loader.efi: combine GetMemoryMap and ExitBootServices and retry on error

MFC r292338: UEFI: combine GetMemoryMap and ExitBootServices and retry on error

The EFI memory map may change before or during the first
ExitBootServices call. In that case ExitBootServices returns an error,
and GetMemoryMap and ExitBootServices must be retried.

Glue together calls to GetMemoryMap(), ExitBootServices() and storage of
(now up-to-date) MODINFOMD_EFI_MAP metadata within a single function.

That new function - bi_add_efi_data_and_exit() - uses space previously
allocated in bi_load_efi_data() to store the memory map (it will fail if
that space is too short). It handles re-calling GetMemoryMap() once to
update the map key if necessary. Finally, if ExitBootServices() is
successful, it stores the memory map and its header as MODINFOMD_EFI_MAP
metadata.

ExitBootServices() calls are now done earlier, from within arch-
independent bi_load() code.

MFC r292442: loader.efi: show EFI error number, not full status value

EFI return values set the high bit to indicate an error. The log
messages changed here are printed only in the case of an error,
so including the error bit is redundant. Also switch to decimal to
match the error definitions (in sys/boot/efi/include/efierr.h).

MFC r292515: loader.efi: refresh size in GetMemoryMap retry loop

If ExitBootServices fails due to a changed efi_mapkey then GetMemoryMap
must be called again. In this case it is also possible for the memory
map to grow, so repeat the initial GetMemoryMap call to fetch the new
size.

Also roll bi_add_efi_data_and_exit into bi_load_efi_data as there's no
need for it to be a separate function.

PR:		202455
Relnotes:	Yes
Sponsored by:	The FreeBSD Foundation

3 files changed, 56 insertions, 52 deletions

diff --git a/sys/boot/efi/loader/arch/amd64/elf64_freebsd.c b/sys/boot/efi/loader/arch/amd64/elf64_freebsd.c
index 0c26072..c1dbec2 100644
--- a/sys/boot/efi/loader/arch/amd64/elf64_freebsd.c
+++ b/sys/boot/efi/loader/arch/amd64/elf64_freebsd.c
@@ -174,13 +174,6 @@ elf64_exec(struct preloaded_file *fp)
 	if (err != 0)
 		return(err);
 
-	status = BS->ExitBootServices(IH, efi_mapkey);
-	if (EFI_ERROR(status)) {
-		printf("%s: ExitBootServices() returned 0x%lx\n", __func__,
-		    (long)status);
-		return (EINVAL);
-	}
-
 	dev_cleanup();
 
 	trampoline(trampstack, efi_copy_finish, kernend, modulep, PT4,
diff --git a/sys/boot/efi/loader/bootinfo.c b/sys/boot/efi/loader/bootinfo.c
index 599ac5b..f3bb9cc 100644
--- a/sys/boot/efi/loader/bootinfo.c
+++ b/sys/boot/efi/loader/bootinfo.c
@@ -48,8 +48,6 @@ __FBSDID("$FreeBSD$");
 #include "framebuffer.h"
 #include "loader_efi.h"
 
-UINTN efi_mapkey;
-
 static const char howto_switches[] = "aCdrgDmphsv";
 static int howto_masks[] = {
 	RB_ASKNAME, RB_CDROM, RB_KDB, RB_DFLTROOT, RB_GDB, RB_MULTIPLE,
@@ -230,7 +228,8 @@ bi_load_efi_data(struct preloaded_file *kfp)
 	EFI_PHYSICAL_ADDRESS addr;
 	EFI_STATUS status;
 	size_t efisz;
-	UINTN mmsz, pages, sz;
+	UINTN efi_mapkey;
+	UINTN mmsz, pages, retry, sz;
 	UINT32 mmver;
 	struct efi_map_header *efihdr;
 	struct efi_fb efifb;
@@ -252,49 +251,63 @@ bi_load_efi_data(struct preloaded_file *kfp)
 	efisz = (sizeof(struct efi_map_header) + 0xf) & ~0xf;
 
 	/*
-	 * Allocate enough pages to hold the bootinfo block and the memory
-	 * map EFI will return to us. The memory map has an unknown size,
-	 * so we have to determine that first. Note that the AllocatePages
-	 * call can itself modify the memory map, so we have to take that
-	 * into account as well. The changes to the memory map are caused
-	 * by splitting a range of free memory into two (AFAICT), so that
-	 * one is marked as being loader data.
+	 * It is possible that the first call to ExitBootServices may change
+	 * the map key. Fetch a new map key and retry ExitBootServices in that
+	 * case.
 	 */
-	sz = 0;
-	BS->GetMemoryMap(&sz, NULL, &efi_mapkey, &mmsz, &mmver);
-	sz += mmsz;
-	sz = (sz + 0xf) & ~0xf;
-	pages = EFI_SIZE_TO_PAGES(sz + efisz);
-	status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData, pages,
-	    &addr);
-	if (EFI_ERROR(status)) {
-		printf("%s: AllocatePages() returned 0x%lx\n", __func__,
-		    (long)status);
-		return (ENOMEM);
-	}
+	for (retry = 2; retry > 0; retry--) {
+		/*
+		 * Allocate enough pages to hold the bootinfo block and the
+		 * memory map EFI will return to us. The memory map has an
+		 * unknown size, so we have to determine that first. Note that
+		 * the AllocatePages call can itself modify the memory map, so
+		 * we have to take that into account as well. The changes to
+		 * the memory map are caused by splitting a range of free
+		 * memory into two (AFAICT), so that one is marked as being
+		 * loader data.
+		 */
+		sz = 0;
+		BS->GetMemoryMap(&sz, NULL, &efi_mapkey, &mmsz, &mmver);
+		sz += mmsz;
+		sz = (sz + 0xf) & ~0xf;
+		pages = EFI_SIZE_TO_PAGES(sz + efisz);
+		status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData,
+		     pages, &addr);
+		if (EFI_ERROR(status)) {
+			printf("%s: AllocatePages error %lu\n", __func__,
+			    (unsigned long)(status & ~EFI_ERROR_MASK));
+			return (ENOMEM);
+		}
 
-	/*
-	 * Read the memory map and stash it after bootinfo. Align the
-	 * memory map on a 16-byte boundary (the bootinfo block is page
-	 * aligned).
-	 */
-	efihdr = (struct efi_map_header *)addr;
-	mm = (void *)((uint8_t *)efihdr + efisz);
-	sz = (EFI_PAGE_SIZE * pages) - efisz;
-	status = BS->GetMemoryMap(&sz, mm, &efi_mapkey, &mmsz, &mmver);
-	if (EFI_ERROR(status)) {
-		printf("%s: GetMemoryMap() returned 0x%lx\n", __func__,
-		    (long)status);
-		return (EINVAL);
+		/*
+		 * Read the memory map and stash it after bootinfo. Align the
+		 * memory map on a 16-byte boundary (the bootinfo block is page
+		 * aligned).
+		 */
+		efihdr = (struct efi_map_header *)addr;
+		mm = (void *)((uint8_t *)efihdr + efisz);
+		sz = (EFI_PAGE_SIZE * pages) - efisz;
+
+		status = BS->GetMemoryMap(&sz, mm, &efi_mapkey, &mmsz, &mmver);
+		if (EFI_ERROR(status)) {
+			printf("%s: GetMemoryMap error %lu\n", __func__,
+			    (unsigned long)(status & ~EFI_ERROR_MASK));
+			return (EINVAL);
+		}
+		status = BS->ExitBootServices(IH, efi_mapkey);
+		if (EFI_ERROR(status) == 0) {
+			efihdr->memory_size = sz;
+			efihdr->descriptor_size = mmsz;
+			efihdr->descriptor_version = mmver;
+			file_addmetadata(kfp, MODINFOMD_EFI_MAP, efisz + sz,
+			    efihdr);
+			return (0);
+		}
+		BS->FreePages(addr, pages);
 	}
-
-	efihdr->memory_size = sz;
-	efihdr->descriptor_size = mmsz;
-	efihdr->descriptor_version = mmver;
-
-	file_addmetadata(kfp, MODINFOMD_EFI_MAP, efisz + sz, efihdr);
-
-	return (0);
+	printf("ExitBootServices error %lu\n",
+	    (unsigned long)(status & ~EFI_ERROR_MASK));
+	return (EINVAL);
 }
 
 /*
diff --git a/sys/boot/efi/loader/loader_efi.h b/sys/boot/efi/loader/loader_efi.h
index f98f094..5819d78 100644
--- a/sys/boot/efi/loader/loader_efi.h
+++ b/sys/boot/efi/loader/loader_efi.h
@@ -44,8 +44,6 @@ ssize_t	efi_copyout(const vm_offset_t src, void *dest, const size_t len);
 ssize_t	efi_readin(const int fd, vm_offset_t dest, const size_t len);
 void * efi_translate(vm_offset_t ptr);
 
-extern UINTN efi_mapkey;
-
 void	efi_copy_finish(void);
 
 #endif	/* _LOADER_EFI_COPY_H_ */