Switch to an MI implementation of kmap_atomic() and implement

kmap_atomic_prot().  Use this to unstub ttm_copy_io_ttm_page()
and ttm_copy_ttm_io_page().  This fixes suspend/resume of machines
with certain radeondrm(4) hardware.

Based on a diff from jsg@.  Tested by Edd Barrett and Alf Schlichting.
ok jsg@

3 files changed, 33 insertions, 34 deletions

diff --git a/sys/dev/pci/drm/drm_linux.c b/sys/dev/pci/drm/drm_linux.c
index 126c078b56e..72c53210f6f 100644
--- a/sys/dev/pci/drm/drm_linux.c
+++ b/sys/dev/pci/drm/drm_linux.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: drm_linux.c,v 1.81 2021/07/26 06:24:22 jsg Exp $	*/
+/*	$OpenBSD: drm_linux.c,v 1.82 2021/07/28 13:28:04 kettenis Exp $	*/
 /*
  * Copyright (c) 2013 Jonathan Gray <jsg@openbsd.org>
  * Copyright (c) 2015, 2016 Mark Kettenis <kettenis@openbsd.org>
@@ -571,6 +571,29 @@ kunmap_va(void *addr)
 #endif
 }
 
+vaddr_t kmap_atomic_va;
+int kmap_atomic_inuse;
+
+void *
+kmap_atomic_prot(struct vm_page *pg, pgprot_t prot)
+{
+	KASSERT(!kmap_atomic_inuse);
+
+	kmap_atomic_inuse = 1;
+	pmap_kenter_pa(kmap_atomic_va, VM_PAGE_TO_PHYS(pg) | prot,
+	    PROT_READ | PROT_WRITE);
+	return (void *)kmap_atomic_va;
+}
+
+void
+kunmap_atomic(void *addr)
+{
+	KASSERT(kmap_atomic_inuse);
+	
+	pmap_kremove(kmap_atomic_va, PAGE_SIZE);
+	kmap_atomic_inuse = 0;
+}
+
 void *
 vmap(struct vm_page **pages, unsigned int npages, unsigned long flags,
      pgprot_t prot)
@@ -2348,6 +2371,9 @@ drm_linux_init(void)
 
 	pool_init(&idr_pool, sizeof(struct idr_entry), 0, IPL_TTY, 0,
 	    "idrpl", NULL);
+
+	kmap_atomic_va =
+	    (vaddr_t)km_alloc(PAGE_SIZE, &kv_any, &kp_none, &kd_waitok);
 }
 
 void
diff --git a/sys/dev/pci/drm/include/linux/highmem.h b/sys/dev/pci/drm/include/linux/highmem.h
index 3ce510bfd7d..170f0be8f90 100644
--- a/sys/dev/pci/drm/include/linux/highmem.h
+++ b/sys/dev/pci/drm/include/linux/highmem.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: highmem.h,v 1.3 2020/06/14 15:20:07 jsg Exp $	*/
+/*	$OpenBSD: highmem.h,v 1.4 2021/07/28 13:28:05 kettenis Exp $	*/
 /*
  * Copyright (c) 2013, 2014, 2015 Mark Kettenis
  *
@@ -21,39 +21,20 @@
 #include <sys/param.h>
 #include <uvm/uvm_extern.h>
 #include <linux/uaccess.h>
+#include <asm/pgtable.h>
 
 void	*kmap(struct vm_page *);
-void	 kunmap_va(void *addr);
+void	kunmap_va(void *addr);
 
 #define kmap_to_page(ptr)	(ptr)
 
-#if defined(__i386__) || defined(__amd64__)
+void	*kmap_atomic_prot(struct vm_page *, pgprot_t);
+void	kunmap_atomic(void *);
 
 static inline void *
 kmap_atomic(struct vm_page *pg)
 {
-	vaddr_t va;
-
-#if defined (__HAVE_PMAP_DIRECT)
-	va = pmap_map_direct(pg);
-#else
-	extern vaddr_t pmap_tmpmap_pa(paddr_t);
-	va = pmap_tmpmap_pa(VM_PAGE_TO_PHYS(pg));
-#endif
-	return (void *)va;
+	return kmap_atomic_prot(pg, PAGE_KERNEL);
 }
 
-static inline void
-kunmap_atomic(void *addr)
-{
-#if defined (__HAVE_PMAP_DIRECT)
-	pmap_unmap_direct((vaddr_t)addr);
-#else
-	extern void pmap_tmpunmap_pa(void);
-	pmap_tmpunmap_pa();
-#endif
-}
-
-#endif /* defined(__i386__) || defined(__amd64__) */
-
 #endif
diff --git a/sys/dev/pci/drm/ttm/ttm_bo_util.c b/sys/dev/pci/drm/ttm/ttm_bo_util.c
index e8db6961307..e8aa52a0a51 100644
--- a/sys/dev/pci/drm/ttm/ttm_bo_util.c
+++ b/sys/dev/pci/drm/ttm/ttm_bo_util.c
@@ -186,9 +186,6 @@ static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
 				unsigned long page,
 				pgprot_t prot)
 {
-	STUB();
-	return -ENOSYS;
-#ifdef notyet
 	struct vm_page *d = ttm->pages[page];
 	void *dst;
 
@@ -205,16 +202,12 @@ static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
 	kunmap_atomic(dst);
 
 	return 0;
-#endif
 }
 
 static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
 				unsigned long page,
 				pgprot_t prot)
 {
-	STUB();
-	return -ENOSYS;
-#ifdef notyet
 	struct vm_page *s = ttm->pages[page];
 	void *src;
 
@@ -231,7 +224,6 @@ static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
 	kunmap_atomic(src);
 
 	return 0;
-#endif
 }
 
 int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,