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authorLinus Torvalds <torvalds@linux-foundation.org>2024-07-25 12:33:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-07-25 12:33:08 -0700
commitf9bcc61ad1fbe7dbc6bdd71d31254e429100a009 (patch)
tree3b35885ba936318985bf6a21339173750e9fdeb7 /arch/um/include/asm
parentc2a96b7f187fb6a455836d4a6e113947ff11de97 (diff)
parent98ff534ec2cd02496c166614e6c1391d8e092e51 (diff)
Merge tag 'uml-for-linus-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux
Pull UML updates from Richard Weinberger: - Support for preemption - i386 Rust support - Huge cleanup by Benjamin Berg - UBSAN support - Removal of dead code * tag 'uml-for-linus-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (41 commits) um: vector: always reset vp->opened um: vector: remove vp->lock um: register power-off handler um: line: always fill *error_out in setup_one_line() um: remove pcap driver from documentation um: Enable preemption in UML um: refactor TLB update handling um: simplify and consolidate TLB updates um: remove force_flush_all from fork_handler um: Do not flush MM in flush_thread um: Delay flushing syscalls until the thread is restarted um: remove copy_context_skas0 um: remove LDT support um: compress memory related stub syscalls while adding them um: Rework syscall handling um: Add generic stub_syscall6 function um: Create signal stack memory assignment in stub_data um: Remove stub-data.h include from common-offsets.h um: time-travel: fix signal blocking race/hang um: time-travel: remove time_exit() ...
Diffstat (limited to 'arch/um/include/asm')
-rw-r--r--arch/um/include/asm/mmu.h10
-rw-r--r--arch/um/include/asm/mmu_context.h2
-rw-r--r--arch/um/include/asm/pgtable.h32
-rw-r--r--arch/um/include/asm/tlbflush.h46
4 files changed, 73 insertions, 17 deletions
diff --git a/arch/um/include/asm/mmu.h b/arch/um/include/asm/mmu.h
index f2923c767bb9..a3eaca41ff61 100644
--- a/arch/um/include/asm/mmu.h
+++ b/arch/um/include/asm/mmu.h
@@ -7,15 +7,13 @@
#define __ARCH_UM_MMU_H
#include <mm_id.h>
-#include <asm/mm_context.h>
typedef struct mm_context {
struct mm_id id;
- struct uml_arch_mm_context arch;
-} mm_context_t;
-/* Avoid tangled inclusion with asm/ldt.h */
-extern long init_new_ldt(struct mm_context *to_mm, struct mm_context *from_mm);
-extern void free_ldt(struct mm_context *mm);
+ /* Address range in need of a TLB sync */
+ unsigned long sync_tlb_range_from;
+ unsigned long sync_tlb_range_to;
+} mm_context_t;
#endif
diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h
index 68e2eb9cfb47..23dcc914d44e 100644
--- a/arch/um/include/asm/mmu_context.h
+++ b/arch/um/include/asm/mmu_context.h
@@ -13,8 +13,6 @@
#include <asm/mm_hooks.h>
#include <asm/mmu.h>
-extern void force_flush_all(void);
-
#define activate_mm activate_mm
static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
{
diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index e1ece21dbe3f..5bb397b65efb 100644
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h
@@ -244,6 +244,38 @@ static inline void set_pte(pte_t *pteptr, pte_t pteval)
#define PFN_PTE_SHIFT PAGE_SHIFT
+static inline void um_tlb_mark_sync(struct mm_struct *mm, unsigned long start,
+ unsigned long end)
+{
+ if (!mm->context.sync_tlb_range_to) {
+ mm->context.sync_tlb_range_from = start;
+ mm->context.sync_tlb_range_to = end;
+ } else {
+ if (start < mm->context.sync_tlb_range_from)
+ mm->context.sync_tlb_range_from = start;
+ if (end > mm->context.sync_tlb_range_to)
+ mm->context.sync_tlb_range_to = end;
+ }
+}
+
+#define set_ptes set_ptes
+static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte, int nr)
+{
+ /* Basically the default implementation */
+ size_t length = nr * PAGE_SIZE;
+
+ for (;;) {
+ set_pte(ptep, pte);
+ if (--nr == 0)
+ break;
+ ptep++;
+ pte = __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT));
+ }
+
+ um_tlb_mark_sync(mm, addr, addr + length);
+}
+
#define __HAVE_ARCH_PTE_SAME
static inline int pte_same(pte_t pte_a, pte_t pte_b)
{
diff --git a/arch/um/include/asm/tlbflush.h b/arch/um/include/asm/tlbflush.h
index a5bda890390d..db997976b6ea 100644
--- a/arch/um/include/asm/tlbflush.h
+++ b/arch/um/include/asm/tlbflush.h
@@ -9,23 +9,51 @@
#include <linux/mm.h>
/*
- * TLB flushing:
+ * In UML, we need to sync the TLB over by using mmap/munmap/mprotect syscalls
+ * from the process handling the MM (which can be the kernel itself).
+ *
+ * To track updates, we can hook into set_ptes and flush_tlb_*. With set_ptes
+ * we catch all PTE transitions where memory that was unusable becomes usable.
+ * While with flush_tlb_* we can track any memory that becomes unusable and
+ * even if a higher layer of the page table was modified.
+ *
+ * So, we simply track updates using both methods and mark the memory area to
+ * be synced later on. The only special case is that flush_tlb_kern_* needs to
+ * be executed immediately as there is no good synchronization point in that
+ * case. In contrast, in the set_ptes case we can wait for the next kernel
+ * segfault before we do the synchornization.
*
- * - flush_tlb() flushes the current mm struct TLBs
* - flush_tlb_all() flushes all processes TLBs
* - flush_tlb_mm(mm) flushes the specified mm context TLB's
* - flush_tlb_page(vma, vmaddr) flushes one page
- * - flush_tlb_kernel_vm() flushes the kernel vm area
* - flush_tlb_range(vma, start, end) flushes a range of pages
+ * - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
*/
+extern int um_tlb_sync(struct mm_struct *mm);
+
extern void flush_tlb_all(void);
extern void flush_tlb_mm(struct mm_struct *mm);
-extern void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
- unsigned long end);
-extern void flush_tlb_page(struct vm_area_struct *vma, unsigned long address);
-extern void flush_tlb_kernel_vm(void);
-extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
-extern void __flush_tlb_one(unsigned long addr);
+
+static inline void flush_tlb_page(struct vm_area_struct *vma,
+ unsigned long address)
+{
+ um_tlb_mark_sync(vma->vm_mm, address, address + PAGE_SIZE);
+}
+
+static inline void flush_tlb_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ um_tlb_mark_sync(vma->vm_mm, start, end);
+}
+
+static inline void flush_tlb_kernel_range(unsigned long start,
+ unsigned long end)
+{
+ um_tlb_mark_sync(&init_mm, start, end);
+
+ /* Kernel needs to be synced immediately */
+ um_tlb_sync(&init_mm);
+}
#endif