6 files changed, 37 insertions, 20 deletions

diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 1995d1a84060..214d4158089a 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -58,7 +58,7 @@ struct thread_info {
         struct cpu_context_save cpu_context;    /* cpu context */
         __u32                   syscall;        /* syscall number */
         __u8                    used_cp[16];    /* thread used copro */
-        unsigned long           tp_value;
+        unsigned long           tp_value[2];    /* TLS registers */
 #ifdef CONFIG_CRUNCH
         struct crunch_state     crunchstate;
 #endif
diff --git a/arch/arm/include/asm/tls.h b/arch/arm/include/asm/tls.h
index 73409e6c0251..83259b873333 100644
--- a/arch/arm/include/asm/tls.h
+++ b/arch/arm/include/asm/tls.h
@@ -2,27 +2,30 @@
 #define __ASMARM_TLS_H
 
 #ifdef __ASSEMBLY__
-        .macro set_tls_none, tp, tmp1, tmp2
+#include <asm/asm-offsets.h>
+        .macro switch_tls_none, base, tp, tpuser, tmp1, tmp2
         .endm
 
-        .macro set_tls_v6k, tp, tmp1, tmp2
+        .macro switch_tls_v6k, base, tp, tpuser, tmp1, tmp2
+        mrc     p15, 0, \tmp2, c13, c0, 2       @ get the user r/w register
         mcr     p15, 0, \tp, c13, c0, 3         @ set TLS register
-        mov     \tmp1, #0
-        mcr     p15, 0, \tmp1, c13, c0, 2       @ clear user r/w TLS register
+        mcr     p15, 0, \tpuser, c13, c0, 2     @ and the user r/w register
+        str     \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
         .endm
 
-        .macro set_tls_v6, tp, tmp1, tmp2
+        .macro switch_tls_v6, base, tp, tpuser, tmp1, tmp2
         ldr     \tmp1, =elf_hwcap
         ldr     \tmp1, [\tmp1, #0]
         mov     \tmp2, #0xffff0fff
         tst     \tmp1, #HWCAP_TLS               @ hardware TLS available?
-        mcrne   p15, 0, \tp, c13, c0, 3         @ yes, set TLS register
-        movne   \tmp1, #0
-        mcrne   p15, 0, \tmp1, c13, c0, 2       @ clear user r/w TLS register
         streq   \tp, [\tmp2, #-15]              @ set TLS value at 0xffff0ff0
+        mrcne   p15, 0, \tmp2, c13, c0, 2       @ get the user r/w register
+        mcrne   p15, 0, \tp, c13, c0, 3         @ yes, set TLS register
+        mcrne   p15, 0, \tpuser, c13, c0, 2     @ set user r/w register
+        strne   \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
         .endm
 
-        .macro set_tls_software, tp, tmp1, tmp2
+        .macro switch_tls_software, base, tp, tpuser, tmp1, tmp2
         mov     \tmp1, #0xffff0fff
         str     \tp, [\tmp1, #-15]              @ set TLS value at 0xffff0ff0
         .endm
@@ -31,19 +34,30 @@
 #ifdef CONFIG_TLS_REG_EMUL
 #define tls_emu         1
 #define has_tls_reg             1
-#define set_tls         set_tls_none
+#define switch_tls      switch_tls_none
 #elif defined(CONFIG_CPU_V6)
 #define tls_emu         0
 #define has_tls_reg             (elf_hwcap & HWCAP_TLS)
-#define set_tls         set_tls_v6
+#define switch_tls      switch_tls_v6
 #elif defined(CONFIG_CPU_32v6K)
 #define tls_emu         0
 #define has_tls_reg             1
-#define set_tls         set_tls_v6k
+#define switch_tls      switch_tls_v6k
 #else
 #define tls_emu         0
 #define has_tls_reg             0
-#define set_tls         set_tls_software
+#define switch_tls      switch_tls_software
 #endif
 
+#ifndef __ASSEMBLY__
+static inline unsigned long get_tpuser(void)
+{
+        unsigned long reg = 0;
+
+        if (has_tls_reg && !tls_emu)
+                __asm__("mrc p15, 0, %0, c13, c0, 2" : "=r" (reg));
+
+        return reg;
+}
+#endif
 #endif  /* __ASMARM_TLS_H */
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 582b405befc5..a39cfc2a1f90 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -685,15 +685,16 @@ ENTRY(__switch_to)
  UNWIND(.fnstart        )
  UNWIND(.cantunwind     )
         add     ip, r1, #TI_CPU_SAVE
-        ldr     r3, [r2, #TI_TP_VALUE]
  ARM(   stmia   ip!, {r4 - sl, fp, sp, lr} )    @ Store most regs on stack
  THUMB( stmia   ip!, {r4 - sl, fp}         )    @ Store most regs on stack
  THUMB( str     sp, [ip], #4               )
  THUMB( str     lr, [ip], #4               )
+        ldr     r4, [r2, #TI_TP_VALUE]
+        ldr     r5, [r2, #TI_TP_VALUE + 4]
 #ifdef CONFIG_CPU_USE_DOMAINS
         ldr     r6, [r2, #TI_CPU_DOMAIN]
 #endif
-        set_tls r3, r4, r5
+        switch_tls r1, r4, r5, r3, r7
 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
         ldr     r7, [r2, #TI_TASK]
         ldr     r8, =__stack_chk_guard
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index f21970316836..087064148ebf 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -39,6 +39,7 @@
 #include <asm/thread_notify.h>
 #include <asm/stacktrace.h>
 #include <asm/mach/time.h>
+#include <asm/tls.h>
 
 #ifdef CONFIG_CC_STACKPROTECTOR
 #include <linux/stackprotector.h>
@@ -343,7 +344,8 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start,
         clear_ptrace_hw_breakpoint(p);
 
         if (clone_flags & CLONE_SETTLS)
-                thread->tp_value = childregs->ARM_r3;
+                thread->tp_value[0] = childregs->ARM_r3;
+        thread->tp_value[1] = get_tpuser();
 
         thread_notify(THREAD_NOTIFY_COPY, thread);
 
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 03deeffd9f6d..2bc1514d6dbe 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -849,7 +849,7 @@ long arch_ptrace(struct task_struct *child, long request,
 #endif
 
                 case PTRACE_GET_THREAD_AREA:
-                        ret = put_user(task_thread_info(child)->tp_value,
+                        ret = put_user(task_thread_info(child)->tp_value[0],
                                        datap);
                         break;
 
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 18b32e8e4497..517bfd4da1c9 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -581,7 +581,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
                 return regs->ARM_r0;
 
         case NR(set_tls):
-                thread->tp_value = regs->ARM_r0;
+                thread->tp_value[0] = regs->ARM_r0;
                 if (tls_emu)
                         return 0;
                 if (has_tls_reg) {
@@ -699,7 +699,7 @@ static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
         int reg = (instr >> 12) & 15;
         if (reg == 15)
                 return 1;
-        regs->uregs[reg] = current_thread_info()->tp_value;
+        regs->uregs[reg] = current_thread_info()->tp_value[0];
         regs->ARM_pc += 4;
         return 0;
 }