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-rw-r--r--arch/um/Makefile1
-rw-r--r--arch/um/drivers/rtc_user.c2
-rw-r--r--arch/um/drivers/ubd_user.c2
-rw-r--r--arch/um/drivers/vector_kern.c42
-rw-r--r--arch/um/include/asm/asm-prototypes.h5
-rw-r--r--arch/um/include/asm/thread_info.h4
-rw-r--r--arch/um/kernel/mem.c1
-rw-r--r--arch/um/kernel/process.c20
-rw-r--r--arch/um/kernel/trap.c129
9 files changed, 155 insertions, 51 deletions
diff --git a/arch/um/Makefile b/arch/um/Makefile
index 00b63bac5eff..3317d87e2092 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -151,5 +151,6 @@ MRPROPER_FILES += $(HOST_DIR)/include/generated
archclean:
@find . \( -name '*.bb' -o -name '*.bbg' -o -name '*.da' \
-o -name '*.gcov' \) -type f -print | xargs rm -f
+ $(Q)$(MAKE) -f $(srctree)/Makefile ARCH=$(HEADER_ARCH) clean
export HEADER_ARCH SUBARCH USER_CFLAGS CFLAGS_NO_HARDENING DEV_NULL_PATH
diff --git a/arch/um/drivers/rtc_user.c b/arch/um/drivers/rtc_user.c
index 7c3cec4c68cf..006a5a164ea9 100644
--- a/arch/um/drivers/rtc_user.c
+++ b/arch/um/drivers/rtc_user.c
@@ -28,7 +28,7 @@ int uml_rtc_start(bool timetravel)
int err;
if (timetravel) {
- int err = os_pipe(uml_rtc_irq_fds, 1, 1);
+ err = os_pipe(uml_rtc_irq_fds, 1, 1);
if (err)
goto fail;
} else {
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index b4f8b8e60564..592b899820d6 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -41,7 +41,7 @@ int start_io_thread(unsigned long sp, int *fd_out)
*fd_out = fds[1];
err = os_set_fd_block(*fd_out, 0);
- err = os_set_fd_block(kernel_fd, 0);
+ err |= os_set_fd_block(kernel_fd, 0);
if (err) {
printk("start_io_thread - failed to set nonblocking I/O.\n");
goto out_close;
diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
index 64c09db392c1..7a88b13d289f 100644
--- a/arch/um/drivers/vector_kern.c
+++ b/arch/um/drivers/vector_kern.c
@@ -1592,35 +1592,19 @@ static void vector_eth_configure(
device->dev = dev;
- *vp = ((struct vector_private)
- {
- .list = LIST_HEAD_INIT(vp->list),
- .dev = dev,
- .unit = n,
- .options = get_transport_options(def),
- .rx_irq = 0,
- .tx_irq = 0,
- .parsed = def,
- .max_packet = get_mtu(def) + ETH_HEADER_OTHER,
- /* TODO - we need to calculate headroom so that ip header
- * is 16 byte aligned all the time
- */
- .headroom = get_headroom(def),
- .form_header = NULL,
- .verify_header = NULL,
- .header_rxbuffer = NULL,
- .header_txbuffer = NULL,
- .header_size = 0,
- .rx_header_size = 0,
- .rexmit_scheduled = false,
- .opened = false,
- .transport_data = NULL,
- .in_write_poll = false,
- .coalesce = 2,
- .req_size = get_req_size(def),
- .in_error = false,
- .bpf = NULL
- });
+ INIT_LIST_HEAD(&vp->list);
+ vp->dev = dev;
+ vp->unit = n;
+ vp->options = get_transport_options(def);
+ vp->parsed = def;
+ vp->max_packet = get_mtu(def) + ETH_HEADER_OTHER;
+ /*
+ * TODO - we need to calculate headroom so that ip header
+ * is 16 byte aligned all the time
+ */
+ vp->headroom = get_headroom(def);
+ vp->coalesce = 2;
+ vp->req_size = get_req_size(def);
dev->features = dev->hw_features = (NETIF_F_SG | NETIF_F_FRAGLIST);
INIT_WORK(&vp->reset_tx, vector_reset_tx);
diff --git a/arch/um/include/asm/asm-prototypes.h b/arch/um/include/asm/asm-prototypes.h
index 5898a26daa0d..408b31d59127 100644
--- a/arch/um/include/asm/asm-prototypes.h
+++ b/arch/um/include/asm/asm-prototypes.h
@@ -1 +1,6 @@
#include <asm-generic/asm-prototypes.h>
+#include <asm/checksum.h>
+
+#ifdef CONFIG_UML_X86
+extern void cmpxchg8b_emu(void);
+#endif
diff --git a/arch/um/include/asm/thread_info.h b/arch/um/include/asm/thread_info.h
index c7b4b49826a2..40d823f36c09 100644
--- a/arch/um/include/asm/thread_info.h
+++ b/arch/um/include/asm/thread_info.h
@@ -68,7 +68,11 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
#define _TIF_MEMDIE (1 << TIF_MEMDIE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
+#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
+#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL | \
+ _TIF_NOTIFY_RESUME)
+
#endif
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index a5b4fe2ad931..6ca9ea4a230b 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -70,6 +70,7 @@ void __init mem_init(void)
map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
memblock_free((void *)brk_end, uml_reserved - brk_end);
uml_reserved = brk_end;
+ min_low_pfn = PFN_UP(__pa(uml_reserved));
/* this will put all low memory onto the freelists */
memblock_free_all();
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 9c6cf03ed02b..eaeeedd62930 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -81,14 +81,18 @@ struct task_struct *__switch_to(struct task_struct *from, struct task_struct *to
void interrupt_end(void)
{
struct pt_regs *regs = &current->thread.regs;
-
- if (need_resched())
- schedule();
- if (test_thread_flag(TIF_SIGPENDING) ||
- test_thread_flag(TIF_NOTIFY_SIGNAL))
- do_signal(regs);
- if (test_thread_flag(TIF_NOTIFY_RESUME))
- resume_user_mode_work(regs);
+ unsigned long thread_flags;
+
+ thread_flags = read_thread_flags();
+ while (thread_flags & _TIF_WORK_MASK) {
+ if (thread_flags & _TIF_NEED_RESCHED)
+ schedule();
+ if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
+ do_signal(regs);
+ if (thread_flags & _TIF_NOTIFY_RESUME)
+ resume_user_mode_work(regs);
+ thread_flags = read_thread_flags();
+ }
}
int get_current_pid(void)
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 97c8df9c4401..9077bdb26cc3 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -18,6 +18,122 @@
#include <skas.h>
/*
+ * NOTE: UML does not have exception tables. As such, this is almost a copy
+ * of the code in mm/memory.c, only adjusting the logic to simply check whether
+ * we are coming from the kernel instead of doing an additional lookup in the
+ * exception table.
+ * We can do this simplification because we never get here if the exception was
+ * fixable.
+ */
+static inline bool get_mmap_lock_carefully(struct mm_struct *mm, bool is_user)
+{
+ if (likely(mmap_read_trylock(mm)))
+ return true;
+
+ if (!is_user)
+ return false;
+
+ return !mmap_read_lock_killable(mm);
+}
+
+static inline bool mmap_upgrade_trylock(struct mm_struct *mm)
+{
+ /*
+ * We don't have this operation yet.
+ *
+ * It should be easy enough to do: it's basically a
+ * atomic_long_try_cmpxchg_acquire()
+ * from RWSEM_READER_BIAS -> RWSEM_WRITER_LOCKED, but
+ * it also needs the proper lockdep magic etc.
+ */
+ return false;
+}
+
+static inline bool upgrade_mmap_lock_carefully(struct mm_struct *mm, bool is_user)
+{
+ mmap_read_unlock(mm);
+ if (!is_user)
+ return false;
+
+ return !mmap_write_lock_killable(mm);
+}
+
+/*
+ * Helper for page fault handling.
+ *
+ * This is kind of equivalend to "mmap_read_lock()" followed
+ * by "find_extend_vma()", except it's a lot more careful about
+ * the locking (and will drop the lock on failure).
+ *
+ * For example, if we have a kernel bug that causes a page
+ * fault, we don't want to just use mmap_read_lock() to get
+ * the mm lock, because that would deadlock if the bug were
+ * to happen while we're holding the mm lock for writing.
+ *
+ * So this checks the exception tables on kernel faults in
+ * order to only do this all for instructions that are actually
+ * expected to fault.
+ *
+ * We can also actually take the mm lock for writing if we
+ * need to extend the vma, which helps the VM layer a lot.
+ */
+static struct vm_area_struct *
+um_lock_mm_and_find_vma(struct mm_struct *mm,
+ unsigned long addr, bool is_user)
+{
+ struct vm_area_struct *vma;
+
+ if (!get_mmap_lock_carefully(mm, is_user))
+ return NULL;
+
+ vma = find_vma(mm, addr);
+ if (likely(vma && (vma->vm_start <= addr)))
+ return vma;
+
+ /*
+ * Well, dang. We might still be successful, but only
+ * if we can extend a vma to do so.
+ */
+ if (!vma || !(vma->vm_flags & VM_GROWSDOWN)) {
+ mmap_read_unlock(mm);
+ return NULL;
+ }
+
+ /*
+ * We can try to upgrade the mmap lock atomically,
+ * in which case we can continue to use the vma
+ * we already looked up.
+ *
+ * Otherwise we'll have to drop the mmap lock and
+ * re-take it, and also look up the vma again,
+ * re-checking it.
+ */
+ if (!mmap_upgrade_trylock(mm)) {
+ if (!upgrade_mmap_lock_carefully(mm, is_user))
+ return NULL;
+
+ vma = find_vma(mm, addr);
+ if (!vma)
+ goto fail;
+ if (vma->vm_start <= addr)
+ goto success;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ goto fail;
+ }
+
+ if (expand_stack_locked(vma, addr))
+ goto fail;
+
+success:
+ mmap_write_downgrade(mm);
+ return vma;
+
+fail:
+ mmap_write_unlock(mm);
+ return NULL;
+}
+
+/*
* Note this is constrained to return 0, -EFAULT, -EACCES, -ENOMEM by
* segv().
*/
@@ -43,21 +159,10 @@ int handle_page_fault(unsigned long address, unsigned long ip,
if (is_user)
flags |= FAULT_FLAG_USER;
retry:
- mmap_read_lock(mm);
- vma = find_vma(mm, address);
- if (!vma)
- goto out;
- if (vma->vm_start <= address)
- goto good_area;
- if (!(vma->vm_flags & VM_GROWSDOWN))
- goto out;
- if (is_user && !ARCH_IS_STACKGROW(address))
- goto out;
- vma = expand_stack(mm, address);
+ vma = um_lock_mm_and_find_vma(mm, address, is_user);
if (!vma)
goto out_nosemaphore;
-good_area:
*code_out = SEGV_ACCERR;
if (is_write) {
if (!(vma->vm_flags & VM_WRITE))
generated by cgit v1.2.3 (git 2.39.0) at 2025-08-21 06:18:02 +0300