@@ -121,6 +121,13 @@ config EARLY_UART_BASE_ADDRESS
hex "Early printk, physical base address of debug UART"
range 0x0 0xffffffff if ARM_32
+config EARLY_UART_SIZE
+ depends on EARLY_PRINTK
+ depends on MPU
+ hex "Early printk, physical size of debug UART"
+ range 0x0 0xffffffff if ARM_32
+ default 0x1000
+
config EARLY_UART_PL011_BAUD_RATE
depends on EARLY_UART_PL011
int "Early printk UART baud rate for pl011"
@@ -11,8 +11,10 @@
#define REGION_TEXT_PRBAR 0x38 /* SH=11 AP=10 XN=00 */
#define REGION_RO_PRBAR 0x3A /* SH=11 AP=10 XN=10 */
#define REGION_DATA_PRBAR 0x32 /* SH=11 AP=00 XN=10 */
+#define REGION_DEVICE_PRBAR 0x22 /* SH=10 AP=00 XN=10 */
#define REGION_NORMAL_PRLAR 0x0f /* NS=0 ATTR=111 EN=1 */
+#define REGION_DEVICE_PRLAR 0x09 /* NS=0 ATTR=100 EN=1 */
/*
* Macro to prepare and set a EL2 MPU memory region.
@@ -138,6 +140,13 @@ FUNC(enable_boot_cpu_mm)
ldr x2, =__bss_end
prepare_xen_region x0, x1, x2, x3, x4, x5
+#ifdef CONFIG_EARLY_PRINTK
+ /* Xen early UART section. */
+ ldr x1, =CONFIG_EARLY_UART_BASE_ADDRESS
+ ldr x2, =(CONFIG_EARLY_UART_BASE_ADDRESS + CONFIG_EARLY_UART_SIZE)
+ prepare_xen_region x0, x1, x2, x3, x4, x5, attr_prbar=REGION_DEVICE_PRBAR, attr_prlar=REGION_DEVICE_PRLAR
+#endif
+
b enable_mpu
ret
END(enable_boot_cpu_mm)
@@ -15,6 +15,29 @@
#ifdef CONFIG_EARLY_PRINTK
+#if defined(CONFIG_MPU)
+
+/*
+ * For MPU systems, there is no VMSA support in EL2, so we use VA == PA
+ * for EARLY_UART_VIRTUAL_ADDRESS.
+ */
+#define EARLY_UART_VIRTUAL_ADDRESS CONFIG_EARLY_UART_BASE_ADDRESS
+
+/*
+ * User-defined EARLY_UART_BASE_ADDRESS and EARLY_UART_SIZE must be aligned to
+ * minimum size of MPU region.
+ */
+
+#if (EARLY_UART_BASE_ADDRESS % MPU_REGION_ALIGN) != 0
+#error "EARLY_UART_BASE_ADDRESS must be aligned to minimum MPU region size"
+#endif
+
+#if (EARLY_UART_SIZE % MPU_REGION_ALIGN) != 0
+#error "EARLY_UART_SIZE must be aligned to minimum MPU region size"
+#endif
+
+#elif defined(CONFIG_MMU)
+
/* need to add the uart address offset in page to the fixmap address */
#define EARLY_UART_VIRTUAL_ADDRESS \
(FIXMAP_ADDR(FIX_CONSOLE) + (CONFIG_EARLY_UART_BASE_ADDRESS & ~PAGE_MASK))
@@ -22,6 +45,9 @@
#define TEMPORARY_EARLY_UART_VIRTUAL_ADDRESS \
(TEMPORARY_FIXMAP_ADDR(FIX_CONSOLE) + (CONFIG_EARLY_UART_BASE_ADDRESS & ~PAGE_MASK))
-#endif /* !CONFIG_EARLY_PRINTK */
+#else
+#error "Unknown Memory management system"
+#endif
+#endif /* !CONFIG_EARLY_PRINTK */
#endif
CONFIG_EARLY_UART_SIZE is introduced to let user provide physical size of early UART. Unlike MMU where we map a page in the virtual address space, here we need to know the exact physical size to be mapped. As VA == PA in case of MPU, the memory layout follows exactly the hardware configuration. As a consequence, we set EARLY_UART_VIRTUAL_ADDRESS as physical address. EARLY_UART_BASE_ADDRESS and EARLY_UART_SIZE should be aligned to the minimum size of MPU region (ie 64 bits) as per the hardware restrictions. Refer ARM DDI 0600A.d ID120821 A1.3 "A minimum protection region size of 64 bytes.". UART is mapped as nGnRE region (as specified by ATTR=100 , refer G1.3.13, MAIR_EL2, "---0100 Device memory nGnRE") and Doc ID - 102670_0101_02_en Table 4-3, Armv8 architecture memory types (nGnRE - Corresponds to Device in Armv7 architecture). Also, it is mapped as outer shareable, RW at EL2 only and execution of instructions from the region is not permitted. Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com> --- Changes from :- v1 - 1. UART base address and size should be aligned to the minimum size of MPU region (and not PAGE_SIZE). xen/arch/arm/Kconfig.debug | 7 +++++++ xen/arch/arm/arm64/mpu/head.S | 9 ++++++++ xen/arch/arm/include/asm/early_printk.h | 28 ++++++++++++++++++++++++- 3 files changed, 43 insertions(+), 1 deletion(-)