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Date: Wed, 1 Jul 2020 17:28:24 +0200
From: Ard Biesheuvel <ardb@...nel.org>
To: Steve Wahl <steve.wahl@....com>
Cc: Jonathan Corbet <corbet@....net>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
X86 ML <x86@...nel.org>, "H. Peter Anvin" <hpa@...or.com>,
Darren Hart <dvhart@...radead.org>,
Andy Shevchenko <andy@...radead.org>,
Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Paul E. McKenney" <paulmck@...nel.org>,
Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
Juergen Gross <jgross@...e.com>,
Mike Kravetz <mike.kravetz@...cle.com>,
Oliver Neukum <oneukum@...e.com>,
Mike Travis <mike.travis@....com>,
Dimitri Sivanich <dimitri.sivanich@....com>,
Benjamin Thiel <b.thiel@...teo.de>,
Andy Lutomirski <luto@...nel.org>,
Arnd Bergmann <arnd@...db.de>,
James Morris <jmorris@...ei.org>,
David Howells <dhowells@...hat.com>,
Kees Cook <keescook@...omium.org>,
Dave Young <dyoung@...hat.com>,
Dan Williams <dan.j.williams@...el.com>,
Logan Gunthorpe <logang@...tatee.com>,
Alexandre Chartre <alexandre.chartre@...cle.com>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>,
Austin Kim <austindh.kim@...il.com>,
Alexey Dobriyan <adobriyan@...il.com>,
Linux Doc Mailing List <linux-doc@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-efi <linux-efi@...r.kernel.org>,
Russ Anderson <rja@....com>
Subject: Re: [patch 12/13] Remove uv bios and efi code related to (now unused) EFI_UV1_MEMMAP
On Wed, 1 Jul 2020 at 16:18, <steve.wahl@....com> wrote:
>
> With UV1 removed, EFI_UV1_MEMMAP is not used. Remove code used by it
> in arch/x86/platform/uv/bios_uv.c and turn off code in
> arch/x86/platform/efi/efi.c that referenced this code.
>
> Signed-off-by: Steve Wahl <steve.wahl@....com>
Reviewed-by: Ard Biesheuvel <ardb@...nel.org>
> ---
> arch/x86/platform/efi/efi.c | 2
> arch/x86/platform/uv/bios_uv.c | 159 -----------------------------------------
> 2 files changed, 2 insertions(+), 159 deletions(-)
>
> --- linux.orig/arch/x86/platform/uv/bios_uv.c 2020-06-25 16:13:51.765087047 -0500
> +++ linux/arch/x86/platform/uv/bios_uv.c 2020-06-25 16:14:29.821045358 -0500
> @@ -30,17 +30,7 @@ static s64 __uv_bios_call(enum uv_bios_c
> */
> return BIOS_STATUS_UNIMPLEMENTED;
>
> - /*
> - * If EFI_UV1_MEMMAP is set, we need to fall back to using our old EFI
> - * callback method, which uses efi_call() directly, with the kernel page tables:
> - */
> - if (unlikely(efi_enabled(EFI_UV1_MEMMAP))) {
> - kernel_fpu_begin();
> - ret = efi_call((void *)__va(tab->function), (u64)which, a1, a2, a3, a4, a5);
> - kernel_fpu_end();
> - } else {
> - ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, a3, a4, a5);
> - }
> + ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, a3, a4, a5);
>
> return ret;
> }
> @@ -209,150 +199,3 @@ int uv_bios_init(void)
> pr_info("UV: UVsystab: Revision:%x\n", uv_systab->revision);
> return 0;
> }
> -
> -static void __init early_code_mapping_set_exec(int executable)
> -{
> - efi_memory_desc_t *md;
> -
> - if (!(__supported_pte_mask & _PAGE_NX))
> - return;
> -
> - /* Make EFI service code area executable */
> - for_each_efi_memory_desc(md) {
> - if (md->type == EFI_RUNTIME_SERVICES_CODE ||
> - md->type == EFI_BOOT_SERVICES_CODE)
> - efi_set_executable(md, executable);
> - }
> -}
> -
> -void __init efi_uv1_memmap_phys_epilog(pgd_t *save_pgd)
> -{
> - /*
> - * After the lock is released, the original page table is restored.
> - */
> - int pgd_idx, i;
> - int nr_pgds;
> - pgd_t *pgd;
> - p4d_t *p4d;
> - pud_t *pud;
> -
> - nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
> -
> - for (pgd_idx = 0; pgd_idx < nr_pgds; pgd_idx++) {
> - pgd = pgd_offset_k(pgd_idx * PGDIR_SIZE);
> - set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]);
> -
> - if (!pgd_present(*pgd))
> - continue;
> -
> - for (i = 0; i < PTRS_PER_P4D; i++) {
> - p4d = p4d_offset(pgd,
> - pgd_idx * PGDIR_SIZE + i * P4D_SIZE);
> -
> - if (!p4d_present(*p4d))
> - continue;
> -
> - pud = (pud_t *)p4d_page_vaddr(*p4d);
> - pud_free(&init_mm, pud);
> - }
> -
> - p4d = (p4d_t *)pgd_page_vaddr(*pgd);
> - p4d_free(&init_mm, p4d);
> - }
> -
> - kfree(save_pgd);
> -
> - __flush_tlb_all();
> - early_code_mapping_set_exec(0);
> -}
> -
> -pgd_t * __init efi_uv1_memmap_phys_prolog(void)
> -{
> - unsigned long vaddr, addr_pgd, addr_p4d, addr_pud;
> - pgd_t *save_pgd, *pgd_k, *pgd_efi;
> - p4d_t *p4d, *p4d_k, *p4d_efi;
> - pud_t *pud;
> -
> - int pgd;
> - int n_pgds, i, j;
> -
> - early_code_mapping_set_exec(1);
> -
> - n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
> - save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL);
> - if (!save_pgd)
> - return NULL;
> -
> - /*
> - * Build 1:1 identity mapping for UV1 memmap usage. Note that
> - * PAGE_OFFSET is PGDIR_SIZE aligned when KASLR is disabled, while
> - * it is PUD_SIZE ALIGNED with KASLR enabled. So for a given physical
> - * address X, the pud_index(X) != pud_index(__va(X)), we can only copy
> - * PUD entry of __va(X) to fill in pud entry of X to build 1:1 mapping.
> - * This means here we can only reuse the PMD tables of the direct mapping.
> - */
> - for (pgd = 0; pgd < n_pgds; pgd++) {
> - addr_pgd = (unsigned long)(pgd * PGDIR_SIZE);
> - vaddr = (unsigned long)__va(pgd * PGDIR_SIZE);
> - pgd_efi = pgd_offset_k(addr_pgd);
> - save_pgd[pgd] = *pgd_efi;
> -
> - p4d = p4d_alloc(&init_mm, pgd_efi, addr_pgd);
> - if (!p4d) {
> - pr_err("Failed to allocate p4d table!\n");
> - goto out;
> - }
> -
> - for (i = 0; i < PTRS_PER_P4D; i++) {
> - addr_p4d = addr_pgd + i * P4D_SIZE;
> - p4d_efi = p4d + p4d_index(addr_p4d);
> -
> - pud = pud_alloc(&init_mm, p4d_efi, addr_p4d);
> - if (!pud) {
> - pr_err("Failed to allocate pud table!\n");
> - goto out;
> - }
> -
> - for (j = 0; j < PTRS_PER_PUD; j++) {
> - addr_pud = addr_p4d + j * PUD_SIZE;
> -
> - if (addr_pud > (max_pfn << PAGE_SHIFT))
> - break;
> -
> - vaddr = (unsigned long)__va(addr_pud);
> -
> - pgd_k = pgd_offset_k(vaddr);
> - p4d_k = p4d_offset(pgd_k, vaddr);
> - pud[j] = *pud_offset(p4d_k, vaddr);
> - }
> - }
> - pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX;
> - }
> -
> - __flush_tlb_all();
> - return save_pgd;
> -out:
> - efi_uv1_memmap_phys_epilog(save_pgd);
> - return NULL;
> -}
> -
> -void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
> - u32 type, u64 attribute)
> -{
> - unsigned long last_map_pfn;
> -
> - if (type == EFI_MEMORY_MAPPED_IO)
> - return ioremap(phys_addr, size);
> -
> - last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size,
> - PAGE_KERNEL);
> - if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
> - unsigned long top = last_map_pfn << PAGE_SHIFT;
> - efi_ioremap(top, size - (top - phys_addr), type, attribute);
> - }
> -
> - if (!(attribute & EFI_MEMORY_WB))
> - efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
> -
> - return (void __iomem *)__va(phys_addr);
> -}
> --- linux.orig/arch/x86/platform/efi/efi.c 2020-06-25 16:13:54.637083901 -0500
> +++ linux/arch/x86/platform/efi/efi.c 2020-06-25 16:15:14.532996386 -0500
> @@ -496,7 +496,7 @@ void __init efi_init(void)
> efi_print_memmap();
> }
>
> -#if defined(CONFIG_X86_32) || defined(CONFIG_X86_UV)
> +#if defined(CONFIG_X86_32)
>
> void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
> {
>
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