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Date: Mon, 04 Mar 2024 12:07:55 +0000
Message-ID: <86wmqi19pg.wl-maz@kernel.org>
From: Marc Zyngier <maz@kernel.org>
To: Ruidong Tian <tianruidong@linux.alibaba.com>
Cc: catalin.marinas@arm.com,
	will@kernel.org,
	lpieralisi@kernel.org,
	guohanjun@huawei.com,
	sudeep.holla@arm.com,
	xueshuai@linux.alibaba.com,
	baolin.wang@linux.alibaba.com,
	linux-kernel@vger.kernel.org,
	linux-acpi@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Tyler Baicar <baicar@os.amperecomputing.com>
Subject: Re: [PATCH 1/2] ACPI/AEST: Initial AEST driver
In-Reply-To: <20240304111517.33001-2-tianruidong@linux.alibaba.com>
References: <20240304111517.33001-1-tianruidong@linux.alibaba.com>
	<20240304111517.33001-2-tianruidong@linux.alibaba.com>
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On Mon, 04 Mar 2024 11:15:16 +0000,
Ruidong Tian <tianruidong@linux.alibaba.com> wrote:
> 
> From: Tyler Baicar <baicar@os.amperecomputing.com>
> 
> Add support for parsing the ARM Error Source Table and basic handling of
> errors reported through both memory mapped and system register interfaces.
> 
> Assume system register interfaces are only registered with private
> peripheral interrupts (PPIs); otherwise there is no guarantee the
> core handling the error is the core which took the error and has the
> syndrome info in its system registers.
> 
> All detected errors will be collected to a workqueue in irq context and
> print error information later.
> 
> Signed-off-by: Tyler Baicar <baicar@os.amperecomputing.com>
> Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
> ---
>  MAINTAINERS                  |  11 +
>  arch/arm64/include/asm/ras.h |  38 ++
>  drivers/acpi/arm64/Kconfig   |  10 +
>  drivers/acpi/arm64/Makefile  |   1 +
>  drivers/acpi/arm64/aest.c    | 723 +++++++++++++++++++++++++++++++++++
>  include/linux/acpi_aest.h    |  91 +++++
>  include/linux/cpuhotplug.h   |   1 +
>  7 files changed, 875 insertions(+)
>  create mode 100644 arch/arm64/include/asm/ras.h
>  create mode 100644 drivers/acpi/arm64/aest.c
>  create mode 100644 include/linux/acpi_aest.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 2a7a90eeec49..5df845763a9c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -329,6 +329,17 @@ L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
>  S:	Maintained
>  F:	drivers/acpi/arm64
>  
> +ACPI AEST
> +M:	Tyler Baicar <baicar@os.amperecomputing.com>
> +M:	Ruidong Tian <tianruidond@linux.alibaba.com>
> +L:	linux-acpi@vger.kernel.org
> +L:	linux-arm-kernel@lists.infradead.org
> +S:	Supported
> +F:	arch/arm64/include/asm/ras.h
> +F:	drivers/acpi/arm64/aest.c
> +F:	include/linux/acpi_aest.h
> +
> +
>  ACPI FOR RISC-V (ACPI/riscv)
>  M:	Sunil V L <sunilvl@ventanamicro.com>
>  L:	linux-acpi@vger.kernel.org
> diff --git a/arch/arm64/include/asm/ras.h b/arch/arm64/include/asm/ras.h
> new file mode 100644
> index 000000000000..2fb0d9741567
> --- /dev/null
> +++ b/arch/arm64/include/asm/ras.h
> @@ -0,0 +1,38 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __ASM_RAS_H
> +#define __ASM_RAS_H
> +
> +#include <linux/types.h>
> +#include <linux/bits.h>
> +
> +#define ERR_STATUS_AV		BIT(31)
> +#define ERR_STATUS_V		BIT(30)
> +#define ERR_STATUS_UE		BIT(29)
> +#define ERR_STATUS_ER		BIT(28)
> +#define ERR_STATUS_OF		BIT(27)
> +#define ERR_STATUS_MV		BIT(26)
> +#define ERR_STATUS_CE		(BIT(25) | BIT(24))
> +#define ERR_STATUS_DE		BIT(23)
> +#define ERR_STATUS_PN		BIT(22)
> +#define ERR_STATUS_UET		(BIT(21) | BIT(20))
> +#define ERR_STATUS_CI		BIT(19)
> +#define ERR_STATUS_IERR 	GENMASK_ULL(15, 8)
> +#define ERR_STATUS_SERR 	GENMASK_ULL(7, 0)

All these bits need to be defined in arch/arm64/tools/sysreg as
ERXSTATUS_EL1 fields.

> +
> +/* These bit is write-one-to-clear */
> +#define ERR_STATUS_W1TC 	(ERR_STATUS_AV | ERR_STATUS_V | ERR_STATUS_UE | \
> +				ERR_STATUS_ER | ERR_STATUS_OF | ERR_STATUS_MV | \
> +				ERR_STATUS_CE | ERR_STATUS_DE | ERR_STATUS_PN | \
> +				ERR_STATUS_UET | ERR_STATUS_CI)
> +
> +#define RAS_REV_v1_1		0x1

What is this? We already have ID_AA64PFR1_EL1.RAS_frac.

> +
> +struct ras_ext_regs {
> +	u64 err_fr;
> +	u64 err_ctlr;
> +	u64 err_status;
> +	u64 err_addr;
> +	u64 err_misc[4];
> +};
> +
> +#endif	/* __ASM_RAS_H */
> diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig
> index b3ed6212244c..639db671c5cf 100644
> --- a/drivers/acpi/arm64/Kconfig
> +++ b/drivers/acpi/arm64/Kconfig
> @@ -21,3 +21,13 @@ config ACPI_AGDI
>  
>  config ACPI_APMT
>  	bool
> +
> +config ACPI_AEST
> +	bool "ARM Error Source Table Support"
> +
> +	help
> +	  The Arm Error Source Table (AEST) provides details on ACPI
> +	  extensions that enable kernel-first handling of errors in a
> +	  system that supports the Armv8 RAS extensions.
> +
> +	  If set, the kernel will report and log hardware errors.
> diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
> index 726944648c9b..5ea82b196b90 100644
> --- a/drivers/acpi/arm64/Makefile
> +++ b/drivers/acpi/arm64/Makefile
> @@ -6,3 +6,4 @@ obj-$(CONFIG_ACPI_APMT) 	+= apmt.o
>  obj-$(CONFIG_ARM_AMBA)		+= amba.o
>  obj-y				+= dma.o init.o
>  obj-y				+= thermal_cpufreq.o
> +obj-$(CONFIG_ACPI_AEST) 	+= aest.o
> diff --git a/drivers/acpi/arm64/aest.c b/drivers/acpi/arm64/aest.c
> new file mode 100644
> index 000000000000..be0883316449
> --- /dev/null
> +++ b/drivers/acpi/arm64/aest.c
> @@ -0,0 +1,723 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ARM Error Source Table Support
> + *
> + * Copyright (c) 2021, Ampere Computing LLC
> + * Copyright (c) 2021-2024, Alibaba Group.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/acpi_aest.h>
> +#include <linux/cpuhotplug.h>
> +#include <linux/kernel.h>
> +#include <linux/genalloc.h>
> +#include <linux/llist.h>
> +#include <acpi/actbl.h>
> +#include <asm/ras.h>
> +
> +#undef pr_fmt
> +#define pr_fmt(fmt) "ACPI AEST: " fmt
> +
> +#define CASE_READ_CLEAR(x, clear)					\
> +	case (x): {							\
> +		res = read_sysreg_s(SYS_##x##_EL1);			\
> +		if (clear)						\
> +			write_sysreg_s(0, SYS_##x##_EL1);		\
> +		break;							\
> +	}

Please don't use macros with side effects. This is horrible to debug.
Instead, *return* the value from the macro, or pass the variable you
want to affect as a parameter.

Also, what ensures the synchronisation of this write? How is the W1TC
aspect enforced?

> +
> +#define CASE_WRITE(val, x)						\
> +	case (x): {							\
> +		write_sysreg_s((val), SYS_##x##_EL1);			\
> +		break;							\
> +	}
> +
> +static struct acpi_table_header *aest_table;
> +
> +static struct aest_node __percpu **ppi_data;
> +
> +static int *ppi_irqs;
> +static u8 num_ppi;
> +static u8 ppi_idx;
> +
> +static struct work_struct aest_work;
> +
> +static struct gen_pool *aest_node_pool;
> +static struct llist_head aest_node_llist;
> +
> +/*
> + * This memory pool is only to be used to save AEST node in AEST irq context.
> + * Use 8 pages to save AEST node for now (~500 AEST node at most).
> + */
> +#define AEST_NODE_POOLSZ	(8 * PAGE_SIZE)

This doesn't make sense. PAGE_SIZE is a variable concept (ranging from
4 to 64kB). What is this "~500" number coming from? If you want to
store a given number of records, allocate the size you actually want.

> +
> +static u64 aest_sysreg_read_clear(u64 base, u32 offset, bool clear)
> +{
> +	u64 res;
> +
> +	switch (offset) {
> +	CASE_READ_CLEAR(ERXFR, clear)
> +	CASE_READ_CLEAR(ERXCTLR, clear)
> +	CASE_READ_CLEAR(ERXSTATUS, clear)
> +	CASE_READ_CLEAR(ERXADDR, clear)
> +	CASE_READ_CLEAR(ERXMISC0, clear)
> +	CASE_READ_CLEAR(ERXMISC1, clear)
> +	CASE_READ_CLEAR(ERXMISC2, clear)
> +	CASE_READ_CLEAR(ERXMISC3, clear)
> +	default :
> +		res = 0;
> +	}
> +	return res;
> +}
> +
> +static void aest_sysreg_write(u64 base, u32 offset, u64 val)
> +{
> +	switch (offset) {
> +	CASE_WRITE(val, ERXFR)
> +	CASE_WRITE(val, ERXCTLR)
> +	CASE_WRITE(val, ERXSTATUS)
> +	CASE_WRITE(val, ERXADDR)
> +	CASE_WRITE(val, ERXMISC0)
> +	CASE_WRITE(val, ERXMISC1)
> +	CASE_WRITE(val, ERXMISC2)
> +	CASE_WRITE(val, ERXMISC3)
> +	default :
> +		return;
> +	}
> +}
> +
> +static u64 aest_iomem_read_clear(u64 base, u32 offset, bool clear)
> +{
> +	u64 res;
> +
> +	res = readq((void *)(base + offset));
> +	if (clear)
> +		writeq(0, (void *)(base + offset));

Do you need the explicit synchronisation? What ordering are you trying
to guarantee?

> +	return res;
> +}
> +
> +static void aest_iomem_write(u64 base, u32 offset, u64 val)
> +{
> +	writeq(val, (void *)(base + offset));

Same question.

> +}
> +
> +static void aest_print(struct aest_node_llist *lnode)
> +{
> +	static atomic_t seqno;

Uninitialised atomic?

> +	unsigned int curr_seqno;
> +	char pfx_seq[64];

Magic number?

> +	int index;
> +	struct ras_ext_regs *regs;
> +
> +	curr_seqno = atomic_inc_return(&seqno);
> +	snprintf(pfx_seq, sizeof(pfx_seq), "{%u}" HW_ERR, curr_seqno);
> +	pr_info("%sHardware error from %s\n", pfx_seq, lnode->node_name);
> +
> +	switch (lnode->type) {
> +	case ACPI_AEST_PROCESSOR_ERROR_NODE:
> +		pr_err("%s Error from CPU%d\n", pfx_seq, lnode->id0);
> +		break;
> +	case ACPI_AEST_MEMORY_ERROR_NODE:
> +		pr_err("%s Error from memory at SRAT proximity domain 0x%x\n",
> +			pfx_seq, lnode->id0);
> +		break;
> +	case ACPI_AEST_SMMU_ERROR_NODE:
> +		pr_err("%s Error from SMMU IORT node 0x%x subcomponent 0x%x\n",
> +			pfx_seq, lnode->id0, lnode->id1);
> +		break;
> +	case ACPI_AEST_VENDOR_ERROR_NODE:
> +		pr_err("%s Error from vendor hid 0x%x uid 0x%x\n",
> +			pfx_seq, lnode->id0, lnode->id1);
> +		break;
> +	case ACPI_AEST_GIC_ERROR_NODE:
> +		pr_err("%s Error from GIC type 0x%x instance 0x%x\n",
> +			pfx_seq, lnode->id0, lnode->id1);
> +		break;
> +	default:
> +		pr_err("%s Unknown AEST node type\n", pfx_seq);
> +		return;
> +	}
> +
> +	index = lnode->index;
> +	regs = &lnode->regs;
> +
> +	pr_err("%s  ERR%uFR: 0x%llx\n", pfx_seq, index, regs->err_fr);
> +	pr_err("%s  ERR%uCTRL: 0x%llx\n", pfx_seq, index, regs->err_ctlr);
> +	pr_err("%s  ERR%uSTATUS: 0x%llx\n", pfx_seq, index, regs->err_status);
> +	if (regs->err_status & ERR_STATUS_AV)
> +		pr_err("%s  ERR%uADDR: 0x%llx\n", pfx_seq, index, regs->err_addr);
> +
> +	if (regs->err_status & ERR_STATUS_MV) {
> +		pr_err("%s  ERR%uMISC0: 0x%llx\n", pfx_seq, index, regs->err_misc[0]);
> +		pr_err("%s  ERR%uMISC1: 0x%llx\n", pfx_seq, index, regs->err_misc[1]);
> +		pr_err("%s  ERR%uMISC2: 0x%llx\n", pfx_seq, index, regs->err_misc[2]);
> +		pr_err("%s  ERR%uMISC3: 0x%llx\n", pfx_seq, index, regs->err_misc[3]);
> +	}
> +}
> +
> +
> +static void aest_node_pool_process(struct work_struct *__unused)
> +{
> +	struct llist_node *head;
> +	struct aest_node_llist *lnode, *tmp;
> +
> +	head = llist_del_all(&aest_node_llist);
> +	if (!head)
> +		return;
> +
> +	head = llist_reverse_order(head);
> +	llist_for_each_entry_safe(lnode, tmp, head, llnode) {
> +		aest_print(lnode);
> +		gen_pool_free(aest_node_pool, (unsigned long)lnode,
> +				sizeof(*lnode));
> +	}
> +}
> +
> +static int aest_node_gen_pool_add(struct aest_node *node, int index,
> +				struct ras_ext_regs *regs)
> +{
> +	struct aest_node_llist *list;
> +
> +	if (!aest_node_pool)
> +		return -EINVAL;
> +
> +	list = (void *)gen_pool_alloc(aest_node_pool, sizeof(*list));
> +	if (!list)
> +		return -ENOMEM;
> +
> +	list->type = node->type;
> +	list->node_name = node->name;
> +	switch (node->type) {
> +	case ACPI_AEST_PROCESSOR_ERROR_NODE:
> +		list->id0 = node->spec.processor.processor_id;
> +		if (node->spec.processor.flags & (ACPI_AEST_PROC_FLAG_SHARED |
> +						ACPI_AEST_PROC_FLAG_GLOBAL))
> +			list->id0 = smp_processor_id();
> +
> +		list->id1 = node->spec.processor.resource_type;
> +		break;
> +	case ACPI_AEST_MEMORY_ERROR_NODE:
> +		list->id0 = node->spec.memory.srat_proximity_domain;
> +		break;
> +	case ACPI_AEST_SMMU_ERROR_NODE:
> +		list->id0 = node->spec.smmu.iort_node_reference;
> +		list->id1 = node->spec.smmu.subcomponent_reference;
> +		break;
> +	case ACPI_AEST_VENDOR_ERROR_NODE:
> +		list->id0 = node->spec.vendor.acpi_hid;
> +		list->id1 = node->spec.vendor.acpi_uid;
> +		break;
> +	case ACPI_AEST_GIC_ERROR_NODE:
> +		list->id0 = node->spec.gic.interface_type;
> +		list->id1 = node->spec.gic.instance_id;
> +		break;
> +	default:
> +		list->id0 = 0;
> +		list->id1 = 0;
> +	}
> +
> +	memcpy(&list->regs, regs, sizeof(*regs));

You have vmalloced the record. Why do you need to copy it instead of
simply pointing to it?

> +	list->index = index;
> +	llist_add(&list->llnode, &aest_node_llist);
> +
> +	return 0;
> +}
> +
> +static int aest_node_pool_init(void)
> +{
> +	unsigned long addr, size;
> +	int rc;
> +
> +	if (aest_node_pool)
> +		return 0;
> +
> +	aest_node_pool = gen_pool_create(ilog2(sizeof(struct aest_node_llist)), -1);
> +	if (!aest_node_pool)
> +		return -ENOMEM;
> +
> +	size = PAGE_ALIGN(AEST_NODE_POOLSZ);
> +	addr = (unsigned long)vmalloc(size);
> +	if (!addr)
> +		goto err_pool_alloc;
> +
> +	rc = gen_pool_add(aest_node_pool, addr, size, -1);
> +	if (rc)
> +		goto err_pool_add;
> +
> +	return 0;
> +
> +err_pool_add:
> +	vfree((void *)addr);
> +
> +err_pool_alloc:
> +	gen_pool_destroy(aest_node_pool);
> +
> +	return -ENOMEM;
> +}
> +
> +static void aest_log(struct aest_node *node, int index, struct ras_ext_regs *regs)
> +{
> +	if (!aest_node_gen_pool_add(node, index, regs))
> +		schedule_work(&aest_work);
> +}
> +
> +/*
> + * you must select cpu number first in order to operate RAS register belonged
> + * that cpu.
> + */
> +static void aest_select_cpu(struct aest_node *node, int i)
> +{
> +	if (node->interface.type == ACPI_AEST_NODE_SYSTEM_REGISTER) {
> +		write_sysreg_s(i, SYS_ERRSELR_EL1);

ERRSELR_EL1 doesn't select a CPU. It selects a RAS record. How records
and CPUs are mapped isn't specified in the architecture.

> +		isb();
> +	}
> +}
> +
> +static void aest_proc(struct aest_node *node)
> +{
> +	struct ras_ext_regs regs = {0};
> +	struct aest_access *access;
> +	int i;
> +	u64 regs_p;
> +
> +
> +	for (i = node->interface.record_start; i < node->interface.record_end; i++) {
> +		/* 1b: Error record at i index is not implemented */
> +		if (test_bit(i, &node->interface.record_implemented))
> +			continue;
> +
> +		aest_select_cpu(node, i);
> +
> +		access = node->access;
> +		regs_p = (u64)&node->interface.regs[i];
> +
> +		regs.err_status = access->read_clear(regs_p, ERXSTATUS, false);
> +		if (!(regs.err_status & ERR_STATUS_V))
> +			continue;
> +
> +		if (regs.err_status & ERR_STATUS_AV)
> +			regs.err_addr = access->read_clear(regs_p, ERXADDR, false);
> +
> +		regs.err_fr = access->read_clear(regs_p, ERXFR, false);
> +		regs.err_ctlr = access->read_clear(regs_p, ERXCTLR, false);
> +
> +		if (regs.err_status & ERR_STATUS_MV) {
> +			bool clear = node->interface.flags & ACPI_AEST_INTERFACE_CLEAR_MISC;
> +
> +			regs.err_misc[0] = access->read_clear(regs_p, ERXMISC0, clear);
> +			regs.err_misc[1] = access->read_clear(regs_p, ERXMISC1, clear);
> +			regs.err_misc[2] = access->read_clear(regs_p, ERXMISC2, clear);
> +			regs.err_misc[3] = access->read_clear(regs_p, ERXMISC3, clear);
> +		}
> +
> +		aest_log(node, i, &regs);
> +
> +		if (regs.err_status & ERR_STATUS_UE)
> +			panic("AEST: uncorrectable error encountered");
> +
> +		/* Write-one-to-clear the bits we've seen */
> +		regs.err_status &= ERR_STATUS_W1TC;
> +
> +		/* Multi bit filed need to write all-ones to clear. */
> +		if (regs.err_status & ERR_STATUS_CE)
> +			regs.err_status |= ERR_STATUS_CE;
> +
> +		/* Multi bit filed need to write all-ones to clear. */
> +		if (regs.err_status & ERR_STATUS_UET)
> +			regs.err_status |= ERR_STATUS_UET;
> +
> +		access->write(regs_p, ERXSTATUS, regs.err_status);
> +	}
> +}
> +
> +static irqreturn_t aest_irq_func(int irq, void *input)
> +{
> +	struct aest_node *node = input;
> +
> +	aest_proc(node);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int __init aest_register_gsi(u32 gsi, int trigger, void *data,
> +					irq_handler_t aest_irq_func)
> +{
> +	int cpu, irq;
> +
> +	irq = acpi_register_gsi(NULL, gsi, trigger, ACPI_ACTIVE_HIGH);
> +
> +	if (irq == -EINVAL) {
> +		pr_err("failed to map AEST GSI %d\n", gsi);
> +		return -EINVAL;
> +	}
> +
> +	if (gsi < 16) {
> +		pr_err("invalid GSI %d\n", gsi);
> +		return -EINVAL;
> +	} else if (gsi < 32) {
> +		if (ppi_idx >= AEST_MAX_PPI) {
> +			pr_err("Unable to register PPI %d\n", gsi);
> +			return -EINVAL;
> +		}
> +		ppi_irqs[ppi_idx] = irq;
> +		enable_percpu_irq(irq, IRQ_TYPE_NONE);

Enabling the PPI before requesting it? Looks... great. And how does
this work on a system that supports EPPIs, which are in the
[1119:1056] range?

Also, if you get a trigger as a parameter, why the IRQ_TYPE_NONE?


> +		for_each_possible_cpu(cpu) {
> +			memcpy(per_cpu_ptr(ppi_data[ppi_idx], cpu), data,
> +			       sizeof(struct aest_node));
> +		}
> +		if (request_percpu_irq(irq, aest_irq_func, "AEST",
> +				       ppi_data[ppi_idx++])) {
> +			pr_err("failed to register AEST IRQ %d\n", irq);
> +			return -EINVAL;
> +		}
> +	} else if (gsi < 1020) {
> +		if (request_irq(irq, aest_irq_func, IRQF_SHARED, "AEST",
> +				data)) {

Why SHARED? Who would share a RAS interrupt?????

> +			pr_err("failed to register AEST IRQ %d\n", irq);
> +			return -EINVAL;

Same question about extended SPIs.

All in all, this whole logic is totally useless. It isn't the driver's
job to classify the GIC INTIDs...

	M.

-- 
Without deviation from the norm, progress is not possible.