git: c399283c71e3 - main - Add an loader command on arm64 to sync the cache

The branch main has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=c399283c71e310e1573e8d27f9cb9d27a4ea3376

commit c399283c71e310e1573e8d27f9cb9d27a4ea3376
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2021-12-20 13:42:15 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2021-12-20 13:58:36 +0000

    Add an loader command on arm64 to sync the cache
    
    On boot we don't need to perform any CPU cache management when the IDC
    and DIC fields in the ctr_el0 register are set. Add a command to tell
    loader to ignore these fields. This could be useful, for example, if the
    hardware is misreporting the values and we are missing a quirk to enable
    it.
    
    It is not expected this will be needed, but is only intended as a
    workaround to ensure the kernel can still boot.
    
    Sponsored by:   The FreeBSD Foundation
---
 stand/arm64/libarm64/cache.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/stand/arm64/libarm64/cache.c b/stand/arm64/libarm64/cache.c
index ff52572399ac..105e08cb4257 100644
--- a/stand/arm64/libarm64/cache.c
+++ b/stand/arm64/libarm64/cache.c
@@ -37,17 +37,30 @@ __FBSDID("$FreeBSD$");
 #include <stand.h>
 #include <efi.h>
 
+#include "bootstrap.h"
 #include "cache.h"
 
+static long cache_flags;
+#define	CACHE_FLAG_DIC_OFF	(1<<0)
+#define	CACHE_FLAG_IDC_OFF	(1<<1)
+
 static bool
 get_cache_dic(uint64_t ctr)
 {
+	if ((cache_flags & CACHE_FLAG_DIC_OFF) != 0) {
+		return (false);
+	}
+
 	return (CTR_DIC_VAL(ctr) != 0);
 }
 
 static bool
 get_cache_idc(uint64_t ctr)
 {
+	if ((cache_flags & CACHE_FLAG_IDC_OFF) != 0) {
+		return (false);
+	}
+
 	return (CTR_IDC_VAL(ctr) != 0);
 }
 
@@ -112,3 +125,28 @@ cpu_inval_icache(void)
 		    : : : "memory");
 	}
 }
+
+static int
+command_cache_flags(int argc, char *argv[])
+{
+	char *cp;
+	long new_flags;
+
+	if (argc == 3) {
+		if (strcmp(argv[1], "set") == 0) {
+			new_flags = strtol(argv[2], &cp, 0);
+			if (cp[0] != '\0') {
+				printf("Invalid flags\n");
+			} else {
+				printf("Setting cache flags to %#lx\n",
+				    new_flags);
+				cache_flags = new_flags;
+				return (CMD_OK);
+			}
+		}
+	}
+
+	printf("usage: cache_flags set <value>\n");
+	return (CMD_ERROR);
+}
+COMMAND_SET(cache_flags, "cache_flags", "Set cache flags", command_cache_flags);