diff options
| -rw-r--r-- | arch/x86/kernel/vmlinux.lds.S | 25 | ||||
| -rw-r--r-- | arch/x86/mm/mem_encrypt_identity.c | 22 |
2 files changed, 45 insertions, 2 deletions
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index ca2252ca6ad7..147cd020516a 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -387,6 +387,31 @@ SECTIONS . = ALIGN(PAGE_SIZE); /* keep VO_INIT_SIZE page aligned */ _end = .; +#ifdef CONFIG_AMD_MEM_ENCRYPT + /* + * Early scratch/workarea section: Lives outside of the kernel proper + * (_text - _end). + * + * Resides after _end because even though the .brk section is after + * __end_of_kernel_reserve, the .brk section is later reserved as a + * part of the kernel. Since it is located after __end_of_kernel_reserve + * it will be discarded and become part of the available memory. As + * such, it can only be used by very early boot code and must not be + * needed afterwards. + * + * Currently used by SME for performing in-place encryption of the + * kernel during boot. Resides on a 2MB boundary to simplify the + * pagetable setup used for SME in-place encryption. + */ + . = ALIGN(HPAGE_SIZE); + .init.scratch : AT(ADDR(.init.scratch) - LOAD_OFFSET) { + __init_scratch_begin = .; + *(.init.scratch) + . = ALIGN(HPAGE_SIZE); + __init_scratch_end = .; + } +#endif + STABS_DEBUG DWARF_DEBUG diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c index 4aa9b1480866..6a8dd483f7d9 100644 --- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -73,6 +73,19 @@ struct sme_populate_pgd_data { unsigned long vaddr_end; }; +/* + * This work area lives in the .init.scratch section, which lives outside of + * the kernel proper. It is sized to hold the intermediate copy buffer and + * more than enough pagetable pages. + * + * By using this section, the kernel can be encrypted in place and it + * avoids any possibility of boot parameters or initramfs images being + * placed such that the in-place encryption logic overwrites them. This + * section is 2MB aligned to allow for simple pagetable setup using only + * PMD entries (see vmlinux.lds.S). + */ +static char sme_workarea[2 * PMD_PAGE_SIZE] __section(.init.scratch); + static char sme_cmdline_arg[] __initdata = "mem_encrypt"; static char sme_cmdline_on[] __initdata = "on"; static char sme_cmdline_off[] __initdata = "off"; @@ -314,8 +327,13 @@ void __init sme_encrypt_kernel(struct boot_params *bp) } #endif - /* Set the encryption workarea to be immediately after the kernel */ - workarea_start = kernel_end; + /* + * We're running identity mapped, so we must obtain the address to the + * SME encryption workarea using rip-relative addressing. + */ + asm ("lea sme_workarea(%%rip), %0" + : "=r" (workarea_start) + : "p" (sme_workarea)); /* * Calculate required number of workarea bytes needed: |