[PATCH RFC 3/3] arm64: Enable/disable D-cache before/after sha verification

[Pratyush Anand]

Enable D cache before SHA verification and disable it before switching
to kernel.

Since we only map RAM area, therefore currently no printf is allowed
between d-cache enable and disable events. Identity mapping for port
area with device type memory attributes need to be created for printf to
work.

Signed-off-by: Pratyush Anand <panand at redhat.com>
---
 purgatory/arch/arm64/purgatory-arm64.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/purgatory/arch/arm64/purgatory-arm64.c b/purgatory/arch/arm64/purgatory-arm64.c
index 3a1c9243bfa2..e045039039b6 100644
--- a/purgatory/arch/arm64/purgatory-arm64.c
+++ b/purgatory/arch/arm64/purgatory-arm64.c
@@ -2,6 +2,7 @@
  * ARM64 purgatory.
  */
 
+#include "cache.h"
 #include <stdint.h>
 #include <purgatory.h>
 
@@ -10,6 +11,8 @@
 extern uint32_t *arm64_sink;
 extern void (*arm64_kernel_entry)(uint64_t);
 extern uint64_t arm64_dtb_addr;
+extern uint64_t arm64_ram_start;
+extern uint64_t arm64_ram_end;
 
 static void wait_for_xmit_complete(void)
 {
@@ -44,14 +47,23 @@ void putchar(int ch)
 	}
 }
 
+uint64_t page_table[PAGE_TABLE_SIZE / sizeof(uint64_t)] __attribute__ ((aligned (PAGE_TABLE_SIZE))) = { };
+extern void enable_dcache(uint64_t , uint64_t , uint64_t *);
+extern void disable_dcache(uint64_t , uint64_t);
+
 void setup_arch(void)
 {
 	printf("purgatory: kernel_entry: %lx\n",
 		(unsigned long)arm64_kernel_entry);
 	printf("purgatory: dtb:          %lx\n", arm64_dtb_addr);
+	printf("purgatory: RAM start: %lx\n", arm64_ram_start);
+	printf("purgatory: RAM end: %lx\n", arm64_ram_end);
+
+	enable_dcache(arm64_ram_start, arm64_ram_end, page_table);
 }
 
 void post_verification_setup_arch(void)
 {
+	disable_dcache(arm64_ram_start, arm64_ram_end);
 	arm64_kernel_entry(arm64_dtb_addr);
 }
-- 
2.1.0