On Tue, 27 Aug 2024 at 00:42, Ross Philipson <ross.philipson@xxxxxxxxxx> wrote: > > The MLE (measured launch environment) header must be locatable by the > boot loader and TXT must be setup to do a launch with this header's > location. While the offset to the kernel_info structure does not need > to be at a fixed offset, the offsets in the header must be relative > offsets from the start of the setup kernel. The support in the linker > file achieves this. > > Signed-off-by: Ross Philipson <ross.philipson@xxxxxxxxxx> > Suggested-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > --- > arch/x86/boot/compressed/kernel_info.S | 50 +++++++++++++++++++++++--- > arch/x86/boot/compressed/vmlinux.lds.S | 7 ++++ > 2 files changed, 53 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/boot/compressed/kernel_info.S b/arch/x86/boot/compressed/kernel_info.S > index f818ee8fba38..a0604a0d1756 100644 > --- a/arch/x86/boot/compressed/kernel_info.S > +++ b/arch/x86/boot/compressed/kernel_info.S > @@ -1,12 +1,20 @@ > /* SPDX-License-Identifier: GPL-2.0 */ > > +#include <linux/linkage.h> > #include <asm/bootparam.h> > > - .section ".rodata.kernel_info", "a" > +/* > + * The kernel_info structure is not placed at a fixed offest in the > + * kernel image. So this macro and the support in the linker file > + * allow the relative offsets for the MLE header within the kernel > + * image to be configured at build time. > + */ > +#define roffset(X) ((X) - kernel_info) > > - .global kernel_info > + .section ".rodata.kernel_info", "a" > > -kernel_info: > + .balign 16 > +SYM_DATA_START(kernel_info) > /* Header, Linux top (structure). */ > .ascii "LToP" > /* Size. */ > @@ -17,6 +25,40 @@ kernel_info: > /* Maximal allowed type for setup_data and setup_indirect structs. */ > .long SETUP_TYPE_MAX > > + /* Offset to the MLE header structure */ > +#if IS_ENABLED(CONFIG_SECURE_LAUNCH) > + .long roffset(mle_header_offset) > +#else > + .long 0 > +#endif > + > kernel_info_var_len_data: > /* Empty for time being... */ > -kernel_info_end: > +SYM_DATA_END_LABEL(kernel_info, SYM_L_LOCAL, kernel_info_end) > + > +#if IS_ENABLED(CONFIG_SECURE_LAUNCH) > + /* > + * The MLE Header per the TXT Specification, section 2.1 > + * MLE capabilities, see table 4. Capabilities set: > + * bit 0: Support for GETSEC[WAKEUP] for RLP wakeup > + * bit 1: Support for RLP wakeup using MONITOR address > + * bit 2: The ECX register will contain the pointer to the MLE page table > + * bit 5: TPM 1.2 family: Details/authorities PCR usage support > + * bit 9: Supported format of TPM 2.0 event log - TCG compliant > + */ > +SYM_DATA_START(mle_header) > + .long 0x9082ac5a /* UUID0 */ > + .long 0x74a7476f /* UUID1 */ > + .long 0xa2555c0f /* UUID2 */ > + .long 0x42b651cb /* UUID3 */ > + .long 0x00000034 /* MLE header size */ > + .long 0x00020002 /* MLE version 2.2 */ > + .long roffset(sl_stub_entry_offset) /* Linear entry point of MLE (virt. address) */ > + .long 0x00000000 /* First valid page of MLE */ > + .long 0x00000000 /* Offset within binary of first byte of MLE */ > + .long roffset(_edata_offset) /* Offset within binary of last byte + 1 of MLE */ > + .long 0x00000227 /* Bit vector of MLE-supported capabilities */ > + .long 0x00000000 /* Starting linear address of command line (unused) */ > + .long 0x00000000 /* Ending linear address of command line (unused) */ > +SYM_DATA_END(mle_header) > +#endif > diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S > index 083ec6d7722a..f82184801462 100644 > --- a/arch/x86/boot/compressed/vmlinux.lds.S > +++ b/arch/x86/boot/compressed/vmlinux.lds.S > @@ -118,3 +118,10 @@ SECTIONS > } > ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!") > } > + > +#ifdef CONFIG_SECURE_LAUNCH > +PROVIDE(kernel_info_offset = ABSOLUTE(kernel_info - startup_32)); > +PROVIDE(mle_header_offset = kernel_info_offset + ABSOLUTE(mle_header - startup_32)); > +PROVIDE(sl_stub_entry_offset = kernel_info_offset + ABSOLUTE(sl_stub_entry - startup_32)); > +PROVIDE(_edata_offset = kernel_info_offset + ABSOLUTE(_edata - startup_32)); > +#endif > -- > 2.39.3 >
