[Skiboot] [PATCH v2 2/2] core: Implement non-FSP dump region opal call

[Benjamin Herrenschmidt]

On Mon, 2018-05-28 at 13:25 +0930, Joel Stanley wrote:
> This provides an implementation of the OPAL_REGISTER_DUMP_REGION and
> OPAL_UNREGISTER_DUMP_REGION calls that can be used by non-FSP systems,
> and performs that registration for all astbmc platforms.
> 
> This pointer will be used by eg. pdbg to fetch the host kernel's log
> buffer over FSI.
> 
> We unconditionally clear the value on a reboot (both fast-reboot and
> reliable reboot) to reduce the chance of debug tools getting the wrong
> buffer.

I wouldn't make it BMC specific.

Instead, I would suggest you:

 - Add "generic" OPAL calls that populate the debug descritor (ie,
statically defined using OPAL_CALL).

 - Make the above call an optional machine.register_dump_region

 - Make FSP machines populate the above to *also* register with the
FSP.

That way we can also use/create similar tools (or just getmemproc) to
get to the kernel dmesg via the debug descriptor on FSP systems.

Cheers,
Ben.

> Signed-off-by: Joel Stanley <joel at jms.id.au>
> ---
> v2:
>  Rename dump.h to dump-region.h
>  Add comment to init.c
> ---
>  core/Makefile.inc         |  2 +-
>  core/dump-region.c        | 61 +++++++++++++++++++++++++++++++++++++++
>  core/init.c               |  4 +++
>  include/dump-region.h     | 26 +++++++++++++++++
>  platforms/astbmc/common.c |  4 +++
>  5 files changed, 96 insertions(+), 1 deletion(-)
>  create mode 100644 core/dump-region.c
>  create mode 100644 include/dump-region.h
> 
> diff --git a/core/Makefile.inc b/core/Makefile.inc
> index d36350590edb..2d2f74778f4c 100644
> --- a/core/Makefile.inc
> +++ b/core/Makefile.inc
> @@ -9,7 +9,7 @@ CORE_OBJS += vpd.o hostservices.o platform.o nvram.o nvram-format.o hmi.o
>  CORE_OBJS += console-log.o ipmi.o time-utils.o pel.o pool.o errorlog.o
>  CORE_OBJS += timer.o i2c.o rtc.o flash.o sensor.o ipmi-opal.o
>  CORE_OBJS += flash-subpartition.o bitmap.o buddy.o pci-quirk.o powercap.o psr.o
> -CORE_OBJS += pci-dt-slot.o direct-controls.o cpufeatures.o
> +CORE_OBJS += pci-dt-slot.o direct-controls.o cpufeatures.o dump-region.o
>  
>  ifeq ($(SKIBOOT_GCOV),1)
>  CORE_OBJS += gcov-profiling.o
> diff --git a/core/dump-region.c b/core/dump-region.c
> new file mode 100644
> index 000000000000..e42486f99ebf
> --- /dev/null
> +++ b/core/dump-region.c
> @@ -0,0 +1,61 @@
> +/* Copyright 2018 IBM Corp.
> + *
> + * Licensed under the Apache License, Version 2.0 (the "License");
> + * you may not use this file except in compliance with the License.
> + * You may obtain a copy of the License at
> + *
> + * 	http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
> + * implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +
> +#define pr_fmt(fmt) "DUMP: " fmt
> +
> +#include <opal.h>
> +#include <skiboot.h>
> +
> +#include <dump-region.h>
> +
> +static int64_t bmc_opal_register_dump_region(uint32_t id,
> +					     uint64_t addr, uint64_t size)
> +{
> +	if (id != OPAL_DUMP_REGION_LOG_BUF) {
> +		prerror("Unsupported log region id %02x\n", id);
> +		return OPAL_UNSUPPORTED;
> +	}
> +
> +	if (size <= 0) {
> +		prerror("Invalid log size %lld\n", size);
> +		return OPAL_PARAMETER;
> +	}
> +
> +	prlog(PR_INFO, "Registered log buf at 0x%016llx\n", addr);
> +	debug_descriptor.log_buf_phys = addr;
> +
> +	return OPAL_SUCCESS;
> +}
> +
> +static int64_t bmc_opal_unregister_dump_region(uint32_t id)
> +{
> +	if (id != OPAL_DUMP_REGION_LOG_BUF) {
> +		prlog(PR_DEBUG, "Unsupported log region id %02x\n", id);
> +		return OPAL_UNSUPPORTED;
> +	}
> +	prlog(PR_INFO, "Unregistered log buf\n");
> +	debug_descriptor.log_buf_phys = 0;
> +
> +	return OPAL_SUCCESS;
> +}
> +
> +void bmc_dump_region_init(void)
> +{
> +	opal_register(OPAL_REGISTER_DUMP_REGION,
> +		      bmc_opal_register_dump_region, 3);
> +	opal_register(OPAL_UNREGISTER_DUMP_REGION,
> +		      bmc_opal_unregister_dump_region, 1);
> +};
> diff --git a/core/init.c b/core/init.c
> index 3b887a24d11c..c1c352858e06 100644
> --- a/core/init.c
> +++ b/core/init.c
> @@ -563,6 +563,10 @@ void __noreturn load_and_boot_kernel(bool is_reboot)
>  
>  	mem_dump_free();
>  
> +	/* Zero out memory location before the next kernel starts, in case the
> +	 * previous kernel did not unregister */
> +	debug_descriptor.log_buf_phys = 0;
> +
>  	/* Take processours out of nap */
>  	cpu_set_sreset_enable(false);
>  	cpu_set_ipi_enable(false);
> diff --git a/include/dump-region.h b/include/dump-region.h
> new file mode 100644
> index 000000000000..b629e66a85e6
> --- /dev/null
> +++ b/include/dump-region.h
> @@ -0,0 +1,26 @@
> +/* Copyright 2018 IBM Corp.
> + *
> + * Licensed under the Apache License, Version 2.0 (the "License");
> + * you may not use this file except in compliance with the License.
> + * You may obtain a copy of the License at
> + *
> + * 	http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
> + * implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +
> +#ifndef __DUMP_H
> +#define __DUMP_H
> +
> +/*
> + * Initialise dump region registration OPAL calls for bmc systems.
> + */
> +void bmc_dump_region_init(void);
> +
> +#endif
> +
> diff --git a/platforms/astbmc/common.c b/platforms/astbmc/common.c
> index 30c2714f94b9..ca8ec7e8c0ce 100644
> --- a/platforms/astbmc/common.c
> +++ b/platforms/astbmc/common.c
> @@ -26,6 +26,7 @@
>  #include <bt.h>
>  #include <errorlog.h>
>  #include <lpc.h>
> +#include <dump-region.h>
>  
>  #include "astbmc.h"
>  
> @@ -156,6 +157,9 @@ void astbmc_init(void)
>  
>  	/* Add BMC firmware info to device tree */
>  	ipmi_dt_add_bmc_info();
> +
> +	/* Enable dump region OPAL calls */
> +	bmc_dump_region_init();
>  }
>  
>  int64_t astbmc_ipmi_power_down(uint64_t request)