taken
* after interrupts are disabled but before the state is updated
* it will appear to restore_all that it is incorrectly returning with
* interrupts disabled
*/
.set push
.set noat
mfc0 k0, CP0_STATUS
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
and k0, ST0_IEP
bnez k0, 1f
mfc0 k0, EP0_EPC
.set noreorder
j k0
rfe
#else
and k0, ST0_IE
bnez k0, 1f
eret
#endif
1:
.set pop
#endif
SAVE_ALL
CLI
TRACE_IRQS_OFF
LONG_L s0, TI_REGS($28)
LONG_S sp, TI_REGS($28)
PTR_LA ra, ret_from_irq
j plat_irq_dispatch
END(handle_int)
__INIT
/*
* Special interrupt vector for MIPS64 ISA & embedded MIPS processors.
* This is a dedicated interrupt exception vector which reduces the
* interrupt processing overhead. The jump instruction will be replaced
* at the initialization time.
*
* Be careful when changing this, it has to be at most 128 bytes
* to fit into space reserved for the exception handler.
*/
NESTED(except_vec4, 0, sp)
1: j 1b /* Dummy, will be replaced */
END(except_vec4)
/*
* EJTAG debug exception handler.
* The EJTAG debug exception entry point is 0xbfc00480, which
* normally is in the boot PROM, so the boot PROM must do a
* unconditional jump to this vector.
*/
NESTED(except_vec_ejtag_debug, 0, sp)
j ejtag_debug_handler
END(except_vec_ejtag_debug)
__FINIT
/*
* Vectored interrupt handler.
* This prototype is copied to ebase + n*IntCtl.VS and patched
* to invoke the handler
*/
NESTED(except_vec_vi, 0, sp)
SAVE_SOME
SAVE_AT
.set push
.set noreorder
#ifdef CONFIG_MIPS_MT_SMTC
/*
* To keep from blindly blocking *all* interrupts
* during service by SMTC kernel, we also want to
* pass the IM value to be cleared.
*/
FEXPORT(except_vec_vi_mori)
ori a0, $0, 0
#endif /* CONFIG_MIPS_MT_SMTC */
FEXPORT(except_vec_vi_lui)
lui v0, 0 /* Patched */
j except_vec_vi_handler
FEXPORT(except_vec_vi_ori)
ori v0, 0 /* Patched */
.set pop
END(except_vec_vi)
EXPORT(except_vec_vi_end)
/*
* Common Vectored Interrupt code
* Complete the register saves and invoke the handler which is passed in $v0
*/
NESTED(except_vec_vi_handler, 0, sp)
SAVE_TEMP
SAVE_STATIC
#ifdef CONFIG_MIPS_MT_SMTC
/*
* SMTC has an interesting problem that interrupts are level-triggered,
* and the CLI macro will clear EXL, potentially causing a duplicate
* interrupt service invocation. So we need to clear the associated
* IM bit of Status prior to doing CLI, and restore it after the
* service routine has been invoked - we must assume that the
* service routine will have cleared the state, and any active
* level represents a new or otherwised unserviced event...
*/
mfc0 t1, CP0_STATUS
and t0, a0, t1
#ifdef CONFIG_MIPS_MT_SMTC_IM_BACKSTOP
mfc0 t2, CP0_TCCONTEXT
or t0, t0, t2
mtc0 t0, CP0_TCCONTEXT
#endif /* CONFIG_MIPS_MT_SMTC_IM_BACKSTOP */
xor t1, t1, t0
mtc0 t1, CP0_STATUS
_ehb
#endif /* CONFIG_MIPS_MT_SMTC */
CLI
#ifdef CONFIG_TRACE_IRQFLAGS
move s0, v0
#ifdef CONFIG_MIPS_MT_SMTC
move s1, a0
#endif
TRACE_IRQS_OFF
#ifdef CONFIG_MIPS_MT_SMTC
move a0, s1
#endif
move v0, s0
#endif
LONG_L s0, TI_REGS($28)
LONG_S sp, TI_REGS($28)
PTR_LA ra, ret_from_irq
jr v0
END(except_vec_vi_handler)
/*
* EJTAG debug exception handler.
*/
NESTED(ejtag_debug_handler, PT_SIZE, sp)
.set push
.set noat
MTC0 k0, CP0_DESAVE
mfc0 k0, CP0_DEBUG
sll k0, k0, 30 # Check for SDBBP.
bgez k0, ejtag_return
PTR_LA k0, ejtag_debug_buffer
LONG_S k1, 0(k0)
SAVE_ALL
move a0, sp
jal ejtag_exception_handler
RESTORE_ALL
PTR_LA k0, ejtag_debug_buffer
LONG_L k1, 0(k0)
ejtag_return:
MFC0 k0, CP0_DESAVE
.set mips32
deret
.set pop
END(ejtag_debug_handler)
/*
* This buffer is reserved for the use of the EJTAG debug
* handler.
*/
.data
EXPORT(ejtag_debug_buffer)
.fill LONGSIZE
.previous
__INIT
/*
* NMI debug exception handler for MIPS reference boards.
* The NMI debug exception entry point is 0xbfc00000, which
* normally is in the boot PROM, so the boot PROM must do a
* unconditional jump to this vector.
*/
NESTED(except_vec_nmi, 0, sp)
j nmi_handler
END(except_vec_nmi)
__FINIT
NESTED(nmi_handler, PT_SIZE, sp)
.set push
.set noat
SAVE_ALL
move a0, sp
jal nmi_exception_handler
RESTORE_ALL
.set mips3
eret
.set pop
END(nmi_handler)
.macro __build_clear_none
.endm
.macro __build_clear_sti
TRACE_IRQS_ON
STI
.endm
.macro __build_clear_cli
CLI
TRACE_IRQS_OFF
.endm
.macro __build_clear_fpe
cfc1 a1, fcr31
li a2, ~(0x3f << 12)
and a2, a1
ctc1 a2, fcr31
TRACE_IRQS_ON
STI
.endm
.macro __build_clear_ade
MFC0 t0, CP0_BADVADDR
PTR_S t0, PT_BVADDR(sp)
KMODE
.endm
.macro __BUILD_silent exception
.endm
/* Gas tries to parse the PRINT argument as a string containing
string escapes and emits bogus warnings if it believes to
recognize an unknown escape code. So make the arguments
start with an n and gas will believe \n is ok ... */
.macro __BUILD_verbose nexception
LONG_L a1, PT_EPC(sp)
#ifdef CONFIG_32BIT
PRINT("Got \nexception at %08lx\012")
#endif
#ifdef CONFIG_64BIT
PRINT("Got \nexception at %016lx\012")
#endif
.endm
.macro __BUILD_count exception
LONG_L t0,exception_count_\exception
LONG_ADDIU t0, 1
LONG_S t0,exception_count_\exception
.comm exception_count\exception, 8, 8
.endm
.macro __BUILD_HANDLER exception handler clear verbose ext
.align 5
NESTED(handle_\exception, PT_SIZE, sp)
.set noat
SAVE_ALL
FEXPORT(handle_\exception\ext)
__BUILD_clear_\clear
.set at
__BUILD_\verbose \exception
move a0, sp
PTR_LA ra, ret_from_exception
j do_\handler
END(handle_\exception)
.endm
.macro BUILD_HANDLER exception handler clear verbose
__BUILD_HANDLER \exception \handler \clear \verbose _int
.endm
BUILD_HANDLER adel ade ade silent /* #4 */
BUILD_HANDLER ades ade ade silent /* #5 */
BUILD_HANDLER ibe be cli silent /* #6 */
BUILD_HANDLER dbe be cli silent /* #7 */
BUILD_HANDLER bp bp sti silent /* #9 */
BUILD_HANDLER ri ri sti silent /* #10 */
BUILD_HANDLER cpu cpu sti silent /* #11 */
BUILD_HANDLER ov ov sti silent /* #12 */
BUILD_HANDLER tr tr sti silent /* #13 */
BUILD_HANDLER fpe fpe fpe silent /* #15 */
BUILD_HANDLER mdmx mdmx sti silent /* #22 */
BUILD_HANDLER watch watch sti verbose /* #23 */
BUILD_HANDLER mcheck mcheck cli verbose /* #24 */
BUILD_HANDLER mt mt sti silent /* #25 */
BUILD_HANDLER dsp dsp sti silent /* #26 */
BUILD_HANDLER reserved reserved sti verbose /* others */
.align 5
LEAF(handle_ri_rdhwr_vivt)
#ifdef CONFIG_MIPS_MT_SMTC
PANIC_PIC("handle_ri_rdhwr_vivt called")
#else
.set push
.set noat
.set noreorder
/* check if TLB contains a entry for EPC */
MFC0 k1, CP0_ENTRYHI
andi k1, 0xff /* ASID_MASK */
MFC0 k0, CP0_EPC
PTR_SRL k0, PAGE_SHIFT + 1
PTR_SLL k0, PAGE_SHIFT + 1
or k1, k0
MTC0 k1, CP0_ENTRYHI
mtc0_tlbw_hazard
tlbp
tlb_probe_hazard
mfc0 k1, CP0_INDEX
.set pop
bltz k1, handle_ri /* slow path */
/* fall thru */
#endif
END(handle_ri_rdhwr_vivt)
LEAF(handle_ri_rdhwr)
.set push
.set noat
.set noreorder
/* 0x7c03e83b: rdhwr v1,$29 */
MFC0 k1, CP0_EPC
lui k0, 0x7c03
lw k1, (k1)
ori k0, 0xe83b
.set reorder
bne k0, k1, handle_ri /* if not ours */
/* The insn is rdhwr. No need to check CAUSE.BD here. */
get_saved_sp /* k1 := current_thread_info */
.set noreorder
MFC0 k0, CP0_EPC
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
ori k1, _THREAD_MASK
xori k1, _THREAD_MASK
LONG_L v1, TI_TP_VALUE(k1)
LONG_ADDIU k0, 4
jr k0
rfe
#else
LONG_ADDIU k0, 4 /* stall on $k0 */
MTC0 k0, CP0_EPC
/* I hope three instructions between MTC0 and ERET are enough... */
ori k1, _THREAD_MASK
xori k1, _THREAD_MASK
LONG_L v1, TI_TP_VALUE(k1)
.set mips3
eret
.set mips0
#endif
.set pop
END(handle_ri_rdhwr)
#ifdef CONFIG_64BIT
/* A temporary overflow handler used by check_daddi(). */
__INIT
BUILD_HANDLER daddi_ov daddi_ov none silent /* #12 */
#endif
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