[PATCH v5 4/8] lib: sbi: Add sbi_domain_check_addr_range() function

[Anup Patel]

We add sbi_domain_check_addr_range() helper function to check
whether a given address range is accessible under a particular
domain.

Signed-off-by: Anup Patel <apatel at ventanamicro.com>
Reviewed-by: Atish Patra <atishp at rivosinc.com>
Reviewed-by: Xiang W <wxjstz at 126.com>
Reviewed-by: Bin Meng <bmeng at tinylab.org>
---
 include/sbi/sbi_domain.h | 15 +++++++++
 lib/sbi/sbi_domain.c     | 69 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 84 insertions(+)

diff --git a/include/sbi/sbi_domain.h b/include/sbi/sbi_domain.h
index bbb3eff..ab1a944 100644
--- a/include/sbi/sbi_domain.h
+++ b/include/sbi/sbi_domain.h
@@ -196,6 +196,21 @@ bool sbi_domain_check_addr(const struct sbi_domain *dom,
 			   unsigned long addr, unsigned long mode,
 			   unsigned long access_flags);
 
+/**
+ * Check whether we can access specified address range for given mode and
+ * memory region flags under a domain
+ * @param dom pointer to domain
+ * @param addr the start of the address range to be checked
+ * @param size the size of the address range to be checked
+ * @param mode the privilege mode of access
+ * @param access_flags bitmask of domain access types (enum sbi_domain_access)
+ * @return TRUE if access allowed otherwise FALSE
+ */
+bool sbi_domain_check_addr_range(const struct sbi_domain *dom,
+				 unsigned long addr, unsigned long size,
+				 unsigned long mode,
+				 unsigned long access_flags);
+
 /** Dump domain details on the console */
 void sbi_domain_dump(const struct sbi_domain *dom, const char *suffix);
 
diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
index 60fda01..683b6cf 100644
--- a/lib/sbi/sbi_domain.c
+++ b/lib/sbi/sbi_domain.c
@@ -208,6 +208,44 @@ static bool is_region_before(const struct sbi_domain_memregion *regA,
 	return false;
 }
 
+static const struct sbi_domain_memregion *find_region(
+						const struct sbi_domain *dom,
+						unsigned long addr)
+{
+	unsigned long rstart, rend;
+	struct sbi_domain_memregion *reg;
+
+	sbi_domain_for_each_memregion(dom, reg) {
+		rstart = reg->base;
+		rend = (reg->order < __riscv_xlen) ?
+			rstart + ((1UL << reg->order) - 1) : -1UL;
+		if (rstart <= addr && addr <= rend)
+			return reg;
+	}
+
+	return NULL;
+}
+
+static const struct sbi_domain_memregion *find_next_subset_region(
+				const struct sbi_domain *dom,
+				const struct sbi_domain_memregion *reg,
+				unsigned long addr)
+{
+	struct sbi_domain_memregion *sreg, *ret = NULL;
+
+	sbi_domain_for_each_memregion(dom, sreg) {
+		if (sreg == reg || (sreg->base <= addr) ||
+		    !is_region_subset(sreg, reg))
+			continue;
+
+		if (!ret || (sreg->base < ret->base) ||
+		    ((sreg->base == ret->base) && (sreg->order < ret->order)))
+			ret = sreg;
+	}
+
+	return ret;
+}
+
 static int sanitize_domain(const struct sbi_platform *plat,
 			   struct sbi_domain *dom)
 {
@@ -316,6 +354,37 @@ static int sanitize_domain(const struct sbi_platform *plat,
 	return 0;
 }
 
+bool sbi_domain_check_addr_range(const struct sbi_domain *dom,
+				 unsigned long addr, unsigned long size,
+				 unsigned long mode,
+				 unsigned long access_flags)
+{
+	unsigned long max = addr + size;
+	const struct sbi_domain_memregion *reg, *sreg;
+
+	if (!dom)
+		return false;
+
+	while (addr < max) {
+		reg = find_region(dom, addr);
+		if (!reg)
+			return false;
+
+		if (!sbi_domain_check_addr(dom, addr, mode, access_flags))
+			return false;
+
+		sreg = find_next_subset_region(dom, reg, addr);
+		if (sreg)
+			addr = sreg->base;
+		else if (reg->order < __riscv_xlen)
+			addr = reg->base + (1UL << reg->order);
+		else
+			break;
+	}
+
+	return true;
+}
+
 void sbi_domain_dump(const struct sbi_domain *dom, const char *suffix)
 {
 	u32 i, k;
-- 
2.34.1