Messages in this thread | | | Date | Mon, 14 Jan 2013 11:19:36 -0800 | Subject | Re: [PATCH v7u1 22/31] x86, boot: add fields to support load bzImage and ramdisk above 4G | From | Yinghai Lu <> |
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On Mon, Jan 14, 2013 at 10:59 AM, H. Peter Anvin <hpa@zytor.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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