Dump call stack on TA panic

Adds support for dumping the call stack of a user-mode TA when it
panics. Stack unwinding happens in kernel mode by re-using
abort_print_error() in core/arch/arm/kernel/abort.c. Like for abort
dumps, the helper script scripts/symbolize.py may be used to obtain
source-level information.

This feature is enabled by default. Set CFG_UNWIND=n to disable it
(or CFG_TEE_CORE_DEBUG=n).

In libutee, the utee_panic() syscall wrapper is renamed __utee_panic()
and now takes an additional parameters: a stack pointer, in addition to
the panic code. utee_panic() is written in assembly and pushes some
registers onto the stack before calling __utee_panic(). When it is time
to return from syscall_panic(), tee_svc_sys_return_helper() uses the
stack pointer to get the information needed to unwind the TA stack.
A struct abort_info is created and abort_print_error() is called.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (QEMU)
Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (HiKey 32/64)
Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (QEMUv8)

8 files changed, 30 insertions, 20 deletions

diff --git a/lib/libutee/abort.c b/lib/libutee/abort.c
index 1de88f28..79c071fc 100644
--- a/lib/libutee/abort.c
+++ b/lib/libutee/abort.c
@@ -34,4 +34,7 @@ void abort(void)
 {
 	printf("Abort!\n");
 	utee_panic(0);
+	/* Not reached */
+	while (1)
+		;
 }
diff --git a/lib/libutee/arch/arm/utee_syscalls_a32.S b/lib/libutee/arch/arm/utee_syscalls_a32.S
index dbc661f4..7f375b68 100644
--- a/lib/libutee/arch/arm/utee_syscalls_a32.S
+++ b/lib/libutee/arch/arm/utee_syscalls_a32.S
@@ -64,4 +64,17 @@ UNWIND( .fnend)
 	END_FUNC \name
         .endm
 
+	FUNC utee_panic, :
+UNWIND( .fnstart)
+	push	{r0-r11, lr}
+UNWIND(	.save	{r0-r11, lr})
+	mov	lr, pc
+	push	{lr}
+UNWIND(	.save	{lr})
+	mov	r1, sp
+	bl	__utee_panic
+	/* Not reached */
+UNWIND( .fnend)
+	END_FUNC utee_panic
+
 #include "utee_syscalls_asm.S"
diff --git a/lib/libutee/arch/arm/utee_syscalls_a64.S b/lib/libutee/arch/arm/utee_syscalls_a64.S
index 44bfa4b7..115a619d 100644
--- a/lib/libutee/arch/arm/utee_syscalls_a64.S
+++ b/lib/libutee/arch/arm/utee_syscalls_a64.S
@@ -42,5 +42,12 @@
         END_FUNC \name
         .endm
 
+	FUNC utee_panic, :
+	stp	x29, x30, [sp, #-16]!
+	mov	x1, sp
+	bl	__utee_panic
+	/* Not reached */
+	END_FUNC utee_panic
+
 #include "utee_syscalls_asm.S"
 
diff --git a/lib/libutee/arch/arm/utee_syscalls_asm.S b/lib/libutee/arch/arm/utee_syscalls_asm.S
index 7148daa9..8d525dcb 100644
--- a/lib/libutee/arch/arm/utee_syscalls_asm.S
+++ b/lib/libutee/arch/arm/utee_syscalls_asm.S
@@ -31,7 +31,7 @@
 
         UTEE_SYSCALL utee_log, TEE_SCN_LOG, 2
 
-        UTEE_SYSCALL utee_panic, TEE_SCN_PANIC, 1
+        UTEE_SYSCALL __utee_panic, TEE_SCN_PANIC, 2
 
         UTEE_SYSCALL utee_get_property, TEE_SCN_GET_PROPERTY, 7
 
diff --git a/lib/libutee/assert.c b/lib/libutee/assert.c
index f0144e37..2cb10726 100644
--- a/lib/libutee/assert.c
+++ b/lib/libutee/assert.c
@@ -44,4 +44,7 @@ void _assert_log(const char *expr __maybe_unused,
 void __noreturn _assert_break(void)
 {
 	utee_panic(TEE_ERROR_GENERIC);
+	/* Not reached */
+	while (1)
+		;
 }
diff --git a/lib/libutee/include/tee_api.h b/lib/libutee/include/tee_api.h
index f6423678..28cdf429 100644
--- a/lib/libutee/include/tee_api.h
+++ b/lib/libutee/include/tee_api.h
@@ -33,9 +33,7 @@
 #include <compiler.h>
 #include <tee_api_defines.h>
 #include <tee_api_types.h>
-#if defined(CFG_TEE_PANIC_DEBUG)
 #include <trace.h>
-#endif
 
 /* Property access functions */
 
@@ -75,14 +73,7 @@ TEE_Result TEE_GetNextProperty(TEE_PropSetHandle enumerator);
 
 /* System API - Misc */
 
-void __TEE_Panic(TEE_Result panicCode);
 void TEE_Panic(TEE_Result panicCode);
-#if defined(CFG_TEE_PANIC_DEBUG)
-#define TEE_Panic(c) do { \
-		EMSG("Panic 0x%x", (c)); \
-		__TEE_Panic(c); \
-	} while (0)
-#endif
 
 /* System API - Internal Client API */
 
diff --git a/lib/libutee/include/utee_syscalls.h b/lib/libutee/include/utee_syscalls.h
index 42f7a62f..ed518a04 100644
--- a/lib/libutee/include/utee_syscalls.h
+++ b/lib/libutee/include/utee_syscalls.h
@@ -55,7 +55,8 @@ void utee_return(unsigned long ret) __noreturn;
 
 void utee_log(const void *buf, size_t len);
 
-void utee_panic(unsigned long code) __noreturn;
+/* This is not __noreturn because AArch32 stack unwinding fails otherwise */
+void utee_panic(unsigned long code);
 
 /* prop_set is TEE_PROPSET_xxx*/
 TEE_Result utee_get_property(unsigned long prop_set, unsigned long index,
diff --git a/lib/libutee/tee_api_panic.c b/lib/libutee/tee_api_panic.c
index f3845db0..85366714 100644
--- a/lib/libutee/tee_api_panic.c
+++ b/lib/libutee/tee_api_panic.c
@@ -27,17 +27,9 @@
 #include <tee_api.h>
 #include <utee_syscalls.h>
 
-#undef TEE_Panic
-
 /* System API - Misc */
 
-void __noreturn __TEE_Panic(TEE_Result panicCode)
+void TEE_Panic(TEE_Result panicCode)
 {
 	utee_panic(panicCode);
 }
-
-void __noreturn TEE_Panic(TEE_Result panicCode)
-{
-	__TEE_Panic(panicCode);
-}
-