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Extend umode_wfi test to check U-mode WFI doesn't stall the processor if TW=0 or PMP X check fails

This commit is contained in:
Luke Wren 2022-05-29 17:42:15 +01:00
parent 460fa0bb4a
commit c8afcdbb8f
1 changed files with 30 additions and 7 deletions
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37
test/sim/sw_testcases/umode_wfi.c
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@ -3,14 +3,20 @@
// Check that U-mode execution of a wfi causes an illegal opcode exception if
// and only if the mstatus timeout wait bit is set.
// Also check that a U-mode WFI which fails PMP X check does not stall the
// procesor.
/*EXPECTED-OUTPUT***************************************************************
Do WFI with TW=0:
mcause = 8 // = ecall, meaning normal exit. The test also checks mepc.
mcause = 8 // = ecall, meaning normal exit.
Do WFI with TW=1:
mstatus = 00200000 // Check TW write is reflected in readback
mcause = 2 // = illegal instruction. The test also checks mepc.
mstatus = 00200000 // Check TW write is reflected in readback
mcause = 2 // = illegal instruction
Do WFI with TW=1, IRQs disabled:
mcause = 2 // = illegal instruction
Do PMP-failed WFI, IRQs disabled:
mcause = 1 // = instruction access fault.
*******************************************************************************/
@ -68,10 +74,27 @@ int main() {
tb_printf("mstatus = %08x\n", read_csr(mstatus));
umode_call_and_catch(&do_wfi);
tb_printf("mcause = %u\n", read_csr(mcause));
if (read_csr(mepc) != (uint32_t)&do_wfi) {
tb_puts("mepc doesn't point to wfi\n");
return -1;
}
tb_assert(read_csr(mepc) == (uint32_t)&do_wfi, "mepc doesn't point to wfi\n");
tb_puts("Do WFI with TW=1, IRQs disabled:\n");
// Disable IRQ sources so that WFI will stall forever
write_csr(mie, 0);
// This checks that setting TW stops the WFI state from being entered, as
// well as just raising an exception.
umode_call_and_catch(&do_wfi);
tb_printf("mcause = %u\n", read_csr(mcause));
tb_assert(read_csr(mepc) == (uint32_t)&do_wfi, "mepc doesn't point to wfi\n");
// This was broken at one point: WFI which failed X permission check would
// still enter WFI halt state!
tb_puts("Do PMP-failed WFI, IRQs disabled:\n");
// Clear TW bit again
clear_csr(mstatus, 1u << 21);
// Revoke all U-mode PMP permissions
write_csr(pmpcfg0, 0);
umode_call_and_catch(&do_wfi);
tb_printf("mcause = %u\n", read_csr(mcause));
tb_assert(read_csr(mepc) == (uint32_t)&do_wfi, "mepc doesn't point to wfi\n");
return 0;
}