svn commit: r355132 - head/stand/efi/loader

[Andrew Turner]

Author: andrew
Date: Wed Nov 27 16:52:46 2019
New Revision: 355132
URL: https://svnweb.freebsd.org/changeset/base/355132

Log:
  Support kernels larger than EFI_STAGING_SIZE in loader.efi
  
  With a very large kernel or module the staging area may be too small to
  hold it. When this is the case try to allocate more space before failing
  in the efi copyin/copyout/readin functions.
  
  Reviewed by:	imp, tsoome
  Sponsored by:	DARPA, AFRL
  Differential Revision:	https://reviews.freebsd.org/D22569

Modified:
  head/stand/efi/loader/copy.c

Modified: head/stand/efi/loader/copy.c
==============================================================================
--- head/stand/efi/loader/copy.c	Wed Nov 27 13:46:28 2019	(r355131)
+++ head/stand/efi/loader/copy.c	Wed Nov 27 16:52:46 2019	(r355132)
@@ -185,7 +185,7 @@ out:
 #endif
 #endif
 
-EFI_PHYSICAL_ADDRESS	staging, staging_end;
+EFI_PHYSICAL_ADDRESS	staging, staging_end, staging_base;
 int			stage_offset_set = 0;
 ssize_t			stage_offset;
 
@@ -224,6 +224,7 @@ efi_copy_init(void)
 		    EFI_ERROR_CODE(status));
 		return (status);
 	}
+	staging_base = staging;
 	staging_end = staging + nr_pages * EFI_PAGE_SIZE;
 
 #if defined(__aarch64__) || defined(__arm__)
@@ -240,6 +241,66 @@ efi_copy_init(void)
 	return (0);
 }
 
+static bool
+efi_check_space(vm_offset_t end)
+{
+	EFI_PHYSICAL_ADDRESS addr;
+	EFI_STATUS status;
+	unsigned long nr_pages;
+
+	/* There is already enough space */
+	if (end <= staging_end)
+		return (true);
+
+	end = roundup2(end, EFI_PAGE_SIZE);
+	nr_pages = EFI_SIZE_TO_PAGES(end - staging_end);
+
+#if defined(__i386__) || defined(__amd64__)
+	/* X86 needs all memory to be allocated under the 1G boundary */
+	if (end > 1024*1024*1024)
+		goto before_staging;
+#endif
+
+	/* Try to allocate more space after the previous allocation */
+	addr = staging_end;
+	status = BS->AllocatePages(AllocateAddress, EfiLoaderData, nr_pages,
+	    &addr);
+	if (!EFI_ERROR(status)) {
+		staging_end = staging_end + nr_pages * EFI_PAGE_SIZE;
+		return (true);
+	}
+
+before_staging:
+	/* Try allocating space before the previous allocation */
+	if (staging < nr_pages * EFI_PAGE_SIZE) {
+		printf("Not enough space before allocation\n");
+		return (false);
+	}
+	addr = staging - nr_pages * EFI_PAGE_SIZE;
+#if defined(__aarch64__) || defined(__arm__)
+	/* See efi_copy_init for why this is needed */
+	addr = rounddown2(addr, 2 * 1024 * 1024);
+#endif
+	nr_pages = EFI_SIZE_TO_PAGES(staging_base - addr);
+	status = BS->AllocatePages(AllocateAddress, EfiLoaderData, nr_pages,
+	    &addr);
+	if (!EFI_ERROR(status)) {
+		/*
+		 * Move the old allocation and update the state so
+		 * translation still works.
+		 */
+		staging_base = addr;
+		memmove((void *)staging_base, (void *)staging,
+		    staging_end - staging);
+		stage_offset -= (staging - staging_base);
+		staging = staging_base;
+		return (true);
+	}
+
+	printf("efi_check_space: Unable to expand staging area\n");
+	return (false);
+}
+
 void *
 efi_translate(vm_offset_t ptr)
 {
@@ -257,7 +318,7 @@ efi_copyin(const void *src, vm_offset_t dest, const si
 	}
 
 	/* XXX: Callers do not check for failure. */
-	if (dest + stage_offset + len > staging_end) {
+	if (!efi_check_space(dest + stage_offset + len)) {
 		errno = ENOMEM;
 		return (-1);
 	}
@@ -283,7 +344,7 @@ ssize_t
 efi_readin(const int fd, vm_offset_t dest, const size_t len)
 {
 
-	if (dest + stage_offset + len > staging_end) {
+	if (!efi_check_space(dest + stage_offset + len)) {
 		errno = ENOMEM;
 		return (-1);
 	}