From ed3a88d7dbbb924312a707d5f295b7a31e2f8d2d Mon Sep 17 00:00:00 2001 From: Stafford Horne Date: Thu, 12 May 2022 06:11:21 +0900 Subject: 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 --- arch/openrisc/kernel/head.S | 209 -------------------------------------------- 1 file changed, 209 deletions(-) (limited to 'arch/openrisc/kernel') diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S index 21db50563f97..9b59d0ca665c 100644 --- 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 * -- cgit