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/* Copyright 2013-2014 IBM Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * 	http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <skiboot.h>
#include <stack.h>
#include <opal.h>
#include <processor.h>
#include <cpu.h>

extern uint8_t exc_primary_start;
extern uint8_t exc_primary_end;

extern uint32_t exc_primary_patch_branch;

extern uint8_t exc_secondary_start;
extern uint8_t exc_secondary_end;

extern uint32_t exc_secondary_patch_stack;
extern uint32_t exc_secondary_patch_mfsrr0;
extern uint32_t exc_secondary_patch_mfsrr1;
extern uint32_t exc_secondary_patch_type;
extern uint32_t exc_secondary_patch_mtsrr0;
extern uint32_t exc_secondary_patch_mtsrr1;
extern uint32_t exc_secondary_patch_rfid;

struct lock hmi_lock = LOCK_UNLOCKED;

#define REG		"%016llx"
#define REGS_PER_LINE	4
#define LAST_VOLATILE	13

static void dump_regs(struct stack_frame *stack, uint64_t hmer)
{
	int i;
	uint64_t tfmr;

	if (hmer & SPR_HMER_MALFUNCTION_ALERT)
		printf("HMI: malfunction Alert\n");
	if (hmer & SPR_HMER_HYP_RESOURCE_ERR)
		printf("HMI: Hypervisor resource error.\n");
	if (hmer & SPR_HMER_TFAC_ERROR) {
		tfmr = mfspr(SPR_TFMR);
		printf("HMI: TFAC error: SPRN_TFMR = 0x%016llx\n", tfmr);
	}
	if (hmer & SPR_HMER_TFMR_PARITY_ERROR) {
		tfmr = mfspr(SPR_TFMR);
		printf("HMI: TFMR parity error: SPRN_TFMR = 0x%016llx\n", tfmr);
	}
	printf("TRAP: %04llx\n", stack->type);
	printf("SRR0: "REG" SRR1: "REG"\n", stack->srr0, stack->srr1);
	printf("CFAR: "REG" LR: "REG" CTR: "REG"\n",
		stack->cfar, stack->lr, stack->ctr);
	printf("  CR: %08x  XER: %08x\n", stack->cr, stack->xer);

	for (i = 0;  i < 32;  i++) {
		if ((i % REGS_PER_LINE) == 0)
			printf("\nGPR%02d: ", i);
		printf(REG " ", stack->gpr[i]);
		if (i == LAST_VOLATILE)
			break;
	}
	printf("\n");
}

/*
 * HMER register layout:
 * +===+==========+============================+========+===================+
 * |Bit|Name      |Description                 |PowerKVM|Action             |
 * |   |          |                            |HMI     |                   |
 * |   |          |                            |enabled |                   |
 * |   |          |                            |for this|                   |
 * |   |          |                            |bit ?   |                   |
 * +===+==========+============================+========+===================+
 * |0  |malfunctio|A processor core in the     |Yes     |Raise attn from    |
 * |   |n_allert  |system has checkstopped     |        |sapphire resulting |
 * |   |          |(failed recovery) and has   |        |xstop              |
 * |   |          |requested a CP Sparing      |        |                   |
 * |   |          |to occur. This is           |        |                   |
 * |   |          |broadcasted to every        |        |                   |
 * |   |          |processor in the system     |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |1  |Reserved  |reserved                    |n/a     |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |2  |proc_recv_|Processor recovery occurred |Yes     |Log message and    |
 * |   |done      |error-bit in fir not masked |        |continue working.  |
 * |   |          |(see bit 11)                |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |3  |proc_recv_|Processor went through      |Yes     |Log message and    |
 * |   |error_mask|recovery for an error which |        |continue working.  |
 * |   |ed        |is actually masked for      |        |                   |
 * |   |          |reporting                   |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |4  |          |Timer facility experienced  |Yes     |Raise attn from    |
 * |   |tfac_error|an error.                   |        |sapphire resulting |
 * |   |          |TB, DEC, HDEC, PURR or SPURR|        |xstop              |
 * |   |          |may be corrupted (details in|        |                   |
 * |   |          |TFMR)                       |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |5  |          |TFMR SPR itself is          |Yes     |Raise attn from    |
 * |   |tfmr_parit|corrupted.                  |        |sapphire resulting |
 * |   |y_error   |Entire timing facility may  |        |xstop              |
 * |   |          |be compromised.             |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |6  |ha_overflo| UPS (Uniterrupted Power    |No      |N/A                |
 * |   |w_warning |System) Overflow indication |        |                   |
 * |   |          |indicating that the UPS     |        |                   |
 * |   |          |DirtyAddrTable has          |        |                   |
 * |   |          |reached a limit where it    |        |                   |
 * |   |          |requires PHYP unload support|        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |7  |reserved  |reserved                    |n/a     |n/a                |
 * |---+----------+----------------------------+--------+-------------------|
 * |8  |xscom_fail|An XSCOM operation caused by|No      |We handle it by    |
 * |   |          |a cache inhibited load/store|        |manually reading   |
 * |   |          |from this thread failed. A  |        |HMER register.     |
 * |   |          |trap register is            |        |                   |
 * |   |          |available.                  |        |                   |
 * |   |          |                            |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |9  |xscom_done|An XSCOM operation caused by|No      |We handle it by    |
 * |   |          |a cache inhibited load/store|        |manually reading   |
 * |   |          |from this thread completed. |        |HMER register.     |
 * |   |          |If hypervisor               |        |                   |
 * |   |          |intends to use this bit, it |        |                   |
 * |   |          |is responsible for clearing |        |                   |
 * |   |          |it before performing the    |        |                   |
 * |   |          |xscom operation.            |        |                   |
 * |   |          |NOTE: this bit should always|        |                   |
 * |   |          |be masked in HMEER          |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |10 |reserved  |reserved                    |n/a     |n/a                |
 * |---+----------+----------------------------+--------+-------------------|
 * |11 |proc_recv_|Processor recovery occurred |y       |Log message and    |
 * |   |again     |again before bit2 or bit3   |        |continue working.  |
 * |   |          |was cleared                 |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |12-|reserved  |was temperature sensor      |n/a     |n/a                |
 * |15 |          |passed the critical point on|        |                   |
 * |   |          |the way up                  |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |16 |          |SCOM has set a reserved FIR |No      |n/a                |
 * |   |scom_fir_h|bit to cause recovery       |        |                   |
 * |   |m         |                            |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |17 |trig_fir_h|Debug trigger has set a     |No      |n/a                |
 * |   |mi        |reserved FIR bit to cause   |        |                   |
 * |   |          |recovery                    |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |18 |reserved  |reserved                    |n/a     |n/a                |
 * |---+----------+----------------------------+--------+-------------------|
 * |19 |reserved  |reserved                    |n/a     |n/a                |
 * |---+----------+----------------------------+--------+-------------------|
 * |20 |hyp_resour|A hypervisor resource error |y       |Raise attn from    |
 * |   |ce_err    |occurred: data parity error |        |sapphire resulting |
 * |   |          |on, SPRC0:3; SPR_Modereg or |        |xstop.             |
 * |   |          |HMEER.                      |        |                   |
 * |   |          |Note: this bit will cause an|        |                   |
 * |   |          |check_stop when (HV=1, PR=0 |        |                   |
 * |   |          |and EE=0)                   |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |21-|          |if bit 8 is active, the     |No      |We handle it by    |
 * |23 |xscom_stat|reason will be detailed in  |        |Manually reading   |
 * |   |us        |these bits. see chapter 11.1|        |HMER register.     |
 * |   |          |This bits are information   |        |                   |
 * |   |          |only and always masked      |        |                   |
 * |   |          |(mask = '0')                |        |                   |
 * |   |          |If hypervisor intends to use|        |                   |
 * |   |          |this bit, it is responsible |        |                   |
 * |   |          |for clearing it before      |        |                   |
 * |   |          |performing the xscom        |        |                   |
 * |   |          |operation.                  |        |                   |
 * |---+----------+----------------------------+--------+-------------------|
 * |24-|Not       |Not implemented             |n/a     |n/a                |
 * |63 |implemente|                            |        |                   |
 * |   |d         |                            |        |                   |
 * +-- +----------+----------------------------+--------+-------------------+
 *
 * Above HMER bits can be enabled/disabled by modifying
 * SPR_HMEER_HMI_ENABLE_MASK #define in include/processor.h
 * If you modify support for any of the bits listed above, please make sure
 * you change the above table to refelct that.
 *
 * NOTE: Per Dave Larson, never enable 8,9,21-23
 */

/* make compiler happy with a prototype */
void handle_hmi(struct stack_frame *stack);

void handle_hmi(struct stack_frame *stack)
{
	uint64_t orig_hmer;
	int recover;

	orig_hmer = mfspr(SPR_HMER);
	recover = handle_hmi_exception(orig_hmer, NULL);
	if (recover)
		return;

	/*
	 * Raise attn to crash.
	 *
	 * We get HMI on all threads at the same time. Using locks to avoid
	 * printf messages jumbled up.
	 */
	lock(&hmi_lock);
	dump_regs(stack, orig_hmer);
	/* Should we unlock? We are going down anyway. */
	unlock(&hmi_lock);
	assert(false);
}

/* Called from head.S, thus no prototype */
void exception_entry(struct stack_frame *stack);

void exception_entry(struct stack_frame *stack)
{
	switch(stack->type) {
	case STACK_ENTRY_HMI:
		handle_hmi(stack);
		/* XXX TODO : Implement machine check */
		break;
	case STACK_ENTRY_SOFTPATCH:
		/* XXX TODO : Implement softpatch ? */
		break;
	}
}

static int64_t patch_exception(uint64_t vector, uint64_t glue, bool hv)
{
	uint64_t iaddr;

	/* Copy over primary exception handler */
	memcpy((void *)vector, &exc_primary_start,
	       &exc_primary_end - &exc_primary_start);

	/* Patch branch instruction in primary handler */
	iaddr = vector + exc_primary_patch_branch;
	*(uint32_t *)iaddr |= (glue - iaddr) & 0x03fffffc;

	/* Copy over secondary exception handler */
	memcpy((void *)glue, &exc_secondary_start,
	       &exc_secondary_end - &exc_secondary_start);

	/* Patch-in the vector number */
	*(uint32_t *)(glue + exc_secondary_patch_type) |= vector;

	BUILD_ASSERT(STACK_SIZE < 0x8000);
	BUILD_ASSERT(!(CPU_STACKS_BASE & 0xffff));

	/* Standard exception ? All done */
	if (!hv)
		goto flush;

	/* HV exception, change the SRR's to HSRRs and rfid to hrfid
	 *
	 * The magic is that mfspr/mtspr of SRR can be turned into the
	 * equivalent HSRR version by OR'ing 0x4800. For rfid to hrfid
	 * we OR 0x200.
	 */
	*(uint32_t *)(glue + exc_secondary_patch_mfsrr0) |= 0x4800;
	*(uint32_t *)(glue + exc_secondary_patch_mfsrr1) |= 0x4800;
	*(uint32_t *)(glue + exc_secondary_patch_mtsrr0) |= 0x4800;
	*(uint32_t *)(glue + exc_secondary_patch_mtsrr1) |= 0x4800;
	*(uint32_t *)(glue + exc_secondary_patch_rfid) |= 0x200;

 flush:
	/* On P7 and later all we need is : */
	sync_icache();

	return OPAL_SUCCESS;
}

static int64_t opal_register_exc_handler(uint64_t opal_exception,
					 uint64_t handler_address __unused,
					 uint64_t glue_cache_line)
{
	switch(opal_exception) {
	case OPAL_HYPERVISOR_MAINTENANCE_HANDLER:
		return patch_exception(0xe60, glue_cache_line, true);
#if 0 /* We let Linux handle softpatch */
	case OPAL_SOFTPATCH_HANDLER:
		return patch_exception(0x1500, glue_cache_line, true);
#endif
	default:
		break;
	}
	return OPAL_PARAMETER;
}
opal_call(OPAL_REGISTER_OPAL_EXCEPTION_HANDLER, opal_register_exc_handler, 3);