From 84eb9b2306fd4b8cf4d9328ff661f7684c596642 Mon Sep 17 00:00:00 2001
From: Warner Losh <imp@FreeBSD.org>
Date: Fri, 3 Feb 2023 08:40:22 -0700
Subject: [PATCH] kboot: MI fixups to enable aarch64 booting

A number of bug fixes to loading kernels and modules on aarch64 and amd64.
Fix offset calcuations.
Add a number of debugs, commented out for now (will GC them in the future)

With this, and the MD aarch64 commands, we can linux boot in qemu and on
real hardware.

Sponsored by:		Netflix
Reviewed by:		kevans
Differential Revision:	https://reviews.freebsd.org/D38261
---
 stand/kboot/main.c | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/stand/kboot/main.c b/stand/kboot/main.c
index 7f548fe15b08..6631cb38ae22 100644
--- a/stand/kboot/main.c
+++ b/stand/kboot/main.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <bootstrap.h>
 #include "host_syscall.h"
 #include "kboot.h"
+#include "stand.h"
 
 struct arch_switch	archsw;
 extern void *_end;
@@ -49,6 +50,11 @@ static void kboot_zfs_probe(void);
 
 extern int command_fdt_internal(int argc, char *argv[]);
 
+#define PA_INVAL (vm_offset_t)-1
+static vm_offset_t pa_start = PA_INVAL;
+static vm_offset_t padding;
+static vm_offset_t offset;
+
 static uint64_t commit_limit;
 static uint64_t committed_as;
 static uint64_t mem_avail;
@@ -95,8 +101,8 @@ memory_limits(void)
 int
 kboot_getdev(void **vdev, const char *devspec, const char **path)
 {
-	int rv;
 	struct devdesc **dev = (struct devdesc **)vdev;
+	int				rv;
 
 	/*
 	 * If it looks like this is just a path and no device, go with the
@@ -311,11 +317,13 @@ time(time_t *tloc)
 struct host_kexec_segment loaded_segments[HOST_KEXEC_SEGMENT_MAX];
 int nkexec_segments = 0;
 
+#define SEGALIGN (1ul<<20)
+
 static ssize_t
 get_phys_buffer(vm_offset_t dest, const size_t len, void **buf)
 {
 	int i = 0;
-	const size_t segsize = 8*1024*1024;
+	const size_t segsize = 64*1024*1024;
 
 	if (nkexec_segments == HOST_KEXEC_SEGMENT_MAX)
 		panic("Tried to load too many kexec segments");
@@ -328,7 +336,7 @@ get_phys_buffer(vm_offset_t dest, const size_t len, void **buf)
 
 	loaded_segments[nkexec_segments].buf = host_getmem(segsize);
 	loaded_segments[nkexec_segments].bufsz = segsize;
-	loaded_segments[nkexec_segments].mem = (void *)rounddown2(dest,segsize);
+	loaded_segments[nkexec_segments].mem = (void *)rounddown2(dest,SEGALIGN);
 	loaded_segments[nkexec_segments].memsz = segsize;
 
 	i = nkexec_segments;
@@ -347,9 +355,17 @@ kboot_copyin(const void *src, vm_offset_t dest, const size_t len)
 	ssize_t segsize, remainder;
 	void *destbuf;
 
+	if (pa_start == PA_INVAL) {
+		pa_start = kboot_get_phys_load_segment();
+//		padding = 2 << 20; /* XXX amd64: revisit this when we make it work */
+		padding = 0;
+		offset = dest;
+		get_phys_buffer(pa_start, len, &destbuf);
+	}
+
 	remainder = len;
 	do {
-		segsize = get_phys_buffer(dest, remainder, &destbuf);
+		segsize = get_phys_buffer(dest + pa_start + padding - offset, remainder, &destbuf);
 		bcopy(src, destbuf, segsize);
 		remainder -= segsize;
 		src += segsize;
@@ -367,7 +383,7 @@ kboot_copyout(vm_offset_t src, void *dest, const size_t len)
 
 	remainder = len;
 	do {
-		segsize = get_phys_buffer(src, remainder, &srcbuf);
+		segsize = get_phys_buffer(src + pa_start + padding - offset, remainder, &srcbuf);
 		bcopy(srcbuf, dest, segsize);
 		remainder -= segsize;
 		src += segsize;
@@ -420,17 +436,18 @@ kboot_autoload(void)
 static void
 kboot_kseg_get(int *nseg, void **ptr)
 {
-#if 0
 	int a;
 
+	printf("kseg_get: %d segments\n", nkexec_segments);
+	printf("VA               SZ       PA               MEMSZ\n");
+	printf("---------------- -------- ---------------- -----\n");
 	for (a = 0; a < nkexec_segments; a++) {
-		printf("kseg_get: %jx %jx %jx %jx\n",
+		printf("%016jx %08jx %016jx %08jx\n",
 			(uintmax_t)loaded_segments[a].buf,
 			(uintmax_t)loaded_segments[a].bufsz,
 			(uintmax_t)loaded_segments[a].mem,
 			(uintmax_t)loaded_segments[a].memsz);
 	}
-#endif
 
 	*nseg = nkexec_segments;
 	*ptr = &loaded_segments[0];