svn commit: r344409 - in stable/11/stand/efi: boot1 loader/arch/arm64

[Kyle Evans]

Author: kevans
Date: Thu Feb 21 02:46:32 2019
New Revision: 344409
URL: https://svnweb.freebsd.org/changeset/base/344409

Log:
  MFC r338337: Fix lualoader on arm64
  
  Lua has a few places where it allocates a large buffer on the stack. This
  is normally fine, except there are a few places where there can be multiple
  frames with this buffer. This can cause a stack overflow on some arm64 SoCs.
  
  Fix this by allocating our own stack in loader.efi large enough for these
  objects. The required size has been found by tracing how the stack pointer
  changes in a virtual machine and found to be no larger than 50kB. A
  larger stack is allocated to reduce the likelihood of overflow from future
  changes.

Modified:
  stable/11/stand/efi/boot1/Makefile
  stable/11/stand/efi/loader/arch/arm64/start.S
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/stand/efi/boot1/Makefile
==============================================================================
--- stable/11/stand/efi/boot1/Makefile	Thu Feb 21 02:43:48 2019	(r344408)
+++ stable/11/stand/efi/boot1/Makefile	Thu Feb 21 02:46:32 2019	(r344409)
@@ -6,6 +6,7 @@ PROG=		boot1.sym
 INTERNALPROG=
 WARNS?=		6
 
+CFLAGS+=	-DEFI_BOOT1
 # We implement a slightly non-standard %S in that it always takes a
 # CHAR16 that's common in UEFI-land instead of a wchar_t. This only
 # seems to matter on arm64 where wchar_t defaults to an int instead

Modified: stable/11/stand/efi/loader/arch/arm64/start.S
==============================================================================
--- stable/11/stand/efi/loader/arch/arm64/start.S	Thu Feb 21 02:43:48 2019	(r344408)
+++ stable/11/stand/efi/loader/arch/arm64/start.S	Thu Feb 21 02:46:32 2019	(r344409)
@@ -160,6 +160,23 @@ _start:
 
 	ldp	x0, x1, [sp], #16
 
+#ifndef EFI_BOOT1
+	/*
+	 * Load the stack to use. The default stack may be too small for
+	 * the lua loader.
+	 */
+	adr	x2, initstack_end
+	mov	sp, x2
+#endif
+
 	bl	efi_main
 
 1:	b	1b
+
+#ifndef EFI_BOOT1
+.bss
+	.align	4
+initstack:
+	.space	(64 * 1024)
+initstack_end:
+#endif