openrisc: Remove unused IMMU tlb workardound

This looks to be some historical code that was used to convert TLB
misses on branches from l.bf, l.jal, l.j etc all to a trampoline
using l.jr (jump register).  I don't see this being used and I don't
know the history of it so remove it.

Signed-off-by: Stafford Horne <shorne@gmail.com>

diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S
index 21db50563f9708be6c6d9d776545b7f0f2efacc7..9b59d0ca665ce610df283541ff54dc39cd670281 100644 (file)
--- a/arch/openrisc/kernel/head.S
+++ b/arch/openrisc/kernel/head.S
@@ -1325,215 +1325,6 @@ i_pte_not_present:
 
 /* =================================================[ debugging aids ]=== */
 
-       .align 64
-_immu_trampoline:
-       .space 64
-_immu_trampoline_top:
-
-#define TRAMP_SLOT_0           (0x0)
-#define TRAMP_SLOT_1           (0x4)
-#define TRAMP_SLOT_2           (0x8)
-#define TRAMP_SLOT_3           (0xc)
-#define TRAMP_SLOT_4           (0x10)
-#define TRAMP_SLOT_5           (0x14)
-#define TRAMP_FRAME_SIZE       (0x18)
-
-ENTRY(_immu_trampoline_workaround)
-       // r2 EEA
-       // r6 is physical EEA
-       tophys(r6,r2)
-
-       LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
-       tophys  (r3,r5)                 // r3 is trampoline (physical)
-
-       LOAD_SYMBOL_2_GPR(r4,0x15000000)
-       l.sw    TRAMP_SLOT_0(r3),r4
-       l.sw    TRAMP_SLOT_1(r3),r4
-       l.sw    TRAMP_SLOT_4(r3),r4
-       l.sw    TRAMP_SLOT_5(r3),r4
-
-                                       // EPC = EEA - 0x4
-       l.lwz   r4,0x0(r6)              // load op @ EEA + 0x0 (fc address)
-       l.sw    TRAMP_SLOT_3(r3),r4     // store it to _immu_trampoline_data
-       l.lwz   r4,-0x4(r6)             // load op @ EEA - 0x4 (f8 address)
-       l.sw    TRAMP_SLOT_2(r3),r4     // store it to _immu_trampoline_data
-
-       l.srli  r5,r4,26                // check opcode for write access
-       l.sfeqi r5,0                    // l.j
-       l.bf    0f
-       l.sfeqi r5,0x11                 // l.jr
-       l.bf    1f
-       l.sfeqi r5,1                    // l.jal
-       l.bf    2f
-       l.sfeqi r5,0x12                 // l.jalr
-       l.bf    3f
-       l.sfeqi r5,3                    // l.bnf
-       l.bf    4f
-       l.sfeqi r5,4                    // l.bf
-       l.bf    5f
-99:
-       l.nop
-       l.j     99b                     // should never happen
-       l.nop   1
-
-       // r2 is EEA
-       // r3 is trampoline address (physical)
-       // r4 is instruction
-       // r6 is physical(EEA)
-       //
-       // r5
-
-2:     // l.jal
-
-       /* 19 20 aa aa  l.movhi r9,0xaaaa
-        * a9 29 bb bb  l.ori   r9,0xbbbb
-        *
-        * where 0xaaaabbbb is EEA + 0x4 shifted right 2
-        */
-
-       l.addi  r6,r2,0x4               // this is 0xaaaabbbb
-
-                                       // l.movhi r9,0xaaaa
-       l.ori   r5,r0,0x1920            // 0x1920 == l.movhi r9
-       l.sh    (TRAMP_SLOT_0+0x0)(r3),r5
-       l.srli  r5,r6,16
-       l.sh    (TRAMP_SLOT_0+0x2)(r3),r5
-
-                                       // l.ori   r9,0xbbbb
-       l.ori   r5,r0,0xa929            // 0xa929 == l.ori r9
-       l.sh    (TRAMP_SLOT_1+0x0)(r3),r5
-       l.andi  r5,r6,0xffff
-       l.sh    (TRAMP_SLOT_1+0x2)(r3),r5
-
-       /* falthrough, need to set up new jump offset */
-
-
-0:     // l.j
-       l.slli  r6,r4,6                 // original offset shifted left 6 - 2
-//     l.srli  r6,r6,6                 // original offset shifted right 2
-
-       l.slli  r4,r2,4                 // old jump position: EEA shifted left 4
-//     l.srli  r4,r4,6                 // old jump position: shifted right 2
-
-       l.addi  r5,r3,0xc               // new jump position (physical)
-       l.slli  r5,r5,4                 // new jump position: shifted left 4
-
-       // calculate new jump offset
-       // new_off = old_off + (old_jump - new_jump)
-
-       l.sub   r5,r4,r5                // old_jump - new_jump
-       l.add   r5,r6,r5                // orig_off + (old_jump - new_jump)
-       l.srli  r5,r5,6                 // new offset shifted right 2
-
-       // r5 is new jump offset
-                                       // l.j has opcode 0x0...
-       l.sw    TRAMP_SLOT_2(r3),r5     // write it back
-
-       l.j     trampoline_out
-       l.nop
-
-/* ----------------------------- */
-
-3:     // l.jalr
-
-       /* 19 20 aa aa  l.movhi r9,0xaaaa
-        * a9 29 bb bb  l.ori   r9,0xbbbb
-        *
-        * where 0xaaaabbbb is EEA + 0x4 shifted right 2
-        */
-
-       l.addi  r6,r2,0x4               // this is 0xaaaabbbb
-
-                                       // l.movhi r9,0xaaaa
-       l.ori   r5,r0,0x1920            // 0x1920 == l.movhi r9
-       l.sh    (TRAMP_SLOT_0+0x0)(r3),r5
-       l.srli  r5,r6,16
-       l.sh    (TRAMP_SLOT_0+0x2)(r3),r5
-
-                                       // l.ori   r9,0xbbbb
-       l.ori   r5,r0,0xa929            // 0xa929 == l.ori r9
-       l.sh    (TRAMP_SLOT_1+0x0)(r3),r5
-       l.andi  r5,r6,0xffff
-       l.sh    (TRAMP_SLOT_1+0x2)(r3),r5
-
-       l.lhz   r5,(TRAMP_SLOT_2+0x0)(r3)       // load hi part of jump instruction
-       l.andi  r5,r5,0x3ff             // clear out opcode part
-       l.ori   r5,r5,0x4400            // opcode changed from l.jalr -> l.jr
-       l.sh    (TRAMP_SLOT_2+0x0)(r3),r5 // write it back
-
-       /* falthrough */
-
-1:     // l.jr
-       l.j     trampoline_out
-       l.nop
-
-/* ----------------------------- */
-
-4:     // l.bnf
-5:     // l.bf
-       l.slli  r6,r4,6                 // original offset shifted left 6 - 2
-//     l.srli  r6,r6,6                 // original offset shifted right 2
-
-       l.slli  r4,r2,4                 // old jump position: EEA shifted left 4
-//     l.srli  r4,r4,6                 // old jump position: shifted right 2
-
-       l.addi  r5,r3,0xc               // new jump position (physical)
-       l.slli  r5,r5,4                 // new jump position: shifted left 4
-
-       // calculate new jump offset
-       // new_off = old_off + (old_jump - new_jump)
-
-       l.add   r6,r6,r4                // (orig_off + old_jump)
-       l.sub   r6,r6,r5                // (orig_off + old_jump) - new_jump
-       l.srli  r6,r6,6                 // new offset shifted right 2
-
-       // r6 is new jump offset
-       l.lwz   r4,(TRAMP_SLOT_2+0x0)(r3)       // load jump instruction
-       l.srli  r4,r4,16
-       l.andi  r4,r4,0xfc00            // get opcode part
-       l.slli  r4,r4,16
-       l.or    r6,r4,r6                // l.b(n)f new offset
-       l.sw    TRAMP_SLOT_2(r3),r6     // write it back
-
-       /* we need to add l.j to EEA + 0x8 */
-       tophys  (r4,r2)                 // may not be needed (due to shifts down_
-       l.addi  r4,r4,(0x8 - 0x8)       // jump target = r2 + 0x8 (compensate for 0x8)
-                                       // jump position = r5 + 0x8 (0x8 compensated)
-       l.sub   r4,r4,r5                // jump offset = target - new_position + 0x8
-
-       l.slli  r4,r4,4                 // the amount of info in imediate of jump
-       l.srli  r4,r4,6                 // jump instruction with offset
-       l.sw    TRAMP_SLOT_4(r3),r4     // write it to 4th slot
-
-       /* fallthrough */
-
-trampoline_out:
-       // set up new EPC to point to our trampoline code
-       LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
-       l.mtspr r0,r5,SPR_EPCR_BASE
-
-       // immu_trampoline is (4x) CACHE_LINE aligned
-       // and only 6 instructions long,
-       // so we need to invalidate only 2 lines
-
-       /* Establish cache block size
-          If BS=0, 16;
-          If BS=1, 32;
-          r14 contain block size
-       */
-       l.mfspr r21,r0,SPR_ICCFGR
-       l.andi  r21,r21,SPR_ICCFGR_CBS
-       l.srli  r21,r21,7
-       l.ori   r23,r0,16
-       l.sll   r14,r23,r21
-
-       l.mtspr r0,r5,SPR_ICBIR
-       l.add   r5,r5,r14
-       l.mtspr r0,r5,SPR_ICBIR
-
-       l.jr    r9
-       l.nop
-
 /*
  * DESC: Prints ASCII character stored in r7
  *