On 11/06/2025 15:35, Ayan Kumar Halder wrote:
Define prepare_selector(), read_protection_region() and
write_protection_region() for arm32. Also, define
GENERATE_{READ/WRITE}_PR_REG_OTHERS to access MPU regions from 32 to 255.
Enable pr_{get/set}_{base/limit}(), region_is_valid() for arm32.
Enable pr_of_addr() for arm32.
Signed-off-by: Ayan Kumar Halder <ayan.kumar.hal...@amd.com>
---
Changes from :-
v1 - 1. Enable write_protection_region() for aarch32.
v2 - 1. Enable access to protection regions from 0 - 255.
xen/arch/arm/include/asm/mpu.h | 2 -
xen/arch/arm/mpu/arm32/Makefile | 1 +
xen/arch/arm/mpu/arm32/mm.c | 165 ++++++++++++++++++++++++++++++++
xen/arch/arm/mpu/mm.c | 2 -
4 files changed, 166 insertions(+), 4 deletions(-)
create mode 100644 xen/arch/arm/mpu/arm32/mm.c
diff --git a/xen/arch/arm/include/asm/mpu.h b/xen/arch/arm/include/asm/mpu.h
index 8f06ddac0f..63560c613b 100644
--- a/xen/arch/arm/include/asm/mpu.h
+++ b/xen/arch/arm/include/asm/mpu.h
@@ -25,7 +25,6 @@
#ifndef __ASSEMBLY__
-#ifdef CONFIG_ARM_64
/*
* Set base address of MPU protection region.
*
@@ -85,7 +84,6 @@ static inline bool region_is_valid(const pr_t *pr)
{
return pr->prlar.reg.en;
}
-#endif /* CONFIG_ARM_64 */
#endif /* __ASSEMBLY__ */
diff --git a/xen/arch/arm/mpu/arm32/Makefile b/xen/arch/arm/mpu/arm32/Makefile
index e15ce2f7be..3da872322e 100644
--- a/xen/arch/arm/mpu/arm32/Makefile
+++ b/xen/arch/arm/mpu/arm32/Makefile
@@ -1 +1,2 @@
obj-y += domain-page.o
+obj-y += mm.o
diff --git a/xen/arch/arm/mpu/arm32/mm.c b/xen/arch/arm/mpu/arm32/mm.c
new file mode 100644
index 0000000000..5d3cb6dff7
--- /dev/null
+++ b/xen/arch/arm/mpu/arm32/mm.c
@@ -0,0 +1,165 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <xen/bug.h>
+#include <xen/types.h>
+#include <asm/mpu.h>
+#include <asm/sysregs.h>
+#include <asm/system.h>
+
+#define PRBAR_EL2_(n) HPRBAR##n
+#define PRLAR_EL2_(n) HPRLAR##n
+
+#define GENERATE_WRITE_PR_REG_CASE(num, pr) \
+ case num: \
+ { \
+ WRITE_SYSREG(pr->prbar.bits & ~MPU_REGION_RES0, PRBAR_EL2_(num)); \
+ WRITE_SYSREG(pr->prlar.bits & ~MPU_REGION_RES0, PRLAR_EL2_(num)); \
+ break; \
+ }
+
+#define GENERATE_WRITE_PR_REG_OTHERS(num, pr) \
+ case num: \
+ { \
+ WRITE_SYSREG(pr->prbar.bits & ~MPU_REGION_RES0, HPRBAR); \
+ WRITE_SYSREG(pr->prlar.bits & ~MPU_REGION_RES0, HPRLAR); \
+ break; \
+ }
+
+#define GENERATE_READ_PR_REG_CASE(num, pr) \
+ case num: \
+ { \
+ pr->prbar.bits = READ_SYSREG(PRBAR_EL2_(num)); \
+ pr->prlar.bits = READ_SYSREG(PRLAR_EL2_(num)); \
+ break; \
+ }
+
+#define GENERATE_READ_PR_REG_OTHERS(num, pr) \
+ case num: \
+ { \
+ pr->prbar.bits = READ_SYSREG(HPRBAR); \
+ pr->prlar.bits = READ_SYSREG(HPRLAR); \
+ break; \
+ }
+
+/*
+ * Armv8-R supports direct access and indirect access to the MPU regions
through
+ * registers:
+ * - indirect access involves changing the MPU region selector, issuing an isb
+ * barrier and accessing the selected region through specific registers
+ * - direct access involves accessing specific registers that point to
+ * specific MPU regions, without changing the selector, avoiding the use of
+ * a barrier.
+ * For Arm32 the PR{B,L}AR<n>_ELx (for n=0..31) are used for direct access to
the
+ * first 32 MPU regions.
+ * For MPU region numbered 32..255, one need to set the region number in
PRSELR_ELx,
+ * followed by configuring PR{B,L}AR_ELx.
+ */
+inline void prepare_selector(uint8_t *sel)
+{
+ uint8_t cur_sel = *sel;
+
+ if ( cur_sel > 0x1FU )
+ {
+ WRITE_SYSREG(cur_sel, PRSELR_EL2);
+ isb();
+ }
+}
+
+void read_protection_region(pr_t *pr_read, uint8_t sel)
+{
+ prepare_selector(&sel);
+
+ switch ( sel )
+ {
+ GENERATE_READ_PR_REG_CASE(0, pr_read);
+ GENERATE_READ_PR_REG_CASE(1, pr_read);
+ GENERATE_READ_PR_REG_CASE(2, pr_read);
+ GENERATE_READ_PR_REG_CASE(3, pr_read);
+ GENERATE_READ_PR_REG_CASE(4, pr_read);
+ GENERATE_READ_PR_REG_CASE(5, pr_read);
+ GENERATE_READ_PR_REG_CASE(6, pr_read);
+ GENERATE_READ_PR_REG_CASE(7, pr_read);
+ GENERATE_READ_PR_REG_CASE(8, pr_read);
+ GENERATE_READ_PR_REG_CASE(9, pr_read);
+ GENERATE_READ_PR_REG_CASE(10, pr_read);
+ GENERATE_READ_PR_REG_CASE(11, pr_read);
+ GENERATE_READ_PR_REG_CASE(12, pr_read);
+ GENERATE_READ_PR_REG_CASE(13, pr_read);
+ GENERATE_READ_PR_REG_CASE(14, pr_read);
+ GENERATE_READ_PR_REG_CASE(15, pr_read);
+ GENERATE_READ_PR_REG_CASE(16, pr_read);
+ GENERATE_READ_PR_REG_CASE(17, pr_read);
+ GENERATE_READ_PR_REG_CASE(18, pr_read);
+ GENERATE_READ_PR_REG_CASE(19, pr_read);
+ GENERATE_READ_PR_REG_CASE(20, pr_read);
+ GENERATE_READ_PR_REG_CASE(21, pr_read);
+ GENERATE_READ_PR_REG_CASE(22, pr_read);
+ GENERATE_READ_PR_REG_CASE(23, pr_read);
+ GENERATE_READ_PR_REG_CASE(24, pr_read);
+ GENERATE_READ_PR_REG_CASE(25, pr_read);
+ GENERATE_READ_PR_REG_CASE(26, pr_read);
+ GENERATE_READ_PR_REG_CASE(27, pr_read);
+ GENERATE_READ_PR_REG_CASE(28, pr_read);
+ GENERATE_READ_PR_REG_CASE(29, pr_read);
+ GENERATE_READ_PR_REG_CASE(30, pr_read);
+ GENERATE_READ_PR_REG_CASE(31, pr_read);
+ GENERATE_READ_PR_REG_OTHERS(32 ... 255, pr_read);
This should be 32 ... 254 . Thanks Luca for pointing this out.
The max number of regions supported is 255 (not 256). It is the maximum
value of HMPUIR.
- Ayan
+ default:
+ BUG(); /* Can't happen */
+ break;
+ }
+}
+
+void write_protection_region(const pr_t *pr_write, uint8_t sel)
+{
+ prepare_selector(&sel);
+
+ switch ( sel )
+ {
+ GENERATE_WRITE_PR_REG_CASE(0, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(1, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(2, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(3, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(4, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(5, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(6, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(7, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(8, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(9, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(10, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(11, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(12, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(13, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(14, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(15, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(16, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(17, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(18, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(19, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(20, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(21, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(22, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(23, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(24, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(25, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(26, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(27, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(28, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(29, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(30, pr_write);
+ GENERATE_WRITE_PR_REG_CASE(31, pr_write);
+ GENERATE_WRITE_PR_REG_OTHERS(32 ... 255, pr_write);
+ default:
+ BUG(); /* Can't happen */
+ break;
+ }
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/mpu/mm.c b/xen/arch/arm/mpu/mm.c
index 7ab68fc8c7..ccfb37a67b 100644
--- a/xen/arch/arm/mpu/mm.c
+++ b/xen/arch/arm/mpu/mm.c
@@ -39,7 +39,6 @@ static void __init __maybe_unused build_assertions(void)
BUILD_BUG_ON(PAGE_SIZE != SZ_4K);
}
-#ifdef CONFIG_ARM_64
pr_t pr_of_addr(paddr_t base, paddr_t limit, unsigned int flags)
{
unsigned int attr_idx = PAGE_AI_MASK(flags);
@@ -110,7 +109,6 @@ pr_t pr_of_addr(paddr_t base, paddr_t limit, unsigned int
flags)
return region;
}
-#endif /* CONFIG_ARM_64 */
void __init setup_mm(void)
{
