From af338a51df9012f1b1dca87ddd27a5c66db5b80b Mon Sep 17 00:00:00 2001
Message-Id: <af338a51df9012f1b1dca87ddd27a5c66db5b80b.1489676829.git.panand@redhat.com>
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From: AKASHI Takahiro <takahiro.akashi@linaro.org>
Date: Wed, 15 Mar 2017 18:38:21 +0900
Subject: [PATCH 07/10] arm64: kdump: set up kernel image segment

On arm64, we can use the same kernel image as 1st kernel, but
we have to modify the entry point as well as segments' addresses
in the kernel's elf header in order to load them into correct places.

Minor conflicts was resolved in kexec/arch/arm64/crashdump-arm64.c because
get_crash_kernel_load_range() is not yet backported.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 kexec/arch/arm64/crashdump-arm64.c | 23 +++++++++++++++++++++++
 kexec/arch/arm64/crashdump-arm64.h |  1 +
 kexec/arch/arm64/kexec-arm64.c     | 25 ++++++++++++++++++++-----
 kexec/arch/arm64/kexec-elf-arm64.c | 10 +++++++++-
 4 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
index 83461312d412..9517329e1086 100644
--- a/kexec/arch/arm64/crashdump-arm64.c
+++ b/kexec/arch/arm64/crashdump-arm64.c
@@ -213,3 +213,26 @@ int load_crashdump_segments(struct kexec_info *info)
 
 	return 0;
 }
+
+/*
+ * e_entry and p_paddr are actually in virtual address space.
+ * Those values will be translated to physcal addresses by
+ * using virt_to_phys().
+ * So let's get ready for later use so the memory base (phys_offset)
+ * will be correctly replaced with crash_reserved_mem.start.
+ */
+void modify_ehdr_for_crashdump(struct mem_ehdr *ehdr)
+{
+	struct mem_phdr *phdr;
+	int i;
+
+	ehdr->e_entry += - arm64_mem.phys_offset + crash_reserved_mem.start;
+
+	for (i = 0; i < ehdr->e_phnum; i++) {
+		phdr = &ehdr->e_phdr[i];
+		if (phdr->p_type != PT_LOAD)
+			continue;
+		phdr->p_paddr +=
+			(-arm64_mem.phys_offset + crash_reserved_mem.start);
+	}
+}
diff --git a/kexec/arch/arm64/crashdump-arm64.h b/kexec/arch/arm64/crashdump-arm64.h
index da75a2d0c5f1..382f57154f2a 100644
--- a/kexec/arch/arm64/crashdump-arm64.h
+++ b/kexec/arch/arm64/crashdump-arm64.h
@@ -21,5 +21,6 @@ extern struct memory_range crash_reserved_mem;
 extern struct memory_range elfcorehdr_mem;
 
 extern int load_crashdump_segments(struct kexec_info *info);
+extern void modify_ehdr_for_crashdump(struct mem_ehdr *ehdr);
 
 #endif /* CRASHDUMP_ARM64_H */
diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
index d02b9dac3d33..5a1da2ec1a34 100644
--- a/kexec/arch/arm64/kexec-arm64.c
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -307,12 +307,27 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
 {
 	unsigned long hole;
 
-	hole = locate_hole(info,
-		arm64_mem.text_offset + arm64_mem.image_size,
-		MiB(2), 0, ULONG_MAX, 1);
+	if (info->kexec_flags & KEXEC_ON_CRASH) {
+		unsigned long hole_end;
+
+		hole = (crash_reserved_mem.start < mem_min ?
+				mem_min : crash_reserved_mem.start);
+		hole = _ALIGN_UP(hole, MiB(2));
+		hole_end = hole + arm64_mem.text_offset + arm64_mem.image_size;
+
+		if ((hole_end > mem_max) ||
+		    (hole_end > crash_reserved_mem.end)) {
+			dbgprintf("%s: Crash kernel out of range\n", __func__);
+			hole = ULONG_MAX;
+		}
+	} else {
+		hole = locate_hole(info,
+			arm64_mem.text_offset + arm64_mem.image_size,
+			MiB(2), 0, ULONG_MAX, 1);
 
-	if (hole == ULONG_MAX)
-		dbgprintf("%s: locate_hole failed\n", __func__);
+		if (hole == ULONG_MAX)
+			dbgprintf("%s: locate_hole failed\n", __func__);
+	}
 
 	return hole;
 }
diff --git a/kexec/arch/arm64/kexec-elf-arm64.c b/kexec/arch/arm64/kexec-elf-arm64.c
index c70a37ae7732..842ce21e2387 100644
--- a/kexec/arch/arm64/kexec-elf-arm64.c
+++ b/kexec/arch/arm64/kexec-elf-arm64.c
@@ -9,6 +9,7 @@
 #include <stdlib.h>
 #include <linux/elf.h>
 
+#include "crashdump-arm64.h"
 #include "kexec-arm64.h"
 #include "kexec-elf.h"
 #include "kexec-syscall.h"
@@ -105,7 +106,8 @@ int elf_arm64_load(int argc, char **argv, const char *kernel_buf,
 	}
 
 	arm64_mem.vp_offset = _ALIGN_DOWN(ehdr.e_entry, MiB(2));
-	arm64_mem.vp_offset -= kernel_segment - get_phys_offset();
+	if (!(info->kexec_flags & KEXEC_ON_CRASH))
+		arm64_mem.vp_offset -= kernel_segment - get_phys_offset();
 
 	dbgprintf("%s: kernel_segment: %016lx\n", __func__, kernel_segment);
 	dbgprintf("%s: text_offset:    %016lx\n", __func__,
@@ -127,6 +129,12 @@ int elf_arm64_load(int argc, char **argv, const char *kernel_buf,
 								__func__);
 			goto exit;
 		}
+
+		/*
+		 * offset addresses in order to fit vmlinux
+		 * (elf_exec) into crash kernel's memory
+		 */
+		modify_ehdr_for_crashdump(&ehdr);
 	}
 
 	/* load the kernel */
-- 
2.9.3