From 77e463d1040d6310211ac5162729f5d4afc4dd8c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 30 Jan 2008 13:30:14 +0100 Subject: [PATCH] x86: merge arch/x86/kernel/ldt_32/64.c Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/kernel/Makefile_32 | 2 +- arch/x86/kernel/Makefile_64 | 2 +- arch/x86/kernel/{ldt_64.c => ldt.c} | 25 ++- arch/x86/kernel/ldt_32.c | 253 ---------------------------- 4 files changed, 22 insertions(+), 260 deletions(-) rename arch/x86/kernel/{ldt_64.c => ldt.c} (90%) delete mode 100644 arch/x86/kernel/ldt_32.c diff --git a/arch/x86/kernel/Makefile_32 b/arch/x86/kernel/Makefile_32 index 0cc1981d1e..31ff982bc2 100644 --- a/arch/x86/kernel/Makefile_32 +++ b/arch/x86/kernel/Makefile_32 @@ -6,7 +6,7 @@ extra-y := head_32.o init_task.o vmlinux.lds CPPFLAGS_vmlinux.lds += -Ui386 obj-y := process_32.o signal_32.o entry_32.o traps_32.o irq_32.o \ - ptrace_32.o time_32.o ioport_32.o ldt_32.o setup_32.o i8259_32.o sys_i386_32.o \ + ptrace_32.o time_32.o ioport_32.o ldt.o setup_32.o i8259_32.o sys_i386_32.o \ pci-dma_32.o i386_ksyms_32.o i387_32.o bootflag.o e820_32.o\ quirks.o i8237.o topology.o alternative.o i8253.o tsc_32.o io_delay.o diff --git a/arch/x86/kernel/Makefile_64 b/arch/x86/kernel/Makefile_64 index 08a68f0d8f..9cb3df27c4 100644 --- a/arch/x86/kernel/Makefile_64 +++ b/arch/x86/kernel/Makefile_64 @@ -7,7 +7,7 @@ CPPFLAGS_vmlinux.lds += -Ux86_64 EXTRA_AFLAGS := -traditional obj-y := process_64.o signal_64.o entry_64.o traps_64.o irq_64.o \ - ptrace_64.o time_64.o ioport_64.o ldt_64.o setup_64.o i8259_64.o sys_x86_64.o \ + ptrace_64.o time_64.o ioport_64.o ldt.o setup_64.o i8259_64.o sys_x86_64.o \ x8664_ksyms_64.o i387_64.o syscall_64.o vsyscall_64.o \ setup64.o bootflag.o e820_64.o reboot_64.o quirks.o i8237.o \ pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \ diff --git a/arch/x86/kernel/ldt_64.c b/arch/x86/kernel/ldt.c similarity index 90% rename from arch/x86/kernel/ldt_64.c rename to arch/x86/kernel/ldt.c index 95903938e7..a8cdca3615 100644 --- a/arch/x86/kernel/ldt_64.c +++ b/arch/x86/kernel/ldt.c @@ -50,7 +50,11 @@ static int alloc_ldt(mm_context_t *pc, int mincount, int reload) oldldt = pc->ldt; memset(newldt + oldsize * LDT_ENTRY_SIZE, 0, (mincount - oldsize) * LDT_ENTRY_SIZE); + +#ifdef CONFIG_X86_64 + /* CHECKME: Do we really need this ? */ wmb(); +#endif pc->ldt = newldt; wmb(); pc->size = mincount; @@ -110,11 +114,18 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm) } /* - * Don't touch the LDT register - we're already in the next thread. + * No need to lock the MM as we are the last user + * + * 64bit: Don't touch the LDT register - we're already in the next thread. */ void destroy_context(struct mm_struct *mm) { if (mm->context.size) { +#ifdef CONFIG_X86_32 + /* CHECKME: Can this ever happen ? */ + if (mm == current->active_mm) + clear_LDT(); +#endif if (mm->context.size * LDT_ENTRY_SIZE > PAGE_SIZE) vfree(mm->context.ldt); else @@ -159,10 +170,14 @@ error_return: static int read_default_ldt(void __user *ptr, unsigned long bytecount) { - /* Arbitrary number */ - /* x86-64 default LDT is all zeros */ - if (bytecount > 128) - bytecount = 128; + /* CHECKME: Can we use _one_ random number ? */ +#ifdef CONFIG_X86_32 + unsigned long size = 5 * sizeof(struct desc_struct); +#else + unsigned long size = 128; +#endif + if (bytecount > size) + bytecount = size; if (clear_user(ptr, bytecount)) return -EFAULT; return bytecount; diff --git a/arch/x86/kernel/ldt_32.c b/arch/x86/kernel/ldt_32.c deleted file mode 100644 index bb15753aba..0000000000 --- a/arch/x86/kernel/ldt_32.c +++ /dev/null @@ -1,253 +0,0 @@ -/* - * Copyright (C) 1992 Krishna Balasubramanian and Linus Torvalds - * Copyright (C) 1999 Ingo Molnar - */ - -#include -#include -#include -#include -#include -#include -#include - -#include -#include -#include -#include -#include - -#ifdef CONFIG_SMP -static void flush_ldt(void *null) -{ - if (current->active_mm) - load_LDT(¤t->active_mm->context); -} -#endif - -static int alloc_ldt(mm_context_t *pc, int mincount, int reload) -{ - void *oldldt, *newldt; - int oldsize; - - if (mincount <= pc->size) - return 0; - oldsize = pc->size; - mincount = (mincount + 511) & (~511); - if (mincount * LDT_ENTRY_SIZE > PAGE_SIZE) - newldt = vmalloc(mincount * LDT_ENTRY_SIZE); - else - newldt = kmalloc(mincount * LDT_ENTRY_SIZE, GFP_KERNEL); - - if (!newldt) - return -ENOMEM; - - if (oldsize) - memcpy(newldt, pc->ldt, oldsize * LDT_ENTRY_SIZE); - oldldt = pc->ldt; - memset(newldt + oldsize * LDT_ENTRY_SIZE, 0, - (mincount - oldsize) * LDT_ENTRY_SIZE); - pc->ldt = newldt; - wmb(); - pc->size = mincount; - wmb(); - - if (reload) { -#ifdef CONFIG_SMP - cpumask_t mask; - - preempt_disable(); - load_LDT(pc); - mask = cpumask_of_cpu(smp_processor_id()); - if (!cpus_equal(current->mm->cpu_vm_mask, mask)) - smp_call_function(flush_ldt, NULL, 1, 1); - preempt_enable(); -#else - load_LDT(pc); -#endif - } - if (oldsize) { - if (oldsize * LDT_ENTRY_SIZE > PAGE_SIZE) - vfree(oldldt); - else - kfree(oldldt); - } - return 0; -} - -static inline int copy_ldt(mm_context_t *new, mm_context_t *old) -{ - int err = alloc_ldt(new, old->size, 0); - - if (err < 0) - return err; - memcpy(new->ldt, old->ldt, old->size * LDT_ENTRY_SIZE); - return 0; -} - -/* - * we do not have to muck with descriptors here, that is - * done in switch_mm() as needed. - */ -int init_new_context(struct task_struct *tsk, struct mm_struct *mm) -{ - struct mm_struct *old_mm; - int retval = 0; - - mutex_init(&mm->context.lock); - mm->context.size = 0; - old_mm = current->mm; - if (old_mm && old_mm->context.size > 0) { - mutex_lock(&old_mm->context.lock); - retval = copy_ldt(&mm->context, &old_mm->context); - mutex_unlock(&old_mm->context.lock); - } - return retval; -} - -/* - * No need to lock the MM as we are the last user - */ -void destroy_context(struct mm_struct *mm) -{ - if (mm->context.size) { - if (mm == current->active_mm) - clear_LDT(); - if (mm->context.size * LDT_ENTRY_SIZE > PAGE_SIZE) - vfree(mm->context.ldt); - else - kfree(mm->context.ldt); - mm->context.size = 0; - } -} - -static int read_ldt(void __user *ptr, unsigned long bytecount) -{ - int err; - unsigned long size; - struct mm_struct *mm = current->mm; - - if (!mm->context.size) - return 0; - if (bytecount > LDT_ENTRY_SIZE * LDT_ENTRIES) - bytecount = LDT_ENTRY_SIZE * LDT_ENTRIES; - - mutex_lock(&mm->context.lock); - size = mm->context.size * LDT_ENTRY_SIZE; - if (size > bytecount) - size = bytecount; - - err = 0; - if (copy_to_user(ptr, mm->context.ldt, size)) - err = -EFAULT; - mutex_unlock(&mm->context.lock); - if (err < 0) - goto error_return; - if (size != bytecount) { - /* zero-fill the rest */ - if (clear_user(ptr + size, bytecount - size) != 0) { - err = -EFAULT; - goto error_return; - } - } - return bytecount; -error_return: - return err; -} - -static int read_default_ldt(void __user *ptr, unsigned long bytecount) -{ - int err; - unsigned long size; - - err = 0; - size = 5 * sizeof(struct desc_struct); - if (size > bytecount) - size = bytecount; - - err = size; - if (clear_user(ptr, size)) - err = -EFAULT; - - return err; -} - -static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode) -{ - struct mm_struct *mm = current->mm; - __u32 entry_1, entry_2; - int error; - struct user_desc ldt_info; - - error = -EINVAL; - if (bytecount != sizeof(ldt_info)) - goto out; - error = -EFAULT; - if (copy_from_user(&ldt_info, ptr, sizeof(ldt_info))) - goto out; - - error = -EINVAL; - if (ldt_info.entry_number >= LDT_ENTRIES) - goto out; - if (ldt_info.contents == 3) { - if (oldmode) - goto out; - if (ldt_info.seg_not_present == 0) - goto out; - } - - mutex_lock(&mm->context.lock); - if (ldt_info.entry_number >= mm->context.size) { - error = alloc_ldt(¤t->mm->context, - ldt_info.entry_number + 1, 1); - if (error < 0) - goto out_unlock; - } - - /* Allow LDTs to be cleared by the user. */ - if (ldt_info.base_addr == 0 && ldt_info.limit == 0) { - if (oldmode || LDT_empty(&ldt_info)) { - entry_1 = 0; - entry_2 = 0; - goto install; - } - } - - entry_1 = LDT_entry_a(&ldt_info); - entry_2 = LDT_entry_b(&ldt_info); - if (oldmode) - entry_2 &= ~(1 << 20); - - /* Install the new entry ... */ -install: - write_ldt_entry(mm->context.ldt, ldt_info.entry_number, entry_1, - entry_2); - error = 0; - -out_unlock: - mutex_unlock(&mm->context.lock); -out: - return error; -} - -asmlinkage int sys_modify_ldt(int func, void __user *ptr, - unsigned long bytecount) -{ - int ret = -ENOSYS; - - switch (func) { - case 0: - ret = read_ldt(ptr, bytecount); - break; - case 1: - ret = write_ldt(ptr, bytecount, 1); - break; - case 2: - ret = read_default_ldt(ptr, bytecount); - break; - case 0x11: - ret = write_ldt(ptr, bytecount, 0); - break; - } - return ret; -} -- 2.39.5