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101 lines
2.2 KiB
101 lines
2.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* Test context switching to see if the DSCR SPR is correctly preserved |
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* when within a transaction. |
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* |
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* Note: We assume that the DSCR has been left at the default value (0) |
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* for all CPUs. |
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* |
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* Method: |
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* |
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* Set a value into the DSCR. |
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* |
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* Start a transaction, and suspend it (*). |
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* |
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* Hard loop checking to see if the transaction has become doomed. |
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* |
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* Now that we *may* have been preempted, record the DSCR and TEXASR SPRS. |
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* |
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* If the abort was because of a context switch, check the DSCR value. |
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* Otherwise, try again. |
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* |
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* (*) If the transaction is not suspended we can't see the problem because |
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* the transaction abort handler will restore the DSCR to it's checkpointed |
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* value before we regain control. |
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*/ |
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#include <inttypes.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <assert.h> |
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#include <asm/tm.h> |
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#include "utils.h" |
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#include "tm.h" |
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#include "../pmu/lib.h" |
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#define SPRN_DSCR 0x03 |
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int test_body(void) |
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{ |
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uint64_t rv, dscr1 = 1, dscr2, texasr; |
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SKIP_IF(!have_htm()); |
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SKIP_IF(htm_is_synthetic()); |
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printf("Check DSCR TM context switch: "); |
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fflush(stdout); |
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for (;;) { |
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asm __volatile__ ( |
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/* set a known value into the DSCR */ |
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"ld 3, %[dscr1];" |
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"mtspr %[sprn_dscr], 3;" |
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"li %[rv], 1;" |
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/* start and suspend a transaction */ |
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"tbegin.;" |
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"beq 1f;" |
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"tsuspend.;" |
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/* hard loop until the transaction becomes doomed */ |
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"2: ;" |
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"tcheck 0;" |
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"bc 4, 0, 2b;" |
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/* record DSCR and TEXASR */ |
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"mfspr 3, %[sprn_dscr];" |
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"std 3, %[dscr2];" |
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"mfspr 3, %[sprn_texasr];" |
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"std 3, %[texasr];" |
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"tresume.;" |
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"tend.;" |
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"li %[rv], 0;" |
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"1: ;" |
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: [rv]"=r"(rv), [dscr2]"=m"(dscr2), [texasr]"=m"(texasr) |
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: [dscr1]"m"(dscr1) |
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, [sprn_dscr]"i"(SPRN_DSCR), [sprn_texasr]"i"(SPRN_TEXASR) |
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: "memory", "r3" |
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); |
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assert(rv); /* make sure the transaction aborted */ |
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if ((texasr >> 56) != TM_CAUSE_RESCHED) { |
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continue; |
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} |
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if (dscr2 != dscr1) { |
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printf(" FAIL\n"); |
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return 1; |
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} else { |
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printf(" OK\n"); |
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return 0; |
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} |
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} |
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} |
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static int tm_resched_dscr(void) |
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{ |
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return eat_cpu(test_body); |
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} |
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int main(int argc, const char *argv[]) |
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{ |
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return test_harness(tm_resched_dscr, "tm_resched_dscr"); |
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}
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