From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752989AbXEGBLH (ORCPT ); Sun, 6 May 2007 21:11:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753153AbXEGBLH (ORCPT ); Sun, 6 May 2007 21:11:07 -0400 Received: from ozlabs.org ([203.10.76.45]:56242 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752989AbXEGBLE (ORCPT ); Sun, 6 May 2007 21:11:04 -0400 Subject: [PATCH 2/3] lguest: 2.6.21-mm1 update: lguest-magic-signature.patch From: Rusty Russell To: Andrew Morton Cc: lkml - Kernel Mailing List , virtualization In-Reply-To: <1178500168.7731.23.camel@localhost.localdomain> References: <1178500168.7731.23.camel@localhost.localdomain> Content-Type: text/plain Date: Mon, 07 May 2007 11:10:52 +1000 Message-Id: <1178500252.7731.26.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org paravirt_probe() and its infrastructure proved as popular as it was pretty. In anticipation of its imminent demise, this switches lguest to use a magic string to identify a different entry point. This is not the long-term solution: that will take a new bootloader rev and will hopefully be done in the next few months. Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 25 +++++++++++++++++++++---- drivers/lguest/lguest.c | 2 -- drivers/lguest/lguest_asm.S | 23 +++++++++-------------- 3 files changed, 30 insertions(+), 20 deletions(-) =================================================================== --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -96,6 +96,19 @@ static void *map_zeroed_pages(unsigned l return (void *)addr; } +/* Find magic string marking entry point, return entry point. */ +static unsigned long entry_point(void *start, void *end, + unsigned long page_offset) +{ + void *p; + + for (p = start; p < end; p++) + if (memcmp(p, "GenuineLguest", strlen("GenuineLguest")) == 0) + return (long)p + strlen("GenuineLguest") + page_offset; + + err(1, "Is this image a genuine lguest?"); +} + /* Returns the entry point */ static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr, unsigned long *page_offset) @@ -103,6 +116,7 @@ static unsigned long map_elf(int elf_fd, void *addr; Elf32_Phdr phdr[ehdr->e_phnum]; unsigned int i; + unsigned long start = -1UL, end = 0; /* Sanity checks. */ if (ehdr->e_type != ET_EXEC @@ -131,6 +145,11 @@ static unsigned long map_elf(int elf_fd, *page_offset = phdr[i].p_vaddr - phdr[i].p_paddr; else if (*page_offset != phdr[i].p_vaddr - phdr[i].p_paddr) errx(1, "Page offset of section %i different", i); + + if (phdr[i].p_paddr < start) + start = phdr[i].p_paddr; + if (phdr[i].p_paddr + phdr[i].p_filesz > end) + end = phdr[i].p_paddr + phdr[i].p_filesz; /* We map everything private, writable. */ addr = mmap((void *)phdr[i].p_paddr, @@ -143,8 +162,7 @@ static unsigned long map_elf(int elf_fd, i, addr, (void *)phdr[i].p_paddr); } - /* Entry is physical address: convert to virtual */ - return ehdr->e_entry + *page_offset; + return entry_point((void *)start, (void *)end, *page_offset); } /* This is amazingly reliable. */ @@ -175,8 +193,7 @@ static unsigned long unpack_bzimage(int verbose("Unpacked size %i addr %p\n", len, img); *page_offset = intuit_page_offset(img, len); - /* Entry is physical address: convert to virtual */ - return (unsigned long)img + *page_offset; + return entry_point(img, img + len, *page_offset); } static unsigned long load_bzimage(int fd, unsigned long *page_offset) =================================================================== --- a/drivers/lguest/lguest.c +++ b/drivers/lguest/lguest.c @@ -43,7 +43,6 @@ extern const char lgstart_popf[], lgend_ extern const char lgstart_popf[], lgend_popf[]; extern const char lgstart_pushf[], lgend_pushf[]; extern const char lgstart_iret[], lgend_iret[]; -extern asmlinkage void lguest_maybe_init(void); extern void lguest_iret(void); struct lguest_data lguest_data = { @@ -497,4 +496,3 @@ __init void lguest_init(void) pm_power_off = lguest_power_off; start_kernel(); } -paravirt_probe(lguest_maybe_init); =================================================================== --- a/drivers/lguest/lguest_asm.S +++ b/drivers/lguest/lguest_asm.S @@ -1,29 +1,24 @@ #include #include #include +#include /* FIXME: Once asm/processor-flags.h goes in, include that */ #define X86_EFLAGS_IF 0x00000200 /* - * This is where we begin: head.S notes that paging is already enabled (which - * doesn't happen in native boot) and calls the registered paravirt_probe - * functions one at a time. Ours is a simple assembler test for magic - * registers. If they're correct we jump to lguest_init. + * This is where we begin: we have a magic signature which the launcher looks + * for. The plan is that the Linux boot protocol will be extended with a + * "platform type" field which will guide us here from the normal entry point, + * but for the moment this suffices. * * We put it in .init.text will be discarded after boot. */ .section .init.text, "ax", @progbits -ENTRY(lguest_maybe_init) - cmpl $LGUEST_MAGIC_EBP, %ebp - jne out - cmpl $LGUEST_MAGIC_EDI, %edi - jne out - cmpl $LGUEST_MAGIC_ESI, %esi - jne out - je lguest_init -out: - ret +.ascii "GenuineLguest" + /* Set up initial stack. */ + movl $(init_thread_union+THREAD_SIZE),%esp + jmp lguest_init /* The templates for inline patching. */ #define LGUEST_PATCH(name, insns...) \