| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
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| 2 | /* |
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| 3 | * Hypervisor Maintenance Interrupt (HMI) handling. |
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| 4 | * |
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| 5 | * Copyright 2015 IBM Corporation |
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| 6 | * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> |
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| 7 | */ |
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| 8 | |
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| 9 | #undef DEBUG |
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| 10 | |
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| 11 | #include <linux/types.h> |
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| 12 | #include <linux/compiler.h> |
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| 13 | #include <asm/paca.h> |
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| 14 | #include <asm/hmi.h> |
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| 15 | #include <asm/processor.h> |
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| 16 | |
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| 17 | void wait_for_subcore_guest_exit(void) |
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| 18 | { |
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| 19 | int i; |
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| 20 | |
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| 21 | /* |
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| 22 | * NULL bitmap pointer indicates that KVM module hasn't |
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| 23 | * been loaded yet and hence no guests are running, or running |
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| 24 | * on POWER9 or newer CPU. |
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| 25 | * |
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| 26 | * If no KVM is in use, no need to co-ordinate among threads |
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| 27 | * as all of them will always be in host and no one is going |
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| 28 | * to modify TB other than the opal hmi handler. |
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| 29 | * |
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| 30 | * POWER9 and newer don't need this synchronisation. |
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| 31 | * |
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| 32 | * Hence, just return from here. |
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| 33 | */ |
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| 34 | if (!local_paca->sibling_subcore_state) |
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| 35 | return; |
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| 36 | |
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| 37 | for (i = 0; i < MAX_SUBCORE_PER_CORE; i++) |
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| 38 | while (local_paca->sibling_subcore_state->in_guest[i]) |
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| 39 | cpu_relax(); |
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| 40 | } |
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| 41 | |
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| 42 | void wait_for_tb_resync(void) |
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| 43 | { |
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| 44 | if (!local_paca->sibling_subcore_state) |
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| 45 | return; |
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| 46 | |
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| 47 | while (test_bit(CORE_TB_RESYNC_REQ_BIT, |
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| 48 | &local_paca->sibling_subcore_state->flags)) |
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| 49 | cpu_relax(); |
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| 50 | } |
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| 51 | |
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