[PATCH v5 07/11] crashdump/ppc: Add get_crash_kernel_load_range() function

[eric.devolder@xxxxxxxxxx (Eric DeVolder)]

From: Daniel Kiper <daniel.kiper@xxxxxxxxxx>

Implement get_crash_kernel_load_range() in support of
print crash kernel region size option.

Signed-off-by: Daniel Kiper <daniel.kiper at oracle.com>
Signed-off-by: Eric DeVolder <eric.devolder at oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper at oracle.com>
---
v5: Incorporated feedback:
    - Removed extraneous setting of start and end in get_devtree_value()
    - changes for coding convention and formatting
v4: Incorporated feedback:
    - changes for coding convention and formatting
v3: Incorporated feedback:
    - changes for coding convention and formatting
    - restructured to introduce get_crash_kernel_load_range() for each
      architecture, and then a single function in kexec/kexec.c to call
      the per-architecture get_crash_kernel_load_range() and print the
      result.
    - changed print_crashkernel_region_size() to get_crash_kernel_load_range()
    - introduced get_devtree_value()
v2: Incorporated feedback:
    - utilize the is_crashkernel_mem_reserved() function common in all archs
    - utilize device-tree values to print size
v1: Posted to kexec-tools mailing list
---
 kexec/arch/ppc/crashdump-powerpc.c | 22 +++++++++++++++++++++-
 kexec/arch/ppc/kexec-ppc.c         | 24 ++++++++++++++++++++++++
 kexec/arch/ppc/kexec-ppc.h         |  1 +
 3 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/kexec/arch/ppc/crashdump-powerpc.c b/kexec/arch/ppc/crashdump-powerpc.c
index 3dc35eb..dde6de7 100644
--- a/kexec/arch/ppc/crashdump-powerpc.c
+++ b/kexec/arch/ppc/crashdump-powerpc.c
@@ -16,6 +16,9 @@
 #include "kexec-ppc.h"
 #include "crashdump-powerpc.h"
 
+#define DEVTREE_CRASHKERNEL_BASE "/proc/device-tree/chosen/linux,crashkernel-base"
+#define DEVTREE_CRASHKERNEL_SIZE "/proc/device-tree/chosen/linux,crashkernel-size"
+
 #ifdef CONFIG_PPC64
 static struct crash_elf_info elf_info64 = {
 class: ELFCLASS64,
@@ -397,11 +400,28 @@ void add_usable_mem_rgns(unsigned long long base, unsigned long long size)
 		usablemem_rgns.size, base, size);
 }
 
+int get_crash_kernel_load_range(uint64_t *start, uint64_t *end)
+{
+	unsigned long long value;
+
+	if (!get_devtree_value(DEVTREE_CRASHKERNEL_BASE, &value))
+		*start = value;
+	else
+		return -1;
+
+	if (!get_devtree_value(DEVTREE_CRASHKERNEL_SIZE, &value))
+		*end = *start + value - 1;
+	else
+		return -1;
+
+	return 0;
+}
+
 int is_crashkernel_mem_reserved(void)
 {
 	int fd;
 
-	fd = open("/proc/device-tree/chosen/linux,crashkernel-base", O_RDONLY);
+	fd = open(DEVTREE_CRASHKERNEL_BASE, O_RDONLY);
 	if (fd < 0)
 		return 0;
 	close(fd);
diff --git a/kexec/arch/ppc/kexec-ppc.c b/kexec/arch/ppc/kexec-ppc.c
index d046110..03bec36 100644
--- a/kexec/arch/ppc/kexec-ppc.c
+++ b/kexec/arch/ppc/kexec-ppc.c
@@ -423,6 +423,30 @@ err_out:
 	return -1;
 }
 
+/* Return 0 if fname/value valid, -1 otherwise */
+int get_devtree_value(const char *fname, unsigned long long *value)
+{
+	FILE *file;
+	char buf[MAXBYTES];
+	int n = -1;
+
+	if ((file = fopen(fname, "r"))) {
+		n = fread(buf, 1, MAXBYTES, file);
+		fclose(file);
+	}
+
+	if (n == sizeof(uint32_t))
+		*value = ((uint32_t *)buf)[0];
+	else if (n == sizeof(uint64_t))
+		*value = ((uint64_t *)buf)[0];
+	else {
+		fprintf(stderr, "%s node has invalid size: %d\n", fname, n);
+		return -1;
+	}
+
+	return 0;
+}
+
 /* Get devtree details and create exclude_range array
  * Also create usablemem_ranges for KEXEC_ON_CRASH
  */
diff --git a/kexec/arch/ppc/kexec-ppc.h b/kexec/arch/ppc/kexec-ppc.h
index 904cf48..f8fd678 100644
--- a/kexec/arch/ppc/kexec-ppc.h
+++ b/kexec/arch/ppc/kexec-ppc.h
@@ -75,6 +75,7 @@ extern unsigned long dt_address_cells, dt_size_cells;
 extern int init_memory_region_info(void);
 extern int read_memory_region_limits(int fd, unsigned long long *start,
 					unsigned long long *end);
+extern int get_devtree_value(const char *fname, unsigned long long *pvalue);
 #define COMMAND_LINE_SIZE	512 /* from kernel */
 /*fs2dt*/
 void reserve(unsigned long long where, unsigned long long length);
-- 
2.7.4