Currently, specifying '-d' will print a lot of debugging information
about kexec/kdump loading with kexec_load interface.
However, kexec_file_load prints nothing even though '-d' is specified.
It's very inconvenient to debug or analyze the kexec/kdump loading when
something wrong happened with kexec/kdump itself or develper want to
check the kexec/kdump loading.
In this patchset, a kexec_file flag is KEXEC_FILE_DEBUG added and checked
in code. If it's passed in, debugging message of kexec_file code will be
printed out and can be seen from console and dmesg. Otherwise, the
debugging message is printed via pr_debug().
Note:
****
=====
1) The code in kexec-tools utility also need be changed to support
passing KEXEC_FILE_DEBUG to kernel when 'kexec -s -d' is specified.
The patch link is here:
=========
[PATCH] kexec_file: add kexec_file flag to support debug printing
http://lists.infradead.org/pipermail/kexec/2023-November/028505.html
2) s390 also has kexec_file code, while I am not sure what debugging
information is necessary. So leave it to s390 developer.
Test:
****
====
Testing was done in v1 on x86_64 and arm64. On x86_64, the printed
messages look like below:
--------------------------------------------------------------
kexec measurement buffer for the loaded kernel at 0x207fffe000.
Loaded purgatory at 0x207fff9000
Loaded boot_param, command line and misc at 0x207fff3000 bufsz=0x1180 memsz=0x1180
Loaded 64bit kernel at 0x207c000000 bufsz=0xc88200 memsz=0x3c4a000
Loaded initrd at 0x2079e79000 bufsz=0x2186280 memsz=0x2186280
Final command line is: root=/dev/mapper/fedora_intel--knightslanding--lb--02-root ro
rd.lvm.lv=fedora_intel-knightslanding-lb-02/root console=ttyS0,115200N81 crashkernel=256M
E820 memmap:
0000000000000000-000000000009a3ff (1)
000000000009a400-000000000009ffff (2)
00000000000e0000-00000000000fffff (2)
0000000000100000-000000006ff83fff (1)
000000006ff84000-000000007ac50fff (2)
......
000000207fff6150-000000207fff615f (128)
000000207fff6160-000000207fff714f (1)
000000207fff7150-000000207fff715f (128)
000000207fff7160-000000207fff814f (1)
000000207fff8150-000000207fff815f (128)
000000207fff8160-000000207fffffff (1)
nr_segments = 5
segment[0]: buf=0x000000004e5ece74 bufsz=0x211 mem=0x207fffe000 memsz=0x1000
segment[1]: buf=0x000000009e871498 bufsz=0x4000 mem=0x207fff9000 memsz=0x5000
segment[2]: buf=0x00000000d879f1fe bufsz=0x1180 mem=0x207fff3000 memsz=0x2000
segment[3]: buf=0x000000001101cd86 bufsz=0xc88200 mem=0x207c000000 memsz=0x3c4a000
segment[4]: buf=0x00000000c6e38ac7 bufsz=0x2186280 mem=0x2079e79000 memsz=0x2187000
kexec_file_load: type:0, start:0x207fff91a0 head:0x109e004002 flags:0x8
---------------------------------------------------------------------------
History:
********
=========
v1->v2:
- Take the new format of kexec_dprintk() suggested by Joe which can
reduce kernel text size.
- Fix building error of patch 2 in kernel/crash_core.c reported by LKP.
- Fix building warning on arm64 in patch 4 reported by LKP.
Baoquan He (7):
kexec_file: add kexec_file flag to control debug printing
kexec_file: print out debugging message if required
kexec_file, x86: print out debugging message if required
kexec_file, arm64: print out debugging message if required
kexec_file, ricv: print out debugging message if required
kexec_file, power: print out debugging message if required
kexec_file, parisc: print out debugging message if required
arch/arm64/kernel/kexec_image.c | 2 +-
arch/arm64/kernel/machine_kexec.c | 26 ++++++--------------------
arch/arm64/kernel/machine_kexec_file.c | 6 +++---
arch/parisc/kernel/kexec_file.c | 6 +++---
arch/powerpc/kexec/elf_64.c | 8 ++++----
arch/powerpc/kexec/file_load_64.c | 14 +++++++-------
arch/riscv/kernel/elf_kexec.c | 9 +++++----
arch/riscv/kernel/machine_kexec.c | 26 --------------------------
arch/x86/kernel/crash.c | 2 +-
arch/x86/kernel/kexec-bzimage64.c | 23 ++++++++++++++---------
include/linux/kexec.h | 10 +++++++++-
include/uapi/linux/kexec.h | 1 +
kernel/crash_core.c | 5 ++++-
kernel/kexec_file.c | 12 +++++++++++-
security/integrity/ima/ima_kexec.c | 2 +-
15 files changed, 70 insertions(+), 82 deletions(-)
--
2.41.0
Replace pr_debug() with the newly added kexec_dprintk() in kexec_file
loading related codes.
And also print out e820 memmap passed to 2nd kernel just as kexec_load
interface has been doing.
Signed-off-by: Baoquan He <[email protected]>
---
arch/x86/kernel/crash.c | 2 +-
arch/x86/kernel/kexec-bzimage64.c | 23 ++++++++++++++---------
2 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index c92d88680dbf..df4dbd3aa08c 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -386,7 +386,7 @@ int crash_load_segments(struct kimage *image)
if (ret)
return ret;
image->elf_load_addr = kbuf.mem;
- pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ kexec_dprintk("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
return ret;
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index a61c12c01270..e9ae0eac6bf9 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -82,7 +82,7 @@ static int setup_cmdline(struct kimage *image, struct boot_params *params,
cmdline_ptr[cmdline_len - 1] = '\0';
- pr_debug("Final command line is: %s\n", cmdline_ptr);
+ kexec_dprintk("Final command line is: %s\n", cmdline_ptr);
cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
cmdline_ext_32 = cmdline_ptr_phys >> 32;
@@ -272,7 +272,12 @@ setup_boot_parameters(struct kimage *image, struct boot_params *params,
nr_e820_entries = params->e820_entries;
+ kexec_dprintk("E820 memmap:\n");
for (i = 0; i < nr_e820_entries; i++) {
+ kexec_dprintk("%016llx-%016llx (%d)\n",
+ params->e820_table[i].addr,
+ params->e820_table[i].addr + params->e820_table[i].size - 1,
+ params->e820_table[i].type);
if (params->e820_table[i].type != E820_TYPE_RAM)
continue;
start = params->e820_table[i].addr;
@@ -424,7 +429,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
* command line. Make sure it does not overflow
*/
if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
- pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
+ kexec_dprintk("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
return ERR_PTR(-EINVAL);
}
@@ -445,7 +450,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
return ERR_PTR(ret);
}
- pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem);
+ kexec_dprintk("Loaded purgatory at 0x%lx\n", pbuf.mem);
/*
@@ -490,8 +495,8 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
if (ret)
goto out_free_params;
bootparam_load_addr = kbuf.mem;
- pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
- bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
+ kexec_dprintk("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
/* Load kernel */
kbuf.buffer = kernel + kern16_size;
@@ -505,8 +510,8 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
goto out_free_params;
kernel_load_addr = kbuf.mem;
- pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
- kernel_load_addr, kbuf.bufsz, kbuf.memsz);
+ kexec_dprintk("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ kernel_load_addr, kbuf.bufsz, kbuf.memsz);
/* Load initrd high */
if (initrd) {
@@ -520,8 +525,8 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
goto out_free_params;
initrd_load_addr = kbuf.mem;
- pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
- initrd_load_addr, initrd_len, initrd_len);
+ kexec_dprintk("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ initrd_load_addr, initrd_len, initrd_len);
setup_initrd(params, initrd_load_addr, initrd_len);
}
--
2.41.0