diff options
| -rw-r--r-- | src/security/intel/txt/getsec_enteraccs.S | 74 | ||||
| -rw-r--r-- | src/security/intel/txt/getsec_mtrr_setup.inc | 74 |
2 files changed, 84 insertions, 64 deletions
diff --git a/src/security/intel/txt/getsec_enteraccs.S b/src/security/intel/txt/getsec_enteraccs.S index be038b0607..be3a1b4f0b 100644 --- a/src/security/intel/txt/getsec_enteraccs.S +++ b/src/security/intel/txt/getsec_enteraccs.S @@ -4,7 +4,7 @@ #include <cpu/x86/cr.h> #include <cpu/x86/msr.h> -#define MTRR_HIGH_MASK $((1 << (CONFIG_CPU_ADDR_BITS - 32)) - 1) +#include "getsec_mtrr_setup.inc" .macro PUSH_MSR x movl $(\x), %ecx @@ -166,15 +166,6 @@ cond_clear_var_mtrrs: * Intel TXT Software Development Guide (Document: 315168-015) */ - /* - * Important note: The MTRRs must cache less than a page (4 KiB) - * of unused memory after the BIOS ACM. Failure to do so will - * result in a TXT reset with Class Code 5, Major Error Code 2. - * - * The caller must have checked that there are enough variable - * MTRRs to cache the ACM size prior to invoking this routine. - */ - /* Determine size of AC module */ movl 12(%ebp), %eax /* %eax = acmbase */ movl $1, %ebx @@ -191,60 +182,15 @@ cond_clear_var_mtrrs: movd %eax, %xmm0 /* XMM0: Base address of next MTRR */ movd %ebx, %xmm1 /* XMM1: Remaining size to cache */ - /* Get the number of variable MTRRs */ - movl $(MTRR_CAP_MSR), %ecx - rdmsr - andl $(0xff), %eax - - /* Initialize ECX */ - movl $(MTRR_PHYS_BASE(0)), %ecx - - jmp cond_allocate_var_mtrrs - -body_allocate_var_mtrrs: - - /* Program MTRR base */ - xorl %edx, %edx - movd %xmm0, %eax - orl $(MTRR_TYPE_WRBACK), %eax - wrmsr - incl %ecx /* Move index to MTRR_PHYS_MASK */ - - /* Temporarily transfer MSR index to EDX so that CL can be used */ - movl %ecx, %edx - - /* Determine next size to cache */ - bsr %ebx, %ecx - movl $(1), %ebx - shl %cl, %ebx /* Can only use CL here */ - - /* Restore ECX */ - movl %edx, %ecx - - /* Update saved base address */ - addl %ebx, %eax - movd %eax, %xmm0 - - /* Update saved remaining size */ - movd %xmm1, %eax - subl %ebx, %eax - movd %eax, %xmm1 - - /* Program MTRR mask */ - movl MTRR_HIGH_MASK, %edx - xorl %eax, %eax - subl %ebx, %eax /* %eax = 4GIB - size to cache */ - orl $(MTRR_PHYS_MASK_VALID), %eax - wrmsr - incl %ecx /* Move index to next MTRR_PHYS_BASE */ - -cond_allocate_var_mtrrs: - - /* Check if we still need to cache something */ - movd %xmm1, %ebx - andl %ebx, %ebx - - jnz body_allocate_var_mtrrs + /* + * Important note: The MTRRs must cache less than a page (4 KiB) + * of unused memory after the BIOS ACM. Failure to do so will + * result in a TXT reset with Class Code 5, Major Error Code 2. + * + * The caller must have checked that there are enough variable + * MTRRs to cache the ACM size prior to invoking this routine. + */ + SET_UP_MTRRS_FOR_BIOS_ACM /* * Now that the variable MTRRs have been set up, enable them. diff --git a/src/security/intel/txt/getsec_mtrr_setup.inc b/src/security/intel/txt/getsec_mtrr_setup.inc new file mode 100644 index 0000000000..15e8cc17ad --- /dev/null +++ b/src/security/intel/txt/getsec_mtrr_setup.inc @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include <cpu/x86/mtrr.h> +#include <cpu/x86/msr.h> + +#define MTRR_HIGH_MASK $((1 << (CONFIG_CPU_ADDR_BITS - 32)) - 1) + +/* + * Configure the MTRRs to cache the BIOS ACM. No general-purpose + * registers are preserved. Inputs are taken from SSE registers: + * + * %xmm0: BIOS ACM base + * %xmm1: BIOS ACM size + * + * These two SSE registers are not preserved, but the others are. + */ +.macro SET_UP_MTRRS_FOR_BIOS_ACM + + /* Get the number of variable MTRRs */ + movl $(MTRR_CAP_MSR), %ecx + rdmsr + andl $(0xff), %eax + + /* Initialize ECX */ + movl $(MTRR_PHYS_BASE(0)), %ecx + + jmp cond_allocate_var_mtrrs + +body_allocate_var_mtrrs: + + /* Program MTRR base */ + xorl %edx, %edx + movd %xmm0, %eax + orl $(MTRR_TYPE_WRBACK), %eax + wrmsr + incl %ecx /* Move index to MTRR_PHYS_MASK */ + + /* Temporarily transfer MSR index to EDX so that CL can be used */ + movl %ecx, %edx + + /* Determine next size to cache */ + bsr %ebx, %ecx + movl $(1), %ebx + shl %cl, %ebx /* Can only use CL here */ + + /* Restore ECX */ + movl %edx, %ecx + + /* Update saved base address */ + addl %ebx, %eax + movd %eax, %xmm0 + + /* Update saved remaining size */ + movd %xmm1, %eax + subl %ebx, %eax + movd %eax, %xmm1 + + /* Program MTRR mask */ + movl MTRR_HIGH_MASK, %edx + xorl %eax, %eax + subl %ebx, %eax /* %eax = 4GIB - size to cache */ + orl $(MTRR_PHYS_MASK_VALID), %eax + wrmsr + incl %ecx /* Move index to next MTRR_PHYS_BASE */ + +cond_allocate_var_mtrrs: + + /* Check if we still need to cache something */ + movd %xmm1, %ebx + andl %ebx, %ebx + + jnz body_allocate_var_mtrrs + +.endm |