linux-kernel - [PATCH v5 6/7] x86/crash: pass dm crypt keys to kdump kernel

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Message-ID: <20240607122622.167228-7-coxu@redhat.com>
Date: Fri,  7 Jun 2024 20:26:16 +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>,
	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>,
	Greg KH <gregkh@...uxfoundation.org>,
	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 v5 6/7] x86/crash: pass dm crypt keys to kdump kernel

1st kernel will build up the kernel command parameter dmcryptkeys 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           | 20 ++++++++++++++++++--
 arch/x86/kernel/kexec-bzimage64.c |  7 +++++++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index f06501445cd9..ca7f7d44a433 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -266,6 +266,7 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
 				 unsigned long long mend)
 {
 	unsigned long start, end;
+	int ret;
 
 	cmem->ranges[0].start = mstart;
 	cmem->ranges[0].end = mend;
@@ -274,22 +275,37 @@ 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);
+	ret = crash_exclude_mem_range(cmem, start, end);
+
+	if (ret)
+		return ret;
+
+	/* Exclude dm crypt keys region */
+	if (image->dm_crypt_keys_addr) {
+		start = image->dm_crypt_keys_addr;
+		end = start + image->dm_crypt_keys_sz - 1;
+		return crash_exclude_mem_range(cmem, start, end);
+	}
+
+	return ret;
 }
 
 /* Prepare memory map for crash dump kernel */
 int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 {
+	unsigned int max_nr_ranges = 3;
 	int i, ret = 0;
 	unsigned long flags;
 	struct e820_entry ei;
 	struct crash_memmap_data cmd;
 	struct crash_mem *cmem;
 
-	cmem = vzalloc(struct_size(cmem, ranges, 1));
+	cmem = vzalloc(struct_size(cmem, ranges, max_nr_ranges));
 	if (!cmem)
 		return -ENOMEM;
 
+	cmem->max_nr_ranges = max_nr_ranges;
+
 	memset(&cmd, 0, sizeof(struct crash_memmap_data));
 	cmd.params = params;
 
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 68530fad05f7..9c94428927bd 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_keys_addr != 0)
+			len += sprintf(cmdline_ptr + len,
+					"dmcryptkeys=0x%lx ", image->dm_crypt_keys_addr);
 	}
 	memcpy(cmdline_ptr + len, cmdline, cmdline_len);
 	cmdline_len += len;
@@ -441,6 +445,9 @@ 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_keys(image);
+		if (ret)
+			pr_debug("Either no dm crypt key or error to retrieve the dm crypt key\n");
 	}
 #endif
 
-- 
2.45.1