4 files changed, 66 insertions, 0 deletions
diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig
index 50766cdac1..c85eace851 100644
--- a/src/cpu/x86/Kconfig
+++ b/src/cpu/x86/Kconfig
@@ -126,6 +126,11 @@ config SETUP_XIP_CACHE
 	  non-eviction mode and therefore need to be careful to avoid
 	  eviction.
 
+config X86_CLFLUSH_CAR
+	bool
+	help
+	  Select this on platforms that allow CLFLUSH while operating in CAR.
+
 config HAVE_SMI_HANDLER
 	bool
 	default n
diff --git a/src/cpu/x86/Makefile.inc b/src/cpu/x86/Makefile.inc
index dffc2b1cb9..3ef3a90313 100644
--- a/src/cpu/x86/Makefile.inc
+++ b/src/cpu/x86/Makefile.inc
@@ -5,6 +5,7 @@ subdirs-$(CONFIG_HAVE_SMI_HANDLER) += smm
 subdirs-$(CONFIG_UDELAY_TSC) += tsc
 # Use ARCH_BOOTBLOCK_X86_64 as a proxy for knowing if 64bit is going to be used
 subdirs-$(CONFIG_ARCH_BOOTBLOCK_X86_64) += 64bit
+subdirs-y += cache
 
 subdirs-$(CONFIG_PARALLEL_MP) += name
 ramstage-$(CONFIG_PARALLEL_MP) += mp_init.c
diff --git a/src/cpu/x86/cache/Makefile.inc b/src/cpu/x86/cache/Makefile.inc
new file mode 100644
index 0000000000..759488ec7e
--- /dev/null
+++ b/src/cpu/x86/cache/Makefile.inc
@@ -0,0 +1,2 @@
+romstage-y += cache.c
+ramstage-y += cache.c
diff --git a/src/cpu/x86/cache/cache.c b/src/cpu/x86/cache/cache.c
new file mode 100644
index 0000000000..d02d6d4427
--- /dev/null
+++ b/src/cpu/x86/cache/cache.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <arch/cpu.h>
+#include <cbmem.h>
+#include <console/console.h>
+#include <cpu/x86/cache.h>
+#include <program_loading.h>
+#include <types.h>
+
+bool clflush_supported(void)
+{
+	return (cpuid_edx(1) >> CPUID_FEATURE_CLFLUSH_BIT) & 1;
+}
+
+static void clflush_region(const uintptr_t start, const size_t size)
+{
+	uintptr_t addr;
+	const size_t cl_size = ((cpuid_ebx(1) >> 8) & 0xff) * 8;
+
+	if (!clflush_supported()) {
+		printk(BIOS_DEBUG, "Not flushing cache to RAM, CLFLUSH not supported\n");
+		return;
+	}
+
+	printk(BIOS_SPEW, "CLFLUSH [0x%lx, 0x%lx]\n", start, start + size);
+
+	for (addr = ALIGN_DOWN(start, cl_size); addr < start + size; addr += cl_size)
+		clflush((void *)addr);
+}
+
+/*
+ * For each segment of a program loaded this function is called
+ * to invalidate caches for the addresses of the loaded segment
+ */
+void arch_segment_loaded(uintptr_t start, size_t size, int flags)
+{
+	/* INVD is only called in postcar stage so we only need
+	   to make sure that our code hits dram during romstage. */
+	if (!ENV_CACHE_AS_RAM)
+		return;
+	if (!ENV_ROMSTAGE)
+		return;
+	if (!CONFIG(POSTCAR_STAGE))
+		return;
+	if (!CONFIG(X86_CLFLUSH_CAR))
+		return;
+	if (flags != SEG_FINAL)
+		return;
+
+	/*
+	 * The assumption is made here that DRAM is only ready after cbmem
+	 *  is initialized, to avoid flushing when loading earlier things (e.g. FSP, ...)
+	 */
+	if (!cbmem_online())
+		return;
+
+	clflush_region(start, size);
+}