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Message-ID: <20110907072011.GA19226@in.ibm.com>
Date: Wed, 7 Sep 2011 12:50:11 +0530
From: Mahesh J Salgaonkar <mahesh@...ux.vnet.ibm.com>
To: Anton Blanchard <anton@...ba.org>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
Linux Kernel <linux-kernel@...r.kernel.org>,
Michael Ellerman <michael@...erman.id.au>,
Milton Miller <miltonm@....com>,
"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [RFC PATCH 03/10] fadump: Register for firmware assisted dump.
Hi Anton,
On 2011-08-31 14:20:49 Wed, Anton Blanchard wrote:
>
> Hi,
>
> > +static void fadump_show_config(void)
> > +{
> > + DBG("Support for firmware-assisted dump (fadump): %s\n",
> > + (fw_dump.fadump_supported ? "present" : "no support"));
> > +
> > + if (!fw_dump.fadump_supported)
> > + return;
> > +
> > + DBG("Fadump enabled : %s\n",
> > + (fw_dump.fadump_enabled ? "yes" : "no"));
> > + DBG("Dump Active : %s\n", (fw_dump.dump_active ? "yes" : "no"));
> > + DBG("Dump section sizes:\n");
> > + DBG(" CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
> > + DBG(" HPTE region size : %lx\n", fw_dump.hpte_region_size);
> > + DBG("Boot memory size : %lx\n", fw_dump.boot_memory_size);
> > + DBG("Reserve area start: %lx\n", fw_dump.reserve_dump_area_start);
> > + DBG("Reserve area size : %lx\n", fw_dump.reserve_dump_area_size);
> > +}
> > +
> > +static void show_fadump_mem_struct(const struct fadump_mem_struct *fdm)
> > +{
> > + if (!fdm)
> > + return;
> > +
> > + DBG("--------Firmware-assisted dump memory structure---------\n");
> > + DBG("header.dump_format_version : 0x%08x\n",
> > + fdm->header.dump_format_version);
> > + DBG("header.dump_num_sections : %d\n",
> > + fdm->header.dump_num_sections);
> > + DBG("header.dump_status_flag : 0x%04x\n",
> > + fdm->header.dump_status_flag);
> > + DBG("header.offset_first_dump_section : 0x%x\n",
> > + fdm->header.offset_first_dump_section);
> > +
> > + DBG("header.dd_block_size : %d\n",
> > + fdm->header.dd_block_size);
> > + DBG("header.dd_block_offset : 0x%Lx\n",
> > + fdm->header.dd_block_offset);
> > + DBG("header.dd_num_blocks : %Lx\n",
> > + fdm->header.dd_num_blocks);
> > + DBG("header.dd_offset_disk_path : 0x%x\n",
> > + fdm->header.dd_offset_disk_path);
> > +
> > + DBG("header.max_time_auto : %d\n",
> > + fdm->header.max_time_auto);
> > +
> > + /* Kernel dump sections */
> > + DBG("cpu_state_data.request_flag : 0x%08x\n",
> > + fdm->cpu_state_data.request_flag);
> > + DBG("cpu_state_data.source_data_type : 0x%04x\n",
> > + fdm->cpu_state_data.source_data_type);
> > + DBG("cpu_state_data.error_flags : 0x%04x\n",
> > + fdm->cpu_state_data.error_flags);
> > + DBG("cpu_state_data.source_address : 0x%016Lx\n",
> > + fdm->cpu_state_data.source_address);
> > + DBG("cpu_state_data.source_len : 0x%Lx\n",
> > + fdm->cpu_state_data.source_len);
> > + DBG("cpu_state_data.bytes_dumped : 0x%Lx\n",
> > + fdm->cpu_state_data.bytes_dumped);
> > + DBG("cpu_state_data.destination_address: 0x%016Lx\n",
> > + fdm->cpu_state_data.destination_address);
> > +
> > + DBG("hpte_region.request_flag : 0x%08x\n",
> > + fdm->hpte_region.request_flag);
> > + DBG("hpte_region.source_data_type : 0x%04x\n",
> > + fdm->hpte_region.source_data_type);
> > + DBG("hpte_region.error_flags : 0x%04x\n",
> > + fdm->hpte_region.error_flags);
> > + DBG("hpte_region.source_address : 0x%016Lx\n",
> > + fdm->hpte_region.source_address);
> > + DBG("hpte_region.source_len : 0x%Lx\n",
> > + fdm->hpte_region.source_len);
> > + DBG("hpte_region.bytes_dumped : 0x%Lx\n",
> > + fdm->hpte_region.bytes_dumped);
> > + DBG("hpte_region.destination_address : 0x%016Lx\n",
> > + fdm->hpte_region.destination_address);
> > +
> > + DBG("rmr_region.request_flag : 0x%08x\n",
> > + fdm->rmr_region.request_flag);
> > + DBG("rmr_region.source_data_type : 0x%04x\n",
> > + fdm->rmr_region.source_data_type);
> > + DBG("rmr_region.error_flags : 0x%04x\n",
> > + fdm->rmr_region.error_flags);
> > + DBG("rmr_region.source_address : 0x%016Lx\n",
> > + fdm->rmr_region.source_address);
> > + DBG("rmr_region.source_len : 0x%Lx\n",
> > + fdm->rmr_region.source_len);
> > + DBG("rmr_region.bytes_dumped : 0x%Lx\n",
> > + fdm->rmr_region.bytes_dumped);
> > + DBG("rmr_region.destination_address : 0x%016Lx\n",
> > + fdm->rmr_region.destination_address);
> > +
> > + DBG("--------Firmware-assisted dump memory structure---------\n");
> > +}
> > +
>
> That's an awful lot of debug information. I don't think we need to carry
> this around in the kernel once the feature is working.
Sure, will remove them.
>
> > +static ssize_t fadump_enabled_show(struct kobject *kobj,
> > + struct kobj_attribute *attr,
> > + char *buf)
> > +{
> > + return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
> > +}
> > +
>
> > +static ssize_t fadump_region_show(struct kobject *kobj,
> > + struct kobj_attribute *attr,
> > + char *buf)
> > +{
> > + const struct fadump_mem_struct *fdm_ptr;
> > + ssize_t n = 0;
> > +
> > + if (!fw_dump.fadump_enabled)
> > + return n;
> > +
> > + if (fdm_active)
> > + fdm_ptr = fdm_active;
> > + else
> > + fdm_ptr = &fdm;
> > +
> > + n += sprintf(buf,
> > + "CPU : [%#016llx-%#016llx] %#llx bytes, "
> > + "Dumped: %#llx\n",
> > + fdm_ptr->cpu_state_data.destination_address,
> > + fdm_ptr->cpu_state_data.destination_address +
> > + fdm_ptr->cpu_state_data.source_len - 1,
> > + fdm_ptr->cpu_state_data.source_len,
> > + fdm_ptr->cpu_state_data.bytes_dumped);
> > + n += sprintf(buf + n,
> > + "HPTE: [%#016llx-%#016llx] %#llx bytes, "
> > + "Dumped: %#llx\n",
> > + fdm_ptr->hpte_region.destination_address,
> > + fdm_ptr->hpte_region.destination_address +
> > + fdm_ptr->hpte_region.source_len - 1,
> > + fdm_ptr->hpte_region.source_len,
> > + fdm_ptr->hpte_region.bytes_dumped);
> > + n += sprintf(buf + n,
> > + "DUMP: [%#016llx-%#016llx] %#llx bytes, "
> > + "Dumped: %#llx\n",
> > + fdm_ptr->rmr_region.destination_address,
> > + fdm_ptr->rmr_region.destination_address +
> > + fdm_ptr->rmr_region.source_len - 1,
> > + fdm_ptr->rmr_region.source_len,
> > + fdm_ptr->rmr_region.bytes_dumped);
> > +
> > + if (!fdm_active ||
> > + (fw_dump.reserve_dump_area_start ==
> > + fdm_ptr->cpu_state_data.destination_address))
> > + return n;
> > +
> > + /* Dump is active. Show reserved memory region. */
> > + n += sprintf(buf + n,
> > + " : [%#016llx-%#016llx] %#llx bytes, "
> > + "Dumped: %#llx\n",
> > + (unsigned long long)fw_dump.reserve_dump_area_start,
> > + fdm_ptr->cpu_state_data.destination_address - 1,
> > + fdm_ptr->cpu_state_data.destination_address -
> > + fw_dump.reserve_dump_area_start,
> > + fdm_ptr->cpu_state_data.destination_address -
> > + fw_dump.reserve_dump_area_start);
> > + return n;
> > +}
> > +
> > +static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
> > + 0444, fadump_enabled_show,
> > + NULL);
> > +static struct kobj_attribute fadump_region_attr = __ATTR(fadump_region,
> > + 0444, fadump_region_show, NULL);
> > +
> > +static int fadump_init_sysfs(void)
> > +{
> > + int rc = 0;
> > +
> > + rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
> > + if (rc)
> > + printk(KERN_ERR "fadump: unable to create sysfs file"
> > + " (%d)\n", rc);
> > +
> > + rc = sysfs_create_file(kernel_kobj, &fadump_region_attr.attr);
> > + if (rc)
> > + printk(KERN_ERR "fadump: unable to create sysfs file"
> > + " (%d)\n", rc);
> > + return rc;
> > +}
> > +subsys_initcall(fadump_init_sysfs);
>
> Do we need to dump this all out via sysfs? Will tools depend on this,
> or is it just for debug? It might be better to place in debugfs.
The 'fadump_enabled' sysfs attribute will be used by tool (e.g. kdump
init script) to find out whether fadump is enabled or not and act accordingly.
I will place 'fadump_region' under debugfs as it only shows the fadump memory
reservation map information.
Thanks,
-Mahesh.
--
Mahesh J Salgaonkar
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