[RFC PATCH 2/3] powerpc/fadump: pass additional parameters to dump capture kernel
Hari Bathini
hbathini at linux.ibm.com
Wed Dec 6 07:18:34 AEDT 2023
For fadump case, passing additional parameters to dump capture kernel
helps in minimizing the memory footprint for it and also provides the
flexibility to disable components/modules, like hugepages, that are
hindering the boot process of the special dump capture environment.
Set up a dedicated parameter area to be passed to the capture kernel.
This area type is defined as RTAS_FADUMP_PARAM_AREA. Sysfs attribute
'/sys/kernel/fadump/bootargs_append' is exported to the userspace to
specify the additional parameters to be passed to the capture kernel
Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
---
arch/powerpc/include/asm/fadump-internal.h | 3 +
arch/powerpc/kernel/fadump.c | 80 ++++++++++++++++++++
arch/powerpc/platforms/powernv/opal-fadump.c | 6 +-
arch/powerpc/platforms/pseries/rtas-fadump.c | 35 ++++++++-
arch/powerpc/platforms/pseries/rtas-fadump.h | 11 ++-
5 files changed, 126 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/fadump-internal.h b/arch/powerpc/include/asm/fadump-internal.h
index b3956c400519..81629226b15f 100644
--- a/arch/powerpc/include/asm/fadump-internal.h
+++ b/arch/powerpc/include/asm/fadump-internal.h
@@ -97,6 +97,8 @@ struct fw_dump {
unsigned long cpu_notes_buf_vaddr;
unsigned long cpu_notes_buf_size;
+ unsigned long param_area;
+
/*
* Maximum size supported by firmware to copy from source to
* destination address per entry.
@@ -111,6 +113,7 @@ struct fw_dump {
unsigned long dump_active:1;
unsigned long dump_registered:1;
unsigned long nocma:1;
+ unsigned long param_area_supported:1;
struct fadump_ops *ops;
};
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 757681658dda..98f089747ac9 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1470,6 +1470,7 @@ static ssize_t mem_reserved_show(struct kobject *kobj,
return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size);
}
+
static ssize_t registered_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
@@ -1477,6 +1478,43 @@ static ssize_t registered_show(struct kobject *kobj,
return sprintf(buf, "%d\n", fw_dump.dump_registered);
}
+static ssize_t bootargs_append_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%s\n", (char *)__va(fw_dump.param_area));
+}
+
+static ssize_t bootargs_append_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ char *params;
+
+ if (!fw_dump.fadump_enabled || fw_dump.dump_active)
+ return -EPERM;
+
+ if (count >= COMMAND_LINE_SIZE)
+ return -EINVAL;
+
+ /*
+ * Fail here instead of handling this scenario with
+ * some silly workaround in capture kernel.
+ */
+ if (saved_command_line_len + count >= COMMAND_LINE_SIZE) {
+ pr_err("Appending parameters exceeds cmdline size!\n");
+ return -ENOSPC;
+ }
+
+ params = __va(fw_dump.param_area);
+ strscpy_pad(params, buf, COMMAND_LINE_SIZE);
+ /* Remove newline character at the end. */
+ if (params[count-1] == '\n')
+ params[count-1] = '\0';
+
+ return count;
+}
+
static ssize_t registered_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
@@ -1535,6 +1573,7 @@ static struct kobj_attribute release_attr = __ATTR_WO(release_mem);
static struct kobj_attribute enable_attr = __ATTR_RO(enabled);
static struct kobj_attribute register_attr = __ATTR_RW(registered);
static struct kobj_attribute mem_reserved_attr = __ATTR_RO(mem_reserved);
+static struct kobj_attribute bootargs_append_attr = __ATTR_RW(bootargs_append);
static struct attribute *fadump_attrs[] = {
&enable_attr.attr,
@@ -1611,6 +1650,46 @@ static void __init fadump_init_files(void)
return;
}
+/*
+ * Reserve memory to store additional parameters to be passed
+ * for fadump/capture kernel.
+ */
+static void fadump_setup_param_area(void)
+{
+ phys_addr_t range_start, range_end;
+
+ if (!fw_dump.param_area_supported || fw_dump.dump_active)
+ return;
+
+ /* This memory can't be used by PFW or bootloader as it is shared across kernels */
+ if (radix_enabled()) {
+ /*
+ * Anywhere in the upper half should be good enough as all memory
+ * is accessible in real mode.
+ */
+ range_start = memblock_end_of_DRAM() / 2;
+ range_end = memblock_end_of_DRAM();
+ } else {
+ /*
+ * Passing additional parameters is supported for hash MMU only
+ * if the first memory block size is 768MB or higher.
+ */
+ if (ppc64_rma_size < 0x30000000)
+ return;
+
+ /* 640 MB to 768 MB is not used by bootloader */
+ range_start = 0x28000000;
+ range_end = range_start + 0x4000000;
+ }
+
+ fw_dump.param_area = memblock_phys_alloc_range(COMMAND_LINE_SIZE,
+ COMMAND_LINE_SIZE,
+ range_start,
+ range_end);
+ if (!fw_dump.param_area || sysfs_create_file(fadump_kobj, &bootargs_append_attr.attr))
+ pr_warn("WARNING: Could not setup area to pass additional parameters!\n");
+}
+
/*
* Prepare for firmware-assisted dump.
*/
@@ -1639,6 +1718,7 @@ int __init setup_fadump(void)
}
/* Initialize the kernel dump memory structure and register with f/w */
else if (fw_dump.reserve_dump_area_size) {
+ fadump_setup_param_area();
fw_dump.ops->fadump_init_mem_struct(&fw_dump);
register_fadump();
}
diff --git a/arch/powerpc/platforms/powernv/opal-fadump.c b/arch/powerpc/platforms/powernv/opal-fadump.c
index fa26c21a08d9..13370f5cd5ac 100644
--- a/arch/powerpc/platforms/powernv/opal-fadump.c
+++ b/arch/powerpc/platforms/powernv/opal-fadump.c
@@ -682,8 +682,10 @@ void __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node)
}
}
- fadump_conf->ops = &opal_fadump_ops;
- fadump_conf->fadump_supported = 1;
+ fadump_conf->ops = &opal_fadump_ops;
+ fadump_conf->fadump_supported = 1;
+ /* TODO: Add support to pass additional parameters */
+ fadump_conf->param_area_supported = 0;
/*
* Firmware supports 32-bit field for size. Align it to PAGE_SIZE
diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.c b/arch/powerpc/platforms/pseries/rtas-fadump.c
index 1b05b4cefdfd..18838ae90688 100644
--- a/arch/powerpc/platforms/pseries/rtas-fadump.c
+++ b/arch/powerpc/platforms/pseries/rtas-fadump.c
@@ -18,6 +18,7 @@
#include <asm/page.h>
#include <asm/rtas.h>
+#include <asm/setup.h>
#include <asm/fadump.h>
#include <asm/fadump-internal.h>
@@ -80,6 +81,9 @@ static void __init rtas_fadump_get_config(struct fw_dump *fadump_conf,
last_end = base + size;
fadump_conf->boot_mem_regs_cnt++;
break;
+ case RTAS_FADUMP_PARAM_AREA:
+ fadump_conf->param_area = be64_to_cpu(fdm->rgn[i].destination_address);
+ break;
default:
pr_warn("Section type %d unsupported on this kernel. Ignoring!\n", type);
break;
@@ -153,7 +157,17 @@ static u64 rtas_fadump_init_mem_struct(struct fw_dump *fadump_conf)
sec_cnt++;
}
+ /* Parameters area */
+ if (fadump_conf->param_area) {
+ fdm.rgn[sec_cnt].request_flag = cpu_to_be32(RTAS_FADUMP_REQUEST_FLAG);
+ fdm.rgn[sec_cnt].source_data_type = cpu_to_be16(RTAS_FADUMP_PARAM_AREA);
+ fdm.rgn[sec_cnt].source_address = cpu_to_be64(fadump_conf->param_area);
+ fdm.rgn[sec_cnt].source_len = cpu_to_be64(COMMAND_LINE_SIZE);
+ fdm.rgn[sec_cnt].destination_address = cpu_to_be64(fadump_conf->param_area);
+ sec_cnt++;
+ }
fdm.header.dump_num_sections = cpu_to_be16(sec_cnt);
+
rtas_fadump_update_config(fadump_conf, &fdm);
return addr;
@@ -457,6 +471,13 @@ static int __init rtas_fadump_process(struct fw_dump *fadump_conf)
return rc;
}
break;
+ case RTAS_FADUMP_PARAM_AREA:
+ if (fdm_active->rgn[i].bytes_dumped != fdm_active->rgn[i].source_len ||
+ fdm_active->rgn[i].error_flags != 0) {
+ pr_warn("Failed to process additional parameters! Proceeding anyway..\n");
+ fadump_conf->param_area = 0;
+ }
+ break;
default:
/*
* If the first/crashed kernel added a new region type that the
@@ -532,6 +553,13 @@ static void rtas_fadump_region_show(struct fw_dump *fadump_conf,
be64_to_cpu(fdm_ptr->rgn[i].source_len),
be64_to_cpu(fdm_ptr->rgn[i].bytes_dumped));
break;
+ case RTAS_FADUMP_PARAM_AREA:
+ seq_printf(m, "\n[%#016llx-%#016llx]: cmdline append: '%s'\n",
+ be64_to_cpu(fdm_ptr->rgn[i].destination_address),
+ be64_to_cpu(fdm_ptr->rgn[i].destination_address) +
+ be64_to_cpu(fdm_ptr->rgn[i].source_len) - 1,
+ (char *)__va(be64_to_cpu(fdm_ptr->rgn[i].destination_address)));
+ break;
default:
seq_printf(m, "Unknown region type %d : Src: %#016llx, Dest: %#016llx, ",
type, be64_to_cpu(fdm_ptr->rgn[i].source_address),
@@ -594,9 +622,10 @@ void __init rtas_fadump_dt_scan(struct fw_dump *fadump_conf, u64 node)
if (!token)
return;
- fadump_conf->ibm_configure_kernel_dump = be32_to_cpu(*token);
- fadump_conf->ops = &rtas_fadump_ops;
- fadump_conf->fadump_supported = 1;
+ fadump_conf->ibm_configure_kernel_dump = be32_to_cpu(*token);
+ fadump_conf->ops = &rtas_fadump_ops;
+ fadump_conf->fadump_supported = 1;
+ fadump_conf->param_area_supported = 1;
/* Firmware supports 64-bit value for size, align it to pagesize. */
fadump_conf->max_copy_size = ALIGN_DOWN(U64_MAX, PAGE_SIZE);
diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.h b/arch/powerpc/platforms/pseries/rtas-fadump.h
index 6740f4981bb8..c109abf6befd 100644
--- a/arch/powerpc/platforms/pseries/rtas-fadump.h
+++ b/arch/powerpc/platforms/pseries/rtas-fadump.h
@@ -23,6 +23,9 @@
#define RTAS_FADUMP_HPTE_REGION 0x0002
#define RTAS_FADUMP_REAL_MODE_REGION 0x0011
+/* OS defined sections */
+#define RTAS_FADUMP_PARAM_AREA 0x0100
+
/* Dump request flag */
#define RTAS_FADUMP_REQUEST_FLAG 0x00000001
@@ -31,12 +34,12 @@
/*
* The Firmware Assisted Dump Memory structure supports a maximum of 10 sections
- * in the dump memory structure. Presently, first two sections are used for
- * CPU and HPTE data, while the remaining eight sections can be used for
- * boot memory regions.
+ * in the dump memory structure. Presently, three sections are used for
+ * CPU state data, HPTE & Parameters area, while the remaining seven sections
+ * can be used for boot memory regions.
*/
#define MAX_SECTIONS 10
-#define RTAS_FADUMP_MAX_BOOT_MEM_REGS 8
+#define RTAS_FADUMP_MAX_BOOT_MEM_REGS 7
/* Kernel Dump section info */
struct rtas_fadump_section {
--
2.43.0
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