From 5a302cd06079a285cb24a74c0f60b26866ae4e4d Mon Sep 17 00:00:00 2001
From: snoweay <snoweay@163.com>
Date: Wed, 12 Aug 2020 07:59:06 -0400
Subject: [PATCH] kexec: Quick kexec implementation for arm64

Implement quick kexec on arch/arm64.

Locate kernel segments from reserved memory of range "Quick kexec".
---
 kexec/arch/arm64/iomem.h             |  1 +
 kexec/arch/arm64/kexec-arm64.c       | 42 +++++++++++++++++++++++++-----------
 kexec/arch/arm64/kexec-image-arm64.c | 11 ++++++++++
 3 files changed, 41 insertions(+), 13 deletions(-)

diff --git a/kexec/arch/arm64/iomem.h b/kexec/arch/arm64/iomem.h
index 45d7953..f283f50 100644
--- a/kexec/arch/arm64/iomem.h
+++ b/kexec/arch/arm64/iomem.h
@@ -7,5 +7,6 @@
 #define KERNEL_DATA		"Kernel data\n"
 #define CRASH_KERNEL		"Crash kernel\n"
 #define IOMEM_RESERVED		"reserved\n"
+#define QUICK_KEXEC		"Quick kexec\n"
 
 #endif
diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
index 219ec49..8a3bb69 100644
--- a/kexec/arch/arm64/kexec-arm64.c
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -99,6 +99,9 @@ uint64_t get_vp_offset(void)
 	return arm64_mem.vp_offset;
 }
 
+/* Reserved memory for quick kexec. */
+struct memory_range quick_reserved_mem;
+
 /**
  * arm64_process_image_header - Process the arm64 image header.
  *
@@ -627,23 +630,33 @@ on_error:
 	return result;
 }
 
-unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
+static unsigned long locate_hole_from_range(struct memory_range *range)
 {
 	unsigned long hole;
+	unsigned long hole_end;
 
-	if (info->kexec_flags & KEXEC_ON_CRASH) {
-		unsigned long hole_end;
+	hole = (range->start < mem_min ? mem_min : range->start);
+	hole = _ALIGN_UP(hole, MiB(2));
+	hole_end = hole + arm64_mem.text_offset + arm64_mem.image_size;
 
-		hole = (crash_reserved_mem[usablemem_rgns.size - 1].start < mem_min ?
-				mem_min : crash_reserved_mem[usablemem_rgns.size - 1].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 > range->end)) {
+		dbgprintf("%s: Kexec kernel out of range\n", __func__);
+		hole = ULONG_MAX;
+	}
 
-		if ((hole_end > mem_max) ||
-		    (hole_end > crash_reserved_mem[usablemem_rgns.size - 1].end)) {
-			dbgprintf("%s: Crash kernel out of range\n", __func__);
-			hole = ULONG_MAX;
-		}
+	return hole;
+}
+
+unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
+{
+	unsigned long hole;
+
+	if (info->kexec_flags & KEXEC_ON_CRASH) {
+		hole = locate_hole_from_range(
+			&crash_reserved_mem[usablemem_rgns.size - 1]);
+	} else if (info->kexec_flags & KEXEC_QUICK) {
+		hole = locate_hole_from_range(&quick_reserved_mem);
 	} else {
 		hole = locate_hole(info,
 			arm64_mem.text_offset + arm64_mem.image_size,
@@ -709,6 +722,8 @@ int arm64_load_other_segments(struct kexec_info *info,
 	hole_min = image_base + arm64_mem.image_size;
 	if (info->kexec_flags & KEXEC_ON_CRASH)
 		hole_max = crash_reserved_mem[usablemem_rgns.size - 1].end;
+	else if (info->kexec_flags & KEXEC_QUICK)
+		hole_max = quick_reserved_mem.end;
 	else
 		hole_max = ULONG_MAX;
 
@@ -1050,7 +1050,8 @@ static bool to_be_excluded(char *str, unsigned long long start, unsigned long lo
 
 	if (!strncmp(str, SYSTEM_RAM, strlen(SYSTEM_RAM)) ||
 	    !strncmp(str, KERNEL_CODE, strlen(KERNEL_CODE)) ||
-	    !strncmp(str, KERNEL_DATA, strlen(KERNEL_DATA)))
+	    !strncmp(str, KERNEL_DATA, strlen(KERNEL_DATA)) ||
+	    !strncmp(str, QUICK_KEXEC, strlen(QUICK_KEXEC)))
 		return false;
 	else
 		return true;
diff --git a/kexec/arch/arm64/kexec-image-arm64.c b/kexec/arch/arm64/kexec-image-arm64.c
index aa8f2e2..f22db62 100644
--- a/kexec/arch/arm64/kexec-image-arm64.c
+++ b/kexec/arch/arm64/kexec-image-arm64.c
@@ -13,6 +13,9 @@
 #include "kexec-arm64.h"
 #include "kexec-syscall.h"
 #include "arch/options.h"
+#include "iomem.h"
+
+extern struct memory_range quick_reserved_mem;
 
 int image_arm64_probe(const char *kernel_buf, off_t kernel_size)
 {
@@ -38,6 +41,7 @@ int image_arm64_load(int argc, char **argv, const char *kernel_buf,
 {
 	const struct arm64_image_header *header;
 	unsigned long kernel_segment;
+	unsigned long start, end;
 	int result;
 
 	if (info->file_mode) {
@@ -61,6 +65,13 @@ int image_arm64_load(int argc, char **argv, const char *kernel_buf,
 		return 0;
 	}
 
+	if (info->kexec_flags & KEXEC_QUICK)
+		parse_iomem_single(QUICK_KEXEC, &start, &end);
+	dbgprintf("%s: Get Quick kexec reserved mem from 0x%016lx to 0x%016lx\n",
+		  __func__, start, end);
+	quick_reserved_mem.start = start;
+	quick_reserved_mem.end = end;
+
 	header = (const struct arm64_image_header *)(kernel_buf);
 
 	if (arm64_process_image_header(header))
-- 
2.9.5