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Commit bfc36894 authored by Joel Stanley's avatar Joel Stanley Committed by Benjamin Herrenschmidt
Browse files

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: default avatarJoel Stanley <joel@jms.id.au>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 6e556b47

arch/powerpc/include/asm/opal.h

+4 −0
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/platforms/powernv/Makefile

+1 −0
Original line number Diff line number Diff line 
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

arch/powerpc/platforms/powernv/opal-msglog.c

0 → 100644
+120 −0
Original line number Diff line number Diff line 
/*

 * 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");

}

arch/powerpc/platforms/powernv/opal.c

+3 −1
Original line number Diff line number Diff line
@@ -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;