[bootwrapper PATCH v2 08/13] Announce boot-wrapper mode / exception level

Mark Rutland
2022-01-14T11:00:28Z

When something goes wrong within the boot-wrapper, it can be very
helpful to know where we started from. Add an arch_announce() function
to log this early in the boot process. More information can be added
here in future.

This is logged ot the serial console as:

| Boot-wrapper v0.2
| Entered at EL3

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
---
Makefile.am | 2 +-
arch/aarch32/include/asm/cpu.h | 9 +++++++++
arch/aarch32/init.c | 30 ++++++++++++++++++++++++++++++
arch/aarch64/init.c | 19 +++++++++++++++++++
common/init.c | 6 +++++-
common/platform.c | 24 ++++++++++++++----------
include/platform.h | 1 +
7 files changed, 79 insertions(+), 12 deletions(-)
create mode 100644 arch/aarch32/init.c
create mode 100644 arch/aarch64/init.c

diff --git a/Makefile.am b/Makefile.am
index 0651c38..885a77c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -36,7 +36,7 @@ PSCI_CPU_OFF := 0x84000002
COMMON_SRC := common/
COMMON_OBJ := boot.o bakery_lock.o platform.o lib.o init.o

-ARCH_OBJ := boot.o stack.o utils.o
+ARCH_OBJ := boot.o stack.o utils.o init.o

if BOOTWRAPPER_32
CPPFLAGS += -DBOOTWRAPPER_32
diff --git a/arch/aarch32/include/asm/cpu.h b/arch/aarch32/include/asm/cpu.h
index d691c7b..aa72204 100644
--- a/arch/aarch32/include/asm/cpu.h
+++ b/arch/aarch32/include/asm/cpu.h
@@ -44,6 +44,15 @@
#define sevl() asm volatile ("sev" : : : "memory")
#endif

+static inline unsigned long read_cpsr(void)
+{
+ unsigned long cpsr;
+ asm volatile ("mrs %0, cpsr\n" : "=r" (cpsr));
+ return cpsr;
+}
+
+#define read_cpsr_mode() (read_cpsr() & PSR_MODE_MASK)
+
#define MPIDR "p15, 0, %0, c0, c0, 5"
#define ID_PFR1 "p15, 0, %0, c0, c1, 1"
#define ICIALLU "p15, 0, %0, c7, c5, 0"
diff --git a/arch/aarch32/init.c b/arch/aarch32/init.c
new file mode 100644
index 0000000..b29ebb4
--- /dev/null
+++ b/arch/aarch32/init.c
@@ -0,0 +1,30 @@
+/*
+ * init.c - common boot-wrapper initialization
+ *
+ * Copyright (C) 2021 ARM Limited. All rights reserved.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE.txt file.
+ */
+#include <platform.h>
+
+#include <asm/cpu.h>
+
+static const char *mode_string(void)
+{
+ switch (read_cpsr_mode()) {
+ case PSR_MON:
+ return "PL1";
+ case PSR_HYP:
+ return "PL2 (Non-secure)";
+ default:
+ return "<UNKNOWN MODE>";
+ }
+}
+
+void announce_arch(void)
+{
+ print_string("Entered at ");
+ print_string(mode_string());
+ print_string("\r\n");
+}
diff --git a/arch/aarch64/init.c b/arch/aarch64/init.c
new file mode 100644
index 0000000..82816e7
--- /dev/null
+++ b/arch/aarch64/init.c
@@ -0,0 +1,19 @@
+/*
+ * init.c - common boot-wrapper initialization
+ *
+ * Copyright (C) 2021 ARM Limited. All rights reserved.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE.txt file.
+ */
+#include <cpu.h>
+#include <platform.h>
+
+void announce_arch(void)
+{
+ unsigned char el = mrs(CurrentEl) >> 2;
+
+ print_string("Entered at EL");
+ print_char('0' + el);
+ print_string("\r\n");
+}
diff --git a/common/init.c b/common/init.c
index 9c471c9..2600f73 100644
--- a/common/init.c
+++ b/common/init.c
@@ -11,14 +11,18 @@

static void announce_bootwrapper(void)
{
- print_string("Boot-wrapper v0.2\r\n\r\n");
+ print_string("Boot-wrapper v0.2\r\n");
}

+void announce_arch(void);
+
void cpu_init_bootwrapper(void)
{
if (this_cpu_logical_id() == 0) {
init_uart();
announce_bootwrapper();
+ announce_arch();
+ print_string("\r\n");
init_platform();
}
}
diff --git a/common/platform.c b/common/platform.c
index 47bf547..80d0562 100644
--- a/common/platform.c
+++ b/common/platform.c
@@ -31,21 +31,25 @@
#define V2M_SYS(reg) ((void *)SYSREGS_BASE + V2M_SYS_##reg)
#endif

-void print_string(const char *str)
+void print_char(char c)
{
uint32_t flags;

- while (*str) {
- do
- flags = raw_readl(PL011(UARTFR));
- while (flags & PL011_UARTFR_FIFO_FULL);
+ do {
+ flags = raw_readl(PL011(UARTFR));
+ } while (flags & PL011_UARTFR_FIFO_FULL);
+
+ raw_writel(c, PL011(UARTDR));

- raw_writel(*str++, PL011(UARTDR));
+ do {
+ flags = raw_readl(PL011(UARTFR));
+ } while (flags & PL011_UARTFR_BUSY);
+}

- do
- flags = raw_readl(PL011(UARTFR));
- while (flags & PL011_UARTFR_BUSY);
- }
+void print_string(const char *str)
+{
+ while (*str)
+ print_char(*str++);
}

void init_uart(void)
diff --git a/include/platform.h b/include/platform.h
index e5248e1..237b481 100644
--- a/include/platform.h
+++ b/include/platform.h
@@ -9,6 +9,7 @@
#ifndef __PLATFORM_H
#define __PLATFORM_H

+void print_char(char c);
void print_string(const char *str);
void init_uart(void);

--
2.30.2