ARM: 8757/1: NOMMU: Support PMSAv8 MPU

ARMv8R/M architecture defines new memory protection scheme - PMSAv8
which is not compatible with PMSAv7.

Key differences to PMSAv7 are:
 - Region geometry is defined by base and limit addresses
 - Addresses need to be either 32 or 64 byte aligned
 - No region priority due to overlapping regions are not allowed
 - It is unified, i.e. no distinction between data/instruction regions
 - Memory attributes are controlled via MAIR

This patch implements support for PMSAv8 MPU defined by ARMv8R/M
architecture.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 307 insertions, 0 deletions

diff --git a/arch/arm/mm/pmsa-v8.c b/arch/arm/mm/pmsa-v8.c
new file mode 100644
index 000000000000..617a83def88a
--- /dev/null
+++ b/arch/arm/mm/pmsa-v8.c
@@ -0,0 +1,307 @@
+/*
+ * Based on linux/arch/arm/pmsa-v7.c
+ *
+ * ARM PMSAv8 supporting functions.
+ */
+
+#include <linux/memblock.h>
+#include <linux/range.h>
+
+#include <asm/cp15.h>
+#include <asm/cputype.h>
+#include <asm/mpu.h>
+
+#include <asm/memory.h>
+#include <asm/sections.h>
+
+#include "mm.h"
+
+#ifndef CONFIG_CPU_V7M
+
+#define PRSEL	__ACCESS_CP15(c6, 0, c2, 1)
+#define PRBAR	__ACCESS_CP15(c6, 0, c3, 0)
+#define PRLAR	__ACCESS_CP15(c6, 0, c3, 1)
+
+static inline u32 prlar_read(void)
+{
+	return read_sysreg(PRLAR);
+}
+
+static inline u32 prbar_read(void)
+{
+	return read_sysreg(PRBAR);
+}
+
+static inline void prsel_write(u32 v)
+{
+	write_sysreg(v, PRSEL);
+}
+
+static inline void prbar_write(u32 v)
+{
+	write_sysreg(v, PRBAR);
+}
+
+static inline void prlar_write(u32 v)
+{
+	write_sysreg(v, PRLAR);
+}
+#else
+
+static inline u32 prlar_read(void)
+{
+	return readl_relaxed(BASEADDR_V7M_SCB + PMSAv8_RLAR);
+}
+
+static inline u32 prbar_read(void)
+{
+	return readl_relaxed(BASEADDR_V7M_SCB + PMSAv8_RBAR);
+}
+
+static inline void prsel_write(u32 v)
+{
+	writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv8_RNR);
+}
+
+static inline void prbar_write(u32 v)
+{
+	writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv8_RBAR);
+}
+
+static inline void prlar_write(u32 v)
+{
+	writel_relaxed(v, BASEADDR_V7M_SCB + PMSAv8_RLAR);
+}
+
+#endif
+
+static struct range __initdata io[MPU_MAX_REGIONS];
+static struct range __initdata mem[MPU_MAX_REGIONS];
+
+static unsigned int __initdata mpu_max_regions;
+
+static __init bool is_region_fixed(int number)
+{
+	switch (number) {
+	case PMSAv8_XIP_REGION:
+	case PMSAv8_KERNEL_REGION:
+		return true;
+	default:
+		return false;
+	}
+}
+
+void __init pmsav8_adjust_lowmem_bounds(void)
+{
+	phys_addr_t mem_end;
+	struct memblock_region *reg;
+	bool first = true;
+
+	for_each_memblock(memory, reg) {
+		if (first) {
+			phys_addr_t phys_offset = PHYS_OFFSET;
+
+			/*
+			 * Initially only use memory continuous from
+			 * PHYS_OFFSET */
+			if (reg->base != phys_offset)
+				panic("First memory bank must be contiguous from PHYS_OFFSET");
+			mem_end = reg->base + reg->size;
+			first = false;
+		} else {
+			/*
+			 * memblock auto merges contiguous blocks, remove
+			 * all blocks afterwards in one go (we can't remove
+			 * blocks separately while iterating)
+			 */
+			pr_notice("Ignoring RAM after %pa, memory at %pa ignored\n",
+				  &mem_end, &reg->base);
+			memblock_remove(reg->base, 0 - reg->base);
+			break;
+		}
+	}
+}
+
+static int __init __mpu_max_regions(void)
+{
+	static int max_regions;
+	u32 mpuir;
+
+	if (max_regions)
+		return max_regions;
+
+	mpuir = read_cpuid_mputype();
+
+	max_regions  = (mpuir & MPUIR_DREGION_SZMASK) >> MPUIR_DREGION;
+
+	return max_regions;
+}
+
+static int __init __pmsav8_setup_region(unsigned int number, u32 bar, u32 lar)
+{
+	if (number > mpu_max_regions
+	    || number >= MPU_MAX_REGIONS)
+		return -ENOENT;
+
+	dsb();
+	prsel_write(number);
+	isb();
+	prbar_write(bar);
+	prlar_write(lar);
+
+	mpu_rgn_info.rgns[number].prbar = bar;
+	mpu_rgn_info.rgns[number].prlar = lar;
+
+	mpu_rgn_info.used++;
+
+	return 0;
+}
+
+static int __init pmsav8_setup_ram(unsigned int number, phys_addr_t start,phys_addr_t end)
+{
+	u32 bar, lar;
+
+	if (is_region_fixed(number))
+		return -EINVAL;
+
+	bar = start;
+	lar = (end - 1) & ~(PMSAv8_MINALIGN - 1);;
+
+	bar |= PMSAv8_AP_PL1RW_PL0RW | PMSAv8_RGN_SHARED;
+	lar |= PMSAv8_LAR_IDX(PMSAv8_RGN_NORMAL) | PMSAv8_LAR_EN;
+
+	return __pmsav8_setup_region(number, bar, lar);
+}
+
+static int __init pmsav8_setup_io(unsigned int number, phys_addr_t start,phys_addr_t end)
+{
+	u32 bar, lar;
+
+	if (is_region_fixed(number))
+		return -EINVAL;
+
+	bar = start;
+	lar = (end - 1) & ~(PMSAv8_MINALIGN - 1);;
+
+	bar |= PMSAv8_AP_PL1RW_PL0RW | PMSAv8_RGN_SHARED | PMSAv8_BAR_XN;
+	lar |= PMSAv8_LAR_IDX(PMSAv8_RGN_DEVICE_nGnRnE) | PMSAv8_LAR_EN;
+
+	return __pmsav8_setup_region(number, bar, lar);
+}
+
+static int __init pmsav8_setup_fixed(unsigned int number, phys_addr_t start,phys_addr_t end)
+{
+	u32 bar, lar;
+
+	if (!is_region_fixed(number))
+		return -EINVAL;
+
+	bar = start;
+	lar = (end - 1) & ~(PMSAv8_MINALIGN - 1);
+
+	bar |= PMSAv8_AP_PL1RW_PL0NA | PMSAv8_RGN_SHARED;
+	lar |= PMSAv8_LAR_IDX(PMSAv8_RGN_NORMAL) | PMSAv8_LAR_EN;
+
+	prsel_write(number);
+	isb();
+
+	if (prbar_read() != bar || prlar_read() != lar)
+		return -EINVAL;
+
+	/* Reserved region was set up early, we just need a record for secondaries */
+	mpu_rgn_info.rgns[number].prbar = bar;
+	mpu_rgn_info.rgns[number].prlar = lar;
+
+	mpu_rgn_info.used++;
+
+	return 0;
+}
+
+#ifndef CONFIG_CPU_V7M
+static int __init pmsav8_setup_vector(unsigned int number, phys_addr_t start,phys_addr_t end)
+{
+	u32 bar, lar;
+
+	if (number == PMSAv8_KERNEL_REGION)
+		return -EINVAL;
+
+	bar = start;
+	lar = (end - 1) & ~(PMSAv8_MINALIGN - 1);
+
+	bar |= PMSAv8_AP_PL1RW_PL0NA | PMSAv8_RGN_SHARED;
+	lar |= PMSAv8_LAR_IDX(PMSAv8_RGN_NORMAL) | PMSAv8_LAR_EN;
+
+	return __pmsav8_setup_region(number, bar, lar);
+}
+#endif
+
+void __init pmsav8_setup(void)
+{
+	int i, err = 0;
+	int region = PMSAv8_KERNEL_REGION;
+
+	/* How many regions are supported ? */
+	mpu_max_regions = __mpu_max_regions();
+
+	/* RAM: single chunk of memory */
+	add_range(mem,  ARRAY_SIZE(mem), 0,  memblock.memory.regions[0].base,
+		  memblock.memory.regions[0].base + memblock.memory.regions[0].size);
+
+	/* IO: cover full 4G range */
+	add_range(io, ARRAY_SIZE(io), 0, 0, 0xffffffff);
+
+	/* RAM and IO: exclude kernel */
+	subtract_range(mem, ARRAY_SIZE(mem), __pa(KERNEL_START), __pa(KERNEL_END));
+	subtract_range(io, ARRAY_SIZE(io),  __pa(KERNEL_START), __pa(KERNEL_END));
+
+#ifdef CONFIG_XIP_KERNEL
+	/* RAM and IO: exclude xip */
+	subtract_range(mem, ARRAY_SIZE(mem), CONFIG_XIP_PHYS_ADDR, __pa(_exiprom));
+	subtract_range(io, ARRAY_SIZE(io), CONFIG_XIP_PHYS_ADDR, __pa(_exiprom));
+#endif
+
+#ifndef CONFIG_CPU_V7M
+	/* RAM and IO: exclude vectors */
+	subtract_range(mem, ARRAY_SIZE(mem),  vectors_base, vectors_base + 2 * PAGE_SIZE);
+	subtract_range(io, ARRAY_SIZE(io),  vectors_base, vectors_base + 2 * PAGE_SIZE);
+#endif
+	/* IO: exclude RAM */
+	for (i = 0; i < ARRAY_SIZE(mem); i++)
+		subtract_range(io, ARRAY_SIZE(io), mem[i].start, mem[i].end);
+
+	/* Now program MPU */
+
+#ifdef CONFIG_XIP_KERNEL
+	/* ROM */
+	err |= pmsav8_setup_fixed(PMSAv8_XIP_REGION, CONFIG_XIP_PHYS_ADDR, __pa(_exiprom));
+#endif
+	/* Kernel */
+	err |= pmsav8_setup_fixed(region++, __pa(KERNEL_START), __pa(KERNEL_END));
+
+
+	/* IO */
+	for (i = 0; i < ARRAY_SIZE(io); i++) {
+		if (!io[i].end)
+			continue;
+
+		err |= pmsav8_setup_io(region++, io[i].start, io[i].end);
+	}
+
+	/* RAM */
+	for (i = 0; i < ARRAY_SIZE(mem); i++) {
+		if (!mem[i].end)
+			continue;
+
+		err |= pmsav8_setup_ram(region++, mem[i].start, mem[i].end);
+	}
+
+	/* Vectors */
+#ifndef CONFIG_CPU_V7M
+	err |= pmsav8_setup_vector(region++, vectors_base, vectors_base + 2 * PAGE_SIZE);
+#endif
+	if (err)
+		pr_warn("MPU region initialization failure! %d", err);
+	else
+		pr_info("Using ARM PMSAv8 Compliant MPU. Used %d of %d regions\n",
+			mpu_rgn_info.used, mpu_max_regions);
+}