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powerpc/powernv: Add ultravisor message log interface 

The ultravisor (UV) provides an in-memory console which follows the
OPAL in-memory console structure.

This patch extends the OPAL msglog code to initialize the UV memory
console and provide the "/sys/firmware/ultravisor/msglog" interface
for userspace to view the UV message log.

Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Claudio Carvalho <cclaudio@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190828130521.26764-2-mpe@ellerman.id.au
This commit is contained in:
Claudio Carvalho 2019-08-28 23:05:21 +10:00 committed by Michael Ellerman
parent dea45ea777
commit 68e0aa8ec5
2 changed files with 50 additions and 0 deletions
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5
arch/powerpc/platforms/powernv/powernv.h
View File

@ -30,4 +30,9 @@ extern void opal_event_shutdown(void);
bool cpu_core_split_required(void);
struct memcons;
ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count);
u32 memcons_get_size(struct memcons *mc);
struct memcons *memcons_init(struct device_node *node, const char *mc_prop_name);
#endif /* _POWERNV_H */

45
arch/powerpc/platforms/powernv/ultravisor.c
View File

@ -8,9 +8,15 @@
#include <linux/init.h>
#include <linux/printk.h>
#include <linux/of_fdt.h>
#include <linux/of.h>
#include <asm/ultravisor.h>
#include <asm/firmware.h>
#include <asm/machdep.h>
#include "powernv.h"
static struct kobject *ultravisor_kobj;
int __init early_init_dt_scan_ultravisor(unsigned long node, const char *uname,
int depth, void *data)
@ -22,3 +28,42 @@ int __init early_init_dt_scan_ultravisor(unsigned long node, const char *uname,
pr_debug("Ultravisor detected!\n");
return 1;
}
static struct memcons *uv_memcons;
static ssize_t uv_msglog_read(struct file *file, struct kobject *kobj,
struct bin_attribute *bin_attr, char *to,
loff_t pos, size_t count)
{
return memcons_copy(uv_memcons, to, pos, count);
}
static struct bin_attribute uv_msglog_attr = {
.attr = {.name = "msglog", .mode = 0400},
.read = uv_msglog_read
};
static int __init uv_init(void)
{
struct device_node *node;
if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
return 0;
node = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");
if (!node)
return -ENODEV;
uv_memcons = memcons_init(node, "memcons");
if (!uv_memcons)
return -ENOENT;
uv_msglog_attr.size = memcons_get_size(uv_memcons);
ultravisor_kobj = kobject_create_and_add("ultravisor", firmware_kobj);
if (!ultravisor_kobj)
return -ENOMEM;
return sysfs_create_bin_file(ultravisor_kobj, &uv_msglog_attr);
}
machine_subsys_initcall(powernv, uv_init);