x86/ldt: Rename ldt_struct::size to ::nr_entries

... because this is exactly what it is: the number of entries in the
LDT. Calling it "size" is simply confusing and it is actually begging
to be called "nr_entries" or somesuch, especially if you see constructs
like:

	alloc_size = size * LDT_ENTRY_SIZE;

since LDT_ENTRY_SIZE is the size of a single entry.

There should be no functionality change resulting from this patch, as
the before/after output from tools/testing/selftests/x86/ldt_gdt.c
shows.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170606173116.13977-1-bp@alien8.de
[ Renamed 'n_entries' to 'nr_entries' ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 77a3309..d4d5e1e 100644 (file)
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2333,7 +2333,7 @@ static unsigned long get_segment_base(unsigned int segment)
 
                /* IRQs are off, so this synchronizes with smp_store_release */
                ldt = lockless_dereference(current->active_mm->context.ldt);
-               if (!ldt || idx > ldt->size)
+               if (!ldt || idx > ldt->nr_entries)
                        return 0;
 
                desc = &ldt->entries[idx];

diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index f20d7ea..5a93f62 100644 (file)
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -47,7 +47,7 @@ struct ldt_struct {
         * allocations, but it's not worth trying to optimize.
         */
        struct desc_struct *entries;
-       unsigned int size;
+       unsigned int nr_entries;
 };
 
 /*
@@ -87,7 +87,7 @@ static inline void load_mm_ldt(struct mm_struct *mm)
         */
 
        if (unlikely(ldt))
-               set_ldt(ldt->entries, ldt->size);
+               set_ldt(ldt->entries, ldt->nr_entries);
        else
                clear_LDT();
 #else

diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index de503e7..a870910 100644 (file)
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -31,16 +31,16 @@ static void flush_ldt(void *__mm)
                return;
 
        pc = &mm->context;
-       set_ldt(pc->ldt->entries, pc->ldt->size);
+       set_ldt(pc->ldt->entries, pc->ldt->nr_entries);
 }
 
 /* The caller must call finalize_ldt_struct on the result. LDT starts zeroed. */
-static struct ldt_struct *alloc_ldt_struct(unsigned int size)
+static struct ldt_struct *alloc_ldt_struct(unsigned int num_entries)
 {
        struct ldt_struct *new_ldt;
        unsigned int alloc_size;
 
-       if (size > LDT_ENTRIES)
+       if (num_entries > LDT_ENTRIES)
                return NULL;
 
        new_ldt = kmalloc(sizeof(struct ldt_struct), GFP_KERNEL);
@@ -48,7 +48,7 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int size)
                return NULL;
 
        BUILD_BUG_ON(LDT_ENTRY_SIZE != sizeof(struct desc_struct));
-       alloc_size = size * LDT_ENTRY_SIZE;
+       alloc_size = num_entries * LDT_ENTRY_SIZE;
 
        /*
         * Xen is very picky: it requires a page-aligned LDT that has no
@@ -66,14 +66,14 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int size)
                return NULL;
        }
 
-       new_ldt->size = size;
+       new_ldt->nr_entries = num_entries;
        return new_ldt;
 }
 
 /* After calling this, the LDT is immutable. */
 static void finalize_ldt_struct(struct ldt_struct *ldt)
 {
-       paravirt_alloc_ldt(ldt->entries, ldt->size);
+       paravirt_alloc_ldt(ldt->entries, ldt->nr_entries);
 }
 
 /* context.lock is held */
@@ -92,8 +92,8 @@ static void free_ldt_struct(struct ldt_struct *ldt)
        if (likely(!ldt))
                return;
 
-       paravirt_free_ldt(ldt->entries, ldt->size);
-       if (ldt->size * LDT_ENTRY_SIZE > PAGE_SIZE)
+       paravirt_free_ldt(ldt->entries, ldt->nr_entries);
+       if (ldt->nr_entries * LDT_ENTRY_SIZE > PAGE_SIZE)
                vfree_atomic(ldt->entries);
        else
                free_page((unsigned long)ldt->entries);
@@ -123,14 +123,14 @@ int init_new_context_ldt(struct task_struct *tsk, struct mm_struct *mm)
                goto out_unlock;
        }
 
-       new_ldt = alloc_ldt_struct(old_mm->context.ldt->size);
+       new_ldt = alloc_ldt_struct(old_mm->context.ldt->nr_entries);
        if (!new_ldt) {
                retval = -ENOMEM;
                goto out_unlock;
        }
 
        memcpy(new_ldt->entries, old_mm->context.ldt->entries,
-              new_ldt->size * LDT_ENTRY_SIZE);
+              new_ldt->nr_entries * LDT_ENTRY_SIZE);
        finalize_ldt_struct(new_ldt);
 
        mm->context.ldt = new_ldt;
@@ -153,9 +153,9 @@ void destroy_context_ldt(struct mm_struct *mm)
 
 static int read_ldt(void __user *ptr, unsigned long bytecount)
 {
-       int retval;
-       unsigned long size;
        struct mm_struct *mm = current->mm;
+       unsigned long entries_size;
+       int retval;
 
        mutex_lock(&mm->context.lock);
 
@@ -167,18 +167,18 @@ static int read_ldt(void __user *ptr, unsigned long bytecount)
        if (bytecount > LDT_ENTRY_SIZE * LDT_ENTRIES)
                bytecount = LDT_ENTRY_SIZE * LDT_ENTRIES;
 
-       size = mm->context.ldt->size * LDT_ENTRY_SIZE;
-       if (size > bytecount)
-               size = bytecount;
+       entries_size = mm->context.ldt->nr_entries * LDT_ENTRY_SIZE;
+       if (entries_size > bytecount)
+               entries_size = bytecount;
 
-       if (copy_to_user(ptr, mm->context.ldt->entries, size)) {
+       if (copy_to_user(ptr, mm->context.ldt->entries, entries_size)) {
                retval = -EFAULT;
                goto out_unlock;
        }
 
-       if (size != bytecount) {
+       if (entries_size != bytecount) {
                /* Zero-fill the rest and pretend we read bytecount bytes. */
-               if (clear_user(ptr + size, bytecount - size)) {
+               if (clear_user(ptr + entries_size, bytecount - entries_size)) {
                        retval = -EFAULT;
                        goto out_unlock;
                }
@@ -209,7 +209,7 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
 {
        struct mm_struct *mm = current->mm;
        struct ldt_struct *new_ldt, *old_ldt;
-       unsigned int oldsize, newsize;
+       unsigned int old_nr_entries, new_nr_entries;
        struct user_desc ldt_info;
        struct desc_struct ldt;
        int error;
@@ -248,17 +248,18 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
 
        mutex_lock(&mm->context.lock);
 
-       old_ldt = mm->context.ldt;
-       oldsize = old_ldt ? old_ldt->size : 0;
-       newsize = max(ldt_info.entry_number + 1, oldsize);
+       old_ldt       = mm->context.ldt;
+       old_nr_entries = old_ldt ? old_ldt->nr_entries : 0;
+       new_nr_entries = max(ldt_info.entry_number + 1, old_nr_entries);
 
        error = -ENOMEM;
-       new_ldt = alloc_ldt_struct(newsize);
+       new_ldt = alloc_ldt_struct(new_nr_entries);
        if (!new_ldt)
                goto out_unlock;
 
        if (old_ldt)
-               memcpy(new_ldt->entries, old_ldt->entries, oldsize * LDT_ENTRY_SIZE);
+               memcpy(new_ldt->entries, old_ldt->entries, old_nr_entries * LDT_ENTRY_SIZE);
+
        new_ldt->entries[ldt_info.entry_number] = ldt;
        finalize_ldt_struct(new_ldt);
 

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index b6840bf..9c39ab8 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -142,7 +142,7 @@ void release_thread(struct task_struct *dead_task)
                        pr_warn("WARNING: dead process %s still has LDT? <%p/%d>\n",
                                dead_task->comm,
                                dead_task->mm->context.ldt->entries,
-                               dead_task->mm->context.ldt->size);
+                               dead_task->mm->context.ldt->nr_entries);
                        BUG();
                }
 #endif

diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index f07f83b..5f25cfb 100644 (file)
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -34,7 +34,7 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re
 
                mutex_lock(&child->mm->context.lock);
                if (unlikely(!child->mm->context.ldt ||
-                            seg >= child->mm->context.ldt->size))
+                            seg >= child->mm->context.ldt->nr_entries))
                        addr = -1L; /* bogus selector, access would fault */
                else {
                        desc = &child->mm->context.ldt->entries[seg];

diff --git a/arch/x86/math-emu/fpu_system.h b/arch/x86/math-emu/fpu_system.h
index 5e044d5..a179254 100644 (file)
--- a/arch/x86/math-emu/fpu_system.h
+++ b/arch/x86/math-emu/fpu_system.h
@@ -27,7 +27,7 @@ static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg)
 #ifdef CONFIG_MODIFY_LDT_SYSCALL
        seg >>= 3;
        mutex_lock(&current->mm->context.lock);
-       if (current->mm->context.ldt && seg < current->mm->context.ldt->size)
+       if (current->mm->context.ldt && seg < current->mm->context.ldt->nr_entries)
                ret = current->mm->context.ldt->entries[seg];
        mutex_unlock(&current->mm->context.lock);
 #endif