On 12/01/15 17:26, Elliott, Robert (Persistent Memory) wrote:
Per an hpa suggestion, I compared two versions of grub:
upstream grub (with "linux" in grub.cfg):
tboot_probe boot_params[0] = 0000008000000000 0000000000000070
tboot_probe boot_params[16] = 1000000400032000 0000009100003000
tboot_probe boot_params[32] = 3fa3001000100810 0808080008180000
tboot_probe boot_params[48] = 0000000000000000 0000000000000000
tboot probe boot_params[64] = 0000000000000000 0000000000000000
tboot_probe boot_params[80] = 0000000000000000 0000000000000000
tboot_probe boot_params[96] = 0000000000000000 0000000000000000
tboot_probe boot_params[112] = 0000000000000000 0000000000000000
tboot_probe boot_params[128] = 0000000000000000 0000000000000000
tboot_probe boot_params[144] = 0000000000000000 0000000000000000
tboot_probe boot_params[160] = 0000000000000000 0000000000000000
tboot_probe boot_params[176] = 0000000000000000 0000000000000000
tboot_probe boot_params[192] = 0000000000000000 0000000000000000
...
<no complaint about tboot_addr>
Fedora 22 grub (with "linuxefi" in grub.cfg):
tboot_probe boot_params[0] = 0000000000000000 0000000000000070
tboot_probe boot_params[16] = 0000000400032000 0000009100003000
tboot_probe boot_params[32] = 0000000000100810 0808080008180000
tboot_probe boot_params[48] = 0000010000000100 0000000000000000
tboot_probe boot_params[64] = 557365206120626f 6f74206c6f616465
tboot_probe boot_params[80] = 722e0d0a0a52656d 6f7665206469736b
tboot_probe boot_params[96] = 20616e6420707265 737320616e79206b
tboot_probe boot_params[112] = 657920746f207265 626f6f742e2e2e0d
tboot_probe boot_params[128] = 0a00504500006486 0400000000000000
tboot_probe boot_params[144] = 000001000000a000 06020b020214f017
tboot_probe boot_params[160] = 5c00000000001076 d200104600000002
tboot_probe boot_params[176] = 0000000000000000 0000200000002000
tboot_probe boot_params[192] = 0000000000000000 0000000000000000
...
[ 0.000000] tboot: non-0 tboot_addr 0x6b7369642065766f but it is not of type
E820_RESERVED
In both cases, the kernel is compiled with CONFIG_EFI_STUB=y.
tboot_addr is at offset 88. Offset 64 is an ASCII string that says:
"Use a boot loader.
Remove disk and press any key to reboot..."
and is from arch/x86/boot/header.S, which is placing that string
at offset 64 (0x3c + 4) from .bstext (which precedes .bsdata) if
CONFIG_EFI_STUB is true.
#ifdef CONFIG_EFI_STUB
.org 0x3c
#
# Offset to the PE header.
#
.long pe_header
#endif /* CONFIG_EFI_STUB */
.section ".bsdata", "a"
bugger_off_msg:
.ascii "Use a boot loader.\r\n"
.ascii "\n"
.ascii "Remove disk and press any key to reboot...\r\n"
.byte 0
Most likely the "linuxefi" boot method uses the EFI handover protocol,
however. It looks like they don't start with a properly zeroed structure...
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