powerpc/pseries/nvram: Capture oops/panic reports in ibm, oops-log partition (a5cf4b08) · Commits · e / devices / android_kernel_fairphone_FP5

arch/powerpc/platforms/pseries/nvram.c

+115 −3

Original line number	Diff line number	Diff line
		@@ -16,6 +16,8 @@
		#include <linux/errno.h>
		#include <linux/init.h>
		#include <linux/spinlock.h>
		#include <linux/slab.h>
		#include <linux/kmsg_dump.h>
		#include <asm/uaccess.h>
		#include <asm/nvram.h>
		#include <asm/rtas.h>
		@@ -39,7 +41,7 @@ struct nvram_os_partition {
		const char *name;
		int req_size; /* desired size, in bytes */
		int min_size; /* minimum acceptable size (0 means req_size) */
		long size; /* size of data portion of partition */
		long size; /* size of data portion (excluding err_log_info) */
		long index; /* offset of data portion of partition */
		};

		@@ -50,11 +52,35 @@ static struct nvram_os_partition rtas_log_partition = {
		.index = -1
		};

		static struct nvram_os_partition oops_log_partition = {
		.name = "lnx,oops-log",
		.req_size = 4000,
		.min_size = 2000,
		.index = -1
		};

		static const char *pseries_nvram_os_partitions[] = {
		"ibm,rtas-log",
		"lnx,oops-log",
		NULL
		};

		static void oops_to_nvram(struct kmsg_dumper *dumper,
		enum kmsg_dump_reason reason,
		const char *old_msgs, unsigned long old_len,
		const char *new_msgs, unsigned long new_len);

		static struct kmsg_dumper nvram_kmsg_dumper = {
		.dump = oops_to_nvram
		};

		/* See clobbering_unread_rtas_event() */
		#define NVRAM_RTAS_READ_TIMEOUT 5 /* seconds */
		static unsigned long last_unread_rtas_event; /* timestamp */

		/* We preallocate oops_buf during init to avoid kmalloc during oops/panic. */
		static char *oops_buf;

		static ssize_t pSeries_nvram_read(char buf, size_t count, loff_t index)
		{
		unsigned int i;
		@@ -214,8 +240,11 @@ int nvram_write_os_partition(struct nvram_os_partition part, char buff,
		int nvram_write_error_log(char * buff, int length,
		unsigned int err_type, unsigned int error_log_cnt)
		{
		return nvram_write_os_partition(&rtas_log_partition, buff, length,
		int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
		err_type, error_log_cnt);
		if (!rc)
		last_unread_rtas_event = get_seconds();
		return rc;
		}

		/* nvram_read_error_log
		@@ -274,6 +303,7 @@ int nvram_clear_error_log(void)
		printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
		return rc;
		}
		last_unread_rtas_event = 0;

		return 0;
		}
		@@ -342,9 +372,35 @@ static int __init pseries_nvram_init_os_partition(struct nvram_os_partition
		return 0;
		}

		static void __init nvram_init_oops_partition(int rtas_partition_exists)
		{
		int rc;

		rc = pseries_nvram_init_os_partition(&oops_log_partition);
		if (rc != 0) {
		if (!rtas_partition_exists)
		return;
		pr_notice("nvram: Using %s partition to log both"
		" RTAS errors and oops/panic reports\n",
		rtas_log_partition.name);
		memcpy(&oops_log_partition, &rtas_log_partition,
		sizeof(rtas_log_partition));
		}
		oops_buf = kmalloc(oops_log_partition.size, GFP_KERNEL);
		rc = kmsg_dump_register(&nvram_kmsg_dumper);
		if (rc != 0) {
		pr_err("nvram: kmsg_dump_register() failed; returned %d\n", rc);
		kfree(oops_buf);
		return;
		}
		}

		static int __init pseries_nvram_init_log_partitions(void)
		{
		(void) pseries_nvram_init_os_partition(&rtas_log_partition);
		int rc;

		rc = pseries_nvram_init_os_partition(&rtas_log_partition);
		nvram_init_oops_partition(rc == 0);
		return 0;
		}
		machine_arch_initcall(pseries, pseries_nvram_init_log_partitions);
		@@ -378,3 +434,59 @@ int __init pSeries_nvram_init(void)

		return 0;
		}

		/*
		* Try to capture the last capture_len bytes of the printk buffer. Return
		* the amount actually captured.
		*/
		static size_t capture_last_msgs(const char *old_msgs, size_t old_len,
		const char *new_msgs, size_t new_len,
		char *captured, size_t capture_len)
		{
		if (new_len >= capture_len) {
		memcpy(captured, new_msgs + (new_len - capture_len),
		capture_len);
		return capture_len;
		} else {
		/* Grab the end of old_msgs. */
		size_t old_tail_len = min(old_len, capture_len - new_len);
		memcpy(captured, old_msgs + (old_len - old_tail_len),
		old_tail_len);
		memcpy(captured + old_tail_len, new_msgs, new_len);
		return old_tail_len + new_len;
		}
		}

		/*
		* Are we using the ibm,rtas-log for oops/panic reports? And if so,
		* would logging this oops/panic overwrite an RTAS event that rtas_errd
		* hasn't had a chance to read and process? Return 1 if so, else 0.
		*
		* We assume that if rtas_errd hasn't read the RTAS event in
		* NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to.
		*/
		static int clobbering_unread_rtas_event(void)
		{
		return (oops_log_partition.index == rtas_log_partition.index
		&& last_unread_rtas_event
		&& get_seconds() - last_unread_rtas_event <=
		NVRAM_RTAS_READ_TIMEOUT);
		}

		/* our kmsg_dump callback */
		static void oops_to_nvram(struct kmsg_dumper *dumper,
		enum kmsg_dump_reason reason,
		const char *old_msgs, unsigned long old_len,
		const char *new_msgs, unsigned long new_len)
		{
		static unsigned int oops_count = 0;
		size_t text_len;

		if (clobbering_unread_rtas_event())
		return;

		text_len = capture_last_msgs(old_msgs, old_len, new_msgs, new_len,
		oops_buf, oops_log_partition.size);
		(void) nvram_write_os_partition(&oops_log_partition, oops_buf,
		(int) text_len, ERR_TYPE_KERNEL_PANIC, ++oops_count);
		}