x86: tls32 moved

This renames arch/x86/ia32/tls32.c to arch/x86/kernel/tls.c, which does
nothing now but paves the way to consolidate this code for 32-bit too.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 159 insertions, 0 deletions

diff --git a/arch/x86/kernel/Makefile_64 b/arch/x86/kernel/Makefile_64
index ae95d21ea88..e1ba82e582a 100644
--- a/arch/x86/kernel/Makefile_64
+++ b/arch/x86/kernel/Makefile_64
@@ -13,6 +13,7 @@ obj-y	:= process_64.o signal_64.o entry_64.o traps_64.o irq_64.o \
 		pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \
 		i8253.o io_delay.o rtc.o
 
+obj-$(CONFIG_IA32_EMULATION)	+= tls.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-y				+= cpu/
 obj-y				+= acpi/
diff --git a/arch/x86/kernel/tls.c b/arch/x86/kernel/tls.c
new file mode 100644
index 00000000000..5291596f19b
--- /dev/null
+++ b/arch/x86/kernel/tls.c
@@ -0,0 +1,158 @@
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/user.h>
+
+#include <asm/uaccess.h>
+#include <asm/desc.h>
+#include <asm/system.h>
+#include <asm/ldt.h>
+#include <asm/processor.h>
+#include <asm/proto.h>
+
+/*
+ * sys_alloc_thread_area: get a yet unused TLS descriptor index.
+ */
+static int get_free_idx(void)
+{
+	struct thread_struct *t = &current->thread;
+	int idx;
+
+	for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
+		if (desc_empty((struct n_desc_struct *)(t->tls_array) + idx))
+			return idx + GDT_ENTRY_TLS_MIN;
+	return -ESRCH;
+}
+
+/*
+ * Set a given TLS descriptor:
+ * When you want addresses > 32bit use arch_prctl()
+ */
+int do_set_thread_area(struct thread_struct *t, struct user_desc __user *u_info)
+{
+	struct user_desc info;
+	struct n_desc_struct *desc;
+	int cpu, idx;
+
+	if (copy_from_user(&info, u_info, sizeof(info)))
+		return -EFAULT;
+
+	idx = info.entry_number;
+
+	/*
+	 * index -1 means the kernel should try to find and
+	 * allocate an empty descriptor:
+	 */
+	if (idx == -1) {
+		idx = get_free_idx();
+		if (idx < 0)
+			return idx;
+		if (put_user(idx, &u_info->entry_number))
+			return -EFAULT;
+	}
+
+	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
+		return -EINVAL;
+
+	desc = ((struct n_desc_struct *)t->tls_array) + idx - GDT_ENTRY_TLS_MIN;
+
+	/*
+	 * We must not get preempted while modifying the TLS.
+	 */
+	cpu = get_cpu();
+
+	if (LDT_empty(&info)) {
+		desc->a = 0;
+		desc->b = 0;
+	} else {
+		desc->a = LDT_entry_a(&info);
+		desc->b = LDT_entry_b(&info);
+	}
+	if (t == &current->thread)
+		load_TLS(t, cpu);
+
+	put_cpu();
+	return 0;
+}
+
+asmlinkage long sys32_set_thread_area(struct user_desc __user *u_info)
+{
+	return do_set_thread_area(&current->thread, u_info);
+}
+
+
+/*
+ * Get the current Thread-Local Storage area:
+ */
+
+#define GET_LIMIT(desc) ( \
+	((desc)->a & 0x0ffff) | \
+	 ((desc)->b & 0xf0000) )
+
+#define GET_32BIT(desc)		(((desc)->b >> 22) & 1)
+#define GET_CONTENTS(desc)	(((desc)->b >> 10) & 3)
+#define GET_WRITABLE(desc)	(((desc)->b >>  9) & 1)
+#define GET_LIMIT_PAGES(desc)	(((desc)->b >> 23) & 1)
+#define GET_PRESENT(desc)	(((desc)->b >> 15) & 1)
+#define GET_USEABLE(desc)	(((desc)->b >> 20) & 1)
+#define GET_LONGMODE(desc)	(((desc)->b >> 21) & 1)
+
+int do_get_thread_area(struct thread_struct *t, struct user_desc __user *u_info)
+{
+	struct user_desc info;
+	struct n_desc_struct *desc;
+	int idx;
+
+	if (get_user(idx, &u_info->entry_number))
+		return -EFAULT;
+	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
+		return -EINVAL;
+
+	desc = ((struct n_desc_struct *)t->tls_array) + idx - GDT_ENTRY_TLS_MIN;
+
+	memset(&info, 0, sizeof(struct user_desc));
+	info.entry_number = idx;
+	info.base_addr = get_desc_base(desc);
+	info.limit = GET_LIMIT(desc);
+	info.seg_32bit = GET_32BIT(desc);
+	info.contents = GET_CONTENTS(desc);
+	info.read_exec_only = !GET_WRITABLE(desc);
+	info.limit_in_pages = GET_LIMIT_PAGES(desc);
+	info.seg_not_present = !GET_PRESENT(desc);
+	info.useable = GET_USEABLE(desc);
+	info.lm = GET_LONGMODE(desc);
+
+	if (copy_to_user(u_info, &info, sizeof(info)))
+		return -EFAULT;
+	return 0;
+}
+
+asmlinkage long sys32_get_thread_area(struct user_desc __user *u_info)
+{
+	return do_get_thread_area(&current->thread, u_info);
+}
+
+
+int ia32_child_tls(struct task_struct *p, struct pt_regs *childregs)
+{
+	struct n_desc_struct *desc;
+	struct user_desc info;
+	struct user_desc __user *cp;
+	int idx;
+
+	cp = (void __user *)childregs->rsi;
+	if (copy_from_user(&info, cp, sizeof(info)))
+		return -EFAULT;
+	if (LDT_empty(&info))
+		return -EINVAL;
+
+	idx = info.entry_number;
+	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
+		return -EINVAL;
+
+	desc = (struct n_desc_struct *)(p->thread.tls_array) + idx - GDT_ENTRY_TLS_MIN;
+	desc->a = LDT_entry_a(&info);
+	desc->b = LDT_entry_b(&info);
+
+	return 0;
+}