powerpc/powernv: Add OPAL message log interface

OPAL provides an in-memory circular buffer containing a message log
populated with various runtime messages produced by the firmware.

Provide a sysfs interface /sys/firmware/opal/msglog for userspace to
view the messages.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Joel Stanley 2014-04-01 14:28:19 +10:30 committed by Benjamin Herrenschmidt
parent 6e556b4710
commit bfc36894a4
4 changed files with 128 additions and 1 deletions

View File

@ -730,6 +730,9 @@ typedef struct oppanel_line {
/* /sys/firmware/opal */
extern struct kobject *opal_kobj;
/* /ibm,opal */
extern struct device_node *opal_node;
/* API functions */
int64_t opal_console_write(int64_t term_number, __be64 *length,
const uint8_t *buffer);
@ -920,6 +923,7 @@ extern void opal_flash_init(void);
extern int opal_elog_init(void);
extern void opal_platform_dump_init(void);
extern void opal_sys_param_init(void);
extern void opal_msglog_init(void);
extern int opal_machine_check(struct pt_regs *regs);
extern bool opal_mce_check_early_recovery(struct pt_regs *regs);

View File

@ -1,6 +1,7 @@
obj-y += setup.o opal-takeover.o opal-wrappers.o opal.o opal-async.o
obj-y += opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
obj-y += rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
obj-y += opal-msglog.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_PCI) += pci.o pci-p5ioc2.o pci-ioda.o

View File

@ -0,0 +1,120 @@
/*
* PowerNV OPAL in-memory console interface
*
* Copyright 2014 IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/io.h>
#include <asm/opal.h>
#include <linux/debugfs.h>
#include <linux/of.h>
#include <linux/types.h>
#include <asm/barrier.h>
/* OPAL in-memory console. Defined in OPAL source at core/console.c */
struct memcons {
__be64 magic;
#define MEMCONS_MAGIC 0x6630696567726173L
__be64 obuf_phys;
__be64 ibuf_phys;
__be32 obuf_size;
__be32 ibuf_size;
__be32 out_pos;
#define MEMCONS_OUT_POS_WRAP 0x80000000u
#define MEMCONS_OUT_POS_MASK 0x00ffffffu
__be32 in_prod;
__be32 in_cons;
};
static ssize_t opal_msglog_read(struct file *file, struct kobject *kobj,
struct bin_attribute *bin_attr, char *to,
loff_t pos, size_t count)
{
struct memcons *mc = bin_attr->private;
const char *conbuf;
size_t ret, first_read = 0;
uint32_t out_pos, avail;
if (!mc)
return -ENODEV;
out_pos = be32_to_cpu(ACCESS_ONCE(mc->out_pos));
/* Now we've read out_pos, put a barrier in before reading the new
* data it points to in conbuf. */
smp_rmb();
conbuf = phys_to_virt(be64_to_cpu(mc->obuf_phys));
/* When the buffer has wrapped, read from the out_pos marker to the end
* of the buffer, and then read the remaining data as in the un-wrapped
* case. */
if (out_pos & MEMCONS_OUT_POS_WRAP) {
out_pos &= MEMCONS_OUT_POS_MASK;
avail = be32_to_cpu(mc->obuf_size) - out_pos;
ret = memory_read_from_buffer(to, count, &pos,
conbuf + out_pos, avail);
if (ret < 0)
goto out;
first_read = ret;
to += first_read;
count -= first_read;
pos -= avail;
}
/* Sanity check. The firmware should not do this to us. */
if (out_pos > be32_to_cpu(mc->obuf_size)) {
pr_err("OPAL: memory console corruption. Aborting read.\n");
return -EINVAL;
}
ret = memory_read_from_buffer(to, count, &pos, conbuf, out_pos);
if (ret < 0)
goto out;
ret += first_read;
out:
return ret;
}
static struct bin_attribute opal_msglog_attr = {
.attr = {.name = "msglog", .mode = 0444},
.read = opal_msglog_read
};
void __init opal_msglog_init(void)
{
u64 mcaddr;
struct memcons *mc;
if (of_property_read_u64(opal_node, "ibm,opal-memcons", &mcaddr)) {
pr_warn("OPAL: Property ibm,opal-memcons not found, no message log\n");
return;
}
mc = phys_to_virt(mcaddr);
if (!mc) {
pr_warn("OPAL: memory console address is invalid\n");
return;
}
if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) {
pr_warn("OPAL: memory console version is invalid\n");
return;
}
opal_msglog_attr.private = mc;
if (sysfs_create_bin_file(opal_kobj, &opal_msglog_attr) != 0)
pr_warn("OPAL: sysfs file creation failed\n");
}

View File

@ -46,7 +46,7 @@ struct mcheck_recoverable_range {
static struct mcheck_recoverable_range *mc_recoverable_range;
static int mc_recoverable_range_len;
static struct device_node *opal_node;
struct device_node *opal_node;
static DEFINE_SPINLOCK(opal_write_lock);
extern u64 opal_mc_secondary_handler[];
static unsigned int *opal_irqs;
@ -602,6 +602,8 @@ static int __init opal_init(void)
opal_platform_dump_init();
/* Setup system parameters interface */
opal_sys_param_init();
/* Setup message log interface. */
opal_msglog_init();
}
return 0;