[U-Boot] [PATCH 097/126] x86: Add support for newer CAR schemes

[Bin Meng <bmeng.cn@gmail.com>]

Hi Simon,

On Wed, Sep 25, 2019 at 10:59 PM Simon Glass <sjg@chromium.org> wrote:
>
> Newer Intel SoCs have different ways of setting up cache-as-ram (CAR).
> Add support for these along with suitable configuration options.
>

I wonder why do we need do this in U-Boot. Isn't FSP-T doing the CAR for us?

> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>
>  arch/x86/Kconfig                        |  16 +
>  arch/x86/cpu/intel_common/Kconfig       |  18 +
>  arch/x86/cpu/intel_common/Makefile      |   8 +
>  arch/x86/cpu/intel_common/car2.S        | 490 ++++++++++++++++++++++++
>  arch/x86/cpu/intel_common/car2_uninit.S |  87 +++++
>  5 files changed, 619 insertions(+)
>  create mode 100644 arch/x86/cpu/intel_common/Kconfig
>  create mode 100644 arch/x86/cpu/intel_common/car2.S
>  create mode 100644 arch/x86/cpu/intel_common/car2_uninit.S
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 556e26080de..e34c71ec4cb 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -876,4 +876,20 @@ config HIGH_TABLE_SIZE
>           Increse it if the default size does not fit the board's needs.
>           This is most likely due to a large ACPI DSDT table is used.
>
> +config INTEL_CAR_CQOS
> +       bool "Support Intel Cache Quality of Service"
> +       help
> +         Cache Quality of Service allows more fine-grained control of cache
> +         usage. As result, it is possible to set up a portion of L2 cache for
> +         CAR and use the remainder for actual caching.
> +
> +#
> +# Each bit in QOS mask controls this many bytes. This is calculated as:
> +# (CACHE_WAYS / CACHE_BITS_PER_MASK) * CACHE_LINE_SIZE * CACHE_SETS
> +#
> +config CACHE_QOS_SIZE_PER_BIT
> +       hex
> +       depends on INTEL_CAR_CQOS
> +       default 0x20000 # 128 KB
> +
>  endmenu
> diff --git a/arch/x86/cpu/intel_common/Kconfig b/arch/x86/cpu/intel_common/Kconfig
> new file mode 100644
> index 00000000000..a4f46b1108b
> --- /dev/null
> +++ b/arch/x86/cpu/intel_common/Kconfig
> @@ -0,0 +1,18 @@
> +config INTEL_PMC
> +       bool "Intel Power-management Controller"
> +       select POWER_MGR
> +       help
> +         Enable support for the common Intel power-management controller which
> +         provides features including checking whether the system started from
> +         resume, powering off the system and enabling/disabling the reset
> +         mechanism.
> +
> +config SPL_INTEL_PMC
> +       bool "Intel Power-management Controller in SPL"
> +       default y if SPL && INTEL_PMC
> +       select SPL_POWER_MGR
> +       help
> +         Enable support for the common Intel power-management controller which
> +         provides features including checking whether the system started from
> +         resume, powering off the system and enabling/disabling the reset
> +         mechanism.

I think the above 2 should not be in this patch

> diff --git a/arch/x86/cpu/intel_common/Makefile b/arch/x86/cpu/intel_common/Makefile
> index 2de567dd9fe..f620747a7d2 100644
> --- a/arch/x86/cpu/intel_common/Makefile
> +++ b/arch/x86/cpu/intel_common/Makefile
> @@ -8,6 +8,14 @@ obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += me_status.o
>  obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += report_platform.o
>  obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += mrc.o
>  endif
> +
> +ifdef CONFIG_FSP_VERSION2
> +obj-$(CONFIG_TPL_BUILD) += car2.o
> +ifndef CONFIG_SPL_BUILD
> +obj-y += car2_uninit.o
> +endif
> +endif
> +
>  obj-y += cpu.o
>  obj-$(CONFIG_SPI_FLASH_INTEL_FAST) += fast_spi.o
>  obj-y += lpc.o
> diff --git a/arch/x86/cpu/intel_common/car2.S b/arch/x86/cpu/intel_common/car2.S
> new file mode 100644
> index 00000000000..ac07fe5ea6a
> --- /dev/null
> +++ b/arch/x86/cpu/intel_common/car2.S
> @@ -0,0 +1,490 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * This file is part of the coreboot project.
> + *
> + * Copyright (C) 2015-2016 Intel Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *

nits: there is already SPDX license

> + */
> +
> +#include <config.h>
> +#include <asm/msr-index.h>
> +#include <asm/mtrr.h>
> +#include <asm/post.h>
> +#include <asm/processor-flags.h>
> +
> +#define KiB 1024
> +
> +.global car_init
> +car_init:
> +       post_code(0x20)
> +
> +       /*
> +        * Use the MTRR default type MSR as a proxy for detecting INIT#.
> +        * Reset the system if any known bits are set in that MSR. That is
> +        * an indication of the CPU not being properly reset.
> +        */
> +check_for_clean_reset:
> +       mov     $MTRR_DEF_TYPE_MSR, %ecx
> +       rdmsr
> +       and     $(MTRR_DEF_TYPE_EN | MTRR_DEF_TYPE_FIX_EN), %eax
> +       cmp     $0, %eax
> +       jz      no_reset
> +       /* perform warm reset */
> +       movw    $0xcf9, %dx
> +       movb    $0x06, %al
> +       outb    %al, %dx
> +
> +no_reset:
> +       post_code(0x21)

Can we use values from post.h?

> +
> +       /* Clear/disable fixed MTRRs */
> +       mov     $fixed_mtrr_list_size, %ebx
> +       xor     %eax, %eax
> +       xor     %edx, %edx
> +
> +clear_fixed_mtrr:
> +       add     $-2, %ebx
> +       movzwl  fixed_mtrr_list(%ebx), %ecx
> +       wrmsr
> +       jnz     clear_fixed_mtrr
> +
> +       post_code(0x22)
> +
> +       /* Figure put how many MTRRs we have, and clear them out */
> +       mov     $MTRR_CAP_MSR, %ecx
> +       rdmsr
> +       movzb   %al, %ebx               /* Number of variable MTRRs */
> +       mov     $MTRR_PHYS_BASE_MSR(0), %ecx
> +       xor     %eax, %eax
> +       xor     %edx, %edx
> +
> +clear_var_mtrr:
> +       wrmsr
> +       inc     %ecx
> +       wrmsr
> +       inc     %ecx
> +       dec     %ebx
> +       jnz     clear_var_mtrr
> +
> +       post_code(0x23)
> +
> +       /* Configure default memory type to uncacheable (UC) */
> +       mov     $MTRR_DEF_TYPE_MSR, %ecx
> +       rdmsr
> +       /* Clear enable bits and set default type to UC. */
> +       and     $~(MTRR_DEF_TYPE_MASK | MTRR_DEF_TYPE_EN | \
> +                MTRR_DEF_TYPE_FIX_EN), %eax
> +       wrmsr
> +
> +       /* Configure MTRR_PHYS_MASK_HIGH for proper addressing above 4GB

nits: wrong multi-line comment format

> +        * based on the physical address size supported for this processor
> +        * This is based on read from CPUID EAX = 080000008h, EAX bits [7:0]
> +        *
> +        * Examples:
> +        *  MTRR_PHYS_MASK_HIGH = 00000000Fh  For 36 bit addressing
> +        *  MTRR_PHYS_MASK_HIGH = 0000000FFh  For 40 bit addressing
> +        */
> +
> +       movl    $0x80000008, %eax       /* Address sizes leaf */
> +       cpuid
> +       sub     $32, %al
> +       movzx   %al, %eax
> +       xorl    %esi, %esi
> +       bts     %eax, %esi
> +       dec     %esi                    /* esi <- MTRR_PHYS_MASK_HIGH */
> +
> +       post_code(0x24)
> +
> +#if ((CONFIG_DCACHE_RAM_SIZE & (CONFIG_DCACHE_RAM_SIZE - 1)) == 0)
> +       /* Configure CAR region as write-back (WB) */
> +       mov     $MTRR_PHYS_BASE_MSR(0), %ecx
> +       mov     $CONFIG_DCACHE_RAM_BASE, %eax
> +       or      $MTRR_TYPE_WRBACK, %eax
> +       xor     %edx,%edx
> +       wrmsr
> +
> +       /* Configure the MTRR mask for the size region */
> +       mov     $MTRR_PHYS_MASK(0), %ecx
> +       mov     $CONFIG_DCACHE_RAM_SIZE, %eax   /* size mask */
> +       dec     %eax
> +       not     %eax
> +       or      $MTRR_PHYS_MASK_VALID, %eax
> +       movl    %esi, %edx      /* edx <- MTRR_PHYS_MASK_HIGH */
> +       wrmsr
> +#elif (CONFIG_DCACHE_RAM_SIZE == 768 * KiB) /* 768 KiB */
> +       /* Configure CAR region as write-back (WB) */
> +       mov     $MTRR_PHYS_BASE_MSR(0), %ecx
> +       mov     $CONFIG_DCACHE_RAM_BASE, %eax
> +       or      $MTRR_TYPE_WRBACK, %eax
> +       xor     %edx,%edx
> +       wrmsr
> +
> +       mov     $MTRR_PHYS_MASK_MSR(0), %ecx
> +       mov     $(512 * KiB), %eax      /* size mask */
> +       dec     %eax
> +       not     %eax
> +       or      $MTRR_PHYS_MASK_VALID, %eax
> +       movl    %esi, %edx      /* edx <- MTRR_PHYS_MASK_HIGH */
> +       wrmsr
> +
> +       mov     $MTRR_PHYS_BASE_MSR(1), %ecx
> +       mov     $(CONFIG_DCACHE_RAM_BASE + 512 * KiB), %eax
> +       or      $MTRR_TYPE_WRBACK, %eax
> +       xor     %edx,%edx
> +       wrmsr
> +
> +       mov     $MTRR_PHYS_MASK_MSR(1), %ecx
> +       mov     $(256 * KiB), %eax      /* size mask */
> +       dec     %eax
> +       not     %eax
> +       or      $MTRR_PHYS_MASK_VALID, %eax
> +       movl    %esi, %edx      /* edx <- MTRR_PHYS_MASK_HIGH */
> +       wrmsr
> +#else
> +#error "DCACHE_RAM_SIZE is not a power of 2 and setup code is missing"
> +#endif
> +       post_code(0x25)
> +
> +       /* start */
> +/*     mov     $0xffff80a8, %ebx */
> +/*     jmp     *%ebx */
> +.globl _from_bb
> +_from_bb:
> +/*     jmp     car_init_ret */
> +       /* end */
> +
> +       /* Enable variable MTRRs */
> +       mov     $MTRR_DEF_TYPE_MSR, %ecx
> +       rdmsr
> +       or      $MTRR_DEF_TYPE_EN, %eax
> +       wrmsr
> +
> +       /* Enable caching */
> +       mov     %cr0, %eax
> +       and     $~(X86_CR0_CD | X86_CR0_NW), %eax
> +       invd
> +       mov     %eax, %cr0
> +
> +#if IS_ENABLED(CONFIG_INTEL_CAR_NEM)
> +       jmp car_nem
> +#elif IS_ENABLED(CONFIG_INTEL_CAR_CQOS)
> +       jmp car_cqos
> +#elif IS_ENABLED(CONFIG_INTEL_CAR_NEM_ENHANCED)
> +       jmp car_nem_enhanced
> +#else
> +#error "No CAR mechanism selected:
> +#endif
> +       jmp     car_init_ret
> +
> +#if 0
> +.global car_init_done
> +car_init_done:
> +
> +       post_code(0x29)
> +
> +       /* Setup bootblock stack */
> +       mov     $_car_stack_end, %esp
> +
> +       /* Need to align stack to 16 bytes at call instruction. Account for
> +          the two pushes below. */
> +       andl    $0xfffffff0, %esp
> +       sub     $8, %esp
> +
> +       /*push TSC value to stack*/
> +       movd    %mm2, %eax
> +       pushl   %eax    /* tsc[63:32] */
> +       movd    %mm1, %eax
> +       pushl   %eax    /* tsc[31:0] */
> +
> +before_carstage:
> +       post_code(0x2A)
> +
> +       call    bootblock_c_entry

where is this function?

> +       /* Never reached */
> +#endif
> +
> +fixed_mtrr_list:
> +       .word   MTRR_FIX_64K_00000_MSR
> +       .word   MTRR_FIX_16K_80000_MSR
> +       .word   MTRR_FIX_16K_A0000_MSR
> +       .word   MTRR_FIX_4K_C0000_MSR
> +       .word   MTRR_FIX_4K_C8000_MSR
> +       .word   MTRR_FIX_4K_D0000_MSR
> +       .word   MTRR_FIX_4K_D8000_MSR
> +       .word   MTRR_FIX_4K_E0000_MSR
> +       .word   MTRR_FIX_4K_E8000_MSR
> +       .word   MTRR_FIX_4K_F0000_MSR
> +       .word   MTRR_FIX_4K_F8000_MSR
> +fixed_mtrr_list_size = . - fixed_mtrr_list
> +
> +#if IS_ENABLED(CONFIG_INTEL_CAR_NEM)
> +.global car_nem
> +car_nem:
> +       /* Disable cache eviction (setup stage) */
> +       mov     $MSR_EVICT_CTL, %ecx
> +       rdmsr
> +       or      $0x1, %eax
> +       wrmsr
> +
> +       post_code(0x26)
> +
> +       /* Clear the cache memory region. This will also fill up the cache */
> +       movl    $CONFIG_DCACHE_RAM_BASE, %edi
> +       movl    $CONFIG_DCACHE_RAM_SIZE, %ecx
> +       shr     $0x02, %ecx
> +       xor     %eax, %eax
> +       cld
> +       rep     stosl
> +
> +       post_code(0x27)
> +
> +       /* Disable cache eviction (run stage) */
> +       mov     $MSR_EVICT_CTL, %ecx
> +       rdmsr
> +       or      $0x2, %eax
> +       wrmsr
> +
> +       post_code(0x28)
> +
> +       jmp car_init_done
> +
> +#elif IS_ENABLED(CONFIG_INTEL_CAR_CQOS)
> +.global car_cqos
> +car_cqos:
> +       /*
> +        * Create CBM_LEN_MASK based on CBM_LEN
> +        * Get CPUID.(EAX=10H, ECX=2H):EAX.CBM_LEN[bits 4:0]
> +        */
> +       mov $0x10, %eax
> +       mov $0x2,  %ecx
> +       cpuid
> +       and $0x1F, %eax
> +       add $1, %al
> +
> +       mov $1, %ebx
> +       mov %al, %cl
> +       shl %cl, %ebx
> +       sub $1, %ebx
> +
> +       /* Store the CBM_LEN_MASK in mm3 for later use. */
> +       movd %ebx, %mm3
> +
> +       /*
> +        * Disable both L1 and L2 prefetcher. For yet-to-understood reason,
> +        * prefetchers slow down filling cache with rep stos in CQOS mode.
> +        */
> +       mov     $MSR_PREFETCH_CTL, %ecx
> +       rdmsr
> +       or      $(PREFETCH_L1_DISABLE | PREFETCH_L2_DISABLE), %eax
> +       wrmsr
> +
> +#if (CONFIG_DCACHE_RAM_SIZE == CONFIG_L2_CACHE_SIZE)
> +/*
> + * If CAR size is set to full L2 size, mask is calculated as all-zeros.
> + * This is not supported by the CPU/uCode.
> + */
> +#error "CQOS CAR may not use whole L2 cache area"
> +#endif
> +
> +       /* Calculate how many bits to be used for CAR */
> +       xor     %edx, %edx
> +       mov     $CONFIG_DCACHE_RAM_SIZE, %eax   /* dividend */
> +       mov     $CONFIG_CACHE_QOS_SIZE_PER_BIT, %ecx    /* divisor */
> +       div     %ecx            /* result is in eax */
> +       mov     %eax, %ecx      /* save to ecx */
> +       mov     $1, %ebx
> +       shl     %cl, %ebx
> +       sub     $1, %ebx        /* resulting mask is is in ebx */
> +
> +       /* Set this mask for initial cache fill */
> +       mov     $MSR_L2_QOS_MASK(0), %ecx
> +       rdmsr
> +       mov     %ebx, %eax
> +       wrmsr
> +
> +       /* Set CLOS selector to 0 */
> +       mov     $MSR_IA32_PQR_ASSOC, %ecx
> +       rdmsr
> +       and     $~MSR_IA32_PQR_ASSOC_MASK, %edx /* select mask 0 */
> +       wrmsr
> +
> +       /* We will need to block CAR region from evicts */
> +       mov     $MSR_L2_QOS_MASK(1), %ecx
> +       rdmsr
> +       /* Invert bits that are to be used for cache */
> +       mov     %ebx, %eax
> +       xor     $~0, %eax                       /* invert 32 bits */
> +
> +       /*
> +        * Use CBM_LEN_MASK stored in mm3 to set bits based on Capacity Bit
> +        * Mask Length.
> +        */
> +       movd    %mm3, %ebx
> +       and     %ebx, %eax
> +       wrmsr
> +
> +       post_code(0x26)
> +
> +       /* Clear the cache memory region. This will also fill up the cache */
> +       movl    $CONFIG_DCACHE_RAM_BASE, %edi
> +       movl    $CONFIG_DCACHE_RAM_SIZE, %ecx
> +       shr     $0x02, %ecx
> +       xor     %eax, %eax
> +       cld
> +       rep     stosl
> +
> +       post_code(0x27)
> +
> +       /* Cache is populated. Use mask 1 that will block evicts */
> +       mov     $MSR_IA32_PQR_ASSOC, %ecx
> +       rdmsr
> +       and     $~MSR_IA32_PQR_ASSOC_MASK, %edx /* clear index bits first */
> +       or      $1, %edx                        /* select mask 1 */
> +       wrmsr
> +
> +       /* Enable prefetchers */
> +       mov     $MSR_PREFETCH_CTL, %ecx
> +       rdmsr
> +       and     $~(PREFETCH_L1_DISABLE | PREFETCH_L2_DISABLE), %eax
> +       wrmsr
> +
> +       post_code(0x28)
> +
> +/*     jmp car_init_done */
> +       jmp     car_init_ret
> +
> +#elif IS_ENABLED(CONFIG_INTEL_CAR_NEM_ENHANCED)
> +.global car_nem_enhanced
> +car_nem_enhanced:
> +       /* Disable cache eviction (setup stage) */
> +       mov     $MSR_EVICT_CTL, %ecx
> +       rdmsr
> +       or      $0x1, %eax
> +       wrmsr
> +       post_code(0x26)
> +
> +       /* Create n-way set associativity of cache */
> +       xorl    %edi, %edi
> +find_llc_subleaf:
> +       movl    %edi, %ecx
> +       movl    $0x04, %eax
> +       cpuid
> +       inc     %edi
> +       and     $0xe0, %al      /* EAX[7:5] = Cache Level */
> +       cmp     $0x60, %al      /* Check to see if it is LLC */
> +       jnz     find_llc_subleaf
> +
> +       /*
> +        * Set MSR 0xC91 IA32_L3_MASK_! = 0xE/0xFE/0xFFE/0xFFFE
> +        * for 4/8/16 way of LLC
> +       */
> +       shr     $22, %ebx
> +       inc     %ebx
> +       /* Calculate n-way associativity of LLC */
> +       mov     %bl, %cl
> +
> +       /*
> +        * Maximizing RO cacheability while locking in the CAR to a
> +        * single way since that particular way won't be victim candidate
> +        * for evictions.
> +        * This has been done after programing LLC_WAY_MASK_1 MSR
> +        * with desired LLC way as mentioned below.
> +        *
> +        * Hence create Code and Data Size as per request
> +        * Code Size (RO) : Up to 16M
> +        * Data Size (RW) : Up to 256K
> +        */
> +       movl    $0x01, %eax
> +       /*
> +        * LLC Ways -> LLC_WAY_MASK_1:
> +        *  4: 0x000E
> +        *  8: 0x00FE
> +        * 12: 0x0FFE
> +        * 16: 0xFFFE
> +        *
> +        * These MSRs contain one bit per each way of LLC
> +        * - If this bit is '0' - the way is protected from eviction
> +        * - If this bit is '1' - the way is not protected from eviction
> +        */
> +       shl     %cl, %eax
> +       subl    $0x02, %eax
> +       movl    $MSR_IA32_L3_MASK_1, %ecx
> +       xorl    %edx, %edx
> +       wrmsr
> +       /*
> +        * Set MSR 0xC92 IA32_L3_MASK_2 = 0x1
> +        *
> +        * For SKL SOC, data size remains 256K consistently.
> +        * Hence, creating 1-way associative cache for Data
> +       */
> +       mov     $MSR_IA32_L3_MASK_2, %ecx
> +       mov     $0x01, %eax
> +       xorl    %edx, %edx
> +       wrmsr
> +       /*
> +        * Set MSR_IA32_PQR_ASSOC = 0x02
> +        *
> +        * Possible values:
> +        * 0: Default value, no way mask should be applied
> +        * 1: Apply way mask 1 to LLC
> +        * 2: Apply way mask 2 to LLC
> +        * 3: Shouldn't be use in NEM Mode
> +        */
> +       movl    $MSR_IA32_PQR_ASSOC, %ecx
> +       movl    $0x02, %eax
> +       xorl    %edx, %edx
> +       wrmsr
> +
> +       movl    $CONFIG_DCACHE_RAM_BASE, %edi
> +       movl    $CONFIG_DCACHE_RAM_SIZE, %ecx
> +       shr     $0x02, %ecx
> +       xor     %eax, %eax
> +       cld
> +       rep     stosl
> +       /*
> +        * Set MSR_IA32_PQR_ASSOC = 0x01
> +        * At this stage we apply LLC_WAY_MASK_1 to the cache.
> +        * i.e. way 0 is protected from eviction.
> +       */
> +       movl    $MSR_IA32_PQR_ASSOC, %ecx
> +       movl    $0x01, %eax
> +       xorl    %edx, %edx
> +       wrmsr
> +
> +       post_code(0x27)
> +       /*
> +        * Enable No-Eviction Mode Run State by setting
> +        * NO_EVICT_MODE MSR 2E0h bit [1] = '1'.
> +        */
> +
> +       movl    $MSR_EVICT_CTL, %ecx
> +       rdmsr
> +       orl     $0x02, %eax
> +       wrmsr
> +
> +       post_code(0x28)
> +
> +       jmp car_init_done
> +#endif
> +
> +#if CONFIG_IS_ENABLED(X86_16BIT_INIT)
> +_dt_ucode_base_size:
> +       /* These next two fields are filled in by binman */
> +.globl ucode_base
> +ucode_base:    /* Declared in microcode.h */
> +       .long   0                       /* microcode base */
> +.globl ucode_size
> +ucode_size:    /* Declared in microcode.h */
> +       .long   0                       /* microcode size */
> +       .long   CONFIG_SYS_MONITOR_BASE /* code region base */
> +       .long   CONFIG_SYS_MONITOR_LEN  /* code region size */
> +#endif
> diff --git a/arch/x86/cpu/intel_common/car2_uninit.S b/arch/x86/cpu/intel_common/car2_uninit.S
> new file mode 100644
> index 00000000000..4797ac04279
> --- /dev/null
> +++ b/arch/x86/cpu/intel_common/car2_uninit.S
> @@ -0,0 +1,87 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright 2017 Intel Corp.
> + * Copyright 2019 Google LLC
> + * Taken from coreboot file exit_car.S
> + */
> +
> +#include <config.h>
> +#include <asm/msr-index.h>
> +#include <asm/mtrr.h>
> +
> +.text
> +.global car_uninit
> +car_uninit:
> +
> +       /*
> +        * Retrieve return address from stack as it will get trashed below if
> +        * execution is utilizing the cache-as-ram stack.
> +        */
> +       pop     %ebx
> +
> +       /* Disable MTRRs. */
> +       mov     $(MTRR_DEF_TYPE_MSR), %ecx
> +       rdmsr
> +       and     $(~(MTRR_DEF_TYPE_EN | MTRR_DEF_TYPE_FIX_EN)), %eax
> +       wrmsr
> +
> +#ifdef CONFIG_INTEL_CAR_NEM
> +.global car_nem_teardown
> +car_nem_teardown:
> +
> +       /* invalidate cache contents. */
> +       invd
> +
> +       /* Knock down bit 1 then bit 0 of NEM control not combining steps. */
> +       mov     $(MSR_EVICT_CTL), %ecx
> +       rdmsr
> +       and     $(~(1 << 1)), %eax
> +       wrmsr
> +       and     $(~(1 << 0)), %eax
> +       wrmsr
> +
> +#elif IS_ENABLED(CONFIG_INTEL_CAR_CQOS)
> +.global car_cqos_teardown
> +car_cqos_teardown:
> +
> +       /* Go back to all-evicting mode, set both masks to all-1s */
> +       mov     $MSR_L2_QOS_MASK(0), %ecx
> +       rdmsr
> +       mov     $~0, %al
> +       wrmsr
> +
> +       mov     $MSR_L2_QOS_MASK(1), %ecx
> +       rdmsr
> +       mov     $~0, %al
> +       wrmsr
> +
> +       /* Reset CLOS selector to 0 */
> +       mov     $MSR_IA32_PQR_ASSOC, %ecx
> +       rdmsr
> +       and     $~MSR_IA32_PQR_ASSOC_MASK, %edx
> +       wrmsr
> +
> +#elif IS_ENABLED(CONFIG_INTEL_CAR_NEM_ENHANCED)
> +.global car_nem_enhanced_teardown
> +car_nem_enhanced_teardown:
> +
> +       /* invalidate cache contents. */
> +       invd
> +
> +       /* Knock down bit 1 then bit 0 of NEM control not combining steps. */
> +       mov     $(MSR_EVICT_CTL), %ecx
> +       rdmsr
> +       and     $(~(1 << 1)), %eax
> +       wrmsr
> +       and     $(~(1 << 0)), %eax
> +       wrmsr
> +
> +       /* Reset CLOS selector to 0 */
> +       mov     $IA32_PQR_ASSOC, %ecx
> +       rdmsr
> +       and     $~IA32_PQR_ASSOC_MASK, %edx
> +       wrmsr
> +#endif
> +
> +       /* Return to caller. */
> +       jmp     *%ebx
> --

I was not fully convinced we need this in U-Boot if we are using FSP.

Regards,
Bin