From 1c56781cc915d1d2957e5b53717513193476d777 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Sun, 12 Sep 2021 22:41:51 +0300
Subject: [PATCH] amd64 wakeup: rework trampoline page allocation

There is no need to restrict trampoline page table to low 1M, it
should work with any pages below 4G.  Only wakeup code itself should
be below 1M.

Do not waste level 5 page when LA48 mode is used.

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D31931
---
 sys/amd64/acpica/acpi_wakeup.c | 79 +++++++++++++++++++---------------
 1 file changed, 44 insertions(+), 35 deletions(-)

diff --git a/sys/amd64/acpica/acpi_wakeup.c b/sys/amd64/acpica/acpi_wakeup.c
index fba9532e9a64..0f04ccb6f2fc 100644
--- a/sys/amd64/acpica/acpi_wakeup.c
+++ b/sys/amd64/acpica/acpi_wakeup.c
@@ -44,6 +44,7 @@ __FBSDID("$FreeBSD$");
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
+#include <vm/vm_page.h>
 
 #include <machine/clock.h>
 #include <machine/cpu.h>
@@ -82,7 +83,6 @@ static cpuset_t		suspcpus;
 static struct susppcb	**susppcbs;
 #endif
 
-static void		*acpi_alloc_wakeup_handler(void **);
 static void		acpi_stop_beep(void *);
 
 #ifdef SMP
@@ -90,7 +90,7 @@ static int		acpi_wakeup_ap(struct acpi_softc *, int);
 static void		acpi_wakeup_cpus(struct acpi_softc *);
 #endif
 
-#define	ACPI_WAKEPAGES	8
+#define	ACPI_WAKEPT_PAGES	7
 
 #define	WAKECODE_FIXUP(offset, type, val)	do {	\
 	type	*addr;					\
@@ -304,27 +304,35 @@ acpi_wakeup_machdep(struct acpi_softc *sc, int state, int sleep_result,
 	return (sleep_result);
 }
 
-static void *
-acpi_alloc_wakeup_handler(void *wakepages[ACPI_WAKEPAGES])
+static void
+acpi_alloc_wakeup_handler(void **wakeaddr,
+    void *wakept_pages[ACPI_WAKEPT_PAGES])
 {
-	int		i;
+	vm_page_t wakept_m[ACPI_WAKEPT_PAGES];
+	int i;
 
-	memset(wakepages, 0, ACPI_WAKEPAGES * sizeof(*wakepages));
+	*wakeaddr = NULL;
+	memset(wakept_pages, 0, ACPI_WAKEPT_PAGES * sizeof(*wakept_pages));
+	memset(wakept_m, 0, ACPI_WAKEPT_PAGES * sizeof(*wakept_m));
 
 	/*
-	 * Specify the region for our wakeup code.  We want it in the low 1 MB
-	 * region, excluding real mode IVT (0-0x3ff), BDA (0x400-0x4ff), EBDA
-	 * (less than 128KB, below 0xa0000, must be excluded by SMAP and DSDT),
-	 * and ROM area (0xa0000 and above).  The temporary page tables must be
-	 * page-aligned.
+	 * Specify the region for our wakeup code.  We want it in the
+	 * low 1 MB region, excluding real mode IVT (0-0x3ff), BDA
+	 * (0x400-0x4ff), EBDA (less than 128KB, below 0xa0000, must
+	 * be excluded by SMAP and DSDT), and ROM area (0xa0000 and
+	 * above).
 	 */
-	for (i = 0; i < ACPI_WAKEPAGES; i++) {
-		wakepages[i] = contigmalloc(PAGE_SIZE, M_DEVBUF,
-		    M_NOWAIT, 0x500, 0xa0000, PAGE_SIZE, 0ul);
-		if (wakepages[i] == NULL) {
-			printf("%s: can't alloc wake memory\n", __func__);
-			goto freepages;
-		}
+	*wakeaddr = contigmalloc(PAGE_SIZE, M_DEVBUF,
+	    M_NOWAIT, 0x500, 0xa0000, PAGE_SIZE, 0ul);
+	if (*wakeaddr == NULL) {
+		printf("%s: can't alloc wake memory\n", __func__);
+		goto freepages;
+	}
+
+	for (i = 0; i < ACPI_WAKEPT_PAGES - (la57 ? 0 : 1); i++) {
+		wakept_m[i] = pmap_page_alloc_below_4g(true);
+		wakept_pages[i] = (void *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(
+		    wakept_m[i]));
 	}
 	if (EVENTHANDLER_REGISTER(power_resume, acpi_stop_beep, NULL,
 	    EVENTHANDLER_PRI_LAST) == NULL) {
@@ -336,45 +344,46 @@ acpi_alloc_wakeup_handler(void *wakepages[ACPI_WAKEPAGES])
 		susppcbs[i] = malloc(sizeof(**susppcbs), M_DEVBUF, M_WAITOK);
 		susppcbs[i]->sp_fpususpend = alloc_fpusave(M_WAITOK);
 	}
-
-	return (wakepages);
+	return;
 
 freepages:
-	for (i = 0; i < ACPI_WAKEPAGES; i++)
-		if (wakepages[i] != NULL)
-			contigfree(wakepages[i], PAGE_SIZE, M_DEVBUF);
-	return (NULL);
+	if (*wakeaddr != NULL)
+		contigfree(*wakeaddr, PAGE_SIZE, M_DEVBUF);
+	for (i = 0; i < ACPI_WAKEPT_PAGES; i++) {
+		if (wakept_m[i] != NULL)
+			vm_page_free(wakept_m[i]);
+	}
+	*wakeaddr = NULL;
 }
 
 void
 acpi_install_wakeup_handler(struct acpi_softc *sc)
 {
 	static void *wakeaddr;
-	void *wakepages[ACPI_WAKEPAGES];
+	void *wakept_pages[ACPI_WAKEPT_PAGES];
 	uint64_t *pt5, *pt4, *pt3, *pt2_0, *pt2_1, *pt2_2, *pt2_3;
 	vm_paddr_t pt5pa, pt4pa, pt3pa, pt2_0pa, pt2_1pa, pt2_2pa, pt2_3pa;
 	int i;
 
 	if (wakeaddr != NULL)
 		return;
-
-	if (acpi_alloc_wakeup_handler(wakepages) == NULL)
+	acpi_alloc_wakeup_handler(&wakeaddr, wakept_pages);
+	if (wakeaddr == NULL)
 		return;
 
-	wakeaddr = wakepages[0];
 	sc->acpi_wakeaddr = (vm_offset_t)wakeaddr;
 	sc->acpi_wakephys = vtophys(wakeaddr);
 
 	if (la57) {
-		pt5 = wakepages[7];
+		pt5 = wakept_pages[6];
 		pt5pa = vtophys(pt5);
 	}
-	pt4 = wakepages[1];
-	pt3 = wakepages[2];
-	pt2_0 = wakepages[3];
-	pt2_1 = wakepages[4];
-	pt2_2 = wakepages[5];
-	pt2_3 = wakepages[6];
+	pt4 = wakept_pages[0];
+	pt3 = wakept_pages[1];
+	pt2_0 = wakept_pages[2];
+	pt2_1 = wakept_pages[3];
+	pt2_2 = wakept_pages[4];
+	pt2_3 = wakept_pages[5];
 	pt4pa = vtophys(pt4);
 	pt3pa = vtophys(pt3);
 	pt2_0pa = vtophys(pt2_0);