Re: [RFC PATCH] powerpc/powernv: Add ultravisor message log interface
On Tue, Jul 9, 2019 at 6:12 AM Claudio Carvalho wrote:
>
> From: Madhavan Srinivasan
>
> Ultravisor provides an in-memory circular buffer containing a message
> log populated with various runtime message produced by firmware.
>
> Based on "powernv/opal-msglog.c", this patch provides a sysfs interface
> /sys/firmware/opal/uv_msglog for userspace to view the messages.
No, it's a copy and paste of the existing memcons code with "uv"
sprinked around the place. I don't mind stuff being c+p since it's
occasionally justified, but be honest about it.
> diff --git a/arch/powerpc/platforms/powernv/opal-uv-msglog.c
> b/arch/powerpc/platforms/powernv/opal-uv-msglog.c
> new file mode 100644
> index ..87d665d7e6ad
> --- /dev/null
> +++ b/arch/powerpc/platforms/powernv/opal-uv-msglog.c
> @@ -0,0 +1,141 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * PowerNV OPAL in-memory ultravisor console interface
> + *
> + * Copyright 2018 IBM Corp.
> + */
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +
> +/* 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 0x8000u
> +#define MEMCONS_OUT_POS_MASK 0x00ffu
> + __be32 in_prod;
> + __be32 in_cons;
> +};
> +
> +static struct memcons *opal_uv_memcons;
> +
> +ssize_t opal_uv_msglog_copy(char *to, loff_t pos, size_t count)
> +{
> + const char *conbuf;
> + ssize_t ret;
> + size_t first_read = 0;
> + uint32_t out_pos, avail;
> +
> + if (!opal_uv_memcons)
> + return -ENODEV;
> +
> + out_pos = be32_to_cpu(READ_ONCE(opal_uv_memcons->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(opal_uv_memcons->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(opal_uv_memcons->obuf_size) - out_pos;
> +
> + ret = memory_read_from_buffer(to, count, ,
> + conbuf + out_pos, avail);
> +
> + if (ret < 0)
> + goto out;
> +
> + first_read = ret;
> + to += first_read;
> + count -= first_read;
> + pos -= avail;
> +
> + if (count <= 0)
> + goto out;
> + }
> +
> + /* Sanity check. The firmware should not do this to us. */
> + if (out_pos > be32_to_cpu(opal_uv_memcons->obuf_size)) {
> + pr_err("OPAL: memory console corruption. Aborting read.\n");
> + return -EINVAL;
> + }
> +
> + ret = memory_read_from_buffer(to, count, , conbuf, out_pos);
> +
> + if (ret < 0)
> + goto out;
> +
> + ret += first_read;
> +out:
> + return ret;
> +}
Make this take an struct memcons as an argument and use the same
function for the opal and UV consoles. Two copies of the same code
with tricky barrier crap in them is not a good idea.
> +static struct bin_attribute opal_uv_msglog_attr = {
> + .attr = {.name = "uv_msglog", .mode = 0444},
We made the OPAL console only readable to root recently, so the mode
should be 0400.
> + .read = opal_uv_msglog_read
> +};
> +
> +void __init opal_uv_msglog_init(void)
> +{
> + u64 mcaddr;
> + struct memcons *mc;
Declarations are reverse-christmas-tree, so these should be the other
way around.
> +
> + if (of_property_read_u64(opal_node, "ibm,opal-uv-memcons", )) {
> + pr_warn("OPAL: Property ibm,opal-uv-memcons not found\n");
> + return;
> + }
> +
> + mc = phys_to_virt(mcaddr);
> + if (!mc) {
> + pr_warn("OPAL: uv memory console address is invalid\n");
> + return;
> + }
> +
> + if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) {
> + pr_warn("OPAL: uv memory console version is invalid\n");
> + return;
> + }
> +
> + /* Report maximum size */
> + opal_uv_msglog_attr.size = be32_to_cpu(mc->ibuf_size) +
> + be32_to_cpu(mc->obuf_size);
> +
> + opal_uv_memcons = mc;
> +}
You can probably share this too if you make it take the DT property
name of the memcons address as an argument, e.g:
struct memcons *opal_uv_msglog_init(const char *dt_prop_name)
> +
> +void __init
[RFC PATCH] powerpc/powernv: Add ultravisor message log interface
From: Madhavan Srinivasan
Ultravisor provides an in-memory circular buffer containing a message
log populated with various runtime message produced by firmware.
Based on "powernv/opal-msglog.c", this patch provides a sysfs interface
/sys/firmware/opal/uv_msglog for userspace to view the messages.
CC: Joel Stanley
CC: Oliver O'Halloran
Signed-off-by: Madhavan Srinivasan
[ Read ibm,opal-uv-memcons instead of OPAL's ]
Signed-off-by: Ryan Grimm
[ Fix license, update the commit message ]
Signed-off-by: Claudio Carvalho
---
arch/powerpc/include/asm/opal.h | 2 +
arch/powerpc/platforms/powernv/Makefile | 1 +
.../platforms/powernv/opal-uv-msglog.c| 141 ++
arch/powerpc/platforms/powernv/opal.c | 2 +
4 files changed, 146 insertions(+)
create mode 100644 arch/powerpc/platforms/powernv/opal-uv-msglog.c
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 4cc37e708bc7..86299c5d866b 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -351,6 +351,8 @@ extern void opal_platform_dump_init(void);
extern void opal_sys_param_init(void);
extern void opal_msglog_init(void);
extern void opal_msglog_sysfs_init(void);
+extern void opal_uv_msglog_init(void);
+extern void opal_uv_msglog_sysfs_init(void);
extern int opal_async_comp_init(void);
extern int opal_sensor_init(void);
extern int opal_hmi_handler_init(void);
diff --git a/arch/powerpc/platforms/powernv/Makefile
b/arch/powerpc/platforms/powernv/Makefile
index da2e99efbd04..216629c63e1d 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -4,6 +4,7 @@ obj-y += idle.o 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 opal-hmi.o opal-power.o opal-irqchip.o
obj-y += opal-kmsg.o opal-powercap.o opal-psr.o
opal-sensor-groups.o
+obj-y += opal-uv-msglog.o
obj-$(CONFIG_SMP) += smp.o subcore.o subcore-asm.o
obj-$(CONFIG_PCI) += pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o
diff --git a/arch/powerpc/platforms/powernv/opal-uv-msglog.c
b/arch/powerpc/platforms/powernv/opal-uv-msglog.c
new file mode 100644
index ..87d665d7e6ad
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-uv-msglog.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * PowerNV OPAL in-memory ultravisor console interface
+ *
+ * Copyright 2018 IBM Corp.
+ */
+#include
+#include
+#include
+#include
+#include
+#include
+
+/* 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 0x8000u
+#define MEMCONS_OUT_POS_MASK 0x00ffu
+ __be32 in_prod;
+ __be32 in_cons;
+};
+
+static struct memcons *opal_uv_memcons;
+
+ssize_t opal_uv_msglog_copy(char *to, loff_t pos, size_t count)
+{
+ const char *conbuf;
+ ssize_t ret;
+ size_t first_read = 0;
+ uint32_t out_pos, avail;
+
+ if (!opal_uv_memcons)
+ return -ENODEV;
+
+ out_pos = be32_to_cpu(READ_ONCE(opal_uv_memcons->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(opal_uv_memcons->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(opal_uv_memcons->obuf_size) - out_pos;
+
+ ret = memory_read_from_buffer(to, count, ,
+ conbuf + out_pos, avail);
+
+ if (ret < 0)
+ goto out;
+
+ first_read = ret;
+ to += first_read;
+ count -= first_read;
+ pos -= avail;
+
+ if (count <= 0)
+ goto out;
+ }
+
+ /* Sanity check. The firmware should not do this to us. */
+ if (out_pos > be32_to_cpu(opal_uv_memcons->obuf_size)) {
+ pr_err("OPAL: memory console corruption. Aborting read.\n");
+ return -EINVAL;
+ }
+
+ ret = memory_read_from_buffer(to, count, , conbuf, out_pos);
+
+ if (ret < 0)
+ goto out;
+
+ ret += first_read;
+out:
+ return ret;
+}
+
+static ssize_t opal_uv_msglog_read(struct file *file, struct kobject *kobj,
+
