[RESEND PATCH] arm64: support more than one crash kernel regions

* [RESEND PATCH] arm64: support more than one crash kernel regions
@ 2019-04-08  9:22 Chen Zhou
  2019-04-08  9:36 ` Simon Horman
  0 siblings, 1 reply; 4+ messages in thread
From: Chen Zhou @ 2019-04-08  9:22 UTC (permalink / raw)
  To: horms, takahiro.akashi, kexec; +Cc: Chen Zhou, wangkefeng.wang

When crashkernel is reserved above 4G in memory, kernel should
reserve some amount of low memory for swiotlb and some DMA buffers.
So there may be two crash kernel regions, one is below 4G, the other
is above 4G.

Currently, there is only one crash kernel region on arm64, and pass
"linux,usable-memory-range = <BASE SIZE>" property to crash dump
kernel. Now, we pass
"linux,usable-memory-range = <BASE1 SIZE1 BASE2 SIZE2>" to crash
dump kernel to support two crash kernel regions and load crash
kernel high.

This patch paves the way for the use of arm64 reserving crashkernel
above 4G. The details are as below:
Link: https://lore.kernel.org/linux-arm-kernel/20190403030546.23718-1-chenzhou10@huawei.com/T/#t 

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
 kexec/arch/arm64/crashdump-arm64.c | 44 +++++++++++++++++------------
 kexec/arch/arm64/crashdump-arm64.h |  3 +-
 kexec/arch/arm64/kexec-arm64.c     | 57 +++++++++++++++++++++++++++++---------
 3 files changed, 72 insertions(+), 32 deletions(-)

diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
index 4fd7aa8..158e778 100644
--- a/kexec/arch/arm64/crashdump-arm64.c
+++ b/kexec/arch/arm64/crashdump-arm64.c
@@ -32,11 +32,11 @@ static struct memory_ranges system_memory_rgns = {
 };
 
 /* memory range reserved for crashkernel */
-struct memory_range crash_reserved_mem;
+struct memory_range crash_reserved_mem[CRASH_MAX_RESERVED_RANGES];
 struct memory_ranges usablemem_rgns = {
 	.size = 0,
-	.max_size = 1,
-	.ranges = &crash_reserved_mem,
+	.max_size = CRASH_MAX_RESERVED_RANGES,
+	.ranges = crash_reserved_mem,
 };
 
 struct memory_range elfcorehdr_mem;
@@ -108,7 +108,7 @@ int is_crashkernel_mem_reserved(void)
 	if (!usablemem_rgns.size)
 		kexec_iomem_for_each_line(NULL, iomem_range_callback, NULL);
 
-	return crash_reserved_mem.start != crash_reserved_mem.end;
+	return usablemem_rgns.size;
 }
 
 /*
@@ -122,6 +122,8 @@ int is_crashkernel_mem_reserved(void)
  */
 static int crash_get_memory_ranges(void)
 {
+	int i;
+
 	/*
 	 * First read all memory regions that can be considered as
 	 * system memory including the crash area.
@@ -129,16 +131,19 @@ static int crash_get_memory_ranges(void)
 	if (!usablemem_rgns.size)
 		kexec_iomem_for_each_line(NULL, iomem_range_callback, NULL);
 
-	/* allow only a single region for crash dump kernel */
-	if (usablemem_rgns.size != 1)
+	/* allow one or two region for crash dump kernel */
+	if (!usablemem_rgns.size)
 		return -EINVAL;
 
-	dbgprint_mem_range("Reserved memory range", &crash_reserved_mem, 1);
+	dbgprint_mem_range("Reserved memory range",
+			usablemem_rgns.ranges, usablemem_rgns.size);
 
-	if (mem_regions_exclude(&system_memory_rgns, &crash_reserved_mem)) {
-		fprintf(stderr,
-			"Error: Number of crash memory ranges excedeed the max limit\n");
-		return -ENOMEM;
+	for (i = 0; i < usablemem_rgns.size; i++) {
+		if (mem_regions_exclude(&system_memory_rgns, &crash_reserved_mem[i])) {
+			fprintf(stderr,
+					"Error: Number of crash memory ranges excedeed the max limit\n");
+			return -ENOMEM;
+		}
 	}
 
 	/*
@@ -199,7 +204,8 @@ int load_crashdump_segments(struct kexec_info *info)
 		return EFAILED;
 
 	elfcorehdr = add_buffer_phys_virt(info, buf, bufsz, bufsz, 0,
-		crash_reserved_mem.start, crash_reserved_mem.end,
+		crash_reserved_mem[usablemem_rgns.size - 1].start,
+		crash_reserved_mem[usablemem_rgns.size - 1].end,
 		-1, 0);
 
 	elfcorehdr_mem.start = elfcorehdr;
@@ -217,21 +223,23 @@ int load_crashdump_segments(struct kexec_info *info)
  * virt_to_phys() in add_segment().
  * So let's fix up those values for later use so the memory base
  * (arm64_mm.phys_offset) will be correctly replaced with
- * crash_reserved_mem.start.
+ * crash_reserved_mem[usablemem_rgns.size - 1].start.
  */
 void fixup_elf_addrs(struct mem_ehdr *ehdr)
 {
 	struct mem_phdr *phdr;
 	int i;
 
-	ehdr->e_entry += - arm64_mem.phys_offset + crash_reserved_mem.start;
+	ehdr->e_entry += -arm64_mem.phys_offset +
+		crash_reserved_mem[usablemem_rgns.size - 1].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);
+			(-arm64_mem.phys_offset +
+			 crash_reserved_mem[usablemem_rgns.size - 1].start);
 	}
 }
 
@@ -240,11 +248,11 @@ int get_crash_kernel_load_range(uint64_t *start, uint64_t *end)
 	if (!usablemem_rgns.size)
 		kexec_iomem_for_each_line(NULL, iomem_range_callback, NULL);
 
-	if (!crash_reserved_mem.end)
+	if (!usablemem_rgns.size)
 		return -1;
 
-	*start = crash_reserved_mem.start;
-	*end = crash_reserved_mem.end;
+	*start = crash_reserved_mem[usablemem_rgns.size - 1].start;
+	*end = crash_reserved_mem[usablemem_rgns.size - 1].end;
 
 	return 0;
 }
diff --git a/kexec/arch/arm64/crashdump-arm64.h b/kexec/arch/arm64/crashdump-arm64.h
index 880b83a..c07233f 100644
--- a/kexec/arch/arm64/crashdump-arm64.h
+++ b/kexec/arch/arm64/crashdump-arm64.h
@@ -15,9 +15,10 @@
 #include "kexec.h"
 
 #define CRASH_MAX_MEMORY_RANGES	32
+#define CRASH_MAX_RESERVED_RANGES	8
 
 extern struct memory_ranges usablemem_rgns;
-extern struct memory_range crash_reserved_mem;
+extern struct memory_range crash_reserved_mem[];
 extern struct memory_range elfcorehdr_mem;
 
 extern int load_crashdump_segments(struct kexec_info *info);
diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
index 2992bce..2bf8b66 100644
--- a/kexec/arch/arm64/kexec-arm64.c
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -414,6 +414,34 @@ static int fdt_setprop_range(void *fdt, int nodeoffset,
 	return result;
 }
 
+static int fdt_setprop_ranges(void *fdt, int nodeoffset,
+				const char *name, struct memory_ranges *ranges,
+				uint32_t address_cells, uint32_t size_cells)
+{
+	void *buf, *prop;
+	size_t buf_size;
+	int i, result;
+
+	buf_size = (address_cells + size_cells) * sizeof(uint32_t) *
+		ranges->size;
+	prop = buf = xmalloc(buf_size);
+
+	for (i = 0; i < ranges->size; i++) {
+		fill_property(prop, ranges->ranges[i].start, address_cells);
+		prop += address_cells * sizeof(uint32_t);
+
+		fill_property(prop, ranges->ranges[i].end -
+				ranges->ranges[i].start + 1, size_cells);
+		prop += size_cells * sizeof(uint32_t);
+	}
+
+	result = fdt_setprop(fdt, nodeoffset, name, buf, buf_size);
+
+	free(buf);
+
+	return result;
+}
+
 /**
  * setup_2nd_dtb - Setup the 2nd stage kernel's dtb.
  */
@@ -427,7 +455,7 @@ static int setup_2nd_dtb(struct dtb *dtb, char *command_line, int on_crash)
 	int len, range_len;
 	int nodeoffset;
 	int new_size;
-	int result, kaslr_seed;
+	int i, result, kaslr_seed;
 
 	result = fdt_check_header(dtb->buf);
 
@@ -458,18 +486,21 @@ static int setup_2nd_dtb(struct dtb *dtb, char *command_line, int on_crash)
 		goto on_error;
 	}
 
-	if (!cells_size_fitted(address_cells, size_cells,
-				&crash_reserved_mem)) {
-		fprintf(stderr, "kexec: usable memory range doesn't fit cells-size.\n");
-		result = -EINVAL;
-		goto on_error;
+	for (i = 0; i < usablemem_rgns.size; i++) {
+		if (!cells_size_fitted(address_cells, size_cells,
+					&crash_reserved_mem[i])) {
+			fprintf(stderr,
+					"kexec: usable memory range doesn't fit cells-size.\n");
+			result = -EINVAL;
+			goto on_error;
+		}
 	}
 
 	/* duplicate dt blob */
 	range_len = sizeof(uint32_t) * (address_cells + size_cells);
 	new_size = fdt_totalsize(dtb->buf)
 		+ fdt_prop_len(PROP_ELFCOREHDR, range_len)
-		+ fdt_prop_len(PROP_USABLE_MEM_RANGE, range_len);
+		+ fdt_prop_len(PROP_USABLE_MEM_RANGE, range_len * usablemem_rgns.size);
 
 	new_buf = xmalloc(new_size);
 	result = fdt_open_into(dtb->buf, new_buf, new_size);
@@ -565,8 +596,8 @@ static int setup_2nd_dtb(struct dtb *dtb, char *command_line, int on_crash)
 
 		/* add linux,usable-memory-range */
 		nodeoffset = fdt_path_offset(new_buf, "/chosen");
-		result = fdt_setprop_range(new_buf, nodeoffset,
-				PROP_USABLE_MEM_RANGE, &crash_reserved_mem,
+		result = fdt_setprop_ranges(new_buf, nodeoffset,
+				PROP_USABLE_MEM_RANGE, &usablemem_rgns,
 				address_cells, size_cells);
 		if (result) {
 			dbgprintf("%s: fdt_setprop failed: %s\n", __func__,
@@ -599,13 +630,13 @@ unsigned long arm64_locate_kernel_segment(struct kexec_info *info)
 	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 = (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 > crash_reserved_mem.end)) {
+		    (hole_end > crash_reserved_mem[usablemem_rgns.size - 1].end)) {
 			dbgprintf("%s: Crash kernel out of range\n", __func__);
 			hole = ULONG_MAX;
 		}
@@ -673,7 +704,7 @@ 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.end;
+		hole_max = crash_reserved_mem[usablemem_rgns.size - 1].end;
 	else
 		hole_max = ULONG_MAX;
 
-- 
2.7.4


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