Functions to walk stack and print backtrace. The stack's unadorned as
STACK: [@]addr addr addr ...
where the optional @ indicates that addr isn't a return address.
A follow-up patch post-processes the output to pretty-print the stack.
Frame stack walker is just a stub on arm and ppc.
Signed-off-by: Peter Feiner <pfeiner@xxxxxxxxxx>
---
Makefile | 3 ++-
arm/Makefile.common | 1 +
lib/arm/asm/stack.h | 1 +
lib/arm64/asm/stack.h | 1 +
lib/asm-generic/stack.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++
lib/asm-generic/stack.h | 14 +++++++++++++
lib/libcflat.h | 3 +++
lib/powerpc/asm/stack.h | 1 +
lib/ppc64/asm/stack.h | 1 +
lib/printf.c | 42 +++++++++++++++++++++++++++++++++++++++
lib/x86/asm/stack.c | 25 +++++++++++++++++++++++
lib/x86/asm/stack.h | 12 +++++++++++
powerpc/Makefile.common | 1 +
x86/Makefile.common | 4 ++++
14 files changed, 161 insertions(+), 1 deletion(-)
create mode 100644 lib/arm/asm/stack.h
create mode 100644 lib/arm64/asm/stack.h
create mode 100644 lib/asm-generic/stack.c
create mode 100644 lib/asm-generic/stack.h
create mode 100644 lib/powerpc/asm/stack.h
create mode 100644 lib/ppc64/asm/stack.h
create mode 100644 lib/x86/asm/stack.c
create mode 100644 lib/x86/asm/stack.h
diff --git a/Makefile b/Makefile
index 72e6711..536f2e6 100644
--- a/Makefile
+++ b/Makefile
@@ -42,7 +42,8 @@ cc-option = $(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null \
CFLAGS += -g
CFLAGS += $(autodepend-flags) -Wall
-CFLAGS += $(call cc-option, -fomit-frame-pointer, "")
+frame-pointer-flag=-f$(if $(KEEP_FRAME_POINTER),no-,)omit-frame-pointer
+CFLAGS += $(call cc-option, $(frame-pointer-flag), "")
CFLAGS += $(call cc-option, -fno-stack-protector, "")
CFLAGS += $(call cc-option, -fno-stack-protector-all, "")
diff --git a/arm/Makefile.common b/arm/Makefile.common
index dd3a0ca..ede8851 100644
--- a/arm/Makefile.common
+++ b/arm/Makefile.common
@@ -39,6 +39,7 @@ cflatobjs += lib/arm/mmu.o
cflatobjs += lib/arm/bitops.o
cflatobjs += lib/arm/psci.o
cflatobjs += lib/arm/smp.o
+cflatobjs += lib/asm-generic/stack.o
libeabi = lib/arm/libeabi.a
eabiobjs = lib/arm/eabi_compat.o
diff --git a/lib/arm/asm/stack.h b/lib/arm/asm/stack.h
new file mode 100644
index 0000000..f101d03
--- /dev/null
+++ b/lib/arm/asm/stack.h
@@ -0,0 +1 @@
+#include <asm-generic/stack.h>
diff --git a/lib/arm64/asm/stack.h b/lib/arm64/asm/stack.h
new file mode 100644
index 0000000..f101d03
--- /dev/null
+++ b/lib/arm64/asm/stack.h
@@ -0,0 +1 @@
+#include <asm-generic/stack.h>
diff --git a/lib/asm-generic/stack.c b/lib/asm-generic/stack.c
new file mode 100644
index 0000000..93219cb
--- /dev/null
+++ b/lib/asm-generic/stack.c
@@ -0,0 +1,53 @@
+#include <libcflat.h>
+#include <asm-generic/stack.h>
+
+int backtrace(const void **return_addrs, int max_depth)
+{
+ static int walking;
+ int depth = 0;
+ void *addr;
+
+ if (walking) {
+ printf("RECURSIVE STACK WALK!!!\n");
+ return 0;
+ }
+ walking = 1;
+
+ /* __builtin_return_address requires a compile-time constant argument */
+#define GET_RETURN_ADDRESS(i) \
+ if (max_depth == i) \
+ goto done; \
+ addr = __builtin_return_address(i); \
+ if (!addr) \
+ goto done; \
+ return_addrs[i] = __builtin_extract_return_addr(addr); \
+ depth = i + 1; \
+
+ GET_RETURN_ADDRESS(0)
+ GET_RETURN_ADDRESS(1)
+ GET_RETURN_ADDRESS(2)
+ GET_RETURN_ADDRESS(3)
+ GET_RETURN_ADDRESS(4)
+ GET_RETURN_ADDRESS(5)
+ GET_RETURN_ADDRESS(6)
+ GET_RETURN_ADDRESS(7)
+ GET_RETURN_ADDRESS(8)
+ GET_RETURN_ADDRESS(9)
+ GET_RETURN_ADDRESS(10)
+ GET_RETURN_ADDRESS(11)
+ GET_RETURN_ADDRESS(12)
+ GET_RETURN_ADDRESS(13)
+ GET_RETURN_ADDRESS(14)
+ GET_RETURN_ADDRESS(15)
+ GET_RETURN_ADDRESS(16)
+ GET_RETURN_ADDRESS(17)
+ GET_RETURN_ADDRESS(18)
+ GET_RETURN_ADDRESS(19)
+ GET_RETURN_ADDRESS(20)
+
+#undef GET_RETURN_ADDRESS
+
+done:
+ walking = 0;
+ return depth;
+}
diff --git a/lib/asm-generic/stack.h b/lib/asm-generic/stack.h
new file mode 100644
index 0000000..381fce4
--- /dev/null
+++ b/lib/asm-generic/stack.h
@@ -0,0 +1,14 @@
+#ifndef _ASMGENERIC_STACK_H_
+#define _ASMGENERIC_STACK_H_
+
+static inline int
+backtrace_frame(const void *frame __attribute__((unused)),
+ const void **return_addrs __attribute__((unused)),
+ int max_depth __attribute__((unused)))
+{
+ return 0;
+}
+
+int backtrace(const void **return_addrs, int max_depth);
+
+#endif
diff --git a/lib/libcflat.h b/lib/libcflat.h
index b58a8a1..55bddca 100644
--- a/lib/libcflat.h
+++ b/lib/libcflat.h
@@ -81,6 +81,9 @@ extern void report_xfail(const char *msg_fmt, bool xfail, bool pass, ...);
extern void report_abort(const char *msg_fmt, ...);
extern int report_summary(void);
+extern void dump_stack(void);
+extern void dump_frame_stack(const void *instruction, const void *frame);
+
#define ARRAY_SIZE(_a) (sizeof(_a)/sizeof((_a)[0]))
#define container_of(ptr, type, member) ({ \
diff --git a/lib/powerpc/asm/stack.h b/lib/powerpc/asm/stack.h
new file mode 100644
index 0000000..f101d03
--- /dev/null
+++ b/lib/powerpc/asm/stack.h
@@ -0,0 +1 @@
+#include <asm-generic/stack.h>
diff --git a/lib/ppc64/asm/stack.h b/lib/ppc64/asm/stack.h
new file mode 100644
index 0000000..f101d03
--- /dev/null
+++ b/lib/ppc64/asm/stack.h
@@ -0,0 +1 @@
+#include <asm-generic/stack.h>
diff --git a/lib/printf.c b/lib/printf.c
index 2aec59a..096e175 100644
--- a/lib/printf.c
+++ b/lib/printf.c
@@ -1,4 +1,5 @@
#include "libcflat.h"
+#include "asm/stack.h"
#define BUFSZ 2000
@@ -259,3 +260,44 @@ int printf(const char *fmt, ...)
puts(buf);
return r;
}
+
+static void print_stack(const void **return_addrs, int depth,
+ bool top_is_return_address)
+{
+ int i = 0;
+
+ printf("\tSTACK:");
+
+ /* @addr indicates a non-return address, as expected by the stack
+ * pretty printer script. */
+ if (depth > 0 && !top_is_return_address) {
+ printf(" @%lx", (unsigned long) return_addrs[0]);
+ i++;
+ }
+
+ for (; i < depth; i++) {
+ printf(" %lx", (unsigned long) return_addrs[i]);
+ }
+ printf("\n");
+}
+
+#define MAX_DEPTH 10
+
+void dump_stack(void)
+{
+ const void *return_addrs[MAX_DEPTH];
+ int depth;
+
+ depth = backtrace(return_addrs, MAX_DEPTH);
+ print_stack(return_addrs, depth, true);
+}
+
+void dump_frame_stack(const void *instruction, const void *frame)
+{
+ const void *return_addrs[MAX_DEPTH];
+ int depth;
+
+ return_addrs[0] = instruction;
+ depth = backtrace_frame(frame, &return_addrs[1], MAX_DEPTH - 1);
+ print_stack(return_addrs, depth + 1, false);
+}
diff --git a/lib/x86/asm/stack.c b/lib/x86/asm/stack.c
new file mode 100644
index 0000000..b30b3b1
--- /dev/null
+++ b/lib/x86/asm/stack.c
@@ -0,0 +1,25 @@
+#include <libcflat.h>
+#include <asm/stack.h>
+
+int backtrace_frame(const void *frame, const void **return_addrs, int max_depth)
+{
+ static int walking;
+ int depth = 0;
+ const unsigned long *bp = (unsigned long *) frame;
+
+ if (walking) {
+ printf("RECURSIVE STACK WALK!!!\n");
+ return 0;
+ }
+ walking = 1;
+
+ for (depth = 0; depth < max_depth; depth++) {
+ return_addrs[depth] = (void *) bp[1];
+ if (return_addrs[depth] == 0)
+ break;
+ bp = (unsigned long *) bp[0];
+ }
+
+ walking = 0;
+ return depth;
+}
diff --git a/lib/x86/asm/stack.h b/lib/x86/asm/stack.h
new file mode 100644
index 0000000..c43bb96
--- /dev/null
+++ b/lib/x86/asm/stack.h
@@ -0,0 +1,12 @@
+#ifndef _X86ASM_STACK_H_
+#define _X86ASM_STACK_H_
+
+int backtrace_frame(const void *frame, const void **return_addrs, int max_depth);
+
+static inline int backtrace(const void **return_addrs, int max_depth)
+{
+ return backtrace_frame(__builtin_frame_address(0), return_addrs,
+ max_depth);
+}
+
+#endif
diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common
index 424983e..ea8f669 100644
--- a/powerpc/Makefile.common
+++ b/powerpc/Makefile.common
@@ -31,6 +31,7 @@ cflatobjs += lib/powerpc/io.o
cflatobjs += lib/powerpc/hcall.o
cflatobjs += lib/powerpc/setup.o
cflatobjs += lib/powerpc/rtas.o
+cflatobjs += lib/asm-generic/stack.o
FLATLIBS = $(libcflat) $(LIBFDT_archive)
%.elf: CFLAGS += $(arch_CFLAGS)
diff --git a/x86/Makefile.common b/x86/Makefile.common
index 3a14fea..c4750f0 100644
--- a/x86/Makefile.common
+++ b/x86/Makefile.common
@@ -12,6 +12,7 @@ cflatobjs += lib/x86/atomic.o
cflatobjs += lib/x86/desc.o
cflatobjs += lib/x86/isr.o
cflatobjs += lib/x86/acpi.o
+cflatobjs += lib/x86/asm/stack.o
$(libcflat): LDFLAGS += -nostdlib
$(libcflat): CFLAGS += -ffreestanding -I lib
@@ -19,6 +20,9 @@ $(libcflat): CFLAGS += -ffreestanding -I lib
CFLAGS += -m$(bits)
CFLAGS += -O1
+# dump_stack.o relies on frame pointers.
+KEEP_FRAME_POINTER := y
+
libgcc := $(shell $(CC) -m$(bits) --print-libgcc-file-name)
FLATLIBS = lib/libcflat.a $(libgcc)
--
2.7.0.rc3.207.g0ac5344
--
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