x86/cache.c: Implement dcache_*

A new ChromeOS automated test will be introduced to check the cbmem log
of diagnostic boot mode. Because the diagnostic boot does not allow
booting into kernel, the test must perform AP reset and then check the
cbmem log afterwards. However, the memory content might not be written
back to memory (from CPU cache) during AP reset because of the cache
snooping mechanism on x86. Hence, some API to flush cache is needed.

Implement dcache_* to allow flushing cache proactively in x86. To avoid
unnecessary flush, check dma_coherent before calling dcache_* functions,
which will be always true in x86. Therefore, this change won't affect
the original functionality.

BUG=b:190026346
TEST=FW_NAME=primus emerge-brya libpayload

Cq-Depend: chromium:3841252
Signed-off-by: Hsin-Te Yuan <yuanhsinte@google.com>
Change-Id: I622d8b1cc652cbe477954a900885d12e6494d94d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66578
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

2 files changed, 135 insertions, 1 deletions

diff --git a/payloads/libpayload/arch/x86/Makefile.inc b/payloads/libpayload/arch/x86/Makefile.inc
index e010329eba..911f9dc91e 100644
--- a/payloads/libpayload/arch/x86/Makefile.inc
+++ b/payloads/libpayload/arch/x86/Makefile.inc
@@ -32,7 +32,7 @@ head.o-y += head.S
 libc-y += main.c sysinfo.c
 libc-y += timer.c coreboot.c util.S
 libc-y += exec.S virtual.c
-libc-y += selfboot.c
+libc-y += selfboot.c cache.c
 libc-y += exception_asm.S exception.c
 libc-y += delay.c
 
diff --git a/payloads/libpayload/arch/x86/cache.c b/payloads/libpayload/arch/x86/cache.c
new file mode 100644
index 0000000000..9fb33bc2b8
--- /dev/null
+++ b/payloads/libpayload/arch/x86/cache.c
@@ -0,0 +1,134 @@
+/*
+ *
+ * Copyright 2022 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stdint.h>
+
+#include <arch/cache.h>
+#include <arch/cpuid.h>
+
+unsigned int dcache_line_bytes(void)
+{
+	/*
+	 * The value returned in EBX[15:8] is in 8-byte increments.
+	 * Cache line size is EBX[15:8] * 8
+	 */
+	return (cpuid_ebx(1) & 0xff00) >> 5;
+}
+
+static inline int cpu_supports_wbnoinvd(void)
+{
+	return (cpuid_ebx(0x80000008) >> 9) & 1;
+}
+
+static inline int cpu_supports_clwb(void)
+{
+	return (cpuid_ebx(7) >> 24) & 1;
+}
+
+static inline int cpu_supports_clflushopt(void)
+{
+	return (cpuid_sub_leaf_ebx(7, 0) >> 23) & 1;
+}
+
+static inline int cpu_supports_clflush(void)
+{
+	return (cpuid_ebx(1) >> 19) & 1;
+}
+
+inline void dcache_invalidate_all(void)
+{
+	asm volatile("invd" ::: "memory");
+}
+
+inline void dcache_clean_invalidate_all(void)
+{
+	asm volatile("wbinvd" ::: "memory");
+}
+
+inline void dcache_clean_all(void)
+{
+	if (cpu_supports_wbnoinvd()) {
+		asm volatile(
+			"sfence\n\t"
+			"wbnoinvd\n\t"
+		::: "memory");
+	} else {
+		dcache_clean_invalidate_all();
+	}
+}
+
+void dcache_clean_by_mva(void const *addr, size_t len)
+{
+	unsigned long line, linesize;
+
+	linesize = dcache_line_bytes();
+	line = (uintptr_t)addr & ~(linesize - 1);
+
+	if (cpu_supports_clwb()) {
+		asm volatile("sfence");
+		while (line < (uintptr_t)addr + len) {
+			asm volatile("clwb (%0)" : : "r"(line) : "memory");
+			line += linesize;
+		}
+	} else {
+		dcache_clean_invalidate_by_mva(addr, len);
+	}
+}
+
+void dcache_invalidate_by_mva(void const *addr, size_t len)
+{
+	/*
+	 * x86 doesn't have a "invalidate without clean" for a cache line, fall
+	 * back to both.
+	 */
+	dcache_clean_invalidate_by_mva(addr, len);
+}
+
+void dcache_clean_invalidate_by_mva(void const *addr, size_t len)
+{
+	unsigned long line, linesize;
+
+	linesize = dcache_line_bytes();
+	line = (uintptr_t)addr & ~(linesize - 1);
+
+	if (cpu_supports_clflushopt()) {
+		asm volatile("sfence");
+		while (line < (uintptr_t)addr + len) {
+			asm volatile("clflushopt (%0)" ::"r"(line) : "memory");
+			line += linesize;
+		}
+	} else if (cpu_supports_clflush()) {
+		asm volatile("sfence");
+		while (line < (uintptr_t)addr + len) {
+			asm volatile("clflush (%0)" : : "r"(line) : "memory");
+			line += linesize;
+		}
+	} else {
+		dcache_clean_invalidate_all();
+	}
+}