[PATCH v3 2/8] kexec: generalize and rename get_kernel_stext_sym()

[AKASHI Takahiro]

From: Pratyush Anand <panand at redhat.com>

get_kernel_stext_sym() has been defined for both arm and i386. Other
architecture might need some other kernel symbol address. Therefore rewrite
this function as generic function to get any kernel symbol address.

More over, kallsyms is not arch specific representation, therefore have
common function for all arches.

Signed-off-by: Pratyush Anand <panand at redhat.com>
[created symbols.c]
Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
 kexec/Makefile                  |  1 +
 kexec/arch/arm/crashdump-arm.c  | 40 +---------------------------------------
 kexec/arch/i386/crashdump-x86.c | 32 +-------------------------------
 kexec/kexec.h                   |  2 ++
 kexec/symbols.c                 | 41 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 46 insertions(+), 70 deletions(-)
 create mode 100644 kexec/symbols.c

diff --git a/kexec/Makefile b/kexec/Makefile
index 39f365f..2b4fb3d 100644
--- a/kexec/Makefile
+++ b/kexec/Makefile
@@ -26,6 +26,7 @@ KEXEC_SRCS_base += kexec/kernel_version.c
 KEXEC_SRCS_base += kexec/lzma.c
 KEXEC_SRCS_base += kexec/zlib.c
 KEXEC_SRCS_base += kexec/kexec-xen.c
+KEXEC_SRCS_base += kexec/symbols.c
 
 KEXEC_GENERATED_SRCS += $(PURGATORY_HEX_C)
 
diff --git a/kexec/arch/arm/crashdump-arm.c b/kexec/arch/arm/crashdump-arm.c
index 4a89b5e..2bc898b 100644
--- a/kexec/arch/arm/crashdump-arm.c
+++ b/kexec/arch/arm/crashdump-arm.c
@@ -73,48 +73,10 @@ static struct crash_elf_info elf_info = {
 
 extern unsigned long long user_page_offset;
 
-/* Retrieve kernel _stext symbol virtual address from /proc/kallsyms */
-static unsigned long long get_kernel_stext_sym(void)
-{
-	const char *kallsyms = "/proc/kallsyms";
-	const char *stext = "_stext";
-	char sym[128];
-	char line[128];
-	FILE *fp;
-	unsigned long long vaddr = 0;
-	char type;
-
-	fp = fopen(kallsyms, "r");
-	if (!fp) {
-		fprintf(stderr, "Cannot open %s\n", kallsyms);
-		return 0;
-	}
-
-	while(fgets(line, sizeof(line), fp) != NULL) {
-		unsigned long long addr;
-
-		if (sscanf(line, "%Lx %c %s", &addr, &type, sym) != 3)
-			continue;
-
-		if (strcmp(sym, stext) == 0) {
-			dbgprintf("kernel symbol %s vaddr = %#llx\n", stext, addr);
-			vaddr = addr;
-			break;
-		}
-	}
-
-	fclose(fp);
-
-	if (vaddr == 0)
-		fprintf(stderr, "Cannot get kernel %s symbol address\n", stext);
-
-	return vaddr;
-}
-
 static int get_kernel_page_offset(struct kexec_info *info,
 		struct crash_elf_info *elf_info)
 {
-	unsigned long long stext_sym_addr = get_kernel_stext_sym();
+	unsigned long long stext_sym_addr = get_kernel_sym("stext");
 	if (stext_sym_addr == 0) {
 		if (user_page_offset != (-1ULL)) {
 			elf_info->page_offset = user_page_offset;
diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
index bbc0f35..664eb3b 100644
--- a/kexec/arch/i386/crashdump-x86.c
+++ b/kexec/arch/i386/crashdump-x86.c
@@ -102,36 +102,6 @@ static int get_kernel_paddr(struct kexec_info *UNUSED(info),
 	return -1;
 }
 
-/* Retrieve kernel _stext symbol virtual address from /proc/kallsyms */
-static unsigned long long get_kernel_stext_sym(void)
-{
-	const char *kallsyms = "/proc/kallsyms";
-	const char *stext = "_stext";
-	char sym[128];
-	char line[128];
-	FILE *fp;
-	unsigned long long vaddr;
-	char type;
-
-	fp = fopen(kallsyms, "r");
-	if (!fp) {
-		fprintf(stderr, "Cannot open %s\n", kallsyms);
-		return 0;
-	}
-
-	while(fgets(line, sizeof(line), fp) != NULL) {
-		if (sscanf(line, "%Lx %c %s", &vaddr, &type, sym) != 3)
-			continue;
-		if (strcmp(sym, stext) == 0) {
-			dbgprintf("kernel symbol %s vaddr = %16llx\n", stext, vaddr);
-			return vaddr;
-		}
-	}
-
-	fprintf(stderr, "Cannot get kernel %s symbol address\n", stext);
-	return 0;
-}
-
 /* Retrieve info regarding virtual address kernel has been compiled for and
  * size of the kernel from /proc/kcore. Current /proc/kcore parsing from
  * from kexec-tools fails because of malformed elf notes. A kernel patch has
@@ -182,7 +152,7 @@ static int get_kernel_vaddr_and_size(struct kexec_info *UNUSED(info),
 
 	/* Traverse through the Elf headers and find the region where
 	 * _stext symbol is located in. That's where kernel is mapped */
-	stext_sym = get_kernel_stext_sym();
+	stext_sym = get_kernel_sym("stext");
 	for(phdr = ehdr.e_phdr; stext_sym && phdr != end_phdr; phdr++) {
 		if (phdr->p_type == PT_LOAD) {
 			unsigned long long saddr = phdr->p_vaddr;
diff --git a/kexec/kexec.h b/kexec/kexec.h
index 9194f1c..b4fafad 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -312,4 +312,6 @@ int xen_kexec_load(struct kexec_info *info);
 int xen_kexec_unload(uint64_t kexec_flags);
 void xen_kexec_exec(void);
 
+extern unsigned long long get_kernel_sym(const char *text);
+
 #endif /* KEXEC_H */
diff --git a/kexec/symbols.c b/kexec/symbols.c
new file mode 100644
index 0000000..ea6e327
--- /dev/null
+++ b/kexec/symbols.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <string.h>
+#include "kexec.h"
+
+/* Retrieve kernel symbol virtual address from /proc/kallsyms */
+unsigned long long get_kernel_sym(const char *text)
+{
+	const char *kallsyms = "/proc/kallsyms";
+	char sym[128];
+	char line[128];
+	FILE *fp;
+	unsigned long long vaddr = 0;
+	char type;
+
+	fp = fopen(kallsyms, "r");
+	if (!fp) {
+		fprintf(stderr, "Cannot open %s\n", kallsyms);
+		return 0;
+	}
+
+	while (fgets(line, sizeof(line), fp) != NULL) {
+		unsigned long long addr;
+
+		if (sscanf(line, "%Lx %c %s", &addr, &type, sym) != 3)
+			continue;
+
+		if (strcmp(sym, text) == 0) {
+			dbgprintf("kernel symbol %s vaddr = %#llx\n",
+								text, addr);
+			vaddr = addr;
+			break;
+		}
+	}
+
+	fclose(fp);
+
+	if (vaddr == 0)
+		fprintf(stderr, "Cannot get kernel %s symbol address\n", text);
+
+	return vaddr;
+}
-- 
2.9.0