[PATCH] makedumpfile/arm64: Add '--mem-usage' support

[Bhupesh Sharma <bhsharma@redhat.com>]

Its good to have the makedumpfile '--mem-usage' support
for arm64 architecture as well, as it allows one to see the page numbers
of current system (1st kernel) in different use.

Using this we can know how many pages are dumpable when different
dump_level is specified.

Normally for x86_64, makedumpfile analyzes the 'System Ram' and
'kernel text' program segment of /proc/kcore excluding
the crashkernel range, then calculates the page number of different
kind per vmcoreinfo.

We use the similar logic for arm64, but in addition make the '--mem-usage'
usage dependent on the VMLINUX file being passed. This is done to allow
information like VA_BITS being determined from kernel symbol like
_stext. This allows us to get the VA_BITS before 'set_kcore_vmcoreinfo()'
is called.

Also I have validated the '--mem-usage' makedumpfile option on several
ppc64/ppc64le and s390x machines, so update the makedumpfile.8
documentation to indicate that '--mem-usage' option is supported
not only on x86_64, but also on ppc64, s390x and arm64.

After this patch, when using the '--mem-usage' option with makedumpfile,
we get the correct information about the different pages. For e.g.
here is an output from my arm64 board:

TYPE		PAGES			EXCLUDABLE	DESCRIPTION
----------------------------------------------------------------------
ZERO		49524           	yes		Pages filled with zero
NON_PRI_CACHE	15143           	yes		Cache pages without private flag
PRI_CACHE	29147           	yes		Cache pages with private flag
USER		3684            	yes		User process pages
FREE		1450569         	yes		Free pages
KERN_DATA	14243           	no		Dumpable kernel data

page size:		65536
Total pages on system:	1562310
Total size on system:	102387548160     Byte

Cc: Masaki Tachibana <mas-tachibana@vf.jp.nec.com>
Cc: Takuya Nakayama <tak-nakayama@tg.jp.nec.com>
Cc: Daisuke Nishimura <dai-nishimura@rc.jp.nec.com>
Signed-off-by: Bhupesh Sharma <bhsharma@redhat.com>
---
 arch/arm64.c   | 51 ++++++++++++++++++++++++++++++++++++++++++++++++---
 makedumpfile.8 | 11 +++++++++--
 makedumpfile.c | 25 +++++++++++++++++++++++--
 makedumpfile.h |  1 +
 4 files changed, 81 insertions(+), 7 deletions(-)

diff --git a/arch/arm64.c b/arch/arm64.c
index 25d7a1f4db98..91f113f6447c 100644
--- a/arch/arm64.c
+++ b/arch/arm64.c
@@ -48,6 +48,12 @@ static unsigned long kimage_voffset;
 #define SZ_64K			(64 * 1024)
 #define SZ_128M			(128 * 1024 * 1024)
 
+#define PAGE_OFFSET_36 ((0xffffffffffffffffUL) << 36)
+#define PAGE_OFFSET_39 ((0xffffffffffffffffUL) << 39)
+#define PAGE_OFFSET_42 ((0xffffffffffffffffUL) << 42)
+#define PAGE_OFFSET_47 ((0xffffffffffffffffUL) << 47)
+#define PAGE_OFFSET_48 ((0xffffffffffffffffUL) << 48)
+
 #define pgd_val(x)		((x).pgd)
 #define pud_val(x)		(pgd_val((x).pgd))
 #define pmd_val(x)		(pud_val((x).pud))
@@ -140,8 +146,6 @@ pud_offset(pgd_t *pgda, pgd_t *pgdv, unsigned long vaddr)
 
 static int calculate_plat_config(void)
 {
-	va_bits = NUMBER(VA_BITS);
-
 	/* derive pgtable_level as per arch/arm64/Kconfig */
 	if ((PAGESIZE() == SZ_16K && va_bits == 36) ||
 			(PAGESIZE() == SZ_64K && va_bits == 42)) {
@@ -188,7 +192,6 @@ get_machdep_info_arm64(void)
 	kimage_voffset = NUMBER(kimage_voffset);
 	info->max_physmem_bits = PHYS_MASK_SHIFT;
 	info->section_size_bits = SECTIONS_SIZE_BITS;
-	info->page_offset = 0xffffffffffffffffUL << (va_bits - 1);
 
 	DEBUG_MSG("kimage_voffset   : %lx\n", kimage_voffset);
 	DEBUG_MSG("max_physmem_bits : %lx\n", info->max_physmem_bits);
@@ -219,6 +222,48 @@ get_xen_info_arm64(void)
 int
 get_versiondep_info_arm64(void)
 {
+	unsigned long long stext;
+
+	/* We can read the _stext symbol from vmlinux and determine the
+	 * VA_BITS and page_offset.
+	 */
+
+	/* Open the vmlinux file */
+	open_kernel_file();
+	set_dwarf_debuginfo("vmlinux", NULL,
+			info->name_vmlinux, info->fd_vmlinux);
+
+	if (!get_symbol_info())
+		return FALSE;
+
+	/* Get the '_stext' symbol */
+	if (SYMBOL(_stext) == NOT_FOUND_SYMBOL) {
+		ERRMSG("Can't get the symbol of _stext.\n");
+		return FALSE;
+	} else {
+		stext = SYMBOL(_stext);
+	}
+
+	/* Derive va_bits as per arch/arm64/Kconfig */
+	if ((stext & PAGE_OFFSET_36) == PAGE_OFFSET_36) {
+		va_bits = 36;
+	} else if ((stext & PAGE_OFFSET_39) == PAGE_OFFSET_39) {
+		va_bits = 39;
+	} else if ((stext & PAGE_OFFSET_42) == PAGE_OFFSET_42) {
+		va_bits = 42;
+	} else if ((stext & PAGE_OFFSET_47) == PAGE_OFFSET_47) {
+		va_bits = 47;
+	} else if ((stext & PAGE_OFFSET_48) == PAGE_OFFSET_48) {
+		va_bits = 48;
+	} else {
+		ERRMSG("Cannot find a proper _stext for calculating VA_BITS\n");
+		return FALSE;
+	}
+
+	info->page_offset = (0xffffffffffffffffUL) << (va_bits - 1);
+
+	DEBUG_MSG("page_offset=%lx, va_bits=%d\n", info->page_offset, va_bits);
+
 	return TRUE;
 }
 
diff --git a/makedumpfile.8 b/makedumpfile.8
index 15db7947d62f..be9620035316 100644
--- a/makedumpfile.8
+++ b/makedumpfile.8
@@ -593,7 +593,7 @@ last cleared on the crashed kernel, through "dmesg --clear" for example.
 
 .TP
 \fB\-\-mem-usage\fR
-This option is only for x86_64.
+This option is currently supported on x86_64, arm64, ppc64 and s390x.
 This option is used to show the page numbers of current system in different
 use. It should be executed in 1st kernel. By the help of this, user can know
 how many pages is dumpable when different dump_level is specified. It analyzes
@@ -601,12 +601,19 @@ the 'System Ram' and 'kernel text' program segment of /proc/kcore excluding
 the crashkernel range, then calculates the page number of different kind per
 vmcoreinfo. So currently /proc/kcore need be specified explicitly.
 
+For arm64, path to vmlinux file should be specified as well.
+
 .br
-.B Example:
+.B Example (for architectures other than arm64):
 .br
 # makedumpfile \-\-mem-usage /proc/kcore
+
+.br
+.B Example (for arm64 architecture):
 .br
 
+# makedumpfile \-\-mem-usage vmlinux /proc/kcore
+.br
 
 .TP
 \fB\-\-diskset=VMCORE\fR
diff --git a/makedumpfile.c b/makedumpfile.c
index ed138d339d9a..b38b5000aa74 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -11090,7 +11090,14 @@ static struct option longopts[] = {
 	{"cyclic-buffer", required_argument, NULL, OPT_CYCLIC_BUFFER},
 	{"eppic", required_argument, NULL, OPT_EPPIC},
 	{"non-mmap", no_argument, NULL, OPT_NON_MMAP},
+#ifdef __aarch64__
+	/* VMLINUX file is required for aarch64 for get
+	 * the symbols required to calculate va_bits.
+	 */
+	{"mem-usage", required_argument, NULL, OPT_MEM_USAGE},
+#else
 	{"mem-usage", no_argument, NULL, OPT_MEM_USAGE},
+#endif
 	{"splitblock-size", required_argument, NULL, OPT_SPLITBLOCK_SIZE},
 	{"work-dir", required_argument, NULL, OPT_WORKING_DIR},
 	{"num-threads", required_argument, NULL, OPT_NUM_THREADS},
@@ -11201,8 +11208,22 @@ main(int argc, char *argv[])
 			info->flag_partial_dmesg = 1;
 			break;
 		case OPT_MEM_USAGE:
-		       info->flag_mem_usage = 1;
-		       break;
+			info->flag_mem_usage = 1;
+#ifdef __aarch64__
+			/* VMLINUX file is required for aarch64 for get
+			 * the symbols required to calculate va_bits and
+			 * it should be the 1st command parameter being
+			 * specified.
+			 */
+			if (strcmp(optarg, "/proc/kcore") == 0) {
+				MSG("vmlinux path should be 1st commandline parameter with --mem-usage option.\n");
+				goto out;
+			}
+			else {
+				info->name_vmlinux = optarg;
+			}
+#endif
+			break;
 		case OPT_COMPRESS_SNAPPY:
 			info->flag_compress = DUMP_DH_COMPRESSED_SNAPPY;
 			break;
diff --git a/makedumpfile.h b/makedumpfile.h
index 01eece231475..f65d91870b73 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -2308,6 +2308,7 @@ struct elf_prstatus {
 /*
  * Function Prototype.
  */
+int open_kernel_file(void);
 mdf_pfn_t get_num_dumpable_cyclic(void);
 mdf_pfn_t get_num_dumpable_cyclic_withsplit(void);
 int get_loads_dumpfile_cyclic(void);
-- 
2.7.4


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