[pxe] Discard queued PXE UDP packets when under memory pressure

The PXE UDP receive queue may grow without limit if the PXE NBP does
not call PXENV_UDP_READ sufficiently frequently.

Fix by implementing a cache discarder for received PXE UDP packets
(similar to the TCP cache discarder).

Reported-by: Tal Shorer <shorer@amazon.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/Makefile.housekeeping

@@ -369,7 +369,6 @@ endif
 # Include architecture-specific include path
 ifdef ARCH
 INCDIRS		+= arch/$(ARCH)/include
-INCDIRS		+= arch/$(ARCH)/include/$(PLATFORM)
 endif
 
 ###############################################################################
@@ -512,6 +511,10 @@ CFLAGS		+= -include include/compiler.h
 #
 CFLAGS		+= -DASM_TCHAR='$(ASM_TCHAR)' -DASM_TCHAR_OPS='$(ASM_TCHAR_OPS)'
 
+# Inhibit the default -Dlinux
+#
+CFLAGS		+= -Ulinux
+
 # CFLAGS for specific object types
 #
 CFLAGS_c	+=

src/Makefile.linux

@@ -8,6 +8,10 @@ SYMBOL_PREFIX	= _ipxe__
 #
 CFLAGS		+= -UNVALGRIND
 
+# The Linux linker script
+#
+LDSCRIPT	= scripts/linux.lds
+
 # Use a two-stage link
 #
 LDFLAGS		+= -r -d

src/arch/arm/Makefile.linux

@@ -0,0 +1,6 @@
+# -*- makefile -*- : Force emacs to use Makefile mode
+
+# Include generic Linux Makefile
+#
+MAKEDEPS	+= Makefile.linux
+include Makefile.linux

src/arch/arm32/Makefile

@@ -5,7 +5,7 @@ SRCDIRS		+= arch/arm32/libgcc
 
 # ARM32-specific flags
 #
-CFLAGS		+= -mthumb -mcpu=cortex-a15 -mabi=aapcs -mfloat-abi=soft
+CFLAGS		+= -mthumb -mcpu=cortex-a15 -mabi=aapcs
 CFLAGS		+= -mword-relocations
 ASFLAGS		+= -mthumb -mcpu=cortex-a15
 
@@ -13,6 +13,11 @@ ASFLAGS		+= -mthumb -mcpu=cortex-a15
 #
 CFLAGS		+= -fshort-wchar
 
+# EFI requires that enums are always 32 bits, and nothing else
+# currently cares
+#
+CFLAGS		+= -fno-short-enums
+
 # Include common ARM Makefile
 MAKEDEPS	+= arch/arm/Makefile
 include arch/arm/Makefile

src/arch/arm32/Makefile.efi

@@ -1,8 +1,8 @@
 # -*- makefile -*- : Force emacs to use Makefile mode
 
-# UEFI requires that enums are always 32 bits
+# EFI uses the soft float ABI
 #
-CFLAGS		+= -fno-short-enums
+CFLAGS		+= -mfloat-abi=soft
 
 # Specify EFI image builder
 #

src/arch/arm32/core/setjmp.S

@@ -1,5 +1,6 @@
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+	.section ".note.GNU-stack", "", %progbits
 	.text
 	.arm
 

src/arch/arm32/include/efi/ipxe/dhcp_arch.h

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
-#ifndef _DHCP_ARCH_H
-#define _DHCP_ARCH_H
-
-/** @file
- *
- * Architecture-specific DHCP options
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#include <ipxe/dhcp.h>
-
-#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_ARM32
-
-#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 3, 10 /* v3.10 */
-
-#endif

src/arch/arm32/include/ipxe/efi/dhcparch.h

@@ -0,0 +1,20 @@
+#ifndef _IPXE_EFI_DHCPARCH_H
+#define _IPXE_EFI_DHCPARCH_H
+
+/** @file
+ *
+ * DHCP client architecture definitions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/dhcp.h>
+
+/** DHCP client architecture */
+#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_ARM32
+
+/** DHCP client network device interface */
+#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 3, 10 /* v3.10 */
+
+#endif /* _IPXE_EFI_DHCPARCH_H */

src/arch/arm32/libgcc/lldivmod.S

@@ -1,5 +1,6 @@
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+	.section ".note.GNU-stack", "", %progbits
 	.text
 	.thumb
 

src/arch/arm32/libgcc/llshift.S

@@ -1,5 +1,6 @@
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
 
+	.section ".note.GNU-stack", "", %progbits
 	.text
 	.arm
 

src/arch/arm64/Makefile.linux

@@ -0,0 +1,10 @@
+# -*- makefile -*- : Force emacs to use Makefile mode
+
+# Starting virtual address
+#
+LDFLAGS += -Ttext=0x400000
+
+# Include generic Linux Makefile
+#
+MAKEDEPS += arch/arm/Makefile.linux
+include arch/arm/Makefile.linux

src/arch/arm64/include/efi/ipxe/dhcp_arch.h

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
-#ifndef _DHCP_ARCH_H
-#define _DHCP_ARCH_H
-
-/** @file
- *
- * Architecture-specific DHCP options
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#include <ipxe/dhcp.h>
-
-#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_ARM64
-
-#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 3, 10 /* v3.10 */
-
-#endif

src/arch/arm64/include/ipxe/efi/dhcparch.h

@@ -0,0 +1,20 @@
+#ifndef _IPXE_EFI_DHCPARCH_H
+#define _IPXE_EFI_DHCPARCH_H
+
+/** @file
+ *
+ * DHCP client architecture definitions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/dhcp.h>
+
+/** DHCP client architecture */
+#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_ARM64
+
+/** DHCP client network device interface */
+#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 3, 10 /* v3.10 */
+
+#endif /* _IPXE_EFI_DHCPARCH_H */

src/arch/i386/Makefile.linux

@@ -1,8 +1,8 @@
 # -*- makefile -*- : Force emacs to use Makefile mode
 
-# Linker script
+# Starting virtual address
 #
-LDSCRIPT = arch/i386/scripts/linux.lds
+LDFLAGS += -Ttext=0x08048000
 
 # Compiler flags for building host API wrapper
 #

src/arch/i386/include/efi/ipxe/dhcp_arch.h

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2010 VMware, Inc.  All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
-#ifndef _DHCP_ARCH_H
-#define _DHCP_ARCH_H
-
-/** @file
- *
- * Architecture-specific DHCP options
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#include <ipxe/dhcp.h>
-
-#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_IA32
-
-#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 3, 10 /* v3.10 */
-
-#endif

src/arch/i386/include/ipxe/efi/dhcparch.h

@@ -0,0 +1,20 @@
+#ifndef _IPXE_EFI_DHCPARCH_H
+#define _IPXE_EFI_DHCPARCH_H
+
+/** @file
+ *
+ * DHCP client architecture definitions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/dhcp.h>
+
+/** DHCP client architecture */
+#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_IA32
+
+/** DHCP client network device interface */
+#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 3, 10 /* v3.10 */
+
+#endif /* _IPXE_EFI_DHCPARCH_H */

src/arch/i386/include/pcbios/ipxe/dhcp_arch.h

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2010 VMware, Inc.  All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
-#ifndef _DHCP_ARCH_H
-#define _DHCP_ARCH_H
-
-/** @file
- *
- * Architecture-specific DHCP options
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#include <ipxe/dhcp.h>
-
-#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_X86
-
-#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 2, 1 /* v2.1 */
-
-#endif

src/arch/x86/Makefile

@@ -22,9 +22,6 @@ SRCDIRS		+= arch/x86/drivers/xen
 SRCDIRS		+= arch/x86/drivers/hyperv
 SRCDIRS		+= arch/x86/transitions
 
-# breaks building some of the linux-related objects
-CFLAGS		+= -Ulinux
-
 # disable valgrind
 CFLAGS		+= -DNVALGRIND
 

src/arch/x86/Makefile.linux

@@ -1,9 +1,5 @@
 # -*- makefile -*- : Force emacs to use Makefile mode
 
-# Include x86 Linux headers
-#
-INCDIRS += arch/x86/include/linux
-
 # Include generic Linux Makefile
 #
 MAKEDEPS	+= Makefile.linux

src/arch/x86/include/ipxe/pcbios/dhcparch.h

@@ -0,0 +1,20 @@
+#ifndef _IPXE_PCBIOS_DHCPARCH_H
+#define _IPXE_PCBIOS_DHCPARCH_H
+
+/** @file
+ *
+ * DHCP client architecture definitions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/dhcp.h>
+
+/** DHCP client architecture */
+#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_X86
+
+/** DHCP client network device interface */
+#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 2, 1 /* v2.1 */
+
+#endif /* _IPXE_PCBIOS_DHCPARCH_H */

src/arch/x86/include/linux/ipxe/dhcp_arch.h

@@ -1,41 +0,0 @@
-/*
- * Copyright (C) 2010 Piotr Jaroszyński <p.jaroszynski@gmail.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
-#ifndef _LINUX_DHCP_ARCH_H
-#define _LINUX_DHCP_ARCH_H
-
-/** @file
- *
- * Architecture-specific DHCP options
- */
-
-FILE_LICENCE(GPL2_OR_LATER_OR_UBDL);
-
-#include <ipxe/dhcp.h>
-
-// Emulate one of the supported arch-platforms
-#include <arch/i386/include/pcbios/ipxe/dhcp_arch.h>
-//#include <arch/i386/include/efi/ipxe/dhcp_arch.h>
-//#include <arch/x86_64/include/efi/ipxe/dhcp_arch.h>
-
-#endif

src/arch/x86/interface/pxe/pxe_udp.c

@@ -12,6 +12,7 @@
 #include <ipxe/uaccess.h>
 #include <ipxe/process.h>
 #include <ipxe/netdevice.h>
+#include <ipxe/malloc.h>
 #include <realmode.h>
 #include <pxe.h>
 
@@ -482,3 +483,28 @@ struct pxe_api_call pxe_udp_api[] __pxe_api_call = {
 	PXE_API_CALL ( PXENV_UDP_READ, pxenv_udp_read,
 		       struct s_PXENV_UDP_READ ),
 };
+
+/**
+ * Discard some cached PXE UDP data
+ *
+ * @ret discarded	Number of cached items discarded
+ */
+static unsigned int pxe_udp_discard ( void ) {
+	struct io_buffer *iobuf;
+	unsigned int discarded = 0;
+
+	/* Try to discard the oldest received UDP packet */
+	iobuf = list_first_entry ( &pxe_udp.list, struct io_buffer, list );
+	if ( iobuf ) {
+		list_del ( &iobuf->list );
+		free_iob ( iobuf );
+		discarded++;
+	}
+
+	return discarded;
+}
+
+/** PXE UDP cache discarder */
+struct cache_discarder pxe_udp_discarder __cache_discarder ( CACHE_NORMAL ) = {
+	.discard = pxe_udp_discard,
+};

src/arch/x86_64/Makefile.linux

@@ -1,8 +1,8 @@
 # -*- makefile -*- : Force emacs to use Makefile mode
 
-# Linker script
+# Starting virtual address
 #
-LDSCRIPT = arch/x86_64/scripts/linux.lds
+LDFLAGS += -Ttext=0x400000
 
 # Include generic Linux Makefile
 #

src/arch/x86_64/include/efi/ipxe/dhcp_arch.h

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2010 VMware, Inc.  All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
-#ifndef _DHCP_ARCH_H
-#define _DHCP_ARCH_H
-
-/** @file
- *
- * Architecture-specific DHCP options
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#include <ipxe/dhcp.h>
-
-#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_X86_64
-
-#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 3, 10 /* v3.10 */
-
-#endif

src/arch/x86_64/include/ipxe/efi/dhcparch.h

@@ -0,0 +1,20 @@
+#ifndef _IPXE_EFI_DHCPARCH_H
+#define _IPXE_EFI_DHCPARCH_H
+
+/** @file
+ *
+ * DHCP client architecture definitions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/dhcp.h>
+
+/** DHCP client architecture */
+#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_X86_64
+
+/** DHCP client network device interface */
+#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 3, 10 /* v3.10 */
+
+#endif /* _IPXE_EFI_DHCPARCH_H */

src/arch/x86_64/include/pcbios/ipxe/dhcp_arch.h

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2010 VMware, Inc.  All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
-#ifndef _DHCP_ARCH_H
-#define _DHCP_ARCH_H
-
-/** @file
- *
- * Architecture-specific DHCP options
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#include <ipxe/dhcp.h>
-
-#define DHCP_ARCH_CLIENT_ARCHITECTURE DHCP_CLIENT_ARCHITECTURE_X86
-
-#define DHCP_ARCH_CLIENT_NDI 1 /* UNDI */ , 2, 1 /* v2.1 */
-
-#endif

src/arch/x86_64/scripts/linux.lds

@@ -1,106 +0,0 @@
-/* -*- sh -*- */
-
-/*
- * Linker script for x86_64 Linux images
- *
- */
-
-OUTPUT_FORMAT ( "elf64-x86-64", "elf64-x86-64", "elf64-x86-64" )
-OUTPUT_ARCH ( i386:x86-64 )
-
-SECTIONS {
-	_max_align = 32;
-
-	. = 0x400000;
-
-	/*
-	 * The text section
-	 *
-	 */
-
-	. = ALIGN ( _max_align );
-	.text : {
-		_text = .;
-		*(.text)
-		*(.text.*)
-		_etext = .;
-	}
-
-	/*
-	 * The rodata section
-	 *
-	 */
-
-	. = ALIGN ( _max_align );
-	.rodata : {
-		_rodata = .;
-		*(.rodata)
-		*(.rodata.*)
-		_erodata = .;
-	}
-
-	/*
-	 * The data section
-	 *
-	 * Adjust the address for the data segment.  We want to adjust up to
-	 * the same address within the page on the next page up.
-	 */
-
-	. = ALIGN (CONSTANT (MAXPAGESIZE)) - ((CONSTANT (MAXPAGESIZE) - .) & (CONSTANT (MAXPAGESIZE) - 1));
-	. = DATA_SEGMENT_ALIGN (CONSTANT (MAXPAGESIZE), CONSTANT (COMMONPAGESIZE));
-	.data : {
-		_data = .;
-		*(.data)
-		*(.data.*)
-		KEEP(*(SORT(.tbl.*)))
-		KEEP(*(.provided))
-		KEEP(*(.provided.*))
-		_edata = .;
-	}
-
-	/*
-	 * The bss section
-	 *
-	 */
-
-	. = ALIGN ( _max_align );
-	.bss : {
-		_bss = .;
-		*(.bss)
-		*(.bss.*)
-		*(COMMON)
-		_ebss = .;
-	}
-
-	/*
-	 * Weak symbols that need zero values if not otherwise defined
-	 *
-	 */
-
-	.weak 0x0 : {
-		_weak = .;
-		*(.weak)
-		*(.weak.*)
-		_eweak = .;
-	}
-	_assert = ASSERT ( ( _weak == _eweak ), ".weak is non-zero length" );
-
-	/*
-	 * Dispose of the comment and note sections to make the link map
-	 * easier to read
-	 *
-	 */
-
-	/DISCARD/ : {
-		*(.comment)
-		*(.comment.*)
-		*(.note)
-		*(.note.*)
-		*(.rel)
-		*(.rel.*)
-		*(.discard)
-		*(.discard.*)
-		*(.sbat)
-		*(.sbat.*)
-	}
-}

src/drivers/net/efi/nii.c

@@ -222,7 +222,7 @@ static int nii_pci_open ( struct nii_nic *nii ) {
 
 	/* Locate PCI I/O protocol */
 	if ( ( rc = efi_locate_device ( device, &efi_pci_io_protocol_guid,
-					&pci_device ) ) != 0 ) {
+					&pci_device, 0 ) ) != 0 ) {
 		DBGC ( nii, "NII %s could not locate PCI I/O protocol: %s\n",
 		       nii->dev.name, strerror ( rc ) );
 		goto err_locate;

src/drivers/net/efi/snp.c

@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_driver.h>
 #include <ipxe/efi/efi_snp.h>
+#include <ipxe/efi/efi_utils.h>
 #include "snpnet.h"
 #include "nii.h"
 
@@ -40,34 +41,60 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  * Check to see if driver supports a device
  *
  * @v device		EFI device handle
+ * @v protocol		Protocol GUID
  * @ret rc		Return status code
  */
-static int snp_supported ( EFI_HANDLE device ) {
+static int snp_nii_supported ( EFI_HANDLE device, EFI_GUID *protocol ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	EFI_HANDLE parent;
 	EFI_STATUS efirc;
+	int rc;
 
 	/* Check that this is not a device we are providing ourselves */
 	if ( find_snpdev ( device ) != NULL ) {
-		DBGCP ( device, "SNP %s is provided by this binary\n",
+		DBGCP ( device, "HANDLE %s is provided by this binary\n",
 			efi_handle_name ( device ) );
 		return -ENOTTY;
 	}
 
-	/* Test for presence of simple network protocol */
-	if ( ( efirc = bs->OpenProtocol ( device,
-					  &efi_simple_network_protocol_guid,
+	/* Test for presence of protocol */
+	if ( ( efirc = bs->OpenProtocol ( device, protocol,
 					  NULL, efi_image_handle, device,
 					  EFI_OPEN_PROTOCOL_TEST_PROTOCOL))!=0){
-		DBGCP ( device, "SNP %s is not an SNP device\n",
-			efi_handle_name ( device ) );
+		DBGCP ( device, "HANDLE %s is not a %s device\n",
+			efi_handle_name ( device ),
+			efi_guid_ntoa ( protocol ) );
 		return -EEFI ( efirc );
 	}
-	DBGC ( device, "SNP %s is an SNP device\n",
-	       efi_handle_name ( device ) );
 
+	/* Check that there are no instances of this protocol further
+	 * up this device path.
+	 */
+	if ( ( rc = efi_locate_device ( device, protocol,
+					&parent, 1 ) ) == 0 ) {
+		DBGC2 ( device, "HANDLE %s has %s-supporting parent ",
+			efi_handle_name ( device ),
+			efi_guid_ntoa ( protocol ) );
+		DBGC2 ( device, "%s\n", efi_handle_name ( parent ) );
+		return -ENOTTY;
+	}
+
+	DBGC ( device, "HANDLE %s is a %s device\n",
+	       efi_handle_name ( device ), efi_guid_ntoa ( protocol ) );
 	return 0;
 }
 
+/**
+ * Check to see if driver supports a device
+ *
+ * @v device		EFI device handle
+ * @ret rc		Return status code
+ */
+static int snp_supported ( EFI_HANDLE device ) {
+
+	return snp_nii_supported ( device, &efi_simple_network_protocol_guid );
+}
+
 /**
  * Check to see if driver supports a device
  *
@@ -75,29 +102,8 @@ static int snp_supported ( EFI_HANDLE device ) {
  * @ret rc		Return status code
  */
 static int nii_supported ( EFI_HANDLE device ) {
-	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
-	EFI_STATUS efirc;
 
-	/* Check that this is not a device we are providing ourselves */
-	if ( find_snpdev ( device ) != NULL ) {
-		DBGCP ( device, "NII %s is provided by this binary\n",
-			efi_handle_name ( device ) );
-		return -ENOTTY;
-	}
-
-	/* Test for presence of NII protocol */
-	if ( ( efirc = bs->OpenProtocol ( device,
-					  &efi_nii31_protocol_guid,
-					  NULL, efi_image_handle, device,
-					  EFI_OPEN_PROTOCOL_TEST_PROTOCOL))!=0){
-		DBGCP ( device, "NII %s is not an NII device\n",
-			efi_handle_name ( device ) );
-		return -EEFI ( efirc );
-	}
-	DBGC ( device, "NII %s is an NII device\n",
-	       efi_handle_name ( device ) );
-
-	return 0;
+	return snp_nii_supported ( device, &efi_nii31_protocol_guid );
 }
 
 /** EFI SNP driver */

src/drivers/net/efi/snponly.c

@@ -80,7 +80,7 @@ static int chained_locate ( struct chained_protocol *chained ) {
 
 	/* Locate handle supporting this protocol */
 	if ( ( rc = efi_locate_device ( device, chained->protocol,
-					&parent ) ) != 0 ) {
+					&parent, 0 ) ) != 0 ) {
 		DBGC ( device, "CHAINED %s does not support %s: %s\n",
 		       efi_handle_name ( device ),
 		       efi_guid_ntoa ( chained->protocol ), strerror ( rc ) );

src/image/efi_image.c

@@ -96,9 +96,7 @@ efi_image_path ( struct image *image, EFI_DEVICE_PATH_PROTOCOL *parent ) {
 	efi_snprintf ( filepath->PathName, ( name_len + 1 /* NUL */ ),
 		       "%s", image->name );
 	end = ( ( ( void * ) filepath ) + filepath_len );
-	end->Type = END_DEVICE_PATH_TYPE;
-	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	end->Length[0] = sizeof ( *end );
+	efi_path_terminate ( end );
 
 	return path;
 }

src/include/ipxe/dhcparch.h

@@ -0,0 +1,16 @@
+#ifndef _IPXE_DHCPARCH_H
+#define _IPXE_DHCPARCH_H
+
+/** @file
+ *
+ * DHCP client architecture definitions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/* Include platform-specific client architecture definitions */
+#define PLATFORM_DHCPARCH(_platform) <ipxe/_platform/dhcparch.h>
+#include PLATFORM_DHCPARCH(PLATFORM)
+
+#endif /* _IPXE_DHCPARCH_H */

src/include/ipxe/efi/efi_path.h

@@ -21,9 +21,25 @@ struct fcp_description;
 struct ib_srp_device;
 struct usb_function;
 
+/**
+ * Terminate device path
+ *
+ * @v end		End of device path to fill in
+ */
+static inline void efi_path_terminate ( EFI_DEVICE_PATH_PROTOCOL *end ) {
+
+	end->Type = END_DEVICE_PATH_TYPE;
+	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
+	end->Length[0] = sizeof ( *end );
+	end->Length[1] = 0;
+}
+
 extern EFI_DEVICE_PATH_PROTOCOL *
 efi_path_next ( EFI_DEVICE_PATH_PROTOCOL *path );
 extern EFI_DEVICE_PATH_PROTOCOL *
+efi_path_prev ( EFI_DEVICE_PATH_PROTOCOL *path,
+		EFI_DEVICE_PATH_PROTOCOL *curr );
+extern EFI_DEVICE_PATH_PROTOCOL *
 efi_path_end ( EFI_DEVICE_PATH_PROTOCOL *path );
 extern size_t efi_path_len ( EFI_DEVICE_PATH_PROTOCOL *path );
 extern unsigned int efi_path_vlan ( EFI_DEVICE_PATH_PROTOCOL *path );

src/include/ipxe/efi/efi_utils.h

@@ -13,7 +13,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 struct device;
 
 extern int efi_locate_device ( EFI_HANDLE device, EFI_GUID *protocol,
-			       EFI_HANDLE *parent );
+			       EFI_HANDLE *parent, unsigned int skip );
 extern int efi_child_add ( EFI_HANDLE parent, EFI_HANDLE child );
 extern void efi_child_del ( EFI_HANDLE parent, EFI_HANDLE child );
 extern void efi_device_info ( EFI_HANDLE device, const char *prefix,

src/include/ipxe/linux/dhcparch.h

@@ -0,0 +1,20 @@
+#ifndef _IPXE_LINUX_DHCPARCH_H
+#define _IPXE_LINUX_DHCPARCH_H
+
+/** @file
+ *
+ * DHCP client architecture definitions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/*
+ * There are no specification-defined values for DHCP architecture for
+ * PXE clients running as Linux userspace applications.  Pretend to be
+ * the equivalent EFI client.
+ *
+ */
+#include <ipxe/efi/dhcparch.h>
+
+#endif /* _IPXE_LINUX_DHCPARCH_H */

src/interface/efi/efi_block.c

@@ -582,9 +582,7 @@ static int efi_block_boot_image ( struct san_device *sandev, EFI_HANDLE handle,
 			 sizeof ( efi_block_boot_filename ) );
 	}
 	end = ( ( ( void * ) filepath ) + filepath_len );
-	end->Type = END_DEVICE_PATH_TYPE;
-	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	end->Length[0] = sizeof ( *end );
+	efi_path_terminate ( end );
 	DBGC ( sandev, "EFIBLK %#02x trying to load %s\n",
 	       sandev->drive, efi_devpath_text ( boot_path ) );
 

src/interface/efi/efi_path.c

@@ -65,6 +65,25 @@ EFI_DEVICE_PATH_PROTOCOL * efi_path_next ( EFI_DEVICE_PATH_PROTOCOL *path ) {
 	return path;
 }
 
+/**
+ * Find previous element of device path
+ *
+ * @v path		Device path, or NULL for no path
+ * @v curr		Current element in device path, or NULL for end of path
+ * @ret prev		Previous element in device path, or NULL
+ */
+EFI_DEVICE_PATH_PROTOCOL * efi_path_prev ( EFI_DEVICE_PATH_PROTOCOL *path,
+					   EFI_DEVICE_PATH_PROTOCOL *curr ) {
+	EFI_DEVICE_PATH_PROTOCOL *tmp;
+
+	/* Find immediately preceding element */
+	while ( ( tmp = efi_path_next ( path ) ) != curr ) {
+		path = tmp;
+	}
+
+	return path;
+}
+
 /**
  * Find end of device path
  *
@@ -72,14 +91,8 @@ EFI_DEVICE_PATH_PROTOCOL * efi_path_next ( EFI_DEVICE_PATH_PROTOCOL *path ) {
  * @ret path_end	End of device path, or NULL
  */
 EFI_DEVICE_PATH_PROTOCOL * efi_path_end ( EFI_DEVICE_PATH_PROTOCOL *path ) {
-	EFI_DEVICE_PATH_PROTOCOL *next;
 
-	/* Find end of device path */
-	while ( ( next = efi_path_next ( path ) ) != NULL ) {
-		path = next;
-	}
-
-	return path;
+	return efi_path_prev ( path, NULL );
 }
 
 /**
@@ -161,9 +174,7 @@ EFI_DEVICE_PATH_PROTOCOL * efi_paths ( EFI_DEVICE_PATH_PROTOCOL *first, ... ) {
 	}
 	va_end ( args );
 	end = dst;
-	end->Type = END_DEVICE_PATH_TYPE;
-	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	end->Length[0] = sizeof ( *end );
+	efi_path_terminate ( end );
 
 	return path;
 }
@@ -223,9 +234,7 @@ EFI_DEVICE_PATH_PROTOCOL * efi_netdev_path ( struct net_device *netdev ) {
 	} else {
 		end = ( ( ( void * ) macpath ) + sizeof ( *macpath ) );
 	}
-	end->Type = END_DEVICE_PATH_TYPE;
-	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	end->Length[0] = sizeof ( *end );
+	efi_path_terminate ( end );
 
 	return path;
 }
@@ -265,9 +274,7 @@ EFI_DEVICE_PATH_PROTOCOL * efi_uri_path ( struct uri *uri ) {
 	uripath->Header.Length[1] = ( uripath_len >> 8 );
 	format_uri ( uri, uripath->Uri, uri_len );
 	end = ( ( ( void * ) path ) + uripath_len );
-	end->Type = END_DEVICE_PATH_TYPE;
-	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	end->Length[0] = sizeof ( *end );
+	efi_path_terminate ( end );
 
 	return path;
 }
@@ -324,9 +331,7 @@ EFI_DEVICE_PATH_PROTOCOL * efi_iscsi_path ( struct iscsi_session *iscsi ) {
 	name = ( ( ( void * ) iscsipath ) + sizeof ( *iscsipath ) );
 	memcpy ( name, iscsi->target_iqn, name_len );
 	end = ( ( ( void * ) name ) + name_len );
-	end->Type = END_DEVICE_PATH_TYPE;
-	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	end->Length[0] = sizeof ( *end );
+	efi_path_terminate ( end );
 
 	/* Free temporary paths */
 	free ( netpath );
@@ -366,9 +371,7 @@ EFI_DEVICE_PATH_PROTOCOL * efi_aoe_path ( struct aoe_device *aoedev ) {
 	satapath.sata.Header.Length[0] = sizeof ( satapath.sata );
 	satapath.sata.HBAPortNumber = aoedev->major;
 	satapath.sata.PortMultiplierPortNumber = aoedev->minor;
-	satapath.end.Type = END_DEVICE_PATH_TYPE;
-	satapath.end.SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	satapath.end.Length[0] = sizeof ( satapath.end );
+	efi_path_terminate ( &satapath.end );
 
 	/* Construct overall device path */
 	path = efi_paths ( netpath, &satapath, NULL );
@@ -409,9 +412,7 @@ EFI_DEVICE_PATH_PROTOCOL * efi_fcp_path ( struct fcp_description *desc ) {
 	path->fc.Header.Length[0] = sizeof ( path->fc );
 	memcpy ( path->fc.WWN, &desc->wwn, sizeof ( path->fc.WWN ) );
 	memcpy ( path->fc.Lun, &desc->lun, sizeof ( path->fc.Lun ) );
-	path->end.Type = END_DEVICE_PATH_TYPE;
-	path->end.SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	path->end.Length[0] = sizeof ( path->end );
+	efi_path_terminate ( &path->end );
 
 	return &path->fc.Header;
 }
@@ -463,9 +464,7 @@ EFI_DEVICE_PATH_PROTOCOL * efi_ib_srp_path ( struct ib_srp_device *ib_srp ) {
 	memcpy ( &ibpath->DeviceId, &id->ib.id_ext,
 		 sizeof ( ibpath->DeviceId ) );
 	end = ( ( ( void * ) ibpath ) + sizeof ( *ibpath ) );
-	end->Type = END_DEVICE_PATH_TYPE;
-	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	end->Length[0] = sizeof ( *end );
+	efi_path_terminate ( end );
 
 	return path;
 }
@@ -511,9 +510,7 @@ EFI_DEVICE_PATH_PROTOCOL * efi_usb_path ( struct usb_function *func ) {
 	/* Construct device path */
 	memcpy ( path, efidev->path, prefix_len );
 	end = ( ( ( void * ) path ) + len - sizeof ( *end ) );
-	end->Type = END_DEVICE_PATH_TYPE;
-	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	end->Length[0] = sizeof ( *end );
+	efi_path_terminate ( end );
 	usbpath = ( ( ( void * ) end ) - sizeof ( *usbpath ) );
 	usbpath->InterfaceNumber = func->interface[0];
 	for ( ; usb ; usbpath--, usb = usb->port->hub->usb ) {

src/interface/efi/efi_snp_hii.c

@@ -704,9 +704,7 @@ int efi_snp_hii_install ( struct efi_snp_device *snpdev ) {
 	vendor_path->Header.Length[0] = sizeof ( *vendor_path );
 	efi_snp_hii_random_guid ( &vendor_path->Guid );
 	path_end = ( ( void * ) ( vendor_path + 1 ) );
-	path_end->Type = END_DEVICE_PATH_TYPE;
-	path_end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
-	path_end->Length[0] = sizeof ( *path_end );
+	efi_path_terminate ( path_end );
 
 	/* Create device path and child handle for HII association */
 	if ( ( efirc = bs->InstallMultipleProtocolInterfaces (

src/interface/efi/efi_utils.c

@@ -23,6 +23,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <string.h>
 #include <errno.h>
 #include <ipxe/efi/efi.h>
+#include <ipxe/efi/efi_path.h>
 #include <ipxe/efi/efi_pci.h>
 #include <ipxe/efi/efi_utils.h>
 
@@ -38,23 +39,26 @@ FILE_LICENCE ( GPL2_OR_LATER );
  * @v device		EFI device handle
  * @v protocol		Protocol GUID
  * @v parent		Parent EFI device handle to fill in
+ * @v skip		Number of protocol-supporting parent devices to skip
  * @ret rc		Return status code
  */
 int efi_locate_device ( EFI_HANDLE device, EFI_GUID *protocol,
-			EFI_HANDLE *parent ) {
+			EFI_HANDLE *parent, unsigned int skip ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	union {
 		EFI_DEVICE_PATH_PROTOCOL *path;
 		void *interface;
-	} path;
-	EFI_DEVICE_PATH_PROTOCOL *devpath;
+	} u;
+	EFI_DEVICE_PATH_PROTOCOL *path;
+	EFI_DEVICE_PATH_PROTOCOL *end;
+	size_t len;
 	EFI_STATUS efirc;
 	int rc;
 
 	/* Get device path */
 	if ( ( efirc = bs->OpenProtocol ( device,
 					  &efi_device_path_protocol_guid,
-					  &path.interface,
+					  &u.interface,
 					  efi_image_handle, device,
 					  EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
 		rc = -EEFI ( efirc );
@@ -62,22 +66,46 @@ int efi_locate_device ( EFI_HANDLE device, EFI_GUID *protocol,
 		       efi_handle_name ( device ), strerror ( rc ) );
 		goto err_open_device_path;
 	}
-	devpath = path.path;
 
-	/* Check for presence of specified protocol */
-	if ( ( efirc = bs->LocateDevicePath ( protocol, &devpath,
-					      parent ) ) != 0 ) {
-		rc = -EEFI ( efirc );
-		DBGC ( device, "EFIDEV %s has no parent supporting %s: %s\n",
-		       efi_handle_name ( device ),
-		       efi_guid_ntoa ( protocol ), strerror ( rc ) );
-		goto err_locate_protocol;
+	/* Create modifiable copy of device path */
+	len = ( efi_path_len ( u.path ) + sizeof ( EFI_DEVICE_PATH_PROTOCOL ));
+	path = malloc ( len );
+	if ( ! path ) {
+		rc = -ENOMEM;
+		goto err_alloc_path;
+	}
+	memcpy ( path, u.path, len );
+
+	/* Locate parent device(s) */
+	while ( 1 ) {
+
+		/* Check for presence of specified protocol */
+		end = path;
+		if ( ( efirc = bs->LocateDevicePath ( protocol, &end,
+						      parent ) ) != 0 ) {
+			rc = -EEFI ( efirc );
+			DBGC ( device, "EFIDEV %s has no parent supporting "
+			       "%s: %s\n", efi_devpath_text ( path ),
+			       efi_guid_ntoa ( protocol ), strerror ( rc ) );
+			goto err_locate_protocol;
+		}
+
+		/* Stop if we have skipped the requested number of devices */
+		if ( ! skip-- )
+			break;
+
+		/* Trim device path */
+		efi_path_terminate ( end );
+		end = efi_path_prev ( path, end );
+		efi_path_terminate ( end );
 	}
 
 	/* Success */
 	rc = 0;
 
  err_locate_protocol:
+	free ( path );
+ err_alloc_path:
 	bs->CloseProtocol ( device, &efi_device_path_protocol_guid,
 			    efi_image_handle, device );
  err_open_device_path:
@@ -150,7 +178,7 @@ static int efi_pci_info ( EFI_HANDLE device, const char *prefix,
 
 	/* Find parent PCI device */
 	if ( ( rc = efi_locate_device ( device, &efi_pci_io_protocol_guid,
-					&pci_device ) ) != 0 ) {
+					&pci_device, 0 ) ) != 0 ) {
 		DBGC ( device, "EFIDEV %s is not a PCI device: %s\n",
 		       efi_handle_name ( device ), strerror ( rc ) );
 		return rc;

src/net/udp/dhcp.c

@@ -46,7 +46,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/dhcp.h>
 #include <ipxe/dhcpopts.h>
 #include <ipxe/dhcppkt.h>
-#include <ipxe/dhcp_arch.h>
+#include <ipxe/dhcparch.h>
 #include <ipxe/features.h>
 #include <config/dhcp.h>
 

src/net/udp/dhcpv6.c

@@ -40,7 +40,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/crc32.h>
 #include <ipxe/errortab.h>
 #include <ipxe/ipv6.h>
-#include <ipxe/dhcp_arch.h>
+#include <ipxe/dhcparch.h>
 #include <ipxe/dhcpv6.h>
 
 /** @file

src/scripts/linux.lds

@@ -1,18 +1,13 @@
 /* -*- sh -*- */
 
 /*
- * Linker script for i386 Linux images
+ * Linker script for Linux images
  *
  */
 
-OUTPUT_FORMAT ( "elf32-i386", "elf32-i386", "elf32-i386" )
-OUTPUT_ARCH ( i386 )
-
 SECTIONS {
 	_max_align = 32;
 
-	. = 0x08048000;
-
 	/*
 	 * The text section
 	 *
@@ -86,16 +81,13 @@ SECTIONS {
 	_assert = ASSERT ( ( _weak == _eweak ), ".weak is non-zero length" );
 
 	/*
-	 * Dispose of the comment and note sections to make the link map
-	 * easier to read
+	 * Dispose of unwanted sections to make the link map easier to read
 	 *
 	 */
 
 	/DISCARD/ : {
 		*(.comment)
 		*(.comment.*)
-		*(.note)
-		*(.note.*)
 		*(.rel)
 		*(.rel.*)
 		*(.discard)

src/usr/pxemenu.c

@@ -204,7 +204,7 @@ static void pxe_menu_draw_item ( struct pxe_menu *menu,
 	buf[ sizeof ( buf ) - 1 ] = '\0';
 
 	/* Draw row */
-	row = ( LINES - menu->num_items + index );
+	row = ( LINES - menu->num_items + index - 1 );
 	color_set ( ( selected ? CPAIR_PXE : CPAIR_DEFAULT ), NULL );
 	mvprintw ( row, 0, "%s", buf );
 	move ( row, 1 );