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Date: Mon, 14 Jan 2013 11:19:36 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: "H. Peter Anvin" <hpa@...or.com>
Cc: Borislav Petkov <bp@...en8.de>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...e.hu>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Jan Kiszka <jan.kiszka@....de>,
Jason Wessel <jason.wessel@...driver.com>,
linux-kernel@...r.kernel.org, Rob Landley <rob@...dley.net>,
Matt Fleming <matt.fleming@...el.com>,
Gokul Caushik <caushik1@...il.com>,
Josh Triplett <josh@...htriplett.org>,
Joe Millenbach <jmillenbach@...il.com>
Subject: Re: [PATCH v7u1 22/31] x86, boot: add fields to support load bzImage
and ramdisk above 4G
On Mon, Jan 14, 2013 at 10:59 AM, H. Peter Anvin <hpa@...or.com> wrote:
> On 01/14/2013 10:57 AM, Yinghai Lu wrote:
>>>
>>> If the sentinel is flagged, zero *all fields not explicitly set by the
>>> broken versions of kexec*, not just your new "ext" fields.
>>
>> other fields are pad* fields, so do we zero out them
>> with memset with exact address?
>> so next times, when someone change pad fields to other ext_*,
>> they don't need to change code again here.
>>
>
> No, there were other fields that were also left uninitialized, per your
> analysis from last year. I don't remember the details, but I seem to
> recall they included the EFI and graphics-related fields.
>
> So yes, just zero them all out.
>
from last year's mail:
---
the one with *
? means set only when lfb_depth > 8
also
0xa2 to 0x1df is not set
struct x86_linux_param_header {
uint8_t orig_x; /* 0x00 */ *
uint8_t orig_y; /* 0x01 */ *
uint16_t ext_mem_k; /* 0x02 -- EXT_MEM_K
sits here */ *
uint16_t orig_video_page; /* 0x04 */ *
uint8_t orig_video_mode; /* 0x06 */ *
uint8_t orig_video_cols; /* 0x07 */ *
uint16_t unused2; /* 0x08 */
uint16_t orig_video_ega_bx; /* 0x0a */ *
uint16_t unused3; /* 0x0c */
uint8_t orig_video_lines; /* 0x0e */ *
uint8_t orig_video_isVGA; /* 0x0f */ *
uint16_t orig_video_points; /* 0x10 */ *
/* VESA graphic mode -- linear frame buffer */
uint16_t lfb_width; /* 0x12 */ *
uint16_t lfb_height; /* 0x14 */ *
uint16_t lfb_depth; /* 0x16 */ *
uint32_t lfb_base; /* 0x18 */ *
uint32_t lfb_size; /* 0x1c */ *
uint16_t cl_magic; /* 0x20 */ *
#define CL_MAGIC_VALUE 0xA33F
uint16_t cl_offset; /* 0x22 */ *
uint16_t lfb_linelength; /* 0x24 */ *
uint8_t red_size; /* 0x26 */ ?
uint8_t red_pos; /* 0x27 */ ?
uint8_t green_size; /* 0x28 */ ?
uint8_t green_pos; /* 0x29 */ ?
uint8_t blue_size; /* 0x2a */ ?
uint8_t blue_pos; /* 0x2b */ ?
uint8_t rsvd_size; /* 0x2c */ ?
uint8_t rsvd_pos; /* 0x2d */ ?
uint16_t vesapm_seg; /* 0x2e */ *
uint16_t vesapm_off; /* 0x30 */
uint16_t pages; /* 0x32 */ *
uint8_t reserved4[12]; /* 0x34 -- 0x3f
reserved for future expansion */
struct apm_bios_info apm_bios_info; /* 0x40 */ *
struct drive_info_struct drive_info; /* 0x80 */ *
struct sys_desc_table sys_desc_table; /* 0xa0 */ * only .length =
0, aka 0xa2 to 0x1df is not set
uint32_t alt_mem_k; /* 0x1e0 */ *
uint8_t reserved5[4]; /* 0x1e4 */
uint8_t e820_map_nr; /* 0x1e8 */ *
uint8_t eddbuf_entries; /* 0x1e9 */ *
uint8_t edd_mbr_sig_buf_entries; /* 0x1ea */ *
uint8_t reserved6[6]; /* 0x1eb */
HEADER..... copied and
or meset 0 and set.
uint8_t reserved16[0x290 - 0x248]; /* 0x248 */
uint32_t edd_mbr_sig_buffer[EDD_MBR_SIG_MAX]; /* 0x290 */ *
#endif
struct e820entry e820_map[E820MAX]; /* 0x2d0 */ *
uint8_t _pad8[48]; /* 0xcd0 */
struct edd_info eddbuf[EDDMAXNR]; /* 0xd00 */ *
/* 0xeec */
#define COMMAND_LINE_SIZE 2048
};
----
in kernel for 0xa2 to 0x1df:
struct sys_desc_table sys_desc_table; /* 0x0a0 */
struct olpc_ofw_header olpc_ofw_header; /* 0x0b0 */
__u32 ext_ramdisk_image; /* 0x0c0 */
__u32 ext_ramdisk_size; /* 0x0c4 */
__u32 ext_cmd_line_ptr; /* 0x0c8 */
__u8 _pad4[116]; /* 0x0cc */
struct edid_info edid_info; /* 0x140 */
struct efi_info efi_info; /* 0x1c0 */
__u32 alt_mem_k; /* 0x1e0 */
so do you mean clear from 0xa2 to 0x1df?
Thanks
Yinghai
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