new file mode 100644
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Start-of-day code for an Armv8-R MPU system.
+ */
+
+#include <asm/early_printk.h>
+#include <asm/arm32/sysregs.h>
+
+/* Backgroud region enable/disable */
+#define SCTLR_ELx_BR BIT(17, UL)
+
+#define REGION_TEXT_PRBAR 0x18 /* SH=11 AP=10 XN=0 */
+#define REGION_RO_PRBAR 0x1D /* SH=11 AP=10 XN=1 */
+#define REGION_DATA_PRBAR 0x19 /* SH=11 AP=00 XN=1 */
+#define REGION_DEVICE_PRBAR 0x11 /* SH=10 AP=00 XN=1 */
+
+#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.
+ * We will also create an according MPU memory region entry, which
+ * is a structure of pr_t, in table \prmap.
+ *
+ * sel: region selector
+ * base: reg storing base address
+ * limit: reg storing limit address
+ * prbar: store computed PRBAR_EL2 value
+ * prlar: store computed PRLAR_EL2 value
+ * maxcount: maximum number of EL2 regions supported
+ * attr_prbar: PRBAR_EL2-related memory attributes. If not specified it will be
+ * REGION_DATA_PRBAR
+ * attr_prlar: PRLAR_EL2-related memory attributes. If not specified it will be
+ * REGION_NORMAL_PRLAR
+ *
+ * Preserves \maxcount
+ * Output:
+ * \sel: Next available region selector index.
+ * Clobbers \base, \limit, \prbar, \prlar
+ *
+ * Note that all parameters using registers should be distinct.
+ */
+.macro prepare_xen_region, sel, base, limit, prbar, prlar, maxcount, attr_prbar=REGION_DATA_PRBAR, attr_prlar=REGION_NORMAL_PRLAR
+ /* Check if the region is empty */
+ cmp \base, \limit
+ beq 1f
+
+ /* Check if the number of regions exceeded the count specified in MPUIR_EL2 */
+ cmp \sel, \maxcount
+ bge fail_insufficient_regions
+
+ /* Prepare value for PRBAR_EL2 reg and preserve it in \prbar.*/
+ and \base, \base, #MPU_REGION_MASK
+ mov \prbar, #\attr_prbar
+ orr \prbar, \prbar, \base
+
+ /* Limit address should be inclusive */
+ sub \limit, \limit, #1
+ and \limit, \limit, #MPU_REGION_MASK
+ mov \prlar, #\attr_prlar
+ orr \prlar, \prlar, \limit
+
+ mcr CP32(\sel, PRSELR_EL2)
+ isb
+ mcr CP32(\prbar, PRBAR_EL2)
+ mcr CP32(\prlar, PRLAR_EL2)
+ dsb sy
+ isb
+
+ add \sel, \sel, #1
+
+1:
+.endm
+
+/*
+ * Failure caused due to insufficient MPU regions.
+ */
+FUNC_LOCAL(fail_insufficient_regions)
+ PRINT("- Selected MPU region is above the implemented number in MPUIR_EL2 -\r\n")
+1: wfe
+ b 1b
+END(fail_insufficient_regions)
+
+/*
+ * Enable EL2 MPU and data cache
+ * If the Background region is enabled, then the MPU uses the default memory
+ * map as the Background region for generating the memory
+ * attributes when MPU is disabled.
+ * Since the default memory map of the Armv8-R AArch64 architecture is
+ * IMPLEMENTATION DEFINED, we intend to turn off the Background region here.
+ *
+ * Clobbers x0
+ *
+ */
+FUNC_LOCAL(enable_mpu)
+ mrc CP32(r0, HSCTLR)
+ bic r0, r0, #SCTLR_ELx_BR /* Disable Background region */
+ orr r0, r0, #SCTLR_Axx_ELx_M /* Enable MPU */
+ orr r0, r0, #SCTLR_Axx_ELx_C /* Enable D-cache */
+ mcr CP32(r0, HSCTLR)
+ isb
+
+ ret
+END(enable_mpu)
+
+/*
+ * Maps the various sections of Xen (decsribed in xen.lds.S) as different MPU
+ * regions.
+ *
+ * Clobbers r0
+ *
+ */
+#define NORMAL_MEM_SIZE 0x001fffff /* 2MB - 1 */
+
+FUNC(enable_boot_cpu_mm)
+ /* Get the number of regions specified in MPUIR_EL2 */
+ mrc CP32(r5, MPUIR_EL2)
+ and r5, r5, #NUM_MPU_REGIONS_MASK
+
+ /* x0: region sel */
+ mov r0, #0
+
+ /* Xen text section. */
+ ldr r1, =_stext
+ ldr r2, =_etext
+ prepare_xen_region r0, r1, r2, r3, r4, r5, attr_prbar=REGION_TEXT_PRBAR
+
+ /* Xen read-only data section. */
+ ldr r1, =_srodata
+ ldr r2, =_erodata
+ prepare_xen_region r0, r1, r2, r3, r4, r5, attr_prbar=REGION_RO_PRBAR
+
+ /* Xen read-only after init and data section. (RW data) */
+ ldr r1, =__ro_after_init_start
+ ldr r2, =__init_begin
+ prepare_xen_region r0, r1, r2, r3, r4, r5
+
+ /* Xen code section. */
+ ldr r1, =__init_begin
+ ldr r2, =__init_data_begin
+ prepare_xen_region r0, r1, r2, r3, r4, r5, attr_prbar=REGION_TEXT_PRBAR
+
+ /* Xen data and BSS section. */
+ ldr r1, =__init_data_begin
+ ldr r2, =__bss_end
+ prepare_xen_region r0, r1, r2, r3, r4, r5
+
+#ifdef CONFIG_EARLY_PRINTK
+ /* Xen early UART section. */
+ ldr r1, =CONFIG_EARLY_UART_BASE_ADDRESS
+ ldr r2, =(CONFIG_EARLY_UART_BASE_ADDRESS + CONFIG_EARLY_UART_SIZE)
+ prepare_xen_region r0, r1, r2, r3, r4, r5, attr_prbar=REGION_DEVICE_PRBAR, attr_prlar=REGION_DEVICE_PRLAR
+#endif
+
+ b enable_mpu
+ ret
+END(enable_boot_cpu_mm)
+
+/*
+ * Local variables:
+ * mode: ASM
+ * indent-tabs-mode: nil
+ * End:
+ */
@@ -1,6 +1,10 @@
#ifndef __ASM_ARM_CPREGS_H
#define __ASM_ARM_CPREGS_H
+#ifdef CONFIG_MPU
+#include <asm/mpu/cpregs.h>
+#endif
+
/*
* AArch32 Co-processor registers.
*
new file mode 100644
@@ -0,0 +1,21 @@
+#ifndef __ASM_ARM_MPU_CPREGS_H
+#define __ASM_ARM_MPU_CPREGS_H
+
+#define HMPUIR p15,4,c0,c0,4
+
+/* CP15 CR6: MPU Protection Region Base/Limit/Select Address Register */
+#define HPRSELR p15,4,c6,c2,1
+#define PRBAR_EL2 p15,4,c6,c3,0
+#define PRLAR_EL2 p15,4,c6,c8,1
+
+#define MPUIR_EL2 HMPUIR
+#define PRSELR_EL2 HPRSELR
+
+#endif
+
+/*
+ * Local variables:
+ * mode: ASM
+ * indent-tabs-mode: nil
+ * End:
+ */
Define enable_boot_cpu_mm() for the Armv8-R AArch64. Like boot-time page table in MMU system, we need a boot-time MPU protection region configuration in MPU system so Xen can fetch code and data from normal memory. To do this, Xen maps the following sections of the binary as separate regions (with permissions) :- 1. Text (Read only at EL2, execution is permitted) 2. RO data (Read only at EL2) 3. RO after init data and RW data (Read/Write at EL2) 4. Init Text (Read only at EL2, execution is permitted) 5. Init data and BSS (Read/Write at EL2) Before creating a region, we check if the count exceeds the number defined in MPUIR_EL2. If so, then the boot fails. Also we check if the region is empty or not. IOW, if the start and end address are same, we skip mapping the region. Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com> --- xen/arch/arm/arm32/mpu/head.S | 164 ++++++++++++++++++++++++++ xen/arch/arm/include/asm/cpregs.h | 4 + xen/arch/arm/include/asm/mpu/cpregs.h | 21 ++++ 3 files changed, 189 insertions(+) create mode 100644 xen/arch/arm/arm32/mpu/head.S create mode 100644 xen/arch/arm/include/asm/mpu/cpregs.h