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Add an loader command on arm64 to sync the cache

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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
This commit is contained in:
Andrew Turner 2021-12-20 13:42:15 +00:00
parent c1381f07f6
commit c399283c71
1 changed files with 38 additions and 0 deletions
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38
stand/arm64/libarm64/cache.c
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@ -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);