[PATCH v3 27/52] xen/mpu: introduce setup_mm_mappings

[Penny Zheng <Penny.Zheng@xxxxxxx>]

Function setup_pagetables is responsible for boot-time pagetable setup
in MMU system at C world.
In MPU system, as we have already built up start-of-day Xen MPU memory
region mapping in assembly boot-time, here we only need to do a few
memory management data initializtion, including reading the number of
maximum MPU regions supported by the EL2 MPU, and setting the according
bitfield for regions enabled in assembly boot-time, in bitmap xen_mpumap_mask.
This bitmap xen_mpumap_mask is responsible for recording the usage of EL2 MPU
memory regions.

In order to keep only one codeflow in arm/setup.c, setup_mm_mappings
, with a more generic name, is introduced to replace setup_pagetables.

Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
v3:
- introduce bitmap xen_mpumap_mask for dynamic allocation on MPU regions
---
 xen/arch/arm/include/asm/arm64/mpu.h     |  1 +
 xen/arch/arm/include/asm/arm64/sysregs.h |  3 +++
 xen/arch/arm/include/asm/mm.h            |  4 ++--
 xen/arch/arm/mmu/mm.c                    |  7 +++++-
 xen/arch/arm/mpu/mm.c                    | 30 ++++++++++++++++++++++++
 xen/arch/arm/setup.c                     |  2 +-
 6 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/include/asm/arm64/mpu.h 
b/xen/arch/arm/include/asm/arm64/mpu.h
index 6ec2c10b14..407fec66c9 100644
--- a/xen/arch/arm/include/asm/arm64/mpu.h
+++ b/xen/arch/arm/include/asm/arm64/mpu.h
@@ -19,6 +19,7 @@
  * or it needs adjustment.
  */
 #define REGION_UART_SEL            0x07
+#define MPUIR_REGION_MASK          ((_AC(1, UL) << 8) - 1)
 
 #ifndef __ASSEMBLY__
 
diff --git a/xen/arch/arm/include/asm/arm64/sysregs.h 
b/xen/arch/arm/include/asm/arm64/sysregs.h
index c41d805fde..a249a660a8 100644
--- a/xen/arch/arm/include/asm/arm64/sysregs.h
+++ b/xen/arch/arm/include/asm/arm64/sysregs.h
@@ -474,6 +474,9 @@
 /* MPU Protection Region Selection Register encode */
 #define PRSELR_EL2  S3_4_C6_C2_1
 
+/* MPU Type registers encode */
+#define MPUIR_EL2   S3_4_C0_C0_4
+
 #endif
 
 /* Access to system registers */
diff --git a/xen/arch/arm/include/asm/mm.h b/xen/arch/arm/include/asm/mm.h
index 5d890a6a45..eb520b49e3 100644
--- a/xen/arch/arm/include/asm/mm.h
+++ b/xen/arch/arm/include/asm/mm.h
@@ -201,8 +201,8 @@ extern unsigned long total_pages;
 
 extern uint64_t init_mm;
 
-/* Boot-time pagetable setup */
-extern void setup_pagetables(unsigned long boot_phys_offset);
+/* Boot-time memory mapping setup */
+extern void setup_mm_mappings(unsigned long boot_phys_offset);
 /* Map FDT in boot pagetable */
 extern void *early_fdt_map(paddr_t fdt_paddr);
 /* Remove early mappings */
diff --git a/xen/arch/arm/mmu/mm.c b/xen/arch/arm/mmu/mm.c
index 43c19fa914..d7d5bf7287 100644
--- a/xen/arch/arm/mmu/mm.c
+++ b/xen/arch/arm/mmu/mm.c
@@ -398,7 +398,7 @@ static void clear_table(void *table)
 
 /* Boot-time pagetable setup.
  * Changes here may need matching changes in head.S */
-void __init setup_pagetables(unsigned long boot_phys_offset)
+static void __init setup_pagetables(unsigned long boot_phys_offset)
 {
     uint64_t ttbr;
     lpae_t pte, *p;
@@ -470,6 +470,11 @@ void __init setup_pagetables(unsigned long 
boot_phys_offset)
 #endif
 }
 
+void setup_mm_mappings(unsigned long boot_phys_offset)
+{
+    setup_pagetables(boot_phys_offset);
+}
+
 static void clear_boot_pagetables(void)
 {
     /*
diff --git a/xen/arch/arm/mpu/mm.c b/xen/arch/arm/mpu/mm.c
index fb6bb721b1..e06a6e5810 100644
--- a/xen/arch/arm/mpu/mm.c
+++ b/xen/arch/arm/mpu/mm.c
@@ -20,6 +20,7 @@
  */
 
 #include <xen/init.h>
+#include <xen/mm.h>
 #include <xen/page-size.h>
 #include <asm/arm64/mpu.h>
 
@@ -27,6 +28,35 @@
 pr_t __aligned(PAGE_SIZE) __section(".data.page_aligned")
      xen_mpumap[ARM_MAX_MPU_MEMORY_REGIONS];
 
+/* Maximum number of supported MPU memory regions by the EL2 MPU. */
+uint8_t __ro_after_init max_xen_mpumap;
+
+/*
+ * Bitmap xen_mpumap_mask is to record the usage of EL2 MPU memory regions.
+ * Bit 0 represents MPU memory region 0, bit 1 represents MPU memory
+ * region 1, ..., and so on.
+ * If a MPU memory region gets enabled, set the according bit to 1.
+ */
+static DECLARE_BITMAP(xen_mpumap_mask, ARM_MAX_MPU_MEMORY_REGIONS);
+
+void __init setup_mm_mappings(unsigned long boot_phys_offset)
+{
+    unsigned int nr_regions = REGION_UART_SEL, i = 0;
+
+    /*
+     * MPUIR_EL2.Region[0:7] identifies the number of regions supported by
+     * the EL2 MPU.
+     */
+    max_xen_mpumap = (uint8_t)(READ_SYSREG(MPUIR_EL2) & MPUIR_REGION_MASK);
+
+    /* Set the bitfield for regions enabled in assembly boot-time. */
+#ifdef CONFIG_EARLY_PRINTK
+    nr_regions = REGION_UART_SEL + 1;
+#endif
+    for ( ; i < nr_regions; i++ )
+        set_bit(i, xen_mpumap_mask);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 6f8dd98d6b..f42b53d17b 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -781,7 +781,7 @@ void __init start_xen(unsigned long boot_phys_offset,
     /* Initialize traps early allow us to get backtrace when an error occurred 
*/
     init_traps();
 
-    setup_pagetables(boot_phys_offset);
+    setup_mm_mappings(boot_phys_offset);
 
     smp_clear_cpu_maps();
 
-- 
2.25.1