The sequence of actions done by device drivers to append their device
specific hardware/firmware logs to /proc/vmcore are as follows:
1. During probe (before hardware is initialized), device drivers
register to the vmcore module (via vmcore_add_device_dump()), with
callback function, along with buffer size and log name needed for
firmware/hardware log collection.
2. vmcore module allocates the buffer with requested size. It adds
an Elf note and invokes the device driver's registered callback
function.
3. Device driver collects all hardware/firmware logs into the buffer
and returns control back to vmcore module.
Ensure that the device dump buffer size is always aligned to page size
so that it can be mmaped.
Also, rename alloc_elfnotes_buf() to vmcore_alloc_buf() to make it more
generic and reserve NT_VMCOREDD note type to indicate vmcore device
dump.
Suggested-by: Eric Biederman .
Signed-off-by: Rahul Lakkireddy
Signed-off-by: Ganesh Goudar
---
v4:
- Made __vmcore_add_device_dump() static.
- Moved compile check to define vmcore_add_device_dump() to
crash_dump.h to fix compilation when vmcore.c is not compiled in.
- Convert ---help--- to help in Kconfig as indicated by checkpatch.
- Rebased to tip.
v3:
- Dropped sysfs crashdd module.
- Added CONFIG_PROC_VMCORE_DEVICE_DUMP to allow configuring device
dump support.
- Moved logic related to adding dumps from crashdd to vmcore module.
- Rename all crashdd* to vmcoredd*.
v2:
- Added ABI Documentation for crashdd.
- Directly use octal permission instead of macro.
Changes since rfc v2:
- Moved exporting crashdd from procfs to sysfs. Suggested by
Stephen Hemminger
- Moved code from fs/proc/crashdd.c to fs/crashdd/ directory.
- Replaced all proc API with sysfs API and updated comments.
- Calling driver callback before creating the binary file under
crashdd sysfs.
- Changed binary dump file permission from S_IRUSR to S_IRUGO.
- Changed module name from CRASH_DRIVER_DUMP to CRASH_DEVICE_DUMP.
rfc v2:
- Collecting logs in 2nd kernel instead of during kernel panic.
Suggested by Eric Biederman .
- Patch added in this series.
fs/proc/Kconfig| 10 +++
fs/proc/vmcore.c | 152 ++---
include/linux/crash_core.h | 4 ++
include/linux/crash_dump.h | 17 +
include/linux/kcore.h | 6 ++
include/uapi/linux/elf.h | 1 +
6 files changed, 181 insertions(+), 9 deletions(-)
diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig
index 1ade1206bb89..504c77a444bd 100644
--- a/fs/proc/Kconfig
+++ b/fs/proc/Kconfig
@@ -43,6 +43,16 @@ config PROC_VMCORE
help
Exports the dump image of crashed kernel in ELF format.
+config PROC_VMCORE_DEVICE_DUMP
+ bool "Device Hardware/Firmware Log Collection"
+ depends on PROC_VMCORE
+ default y
+ help
+ Device drivers can collect the device specific snapshot of
+ their hardware or firmware before they are initialized in
+ crash recovery kernel. If you say Y here, the device dumps
+ will be added as ELF notes to /proc/vmcore
+
config PROC_SYSCTL
bool "Sysctl support (/proc/sys)" if EXPERT
depends on PROC_FS
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index a45f0af22a60..7395462d2f86 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -20,6 +20,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -44,6 +45,12 @@ static u64 vmcore_size;
static struct proc_dir_entry *proc_vmcore;
+#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
+/* Device Dump list and mutex to synchronize access to list */
+static LIST_HEAD(vmcoredd_list);
+static DEFINE_MUTEX(vmcoredd_mutex);
+#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
/*
* Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
* The called function has to take care of module refcounting.
@@ -302,10 +309,8 @@ static const struct vm_operations_struct vmcore_mmap_ops =
{
};
/**
- * alloc_elfnotes_buf - allocate buffer for ELF note segment in
- * vmalloc memory
- *
- * @notes_sz: size of buffer
+ * vmcore_alloc_buf - allocate buffer in vmalloc memory
+ * @sizez: size of buffer
*
* If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
* the buffer to user-space by means of remap_vmalloc_range().
@@ -313,12 +318,12 @@ static const struct vm_operations_struct vmcore_mmap_ops
= {
* If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
* disabled and there's no need to allow users to mmap the buffer.
*/
-static inline char *alloc_elfnotes_buf(size_t notes_sz)
+static inline char *vmcore_alloc_buf(size_t size)
{
#ifdef CONFIG_MMU
- return vmalloc_user(notes_sz);
+ return vmalloc_user(size);
#else
- return vzalloc(notes_sz);
+ return vzalloc(size);
#endif
}
@@ -665,7 +670,7 @@ static int __init merge_note_headers_elf64(char *elfptr,
size_t *elfsz,
return rc;
*notes_sz = roundup
