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linux/arch/blackfin/include/asm/context.S
Bernd Schmidt dbdf20db53 Blackfin arch: Faster C implementation of no-MPU CPLB handler 
This is a mixture ofcMichael McTernan's patch and the existing cplb-mpu code.

We ditch the old cplb-nompu implementation, which is a good example of
why a good algorithm in a HLL is preferrable to a bad algorithm written in
assembly.  Rather than try to construct a table of all posible CPLBs and
search it, we just create a (smaller) table of memory regions and
their attributes.  Some of the data structures are now unified for both
the mpu and nompu cases.  A lot of needless complexity in cplbinit.c is
removed.

Further optimizations:
  * compile cplbmgr.c with a lot of -ffixed-reg options, and omit saving
    these registers on the stack when entering a CPLB exception.
  * lose cli/nop/nop/sti sequences for some workarounds - these don't
  * make
    sense in an exception context

Additional code unification should be possible after this.

[Mike Frysinger <vapier.adi@gmail.com>:
 - convert CPP if statements to C if statements
 - remove redundant statements
 - use a do...while loop rather than a for loop to get slightly better
   optimization and to avoid gcc "may be used uninitialized" warnings ...
   we know that the [id]cplb_nr_bounds variables will never be 0, so this
   is OK
 - the no-mpu code was the last user of MAX_MEM_SIZE and with that rewritten,
   we can punt it
 - add some BUG_ON() checks to make sure we dont overflow the small
   cplb_bounds array
 - add i/d cplb entries for the bootrom because there is functions/data in
   there we want to access
 - we do not need a NULL trailing entry as any time we access the bounds
   arrays, we use the nr_bounds variable
]

Signed-off-by: Michael McTernan <mmcternan@airvana.com>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
2009-01-07 23:14:38 +08:00

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/*
* File: arch/blackfin/kernel/context.S
* Based on:
* Author:
*
* Created:
* Description:
*
* Modified:
* Copyright 2004-2007 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* NOTE! The single-stepping code assumes that all interrupt handlers
* start by saving SYSCFG on the stack with their first instruction.
*/
/*
* Code to save processor context.
* We even save the register which are preserved by a function call
* - r4, r5, r6, r7, p3, p4, p5
*/
.macro save_context_with_interrupts
[--sp] = SYSCFG;
[--sp] = P0; /*orig_p0*/
[--sp] = R0; /*orig_r0*/
[--sp] = ( R7:0, P5:0 );
[--sp] = fp;
[--sp] = usp;
[--sp] = i0;
[--sp] = i1;
[--sp] = i2;
[--sp] = i3;
[--sp] = m0;
[--sp] = m1;
[--sp] = m2;
[--sp] = m3;
[--sp] = l0;
[--sp] = l1;
[--sp] = l2;
[--sp] = l3;
[--sp] = b0;
[--sp] = b1;
[--sp] = b2;
[--sp] = b3;
[--sp] = a0.x;
[--sp] = a0.w;
[--sp] = a1.x;
[--sp] = a1.w;
[--sp] = LC0;
[--sp] = LC1;
[--sp] = LT0;
[--sp] = LT1;
[--sp] = LB0;
[--sp] = LB1;
[--sp] = ASTAT;
[--sp] = r0; /* Skip reserved */
[--sp] = RETS;
r0 = RETI;
[--sp] = r0;
[--sp] = RETX;
[--sp] = RETN;
[--sp] = RETE;
[--sp] = SEQSTAT;
[--sp] = r0; /* Skip IPEND as well. */
/* Switch to other method of keeping interrupts disabled. */
#ifdef CONFIG_DEBUG_HWERR
r0 = 0x3f;
sti r0;
#else
cli r0;
#endif
[--sp] = RETI; /*orig_pc*/
/* Clear all L registers. */
r0 = 0 (x);
l0 = r0;
l1 = r0;
l2 = r0;
l3 = r0;
.endm
.macro save_context_syscall
[--sp] = SYSCFG;
[--sp] = P0; /*orig_p0*/
[--sp] = R0; /*orig_r0*/
[--sp] = ( R7:0, P5:0 );
[--sp] = fp;
[--sp] = usp;
[--sp] = i0;
[--sp] = i1;
[--sp] = i2;
[--sp] = i3;
[--sp] = m0;
[--sp] = m1;
[--sp] = m2;
[--sp] = m3;
[--sp] = l0;
[--sp] = l1;
[--sp] = l2;
[--sp] = l3;
[--sp] = b0;
[--sp] = b1;
[--sp] = b2;
[--sp] = b3;
[--sp] = a0.x;
[--sp] = a0.w;
[--sp] = a1.x;
[--sp] = a1.w;
[--sp] = LC0;
[--sp] = LC1;
[--sp] = LT0;
[--sp] = LT1;
[--sp] = LB0;
[--sp] = LB1;
[--sp] = ASTAT;
[--sp] = r0; /* Skip reserved */
[--sp] = RETS;
r0 = RETI;
[--sp] = r0;
[--sp] = RETX;
[--sp] = RETN;
[--sp] = RETE;
[--sp] = SEQSTAT;
[--sp] = r0; /* Skip IPEND as well. */
[--sp] = RETI; /*orig_pc*/
/* Clear all L registers. */
r0 = 0 (x);
l0 = r0;
l1 = r0;
l2 = r0;
l3 = r0;
.endm
.macro save_context_no_interrupts
[--sp] = SYSCFG;
[--sp] = P0; /* orig_p0 */
[--sp] = R0; /* orig_r0 */
[--sp] = ( R7:0, P5:0 );
[--sp] = fp;
[--sp] = usp;
[--sp] = i0;
[--sp] = i1;
[--sp] = i2;
[--sp] = i3;
[--sp] = m0;
[--sp] = m1;
[--sp] = m2;
[--sp] = m3;
[--sp] = l0;
[--sp] = l1;
[--sp] = l2;
[--sp] = l3;
[--sp] = b0;
[--sp] = b1;
[--sp] = b2;
[--sp] = b3;
[--sp] = a0.x;
[--sp] = a0.w;
[--sp] = a1.x;
[--sp] = a1.w;
[--sp] = LC0;
[--sp] = LC1;
[--sp] = LT0;
[--sp] = LT1;
[--sp] = LB0;
[--sp] = LB1;
[--sp] = ASTAT;
#ifdef CONFIG_KGDB
fp = 0(Z);
r1 = sp;
r1 += 60;
r1 += 60;
r1 += 60;
[--sp] = r1;
#else
[--sp] = r0; /* Skip reserved */
#endif
[--sp] = RETS;
r0 = RETI;
[--sp] = r0;
[--sp] = RETX;
[--sp] = RETN;
[--sp] = RETE;
[--sp] = SEQSTAT;
#ifdef CONFIG_KGDB
r1.l = lo(IPEND);
r1.h = hi(IPEND);
[--sp] = r1;
#else
[--sp] = r0; /* Skip IPEND as well. */
#endif
[--sp] = r0; /*orig_pc*/
/* Clear all L registers. */
r0 = 0 (x);
l0 = r0;
l1 = r0;
l2 = r0;
l3 = r0;
.endm
.macro restore_context_no_interrupts
sp += 4; /* Skip orig_pc */
sp += 4; /* Skip IPEND */
SEQSTAT = [sp++];
RETE = [sp++];
RETN = [sp++];
RETX = [sp++];
r0 = [sp++];
RETI = r0; /* Restore RETI indirectly when in exception */
RETS = [sp++];
sp += 4; /* Skip Reserved */
ASTAT = [sp++];
LB1 = [sp++];
LB0 = [sp++];
LT1 = [sp++];
LT0 = [sp++];
LC1 = [sp++];
LC0 = [sp++];
a1.w = [sp++];
a1.x = [sp++];
a0.w = [sp++];
a0.x = [sp++];
b3 = [sp++];
b2 = [sp++];
b1 = [sp++];
b0 = [sp++];
l3 = [sp++];
l2 = [sp++];
l1 = [sp++];
l0 = [sp++];
m3 = [sp++];
m2 = [sp++];
m1 = [sp++];
m0 = [sp++];
i3 = [sp++];
i2 = [sp++];
i1 = [sp++];
i0 = [sp++];
sp += 4;
fp = [sp++];
( R7 : 0, P5 : 0) = [ SP ++ ];
sp += 8; /* Skip orig_r0/orig_p0 */
SYSCFG = [sp++];
.endm
.macro restore_context_with_interrupts
sp += 4; /* Skip orig_pc */
sp += 4; /* Skip IPEND */
SEQSTAT = [sp++];
RETE = [sp++];
RETN = [sp++];
RETX = [sp++];
RETI = [sp++];
RETS = [sp++];
#ifdef CONFIG_SMP
GET_PDA(p0, r0);
r0 = [p0 + PDA_IRQFLAGS];
#else
p0.h = _bfin_irq_flags;
p0.l = _bfin_irq_flags;
r0 = [p0];
#endif
sti r0;
sp += 4; /* Skip Reserved */
ASTAT = [sp++];
LB1 = [sp++];
LB0 = [sp++];
LT1 = [sp++];
LT0 = [sp++];
LC1 = [sp++];
LC0 = [sp++];
a1.w = [sp++];
a1.x = [sp++];
a0.w = [sp++];
a0.x = [sp++];
b3 = [sp++];
b2 = [sp++];
b1 = [sp++];
b0 = [sp++];
l3 = [sp++];
l2 = [sp++];
l1 = [sp++];
l0 = [sp++];
m3 = [sp++];
m2 = [sp++];
m1 = [sp++];
m0 = [sp++];
i3 = [sp++];
i2 = [sp++];
i1 = [sp++];
i0 = [sp++];
sp += 4;
fp = [sp++];
( R7 : 0, P5 : 0) = [ SP ++ ];
sp += 8; /* Skip orig_r0/orig_p0 */
csync;
SYSCFG = [sp++];
csync;
.endm
.macro save_context_cplb
[--sp] = (R7:0, P5:0);
[--sp] = fp;
[--sp] = a0.x;
[--sp] = a0.w;
[--sp] = a1.x;
[--sp] = a1.w;
[--sp] = LC0;
[--sp] = LC1;
[--sp] = LT0;
[--sp] = LT1;
[--sp] = LB0;
[--sp] = LB1;
[--sp] = RETS;
.endm
.macro restore_context_cplb
RETS = [sp++];
LB1 = [sp++];
LB0 = [sp++];
LT1 = [sp++];
LT0 = [sp++];
LC1 = [sp++];
LC0 = [sp++];
a1.w = [sp++];
a1.x = [sp++];
a0.w = [sp++];
a0.x = [sp++];
fp = [sp++];
(R7:0, P5:0) = [SP++];
.endm
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