From: "H. Peter Anvin" <hpa@zytor.com>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Haren Myneni <hbabu@us.ibm.com>,
Simon Horman <horms@verge.net.au>,
kexec@lists.infradead.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH v6 3/6] kexec, x86: Fix bzImage real-mode booting
Date: Thu, 13 Dec 2012 15:42:55 -0800 [thread overview]
Message-ID: <50CA67FF.90009@zytor.com> (raw)
In-Reply-To: <1355437112-9250-4-git-send-email-yinghai@kernel.org>
On 12/13/2012 02:18 PM, Yinghai Lu wrote:
> + if (real_mode_entry) {
> + /* restore can use heap and load high */
> + real_mode->loader_flags = 0x81;
> + if (real_mode->protocol_version >= 0x0201)
> + real_mode->heap_end_ptr += heap_size - 0x200; /*stack*/
> + }
> +
This code is wrong: the bits at the bottom of this field (LOADED_HIGH)
are kernel->bootloader flags.
The right behavior is:
if (real_mode->protocol_version >= 0x0201) {
real_mode->loader_flag |= CAN_USE_HEAP;
real_mode->heap_end_ptr += heap_size - 0x200; /*stack*/
}
> + regs16.ds = regs16.es = regs16.fs = regs16.gs = setup_base >> 4;
> + regs16.cs = regs16.ds + 0x20;
> + regs16.ip = 0;
> + /* XXX: Documentation/i386/boot.txt says 'ss' must equal 'ds' */
> + regs16.ss = (elf_rel_get_addr(&info->rhdr, "stack_end") - 64*1024) >> 4;
> + /* XXX: Documentation/i386/boot.txt says 'sp' must equal heap_end */
> + regs16.esp = 0xFFFC;
> +
And, pray tell, why aren't they?
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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next prev parent reply other threads:[~2012-12-13 23:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-13 22:18 [PATCH v6 0/6] kexec: put bzImage and ramdisk above 4G for x86 64bit Yinghai Lu
2012-12-13 22:18 ` [PATCH v6 1/6] kexec, x86: add boot header member for version 2.12 Yinghai Lu
2012-12-13 22:18 ` [PATCH v6 2/6] kexec, x86: clean boot_params area for entry-32bit path Yinghai Lu
2012-12-13 22:18 ` [PATCH v6 3/6] kexec, x86: Fix bzImage real-mode booting Yinghai Lu
2012-12-13 23:42 ` H. Peter Anvin [this message]
2012-12-14 0:06 ` Yinghai Lu
2012-12-13 22:18 ` [PATCH v6 4/6] kexec, x86: put ramdisk/cmd_line above 4G for 64bit bzImage Yinghai Lu
2012-12-13 22:18 ` [PATCH v6 5/6] kexec, x86_64: Load bzImage64 above 4G Yinghai Lu
2012-12-13 22:18 ` [PATCH v6 6/6] kexec, x86: handle Crash low kernel range Yinghai Lu
2012-12-14 0:41 ` [PATCH v6 0/6] kexec: put bzImage and ramdisk above 4G for x86 64bit H. Peter Anvin
2012-12-14 0:47 ` Yinghai Lu
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