From: Joerg Roedel <joro@8bytes.org>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@intel.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Juergen Gross <jgross@suse.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>, Jiri Kosina <jkosina@suse.cz>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Brian Gerst <brgerst@gmail.com>,
David Laight <David.Laight@aculab.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
Eduardo Valentin <eduval@amazon.com>,
Greg KH <gregkh@linuxfoundation.org>,
Will Deacon <will.deacon@arm.com>,
aliguori@amazon.com, daniel.gruss@iaik.tugraz.at,
hughd@google.com, keescook@google.com,
Andrea Arcangeli <aarcange@redhat.com>,
Waiman Long <llong@redhat.com>, Pavel Machek <pavel@ucw.cz>,
"David H . Gutteridge" <dhgutteridge@sympatico.ca>,
jroedel@suse.de, joro@8bytes.org
Subject: [PATCH 35/39] x86/ldt: Split out sanity check in map_ldt_struct()
Date: Wed, 18 Jul 2018 11:41:12 +0200 [thread overview]
Message-ID: <1531906876-13451-36-git-send-email-joro@8bytes.org> (raw)
In-Reply-To: <1531906876-13451-1-git-send-email-joro@8bytes.org>
From: Joerg Roedel <jroedel@suse.de>
This splits out the mapping sanity check and the actual
mapping of the LDT to user-space from the map_ldt_struct()
function in a way so that it is re-usable for PAE paging.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kernel/ldt.c | 82 ++++++++++++++++++++++++++++++++++++---------------
1 file changed, 58 insertions(+), 24 deletions(-)
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index e921b3d..69af9a0 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -100,6 +100,49 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int num_entries)
return new_ldt;
}
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+
+static void do_sanity_check(struct mm_struct *mm,
+ bool had_kernel_mapping,
+ bool had_user_mapping)
+{
+ if (mm->context.ldt) {
+ /*
+ * We already had an LDT. The top-level entry should already
+ * have been allocated and synchronized with the usermode
+ * tables.
+ */
+ WARN_ON(!had_kernel_mapping);
+ if (static_cpu_has(X86_FEATURE_PTI))
+ WARN_ON(!had_user_mapping);
+ } else {
+ /*
+ * This is the first time we're mapping an LDT for this process.
+ * Sync the pgd to the usermode tables.
+ */
+ WARN_ON(had_kernel_mapping);
+ if (static_cpu_has(X86_FEATURE_PTI))
+ WARN_ON(had_user_mapping);
+ }
+}
+
+static void map_ldt_struct_to_user(struct mm_struct *mm)
+{
+ pgd_t *pgd = pgd_offset(mm, LDT_BASE_ADDR);
+
+ if (static_cpu_has(X86_FEATURE_PTI) && !mm->context.ldt)
+ set_pgd(kernel_to_user_pgdp(pgd), *pgd);
+}
+
+static void sanity_check_ldt_mapping(struct mm_struct *mm)
+{
+ pgd_t *pgd = pgd_offset(mm, LDT_BASE_ADDR);
+ bool had_kernel = (pgd->pgd != 0);
+ bool had_user = (kernel_to_user_pgdp(pgd)->pgd != 0);
+
+ do_sanity_check(mm, had_kernel, had_user);
+}
+
/*
* If PTI is enabled, this maps the LDT into the kernelmode and
* usermode tables for the given mm.
@@ -115,9 +158,8 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int num_entries)
static int
map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot)
{
-#ifdef CONFIG_PAGE_TABLE_ISOLATION
- bool is_vmalloc, had_top_level_entry;
unsigned long va;
+ bool is_vmalloc;
spinlock_t *ptl;
pgd_t *pgd;
int i;
@@ -131,13 +173,15 @@ map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot)
*/
WARN_ON(ldt->slot != -1);
+ /* Check if the current mappings are sane */
+ sanity_check_ldt_mapping(mm);
+
/*
* Did we already have the top level entry allocated? We can't
* use pgd_none() for this because it doens't do anything on
* 4-level page table kernels.
*/
pgd = pgd_offset(mm, LDT_BASE_ADDR);
- had_top_level_entry = (pgd->pgd != 0);
is_vmalloc = is_vmalloc_addr(ldt->entries);
@@ -172,35 +216,25 @@ map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot)
pte_unmap_unlock(ptep, ptl);
}
- if (mm->context.ldt) {
- /*
- * We already had an LDT. The top-level entry should already
- * have been allocated and synchronized with the usermode
- * tables.
- */
- WARN_ON(!had_top_level_entry);
- if (static_cpu_has(X86_FEATURE_PTI))
- WARN_ON(!kernel_to_user_pgdp(pgd)->pgd);
- } else {
- /*
- * This is the first time we're mapping an LDT for this process.
- * Sync the pgd to the usermode tables.
- */
- WARN_ON(had_top_level_entry);
- if (static_cpu_has(X86_FEATURE_PTI)) {
- WARN_ON(kernel_to_user_pgdp(pgd)->pgd);
- set_pgd(kernel_to_user_pgdp(pgd), *pgd);
- }
- }
+ /* Propagate LDT mapping to the user page-table */
+ map_ldt_struct_to_user(mm);
va = (unsigned long)ldt_slot_va(slot);
flush_tlb_mm_range(mm, va, va + LDT_SLOT_STRIDE, 0);
ldt->slot = slot;
-#endif
return 0;
}
+#else /* !CONFIG_PAGE_TABLE_ISOLATION */
+
+static int
+map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot)
+{
+ return 0;
+}
+#endif /* CONFIG_PAGE_TABLE_ISOLATION */
+
static void free_ldt_pgtables(struct mm_struct *mm)
{
#ifdef CONFIG_PAGE_TABLE_ISOLATION
--
2.7.4
next prev parent reply other threads:[~2018-07-18 9:41 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-18 9:40 [PATCH 00/39 v8] PTI support for x86-32 Joerg Roedel
2018-07-18 9:40 ` [PATCH 01/39] x86/asm-offsets: Move TSS_sp0 and TSS_sp1 to asm-offsets.c Joerg Roedel
2018-07-18 9:40 ` [PATCH 02/39] x86/entry/32: Rename TSS_sysenter_sp0 to TSS_entry2task_stack Joerg Roedel
2018-07-18 9:40 ` [PATCH 03/39] x86/entry/32: Load task stack from x86_tss.sp1 in SYSENTER handler Joerg Roedel
2018-07-18 9:40 ` [PATCH 04/39] x86/entry/32: Put ESPFIX code into a macro Joerg Roedel
2018-07-18 9:40 ` [PATCH 05/39] x86/entry/32: Unshare NMI return path Joerg Roedel
2018-07-18 9:40 ` [PATCH 06/39] x86/entry/32: Split off return-to-kernel path Joerg Roedel
2018-07-18 9:40 ` [PATCH 07/39] x86/entry/32: Enter the kernel via trampoline stack Joerg Roedel
2018-07-18 18:09 ` Brian Gerst
2018-07-19 20:52 ` Thomas Gleixner
2018-07-18 9:40 ` [PATCH 08/39] x86/entry/32: Leave " Joerg Roedel
2018-07-18 9:40 ` [PATCH 09/39] x86/entry/32: Introduce SAVE_ALL_NMI and RESTORE_ALL_NMI Joerg Roedel
2018-07-18 9:40 ` [PATCH 10/39] x86/entry/32: Handle Entry from Kernel-Mode on Entry-Stack Joerg Roedel
2018-10-12 18:29 ` Jan Kiszka
2018-10-13 9:54 ` [PATCH] x86/entry/32: Fix setup of CS high bits Jan Kiszka
2018-10-13 15:12 ` Andy Lutomirski
2018-10-15 13:08 ` Jan Kiszka
2018-10-15 13:14 ` David Laight
2018-10-15 13:18 ` Jan Kiszka
2018-10-15 13:29 ` David Laight
2018-10-15 9:10 ` Joerg Roedel
2018-10-15 14:09 ` [PATCH v2] " Jan Kiszka
2018-10-15 15:09 ` [tip:x86/urgent] x86/entry/32: Clear the " tip-bot for Jan Kiszka
2018-10-18 6:21 ` tip-bot for Jan Kiszka
2018-07-18 9:40 ` [PATCH 11/39] x86/entry/32: Simplify debug entry point Joerg Roedel
2018-07-18 9:40 ` [PATCH 12/39] x86/entry/32: Add PTI cr3 switch to non-NMI entry/exit points Joerg Roedel
2018-07-18 9:40 ` [PATCH 13/39] x86/entry/32: Add PTI cr3 switches to NMI handler code Joerg Roedel
2018-07-18 9:40 ` [PATCH 14/39] x86/entry: Rename update_sp0 to update_task_stack Joerg Roedel
2018-07-18 9:40 ` [PATCH 15/39] x86/pgtable: Rename pti_set_user_pgd to pti_set_user_pgtbl Joerg Roedel
2018-07-18 9:40 ` [PATCH 16/39] x86/pgtable/pae: Unshare kernel PMDs when PTI is enabled Joerg Roedel
2018-07-18 9:40 ` [PATCH 17/39] x86/pgtable/32: Allocate 8k page-tables " Joerg Roedel
2018-07-18 9:40 ` [PATCH 18/39] x86/pgtable: Move pgdp kernel/user conversion functions to pgtable.h Joerg Roedel
2018-07-18 9:40 ` [PATCH 19/39] x86/pgtable: Move pti_set_user_pgtbl() " Joerg Roedel
2018-07-18 9:40 ` [PATCH 20/39] x86/pgtable: Move two more functions from pgtable_64.h " Joerg Roedel
2018-07-18 9:40 ` [PATCH 21/39] x86/mm/pae: Populate valid user PGD entries Joerg Roedel
2018-07-18 9:40 ` [PATCH 22/39] x86/mm/pae: Populate the user page-table with user pgd's Joerg Roedel
2018-07-18 9:41 ` [PATCH 23/39] x86/mm/legacy: " Joerg Roedel
2018-07-18 9:41 ` [PATCH 24/39] x86/mm/pti: Add an overflow check to pti_clone_pmds() Joerg Roedel
2018-07-18 9:41 ` [PATCH 25/39] x86/mm/pti: Define X86_CR3_PTI_PCID_USER_BIT on x86_32 Joerg Roedel
2018-07-18 9:41 ` [PATCH 26/39] x86/mm/pti: Clone CPU_ENTRY_AREA on PMD level " Joerg Roedel
2018-07-18 9:41 ` [PATCH 27/39] x86/mm/pti: Make pti_clone_kernel_text() compile on 32 bit Joerg Roedel
2018-07-18 9:41 ` [PATCH 28/39] x86/mm/pti: Keep permissions when cloning kernel text in pti_clone_kernel_text() Joerg Roedel
2018-07-18 9:41 ` [PATCH 29/39] x86/mm/pti: Introduce pti_finalize() Joerg Roedel
2018-07-18 9:41 ` [PATCH 30/39] x86/mm/pti: Clone entry-text again in pti_finalize() Joerg Roedel
2018-07-18 9:41 ` [PATCH 31/39] x86/mm/dump_pagetables: Define INIT_PGD Joerg Roedel
2018-07-18 9:41 ` [PATCH 32/39] x86/pgtable/pae: Use separate kernel PMDs for user page-table Joerg Roedel
2018-10-05 14:06 ` Arnd Bergmann
2018-07-18 9:41 ` [PATCH 33/39] x86/ldt: Reserve address-space range on 32 bit for the LDT Joerg Roedel
2018-07-18 9:41 ` [PATCH 34/39] x86/ldt: Define LDT_END_ADDR Joerg Roedel
2018-07-18 9:41 ` Joerg Roedel [this message]
2018-07-18 9:41 ` [PATCH 36/39] x86/ldt: Enable LDT user-mapping for PAE Joerg Roedel
2018-07-18 9:41 ` [PATCH 37/39] x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32 Joerg Roedel
2018-07-18 9:41 ` [PATCH 38/39] x86/mm/pti: Add Warning when booting on a PCID capable CPU Joerg Roedel
2018-07-18 9:41 ` [PATCH 39/39] x86/entry/32: Add debug code to check entry/exit cr3 Joerg Roedel
2018-07-18 11:59 ` [PATCH 00/39 v8] PTI support for x86-32 Pavel Machek
2018-07-19 23:21 ` Thomas Gleixner
2018-07-20 7:59 ` Joerg Roedel
-- strict thread matches above, loose matches on Subject: below --
2018-07-11 11:29 [PATCH 00/39 v7] " Joerg Roedel
2018-07-11 11:29 ` [PATCH 35/39] x86/ldt: Split out sanity check in map_ldt_struct() Joerg Roedel
2018-07-13 23:18 ` Andy Lutomirski
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