Messages in this thread Patch in this message | | | Date | Wed, 21 Nov 2012 10:59:46 -0800 | Subject | Re: [PATCH v3 11/12] x86, boot: add fields to support load bzImage and ramdisk high | From | Yinghai Lu <> |
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On Wed, Nov 21, 2012 at 9:17 AM, H. Peter Anvin <hpa@zytor.com> wrote: > On 11/20/2012 11:16 PM, Yinghai Lu wrote: >> >> >> diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt >> index 9efceff..a8263f7 100644 >> --- a/Documentation/x86/boot.txt >> +++ b/Documentation/x86/boot.txt >> @@ -57,6 +57,9 @@ Protocol 2.10: (Kernel 2.6.31) Added a protocol >> for relaxed alignment >> Protocol 2.11: (Kernel 3.6) Added a field for offset of EFI >> handover >> protocol entry point. >> >> +Protocol 2.12: (Kernel 3.9) Added three fields for loading bzImage and >> + ramdisk above 4G with 64bit. >> + >> **** MEMORY LAYOUT >> >> The traditional memory map for the kernel loader, used for Image or >> @@ -182,7 +185,7 @@ Offset Proto Name Meaning >> 0230/4 2.05+ kernel_alignment Physical addr alignment required >> for kernel >> 0234/1 2.05+ relocatable_kernel Whether kernel is relocatable >> or not >> 0235/1 2.10+ min_alignment Minimum alignment, as a power of >> two >> -0236/2 N/A pad3 Unused >> +0236/2 2.12+ xloadflags Boot protocal option flags > > ^^^^^^^^ sorry. > >> 0238/4 2.06+ cmdline_size Maximum size of the kernel command >> line >> 023C/4 2.07+ hardware_subarch Hardware subarchitecture >> 0240/8 2.07+ hardware_subarch_data Subarchitecture-specific >> data >> @@ -193,6 +196,9 @@ Offset Proto Name Meaning >> 0258/8 2.10+ pref_address Preferred loading address >> 0260/4 2.10+ init_size Linear memory required during >> initialization >> 0264/4 2.11+ handover_offset Offset of handover entry point >> +0268/4 2.12+ ext_ramdisk_image ramdisk_image 32 bits > > > "high 32 bits" presumably...
ok
> > >> +026C/4 2.12+ ext_ramdisk_size ramdisk_size high 32 bits >> +0270/4 2.12+ ext_cmd_line_ptr cmd_line_ptr high 32 bits > > > I'm looking at these three fields and I'm getting worried about space -- > there are only two more word-sized fields possible in this structure. Since > these fields are not initialized (default to zero) and almost certainly > aren't useful for people entering via the 16-bit entry point I think we > should move them out of struct setup_header and into the remainder of struct > boot_param.
in boot_param:
struct setup_header hdr; /* setup header */ /* 0x1f1 */ __u8 _pad7[0x290-0x1f1-sizeof(struct setup_header)]; __u32 edd_mbr_sig_buffer[EDD_MBR_SIG_MAX]; /* 0x290 */ struct e820entry e820_map[E820MAX]; /* 0x2d0 */ __u8 _pad8[48]; /* 0xcd0 */ struct edd_info eddbuf[EDDMAXNR]; /* 0xd00 */ __u8 _pad9[276]; /* 0xeec */
so we can use till 0x290.
and after those three dword, will still have 7 left.
> >> diff --git a/arch/x86/boot/compressed/cmdline.c >> b/arch/x86/boot/compressed/cmdline.c >> index b4c913c..00678d3 100644 >> --- a/arch/x86/boot/compressed/cmdline.c >> +++ b/arch/x86/boot/compressed/cmdline.c >> @@ -17,6 +17,9 @@ static unsigned long get_cmd_line_ptr(void) >> { >> unsigned long cmd_line_ptr = real_mode->hdr.cmd_line_ptr; >> >> + if (real_mode->hdr.version >= 0x020c) >> + cmd_line_ptr |= (u64)real_mode->hdr.ext_cmd_line_ptr << >> 32; >> + >> return cmd_line_ptr; >> } > > > No. hdr.version is information from the kernel to the bootloader; it is > meaningless to look at it inside the kernel. > could remove them, but how about vmlinux elf.
when kexec vmlinux elf, it will fake one hdr, and fill version there.
> Same in a bunch of other places. >
Thanks
Yinghai
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