svn commit: r344718 - in head/stand/efi/loader/arch: arm i386

[Rebecca Cran]

Author: bcran
Date: Sat Mar  2 04:02:11 2019
New Revision: 344718
URL: https://svnweb.freebsd.org/changeset/base/344718

Log:
  EFI: don't call printf after ExitBootServices, since it uses Boot Services
  
  ExitBootServices terminates all boot services including console access.
  Attempting to call printf afterwards can result in a crash, depending on the
  implementation.
  
  Move any printf statements to before we call bi_load, and remove any that
  depend on calling bi_load first.
  
  Reviewed by:	imp, tsoome
  Differential Revision:	https://reviews.freebsd.org/D19374

Modified:
  head/stand/efi/loader/arch/arm/exec.c
  head/stand/efi/loader/arch/i386/elf32_freebsd.c

Modified: head/stand/efi/loader/arch/arm/exec.c
==============================================================================
--- head/stand/efi/loader/arch/arm/exec.c	Sat Mar  2 03:17:23 2019	(r344717)
+++ head/stand/efi/loader/arch/arm/exec.c	Sat Mar  2 04:02:11 2019	(r344718)
@@ -74,16 +74,19 @@ __elfN(arm_exec)(struct preloaded_file *fp)
 	e = (Elf_Ehdr *)&fmp->md_data;
 
 	efi_time_fini();
+
+	entry = efi_translate(e->e_entry);
+
+	printf("Kernel entry at 0x%x...\n", (unsigned)entry);
+	printf("Kernel args: %s\n", fp->f_args);
+
 	if ((error = bi_load(fp->f_args, &modulep, &kernend)) != 0) {
 		efi_time_init();
 		return (error);
 	}
 
-	entry = efi_translate(e->e_entry);
-	printf("Kernel entry at 0x%x...\n", (unsigned)entry);
-	printf("Kernel args: %s\n", fp->f_args);
-	printf("modulep: %#x\n", modulep);
-	printf("relocation_offset %llx\n", __elfN(relocation_offset));
+	/* At this point we've called ExitBootServices, so we can't call
+	 * printf or any other function that uses Boot Services */
 
 	dev_cleanup();
 

Modified: head/stand/efi/loader/arch/i386/elf32_freebsd.c
==============================================================================
--- head/stand/efi/loader/arch/i386/elf32_freebsd.c	Sat Mar  2 03:17:23 2019	(r344717)
+++ head/stand/efi/loader/arch/i386/elf32_freebsd.c	Sat Mar  2 04:02:11 2019	(r344718)
@@ -75,14 +75,19 @@ elf32_exec(struct preloaded_file *fp)
     ehdr = (Elf_Ehdr *)&(md->md_data);
 
     efi_time_fini();
+
+    entry = ehdr->e_entry & 0xffffff;
+
+    printf("Start @ 0x%x ...\n", entry);
+
     err = bi_load(fp->f_args, &modulep, &kernend);
     if (err != 0) {
 	efi_time_init();
 	return(err);
     }
-    entry = ehdr->e_entry & 0xffffff;
 
-    printf("Start @ 0x%x ...\n", entry);
+    /* At this point we've called ExitBootServices, so we can't call
+     * printf or any other function that uses Boot Services */
 
     dev_cleanup();
     __exec((void *)entry, boothowto, bootdev, 0, 0, 0, bootinfop, modulep, kernend);