Hi Ayan,
> On 11 Jun 2025, at 15:35, Ayan Kumar Halder <ayan.kumar.hal...@amd.com> 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)); \
Maybe you don’t need '& ~MPU_REGION_RES0’ since your MPU_REGION_RES0 is zero,
here and below
> + 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
Arm32 have PR{B,L}AR but it’s not EL2, you mean HPRBAR here and below
> + * first 32 MPU regions.
> + * For MPU region numbered 32..255, one need to set the region number in
> PRSELR_ELx,
32..254
and also maybe you can use HPRSELR instead of 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 )
can we use 31 here? instead of the hex? It would be quicker to be read by a
developer.
> + {
> + 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);
32 … 254 here and in the below.
> + 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)
> {
> --
> 2.25.1
>
>
Cheers,
Luca
