linux-kernel - [PATCH v4 2/7] kexec_file: print out debugging message if required

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Message-ID: <20231213055747.61826-3-bhe@redhat.com>
Date:   Wed, 13 Dec 2023 13:57:42 +0800
From:   Baoquan He <bhe@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     kexec@...ts.infradead.org, x86@...nel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, linuxppc-dev@...ts.ozlabs.org,
        linux-parisc@...r.kernel.org, akpm@...ux-foundation.org,
        joe@...ches.com, nathan@...nel.org, conor@...nel.org,
        Baoquan He <bhe@...hat.com>
Subject: [PATCH v4 2/7] kexec_file: print out debugging message if required

Then when specifying '-d' for kexec_file_load interface, loaded
locations of kernel/initrd/cmdline etc can be printed out to help
debug.

Here replace pr_debug() with the newly added kexec_dprintk() in
kexec_file loading related codes.

And also print out type/start/head of kimage and flags to help debug.

Signed-off-by: Baoquan He <bhe@...hat.com>
---
 kernel/crash_core.c                |  8 +++++---
 kernel/kexec_file.c                | 11 ++++++++---
 security/integrity/ima/ima_kexec.c |  4 ++--
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index efe87d501c8c..380d0d3acc7b 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -551,9 +551,11 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
 		phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
 		phdr->p_align = 0;
 		ehdr->e_phnum++;
-		pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
-			phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
-			ehdr->e_phnum, phdr->p_offset);
+#ifdef CONFIG_KEXEC_FILE
+		kexec_dprintk("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
+			      phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
+			      ehdr->e_phnum, phdr->p_offset);
+#endif
 		phdr++;
 	}
 
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index aca5dac74044..76de1ac7c424 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -204,6 +204,8 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 	if (ret < 0)
 		return ret;
 	image->kernel_buf_len = ret;
+	kexec_dprintk("kernel: %p kernel_size: %#lx\n",
+		      image->kernel_buf, image->kernel_buf_len);
 
 	/* Call arch image probe handlers */
 	ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
@@ -387,13 +389,14 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 	if (ret)
 		goto out;
 
+	kexec_dprintk("nr_segments = %lu\n", image->nr_segments);
 	for (i = 0; i < image->nr_segments; i++) {
 		struct kexec_segment *ksegment;
 
 		ksegment = &image->segment[i];
-		pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
-			 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
-			 ksegment->memsz);
+		kexec_dprintk("segment[%d]: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
+			      i, ksegment->buf, ksegment->bufsz, ksegment->mem,
+			      ksegment->memsz);
 
 		ret = kimage_load_segment(image, &image->segment[i]);
 		if (ret)
@@ -406,6 +409,8 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 	if (ret)
 		goto out;
 
+	kexec_dprintk("kexec_file_load: type:%u, start:0x%lx head:0x%lx flags:0x%lx\n",
+		      image->type, image->start, image->head, flags);
 	/*
 	 * Free up any temporary buffers allocated which are not needed
 	 * after image has been loaded
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index ad133fe120db..dadc1d138118 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -129,8 +129,8 @@ void ima_add_kexec_buffer(struct kimage *image)
 	image->ima_buffer_size = kexec_segment_size;
 	image->ima_buffer = kexec_buffer;
 
-	pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
-		 kbuf.mem);
+	kexec_dprintk("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
+		      kbuf.mem);
 }
 #endif /* IMA_KEXEC */
 
-- 
2.41.0