From 68e0aa8ec5cedec48dd5b11df84afc956c8f85be Mon Sep 17 00:00:00 2001 From: Claudio Carvalho Date: Wed, 28 Aug 2019 23:05:21 +1000 Subject: [PATCH] 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 Signed-off-by: Michael Ellerman Tested-by: Claudio Carvalho Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190828130521.26764-2-mpe@ellerman.id.au --- arch/powerpc/platforms/powernv/powernv.h | 5 +++ arch/powerpc/platforms/powernv/ultravisor.c | 45 +++++++++++++++++++++ 2 files changed, 50 insertions(+) diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h index fd4a1c5a6369..1aa51c4fa904 100644 --- a/arch/powerpc/platforms/powernv/powernv.h +++ b/arch/powerpc/platforms/powernv/powernv.h @@ -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 */ diff --git a/arch/powerpc/platforms/powernv/ultravisor.c b/arch/powerpc/platforms/powernv/ultravisor.c index 02ac57b4bded..e4a00ad06f9d 100644 --- a/arch/powerpc/platforms/powernv/ultravisor.c +++ b/arch/powerpc/platforms/powernv/ultravisor.c @@ -8,9 +8,15 @@ #include #include #include +#include #include #include +#include + +#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);