platform: renesas/rzfive: Configure Local memory regions as part of root domain

Renesas RZ/Five RISC-V SoC has Instruction local memory and Data local
memory (ILM & DLM) mapped between region 0x30000 - 0x4FFFF. When a
virtual address falls within this range, the MMU doesn't trigger a page
fault; it assumes the virtual address is a physical address which can
cause undesired behaviours for statically linked applications/libraries.

To avoid this, add the ILM/DLM memory regions to the root domain region
of the PMPU with permissions set to 0x0 for S/U modes so that any access
to these regions gets blocked and for M-mode we grant full access (R/W/X).

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

diff --git a/platform/generic/renesas/rzfive/rzfive.c b/platform/generic/renesas/rzfive/rzfive.c
index ca182e3..ee9c9c4 100644 (file)
--- a/platform/generic/renesas/rzfive/rzfive.c
+++ b/platform/generic/renesas/rzfive/rzfive.c
@@ -5,8 +5,27 @@
  */
 
 #include <platform_override.h>
+#include <sbi/sbi_domain.h>
 #include <sbi_utils/fdt/fdt_helper.h>
 
+int renesas_rzfive_early_init(bool cold_boot, const struct fdt_match *match)
+{
+       /*
+        * Renesas RZ/Five RISC-V SoC has Instruction local memory and
+        * Data local memory (ILM & DLM) mapped between region 0x30000
+        * to 0x4FFFF. When a virtual address falls within this range,
+        * the MMU doesn't trigger a page fault; it assumes the virtual
+        * address is a physical address which can cause undesired
+        * behaviours for statically linked applications/libraries. To
+        * avoid this, add the ILM/DLM memory regions to the root domain
+        * region of the PMPU with permissions set to 0x0 for S/U modes
+        * so that any access to these regions gets blocked and for M-mode
+        * we grant full access.
+        */
+       return sbi_domain_root_add_memrange(0x30000, 0x20000, 0x1000,
+                                           SBI_DOMAIN_MEMREGION_M_RWX);
+}
+
 static const struct fdt_match renesas_rzfive_match[] = {
        { .compatible = "renesas,r9a07g043f01" },
        { /* sentinel */ }
@@ -14,4 +33,5 @@ static const struct fdt_match renesas_rzfive_match[] = {
 
 const struct platform_override renesas_rzfive = {
        .match_table = renesas_rzfive_match,
+       .early_init = renesas_rzfive_early_init,
 };