backtrace: Introduce backtrace function

This function diplays the backtrace, the current EL and security state
to allow a post-processing tool to choose the right binary to interpret
the dump.

The output can be fed to GNU addr2line to resolve function names given
an ELF binary compiled with debug information. The "-i" flag is
recommended to improve display in case of inlined functions. The *.dump
files generated during the build process can also be used.

The function works in AArch64 and AArch32. In AArch32 it only works in
A32 mode (without T32 interworking), which is enforced in the Makefile.

Sample output of a backtrace at EL3:

    BACKTRACE: START: function_name
    0: EL3: 0x798
    1: EL3: 0x538
    2: EL3: 0x550
    3: EL3: 0x55c
    4: EL3: 0x568
    5: EL3: 0x5a8
    6: EL3: 0xf4
    BACKTRACE: END: function_name

In order to enable it the new option ENABLE_BACKTRACE must be set to 1.
This option is set to 1 by default only in AArch64 debug builds. As
usual, it can be overridden by the platform makefile and in the build
command line.

Change-Id: Icaff39b0e5188329728be2f3c72b868b2368e794
Co-authored-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>

3 files changed, 32 insertions, 0 deletions

diff --git a/include/lib/aarch32/arch.h b/include/lib/aarch32/arch.h
index 6f0949bb..f9ed56e2 100644
--- a/include/lib/aarch32/arch.h
+++ b/include/lib/aarch32/arch.h
@@ -473,6 +473,8 @@
 #define CCSIDR		p15, 1, c0, c0, 0
 #define HTCR		p15, 4, c2, c0, 2
 #define HMAIR0		p15, 4, c10, c2, 0
+#define ATS1CPR		p15, 0, c7, c8, 0
+#define ATS1HR		p15, 4, c7, c8, 0
 #define DBGOSDLR	p14, 0, c1, c3, 4
 
 /* Debug register defines. The format is: coproc, opt1, CRn, CRm, opt2 */
@@ -513,6 +515,7 @@
 #define VTTBR_64	p15, 6, c2
 #define CNTPCT_64	p15, 0, c14
 #define HTTBR_64	p15, 4, c2
+#define PAR_64		p15, 0, c7
 
 /* 64 bit GICv3 CPU Interface system register defines. The format is: coproc, opt1, CRm */
 #define ICC_SGI1R_EL1_64	p15, 0, c12
@@ -569,6 +572,12 @@
 #define MAKE_MAIR_NORMAL_MEMORY(inner, outer)	\
 		((inner) | ((outer) << MAIR_NORM_OUTER_SHIFT))
 
+/* PAR fields */
+#define PAR_F_SHIFT	U(0)
+#define PAR_F_MASK	ULL(0x1)
+#define PAR_ADDR_SHIFT	U(12)
+#define PAR_ADDR_MASK	(BIT(40) - ULL(1)) /* 40-bits-wide page address */
+
 /*******************************************************************************
  * Definitions for system register interface to AMU for ARMv8.4 onwards
  ******************************************************************************/
diff --git a/include/lib/aarch32/arch_helpers.h b/include/lib/aarch32/arch_helpers.h
index 8eda5cbd..6369a5d7 100644
--- a/include/lib/aarch32/arch_helpers.h
+++ b/include/lib/aarch32/arch_helpers.h
@@ -276,6 +276,10 @@ DEFINE_COPROCR_RW_FUNCS(hdcr, HDCR)
 DEFINE_COPROCR_RW_FUNCS(cnthp_ctl, CNTHP_CTL)
 DEFINE_COPROCR_READ_FUNC(pmcr, PMCR)
 
+DEFINE_COPROCR_RW_FUNCS(ats1cpr, ATS1CPR)
+DEFINE_COPROCR_RW_FUNCS(ats1hr, ATS1HR)
+DEFINE_COPROCR_RW_FUNCS_64(par, PAR_64)
+
 DEFINE_COPROCR_RW_FUNCS(nsacr, NSACR)
 
 /* AArch32 coproc registers for 32bit MMU descriptor support */
@@ -333,6 +337,17 @@ DEFINE_DCOP_PARAM_FUNC(cvac, DCCMVAC)
 	((GET_M32(read_cpsr()) == MODE32_mon) ||	\
 		(IS_IN_SECURE() && (GET_M32(read_cpsr()) != MODE32_usr)))
 
+static inline unsigned int get_current_el(void)
+{
+	if (IS_IN_EL3()) {
+		return 3U;
+	} else if (IS_IN_EL2()) {
+		return 2U;
+	} else {
+		return 1U;
+	}
+}
+
 /* Macros for compatibility with AArch64 system registers */
 #define read_mpidr_el1()	read_mpidr()
 
diff --git a/include/lib/aarch64/arch_helpers.h b/include/lib/aarch64/arch_helpers.h
index 067c374a..d90061f2 100644
--- a/include/lib/aarch64/arch_helpers.h
+++ b/include/lib/aarch64/arch_helpers.h
@@ -155,7 +155,9 @@ DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s12e1r)
 DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s12e1w)
 DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s12e0r)
 DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s12e0w)
+DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s1e1r)
 DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s1e2r)
+DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s1e3r)
 
 void flush_dcache_range(uintptr_t addr, size_t size);
 void clean_dcache_range(uintptr_t addr, size_t size);
@@ -353,6 +355,12 @@ DEFINE_RENAME_SYSREG_READ_FUNC(erxmisc1_el1, ERXMISC1_EL1)
 
 #define IS_IN_EL1() IS_IN_EL(1)
 #define IS_IN_EL3() IS_IN_EL(3)
+#define IS_IN_EL3() IS_IN_EL(3)
+
+static inline unsigned int get_current_el(void)
+{
+	return GET_EL(read_CurrentEl());
+}
 
 /*
  * Check if an EL is implemented from AA64PFR0 register fields. 'el' argument