kexec-tools/0036-kexec-generalize-and-rename-get_kernel_stext_sym.patch

From 325804055e99dbf40af5e6fa546320b821d9d821 Mon Sep 17 00:00:00 2001
From: Pratyush Anand <panand@redhat.com>
Date: Wed, 17 May 2017 14:51:42 +0900
Subject: [PATCH 36/45] kexec: generalize and rename get_kernel_stext_sym()

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@redhat.com>
[created symbols.c]
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Tested-by: David Woodhouse <dwmw@amazon.co.uk>
Tested-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
---
 kexec/Makefile                  |  1 +
 kexec/arch/arm/crashdump-arm.c  | 40 +---------------------------------------
 kexec/arch/i386/crashdump-x86.c | 29 -----------------------------
 kexec/kexec.h                   |  2 ++
 kexec/symbols.c                 | 34 ++++++++++++++++++++++++++++++++++
 5 files changed, 38 insertions(+), 68 deletions(-)
 create mode 100644 kexec/symbols.c

diff --git a/kexec/Makefile b/kexec/Makefile
index 39f365f543d7..2b4fb3d162ec 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 ac76e0a812d5..daa478868b49 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 285dea9abd4b..69a063a5670b 100644
--- a/kexec/arch/i386/crashdump-x86.c
+++ b/kexec/arch/i386/crashdump-x86.c
@@ -102,35 +102,6 @@ static int get_kernel_paddr(struct kexec_info *UNUSED(info),
 	return -1;
 }
 
-/* Retrieve kernel symbol virtual address from /proc/kallsyms */
-static unsigned long long get_kernel_sym(const char *symbol)
-{
-	const char *kallsyms = "/proc/kallsyms";
-	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, "%llx %c %s", &vaddr, &type, sym) != 3)
-			continue;
-		if (strcmp(sym, symbol) == 0) {
-			dbgprintf("kernel symbol %s vaddr = %16llx\n", symbol, vaddr);
-			return vaddr;
-		}
-	}
-
-	dbgprintf("Cannot get kernel %s symbol address\n", symbol);
-	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
diff --git a/kexec/kexec.h b/kexec/kexec.h
index 52bef9b3c0f5..26225d2c002a 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -317,4 +317,6 @@ int xen_kexec_unload(uint64_t kexec_flags);
 void xen_kexec_exec(void);
 int xen_kexec_status(uint64_t kexec_flags);
 
+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 000000000000..e88f7f342d3b
--- /dev/null
+++ b/kexec/symbols.c
@@ -0,0 +1,34 @@
+#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 *symbol)
+{
+	const char *kallsyms = "/proc/kallsyms";
+	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, "%llx %c %s", &vaddr, &type, sym) != 3)
+			continue;
+		if (strcmp(sym, symbol) == 0) {
+			dbgprintf("kernel symbol %s vaddr = %16llx\n",
+					symbol, vaddr);
+			return vaddr;
+		}
+	}
+
+	dbgprintf("Cannot get kernel %s symbol address\n", symbol);
+
+	return 0;
+}
-- 
2.13.0