linux-kernel - [PATCH v2 4/5] x86/crash: pass the dm crypt key to kdump kernel

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Date: Wed, 10 Jan 2024 15:15:19 +0800
From: Coiby Xu <coxu@...hat.com>
To: kexec@...ts.infradead.org
Cc: Ondrej Kozina <okozina@...hat.com>,
	Milan Broz <gmazyland@...il.com>,
	Thomas Staudt <tstaudt@...ibm.com>,
	Daniel P . Berrangé <berrange@...hat.com>,
	Kairui Song <ryncsn@...il.com>,
	dm-devel@...hat.com,
	Jan Pazdziora <jpazdziora@...hat.com>,
	Pingfan Liu <kernelfans@...il.com>,
	Baoquan He <bhe@...hat.com>,
	Dave Young <dyoung@...hat.com>,
	linux-kernel@...r.kernel.org,
	x86@...nel.org,
	Dave Hansen <dave.hansen@...el.com>,
	Vitaly Kuznetsov <vkuznets@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH v2 4/5] x86/crash: pass the dm crypt key to kdump kernel

1st kernel will build up the kernel command parameter dmcryptkey as
similar to elfcorehdr to pass the memory address of the stored info of
dm crypt key to kdump kernel.

Signed-off-by: Coiby Xu <coxu@...hat.com>
---
 arch/x86/kernel/crash.c           | 15 ++++++++++++++-
 arch/x86/kernel/kexec-bzimage64.c |  7 +++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index c92d88680dbf..69e1090f01bc 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -262,6 +262,7 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
 				 unsigned long long mend)
 {
 	unsigned long start, end;
+	int r;
 
 	cmem->ranges[0].start = mstart;
 	cmem->ranges[0].end = mend;
@@ -270,7 +271,19 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
 	/* Exclude elf header region */
 	start = image->elf_load_addr;
 	end = start + image->elf_headers_sz - 1;
-	return crash_exclude_mem_range(cmem, start, end);
+	r = crash_exclude_mem_range(cmem, start, end);
+
+	if (r)
+		return r;
+
+	/* Exclude dm crypt key region */
+	if (image->dm_crypt_key_addr) {
+		start = image->dm_crypt_key_addr;
+		end = start + image->dm_crypt_key_sz - 1;
+		return crash_exclude_mem_range(cmem, start, end);
+	}
+
+	return r;
 }
 
 /* Prepare memory map for crash dump kernel */
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index a61c12c01270..6e8adfe0b417 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -76,6 +76,10 @@ static int setup_cmdline(struct kimage *image, struct boot_params *params,
 	if (image->type == KEXEC_TYPE_CRASH) {
 		len = sprintf(cmdline_ptr,
 			"elfcorehdr=0x%lx ", image->elf_load_addr);
+
+		if (image->dm_crypt_key_addr != 0)
+			len += sprintf(cmdline_ptr + len,
+					"dmcryptkey=0x%lx ", image->dm_crypt_key_addr);
 	}
 	memcpy(cmdline_ptr + len, cmdline, cmdline_len);
 	cmdline_len += len;
@@ -433,6 +437,9 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
 		ret = crash_load_segments(image);
 		if (ret)
 			return ERR_PTR(ret);
+		ret = crash_load_dm_crypt_key(image);
+		if (ret)
+			pr_debug("Either no dm crypt key or error to retrieve the dm crypt key\n");
 	}
 
 	/*
-- 
2.43.0