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lib: utils: Disallow non-root domains from adding M-mode regions

The M-mode regions can only be added to the root domain. The non-root
domains shouldn't be able to add them from FDT.

Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Tested-by: Anup Patel <anup@brainfault.org>
Himanshu Chauhan 1 year ago
parent
commit
3e2f573e70
2 changed files with 19 additions and 0 deletions
  1. 5 0
      include/sbi/sbi_domain.h
  2. 14 0
      lib/utils/fdt/fdt_domain.c

+ 5 - 0
include/sbi/sbi_domain.h

@@ -51,6 +51,11 @@ struct sbi_domain_memregion {
 				 SBI_DOMAIN_MEMREGION_M_WRITABLE | \
 				 SBI_DOMAIN_MEMREGION_M_EXECUTABLE)
 
+#define SBI_DOMAIN_MEMREGION_SU_RWX		\
+				(SBI_DOMAIN_MEMREGION_SU_READABLE | \
+				 SBI_DOMAIN_MEMREGION_SU_WRITABLE | \
+				 SBI_DOMAIN_MEMREGION_SU_EXECUTABLE)
+
 /* Unrestricted M-mode accesses but enfoced on SU-mode */
 #define SBI_DOMAIN_MEMREGION_READABLE		\
 				(SBI_DOMAIN_MEMREGION_SU_READABLE | \

+ 14 - 0
lib/utils/fdt/fdt_domain.c

@@ -239,6 +239,20 @@ static int __fdt_parse_region(void *fdt, int domain_offset,
 	u32 *region_count = opaque;
 	struct sbi_domain_memregion *region;
 
+	/*
+	 * Non-root domains cannot add a region with only M-mode
+	 * access permissions. M-mode regions can only be part of
+	 * root domain.
+	 *
+	 * SU permission bits can't be all zeroes and M-mode permission
+	 * bits must be all set.
+	 */
+	if (!((region_access & SBI_DOMAIN_MEMREGION_SU_ACCESS_MASK)
+	     & SBI_DOMAIN_MEMREGION_SU_RWX)
+	    && ((region_access & SBI_DOMAIN_MEMREGION_M_ACCESS_MASK)
+		& SBI_DOMAIN_MEMREGION_M_RWX))
+		return SBI_EINVAL;
+
 	/* Find next region of the domain */
 	if (FDT_DOMAIN_REGION_MAX_COUNT <= *region_count)
 		return SBI_EINVAL;