Messages in this thread Patch in this message | | | Date | Wed, 31 May 2017 19:08:11 +0200 | From | Borislav Petkov <> | Subject | [RFC PATCH] x86/ldt: Rename ldr_struct.size to .n_entries |
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Hey guys,
do you have anything against the below renaming?
ldt->size is simply confusing while it wants to be called ldt->n_entries as it is used like this throughout the code.
Let me know before I go and run it to check I'm not breaking anything.
Thanks!
--- ... 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 "n_entries" or somesuch 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.
Signed-off-by: Borislav Petkov <bp@suse.de> --- arch/x86/events/core.c | 2 +- arch/x86/include/asm/mmu_context.h | 4 ++-- arch/x86/kernel/ldt.c | 38 +++++++++++++++++++------------------- arch/x86/kernel/process_64.c | 2 +- arch/x86/kernel/step.c | 2 +- 5 files changed, 24 insertions(+), 24 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 637feed9a594..82c3083f53b3 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2343,7 +2343,7 @@ 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->n_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 68b329d77b3a..872e94933b9b 100644 --- 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 n_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->n_entries); else clear_LDT(); #else diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c index d4a15831ac58..da2184f3d100 100644 --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -30,16 +30,16 @@ static void flush_ldt(void *current_mm) return; pc = ¤t->active_mm->context; - set_ldt(pc->ldt->entries, pc->ldt->size); + set_ldt(pc->ldt->entries, pc->ldt->n_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); @@ -47,7 +47,7 @@ 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 @@ -65,14 +65,14 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int size) return NULL; } - new_ldt->size = size; + new_ldt->n_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->n_entries); } /* context.lock is held */ @@ -91,8 +91,8 @@ 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->n_entries); + if (ldt->n_entries * LDT_ENTRY_SIZE > PAGE_SIZE) vfree_atomic(ldt->entries); else free_page((unsigned long)ldt->entries); @@ -122,14 +122,14 @@ 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->n_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->n_entries * LDT_ENTRY_SIZE); finalize_ldt_struct(new_ldt); mm->context.ldt = new_ldt; @@ -152,9 +152,9 @@ 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 num_entries; + int retval; mutex_lock(&mm->context.lock); @@ -166,18 +166,18 @@ 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; + num_entries = mm->context.ldt->n_entries * LDT_ENTRY_SIZE; + if (num_entries > bytecount) + num_entries = bytecount; - if (copy_to_user(ptr, mm->context.ldt->entries, size)) { + if (copy_to_user(ptr, mm->context.ldt->entries, num_entries)) { retval = -EFAULT; goto out_unlock; } - if (size != bytecount) { + if (num_entries != bytecount) { /* Zero-fill the rest and pretend we read bytecount bytes. */ - if (clear_user(ptr + size, bytecount - size)) { + if (clear_user(ptr + num_entries, bytecount - num_entries)) { retval = -EFAULT; goto out_unlock; } @@ -248,7 +248,7 @@ 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; + oldsize = old_ldt ? old_ldt->n_entries : 0; newsize = max(ldt_info.entry_number + 1, oldsize); error = -ENOMEM; diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index b6840bf3940b..95c76edc4587 100644 --- 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->n_entries); BUG(); } #endif diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index f07f83b3611b..59b8b9470ed6 100644 --- 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->n_entries)) addr = -1L; /* bogus selector, access would fault */ else { desc = &child->mm->context.ldt->entries[seg]; -- 2.13.0
-- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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