From 9a93db3f0947484e30e753bbd61a10b17336e20e Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Sun, 11 Dec 2011 02:11:45 +0000 Subject: [PATCH] [pxe] Provide PXENV_FILE_EXIT_HOOK only for ipxelinux.0 builds PXENV_FILE_EXIT_HOOK is designed to allow ipxelinux.0 to unload both the iPXE and pxelinux components without affecting the underlying PXE stack. Unfortunately, it causes unexpected behaviour in other situations, such as when loading a non-embedded pxelinux.0 via undionly.kpxe. For example: PXE ROM -> undionly.kpxe -> pxelinux.0 -> chain.c32 to boot hd0 would cause control to return to iPXE instead of booting from the hard disk. In some cases, this would result in a harmless but confusing "No more network devices" message; in other cases stranger things would happen, such as being returned to the iPXE shell prompt. The fundamental problem is that when pxelinux detects PXENV_FILE_EXIT_HOOK, it may attempt to specify an exit hook and then exit back to iPXE, assuming that iPXE will in turn exit cleanly via the specified exit hook. This is not a valid assumption in the general case, since the action of exiting back to iPXE does not directly cause iPXE to exit itself. (In the specific case of ipxelinux.0, this will work since the embedded script exits as soon as pxelinux.0 exits.) Fix the unexpected behaviour in the non-ipxelinux.0 cases by including support for PXENV_FILE_EXIT_HOOK only when using a new .kkkpxe format. The ipxelinux.0 build process should therefore now use undionly.kkkpxe instead of undionly.kkpxe. Signed-off-by: Michael Brown --- src/arch/i386/Makefile.pcbios | 1 + src/arch/i386/include/pxe_api.h | 6 ++ src/arch/i386/interface/pxe/pxe_exit_hook.c | 60 +++++++++++++++++ src/arch/i386/interface/pxe/pxe_file.c | 74 +++++++-------------- src/arch/i386/prefix/kkkpxeprefix.S | 19 ++++++ src/arch/i386/prefix/pxeprefix.S | 15 +++-- 6 files changed, 120 insertions(+), 55 deletions(-) create mode 100644 src/arch/i386/interface/pxe/pxe_exit_hook.c create mode 100644 src/arch/i386/prefix/kkkpxeprefix.S diff --git a/src/arch/i386/Makefile.pcbios b/src/arch/i386/Makefile.pcbios index 258c5d7d..e1b226f5 100644 --- a/src/arch/i386/Makefile.pcbios +++ b/src/arch/i386/Makefile.pcbios @@ -19,6 +19,7 @@ MEDIA += mrom MEDIA += pxe MEDIA += kpxe MEDIA += kkpxe +MEDIA += kkkpxe MEDIA += lkrn MEDIA += dsk MEDIA += nbi diff --git a/src/arch/i386/include/pxe_api.h b/src/arch/i386/include/pxe_api.h index f4013846..d01c262d 100644 --- a/src/arch/i386/include/pxe_api.h +++ b/src/arch/i386/include/pxe_api.h @@ -1511,6 +1511,12 @@ typedef struct s_PXENV_UNDI_ISR PXENV_UNDI_ISR_t; * @{ */ +/** Minimum possible opcode used within PXE FILE API */ +#define PXENV_FILE_MIN 0x00e0 + +/** Minimum possible opcode used within PXE FILE API */ +#define PXENV_FILE_MAX 0x00ef + /** @defgroup pxenv_file_open PXENV_FILE_OPEN * * FILE OPEN diff --git a/src/arch/i386/interface/pxe/pxe_exit_hook.c b/src/arch/i386/interface/pxe/pxe_exit_hook.c new file mode 100644 index 00000000..507229d8 --- /dev/null +++ b/src/arch/i386/interface/pxe/pxe_exit_hook.c @@ -0,0 +1,60 @@ +/** @file + * + * PXE exit hook + * + */ + +/* + * Copyright (C) 2010 Shao Miller . + * + * 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 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., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include +#include +#include + +/** PXE exit hook */ +extern segoff_t __data16 ( pxe_exit_hook ); +#define pxe_exit_hook __use_data16 ( pxe_exit_hook ) + +/** + * FILE EXIT HOOK + * + * @v file_exit_hook Pointer to a struct + * s_PXENV_FILE_EXIT_HOOK + * @v s_PXENV_FILE_EXIT_HOOK::Hook SEG16:OFF16 to jump to + * @ret #PXENV_EXIT_SUCCESS Successfully set hook + * @ret #PXENV_EXIT_FAILURE We're not an NBP build + * @ret s_PXENV_FILE_EXIT_HOOK::Status PXE status code + * + */ +static PXENV_EXIT_t +pxenv_file_exit_hook ( struct s_PXENV_FILE_EXIT_HOOK *file_exit_hook ) { + DBG ( "PXENV_FILE_EXIT_HOOK" ); + + /* We'll jump to the specified SEG16:OFF16 during exit */ + pxe_exit_hook.segment = file_exit_hook->Hook.segment; + pxe_exit_hook.offset = file_exit_hook->Hook.offset; + file_exit_hook->Status = PXENV_STATUS_SUCCESS; + return PXENV_EXIT_SUCCESS; +} + +/** PXE file API */ +struct pxe_api_call pxe_file_api_exit_hook __pxe_api_call = + PXE_API_CALL ( PXENV_FILE_EXIT_HOOK, pxenv_file_exit_hook, + struct s_PXENV_FILE_EXIT_HOOK ); diff --git a/src/arch/i386/interface/pxe/pxe_file.c b/src/arch/i386/interface/pxe/pxe_file.c index de1cd9be..7daaf919 100644 --- a/src/arch/i386/interface/pxe/pxe_file.c +++ b/src/arch/i386/interface/pxe/pxe_file.c @@ -16,8 +16,6 @@ /* * Copyright (C) 2007 Michael Brown . - * Portions (C) 2010 Shao Miller . - * [PXE exit hook logic] * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as @@ -234,9 +232,6 @@ static PXENV_EXIT_t pxenv_file_exec ( struct s_PXENV_FILE_EXEC *file_exec ) { return PXENV_EXIT_SUCCESS; } -segoff_t __data16 ( pxe_exit_hook ) = { 0, 0 }; -#define pxe_exit_hook __use_data16 ( pxe_exit_hook ) - /** * FILE API CHECK * @@ -253,57 +248,40 @@ segoff_t __data16 ( pxe_exit_hook ) = { 0, 0 }; */ static PXENV_EXIT_t pxenv_file_api_check ( struct s_PXENV_FILE_API_CHECK *file_api_check ) { + struct pxe_api_call *call; + unsigned int mask = 0; + unsigned int offset; + DBG ( "PXENV_FILE_API_CHECK" ); + /* Check for magic value */ if ( file_api_check->Magic != 0x91d447b2 ) { file_api_check->Status = PXENV_STATUS_BAD_FUNC; return PXENV_EXIT_FAILURE; - } else if ( file_api_check->Size < - sizeof(struct s_PXENV_FILE_API_CHECK) ) { + } + + /* Check for required parameter size */ + if ( file_api_check->Size < sizeof ( *file_api_check ) ) { file_api_check->Status = PXENV_STATUS_OUT_OF_RESOURCES; return PXENV_EXIT_FAILURE; - } else { - file_api_check->Status = PXENV_STATUS_SUCCESS; - file_api_check->Size = sizeof(struct s_PXENV_FILE_API_CHECK); - file_api_check->Magic = 0xe9c17b20; - file_api_check->Provider = 0x45585067; /* "iPXE" */ - file_api_check->APIMask = 0x0000007f; /* Functions e0-e6 */ - /* Check to see if we have a PXE exit hook */ - if ( pxe_exit_hook.segment | pxe_exit_hook.offset ) - /* Function e7, also */ - file_api_check->APIMask |= 0x00000080; - file_api_check->Flags = 0; /* None defined */ - return PXENV_EXIT_SUCCESS; - } -} - -/** - * FILE EXIT HOOK - * - * @v file_exit_hook Pointer to a struct - * s_PXENV_FILE_EXIT_HOOK - * @v s_PXENV_FILE_EXIT_HOOK::Hook SEG16:OFF16 to jump to - * @ret #PXENV_EXIT_SUCCESS Successfully set hook - * @ret #PXENV_EXIT_FAILURE We're not an NBP build - * @ret s_PXENV_FILE_EXIT_HOOK::Status PXE status code - * - */ -static PXENV_EXIT_t -pxenv_file_exit_hook ( struct s_PXENV_FILE_EXIT_HOOK *file_exit_hook ) { - DBG ( "PXENV_FILE_EXIT_HOOK" ); - - /* Check to see if we have a PXE exit hook */ - if ( pxe_exit_hook.segment | pxe_exit_hook.offset ) { - /* We'll jump to the specified SEG16:OFF16 during exit */ - pxe_exit_hook.segment = file_exit_hook->Hook.segment; - pxe_exit_hook.offset = file_exit_hook->Hook.offset; - file_exit_hook->Status = PXENV_STATUS_SUCCESS; - return PXENV_EXIT_SUCCESS; } - DBG ( " not NBP" ); - file_exit_hook->Status = PXENV_STATUS_UNSUPPORTED; - return PXENV_EXIT_FAILURE; + /* Determine supported calls */ + for_each_table_entry ( call, PXE_API_CALLS ) { + offset = ( call->opcode - PXENV_FILE_MIN ); + if ( offset <= ( PXENV_FILE_MAX - PXENV_FILE_MIN ) ) + mask |= ( 1 << offset ); + } + + /* Fill in parameters */ + file_api_check->Size = sizeof ( *file_api_check ); + file_api_check->Magic = 0xe9c17b20; + file_api_check->Provider = 0x45585067; /* "iPXE" */ + file_api_check->APIMask = mask; + file_api_check->Flags = 0; /* None defined */ + + file_api_check->Status = PXENV_STATUS_SUCCESS; + return PXENV_EXIT_SUCCESS; } /** PXE file API */ @@ -322,6 +300,4 @@ struct pxe_api_call pxe_file_api[] __pxe_api_call = { struct s_PXENV_FILE_EXEC ), PXE_API_CALL ( PXENV_FILE_API_CHECK, pxenv_file_api_check, struct s_PXENV_FILE_API_CHECK ), - PXE_API_CALL ( PXENV_FILE_EXIT_HOOK, pxenv_file_exit_hook, - struct s_PXENV_FILE_EXIT_HOOK ), }; diff --git a/src/arch/i386/prefix/kkkpxeprefix.S b/src/arch/i386/prefix/kkkpxeprefix.S new file mode 100644 index 00000000..27ed231e --- /dev/null +++ b/src/arch/i386/prefix/kkkpxeprefix.S @@ -0,0 +1,19 @@ +/***************************************************************************** + * PXE prefix that keeps the whole PXE stack present and provides an exit hook + * + * This prefix is essentially intended solely for the case of ipxelinux.0 + ***************************************************************************** + */ + +FILE_LICENCE ( GPL2_OR_LATER ) + +/* Since we have the whole stack, we can use cached DHCP information */ +REQUIRE_OBJECT ( pxeparent_dhcp ) + +/* Provide the PXENV_FILE_EXIT_HOOK API call */ +REQUIRE_OBJECT ( pxe_exit_hook ) + +#define PXELOADER_KEEP_UNDI +#define PXELOADER_KEEP_PXE +#define _pxe_start _kkkpxe_start +#include "pxeprefix.S" diff --git a/src/arch/i386/prefix/pxeprefix.S b/src/arch/i386/prefix/pxeprefix.S index b7468cdf..f59e347a 100644 --- a/src/arch/i386/prefix/pxeprefix.S +++ b/src/arch/i386/prefix/pxeprefix.S @@ -721,11 +721,7 @@ run_ipxe: .section ".text16", "ax", @progbits 1: /* Update the exit hook */ - movw %cs,pxe_exit_hook+2 - push %ax - mov $2f,%ax - mov %ax,pxe_exit_hook - pop %ax + movw %cs, ( pxe_exit_hook + 2 ) /* Run main program */ pushl $main @@ -743,7 +739,14 @@ run_ipxe: /* Jump to hook if applicable */ ljmpw *pxe_exit_hook -2: /* Check PXE stack magic */ + .section ".data16", "aw", @progbits + .globl pxe_exit_hook +pxe_exit_hook: + .word exit_ipxe, 0 + .previous + +exit_ipxe: + /* Check PXE stack magic */ popl %eax cmpl $STACK_MAGIC, %eax jne 1f