Introduce crash console APIs for crash reporting
This patch introduces platform APIs to initialise and
print a character on a designated crash console.
For the FVP platform, PL011_UART0 is the designated
crash console. The platform porting guide is also updated
to document the new APIs.
Change-Id: I5e97d8762082e0c88c8c9bbb479353eac8f11a66
diff --git a/docs/porting-guide.md b/docs/porting-guide.md
index 813d0be..9002a99 100644
--- a/docs/porting-guide.md
+++ b/docs/porting-guide.md
@@ -15,6 +15,7 @@
* Boot Loader stage 3-1 (BL3-1)
* PSCI implementation (in BL3-1)
* Interrupt Management framework (in BL3-1)
+ * Crash Reporting mechanism (in BL3-1)
4. C Library
5. Storage abstraction layer
@@ -1316,6 +1317,41 @@
interrupt id from the relevant _Interrupt Group Register_ (`GICD_IGROUPRn`). It
uses the group value to determine the type of interrupt.
+3.5 Crash Reporting mechanism (in BL3-1)
+----------------------------------------------
+BL3-1 implements a crash reporting mechanism which prints the various registers
+of the CPU to enable quick crash analysis and debugging. It requires that a console
+is designated as the crash console by the platform which will used to print the
+register dump.
+
+The following functions must be implemented by the platform if it wants crash reporting
+mechanism in BL3-1. The functions are implemented in assembly so that they can be
+invoked without a C Runtime stack.
+
+### Function : plat_crash_console_init
+
+ Argument : void
+ Return : int
+
+This API is used by the crash reporting mechanism to intialize the crash console.
+It should only use the general purpose registers x0 to x2 to do the initiaization
+and returns 1 on success.
+
+The FVP port designates the PL011_UART0 as the crash console and calls the
+console_core_init() to initialize the console.
+
+### Function : plat_crash_console_putc
+
+ Argument : int
+ Return : int
+
+This API is used by the crash reporting mechanism to print a character on the
+designated crash console. It should only use general purpose registers x1 and
+x2 to do its work. The parameter and the return value are in general purpose
+register x0.
+
+The FVP port designates the PL011_UART0 as the crash console and calls the
+console_core_putc() to print the character on the console.
4. C Library
-------------
diff --git a/include/common/asm_macros.S b/include/common/asm_macros.S
index 2bccf58..238fa82 100644
--- a/include/common/asm_macros.S
+++ b/include/common/asm_macros.S
@@ -162,3 +162,36 @@
.macro get_up_stack _name, _size
ldr x0, =(\_name + \_size)
.endm
+
+ /*
+ * Helper macro to generate the best mov/movk combinations according
+ * the value to be moved. The 16 bits from '_shift' are tested and
+ * if not zero, they are moved into '_reg' without affecting
+ * other bits.
+ */
+ .macro _mov_imm16 _reg, _val, _shift
+ .if (\_val >> \_shift) & 0xffff
+ .if (\_val & (1 << \_shift - 1))
+ movk \_reg, (\_val >> \_shift) & 0xffff, LSL \_shift
+ .else
+ mov \_reg, \_val & (0xffff << \_shift)
+ .endif
+ .endif
+ .endm
+
+ /*
+ * Helper macro to load arbitrary values into 32 or 64-bit registers
+ * which generates the best mov/movk combinations. Many base addresses
+ * are 64KB aligned the macro will eliminate updating bits 15:0 in
+ * that case
+ */
+ .macro mov_imm _reg, _val
+ .if (\_val) == 0
+ mov \_reg, #0
+ .else
+ _mov_imm16 \_reg, (\_val), 0
+ _mov_imm16 \_reg, (\_val), 16
+ _mov_imm16 \_reg, (\_val), 32
+ _mov_imm16 \_reg, (\_val), 48
+ .endif
+ .endm
diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h
index 1eeaac2..76cc3c5 100644
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -72,6 +72,8 @@
unsigned int platform_get_core_pos(unsigned long mpidr);
unsigned long platform_get_stack(unsigned long mpidr);
void plat_report_exception(unsigned long);
+void plat_crash_console_init(unsigned long base_addr);
+int plat_crash_console_putc(int c);
/*******************************************************************************
* Mandatory BL1 functions
diff --git a/plat/common/aarch64/platform_helpers.S b/plat/common/aarch64/platform_helpers.S
index f6ac13e..5e2d1b1 100644
--- a/plat/common/aarch64/platform_helpers.S
+++ b/plat/common/aarch64/platform_helpers.S
@@ -37,6 +37,8 @@
.weak platform_is_primary_cpu
.weak platform_check_mpidr
.weak plat_report_exception
+ .weak plat_crash_console_init
+ .weak plat_crash_console_putc
/* -----------------------------------------------------
* int platform_get_core_pos(int mpidr);
@@ -79,3 +81,20 @@
*/
func plat_report_exception
ret
+
+ /* -----------------------------------------------------
+ * Placeholder function which should be redefined by
+ * each platform.
+ * -----------------------------------------------------
+ */
+func plat_crash_console_init
+ mov x0, #0
+ ret
+
+ /* -----------------------------------------------------
+ * Placeholder function which should be redefined by
+ * each platform.
+ * -----------------------------------------------------
+ */
+func plat_crash_console_putc
+ ret
diff --git a/plat/fvp/aarch64/fvp_helpers.S b/plat/fvp/aarch64/fvp_helpers.S
index 3cd0b46..823588e 100644
--- a/plat/fvp/aarch64/fvp_helpers.S
+++ b/plat/fvp/aarch64/fvp_helpers.S
@@ -32,6 +32,7 @@
#include <asm_macros.S>
#include <bl_common.h>
#include <gic_v2.h>
+#include <pl011.h>
#include "../drivers/pwrc/fvp_pwrc.h"
#include "../fvp_def.h"
@@ -39,6 +40,8 @@
.globl plat_secondary_cold_boot_setup
.globl platform_mem_init
.globl plat_report_exception
+ .globl plat_crash_console_init
+ .globl plat_crash_console_putc
.macro fvp_choose_gicmmap param1, param2, x_tmp, w_tmp, res
ldr \x_tmp, =VE_SYSREGS_BASE + V2M_SYS_ID
@@ -187,3 +190,30 @@
add x1, x1, #V2M_SYS_LED
str w0, [x1]
ret
+
+ /* Define a crash console for the plaform */
+#define FVP_CRASH_CONSOLE_BASE PL011_UART0_BASE
+
+ /* ---------------------------------------------
+ * int plat_crash_console_init(void)
+ * Function to initialize the crash console
+ * without a C Runtime to print crash report.
+ * Clobber list : x0, x1, x2
+ * ---------------------------------------------
+ */
+func plat_crash_console_init
+ mov_imm x0, FVP_CRASH_CONSOLE_BASE
+ mov_imm x1, PL011_UART0_CLK_IN_HZ
+ mov_imm x2, PL011_BAUDRATE
+ b console_core_init
+
+ /* ---------------------------------------------
+ * int plat_crash_console_putc(void)
+ * Function to print a character on the crash
+ * console without a C Runtime.
+ * Clobber list : x1, x2
+ * ---------------------------------------------
+ */
+func plat_crash_console_putc
+ mov_imm x1, FVP_CRASH_CONSOLE_BASE
+ b console_core_putc