mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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bba4ed011a
Provide support so that kexec can be used to boot a kernel when SME is enabled. Support is needed to allocate pages for kexec without encryption. This is needed in order to be able to reboot in the kernel in the same manner as originally booted. Additionally, when shutting down all of the CPUs we need to be sure to flush the caches and then halt. This is needed when booting from a state where SME was not active into a state where SME is active (or vice-versa). Without these steps, it is possible for cache lines to exist for the same physical location but tagged both with and without the encryption bit. This can cause random memory corruption when caches are flushed depending on which cacheline is written last. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: <kexec@lists.infradead.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Dave Young <dyoung@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Toshimitsu Kani <toshi.kani@hpe.com> Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/b95ff075db3e7cd545313f2fb609a49619a09625.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
/*
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* Helper routines for building identity mapping page tables. This is
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* included by both the compressed kernel and the regular kernel.
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*/
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static void ident_pmd_init(struct x86_mapping_info *info, pmd_t *pmd_page,
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unsigned long addr, unsigned long end)
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{
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addr &= PMD_MASK;
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for (; addr < end; addr += PMD_SIZE) {
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pmd_t *pmd = pmd_page + pmd_index(addr);
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if (pmd_present(*pmd))
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continue;
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set_pmd(pmd, __pmd((addr - info->offset) | info->page_flag));
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}
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}
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static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
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unsigned long addr, unsigned long end)
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{
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unsigned long next;
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for (; addr < end; addr = next) {
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pud_t *pud = pud_page + pud_index(addr);
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pmd_t *pmd;
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next = (addr & PUD_MASK) + PUD_SIZE;
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if (next > end)
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next = end;
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if (info->direct_gbpages) {
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pud_t pudval;
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if (pud_present(*pud))
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continue;
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addr &= PUD_MASK;
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pudval = __pud((addr - info->offset) | info->page_flag);
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set_pud(pud, pudval);
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continue;
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}
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if (pud_present(*pud)) {
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pmd = pmd_offset(pud, 0);
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ident_pmd_init(info, pmd, addr, next);
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continue;
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}
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pmd = (pmd_t *)info->alloc_pgt_page(info->context);
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if (!pmd)
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return -ENOMEM;
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ident_pmd_init(info, pmd, addr, next);
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set_pud(pud, __pud(__pa(pmd) | info->kernpg_flag));
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}
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return 0;
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}
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static int ident_p4d_init(struct x86_mapping_info *info, p4d_t *p4d_page,
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unsigned long addr, unsigned long end)
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{
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unsigned long next;
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for (; addr < end; addr = next) {
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p4d_t *p4d = p4d_page + p4d_index(addr);
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pud_t *pud;
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next = (addr & P4D_MASK) + P4D_SIZE;
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if (next > end)
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next = end;
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if (p4d_present(*p4d)) {
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pud = pud_offset(p4d, 0);
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ident_pud_init(info, pud, addr, next);
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continue;
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}
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pud = (pud_t *)info->alloc_pgt_page(info->context);
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if (!pud)
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return -ENOMEM;
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ident_pud_init(info, pud, addr, next);
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set_p4d(p4d, __p4d(__pa(pud) | info->kernpg_flag));
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}
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return 0;
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}
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int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
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unsigned long pstart, unsigned long pend)
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{
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unsigned long addr = pstart + info->offset;
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unsigned long end = pend + info->offset;
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unsigned long next;
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int result;
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/* Set the default pagetable flags if not supplied */
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if (!info->kernpg_flag)
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info->kernpg_flag = _KERNPG_TABLE;
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for (; addr < end; addr = next) {
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pgd_t *pgd = pgd_page + pgd_index(addr);
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p4d_t *p4d;
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next = (addr & PGDIR_MASK) + PGDIR_SIZE;
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if (next > end)
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next = end;
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if (pgd_present(*pgd)) {
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p4d = p4d_offset(pgd, 0);
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result = ident_p4d_init(info, p4d, addr, next);
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if (result)
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return result;
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continue;
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}
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p4d = (p4d_t *)info->alloc_pgt_page(info->context);
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if (!p4d)
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return -ENOMEM;
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result = ident_p4d_init(info, p4d, addr, next);
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if (result)
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return result;
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if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
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set_pgd(pgd, __pgd(__pa(p4d) | info->kernpg_flag));
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} else {
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/*
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* With p4d folded, pgd is equal to p4d.
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* The pgd entry has to point to the pud page table in this case.
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*/
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pud_t *pud = pud_offset(p4d, 0);
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set_pgd(pgd, __pgd(__pa(pud) | info->kernpg_flag));
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}
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}
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return 0;
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}
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