MIPS: Implement HAVE_CONTEXT_TRACKING.

This enables support for CONFIG_NO_HZ_FULL.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

5 files changed, 86 insertions, 14 deletions

diff --git a/arch/mips/kernel/cpu-bugs64.c b/arch/mips/kernel/cpu-bugs64.c
index de3c25ffd9f9..0c61df281ce6 100644
--- a/arch/mips/kernel/cpu-bugs64.c
+++ b/arch/mips/kernel/cpu-bugs64.c
@@ -6,6 +6,7 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+#include <linux/context_tracking.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/ptrace.h>
@@ -171,8 +172,12 @@ static volatile int daddi_ov __cpuinitdata;
 
 asmlinkage void __init do_daddi_ov(struct pt_regs *regs)
 {
+        enum ctx_state prev_state;
+
+        prev_state = exception_enter();
         daddi_ov = 1;
         regs->cp0_epc += 4;
+        exception_exit(prev_state);
 }
 
 static inline void check_daddi(void)
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 9c6299c733a3..8ae1ebef8b71 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -15,6 +15,7 @@
  * binaries.
  */
 #include <linux/compiler.h>
+#include <linux/context_tracking.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
@@ -534,6 +535,8 @@ static inline int audit_arch(void)
  */
 asmlinkage void syscall_trace_enter(struct pt_regs *regs)
 {
+        user_exit();
+
         /* do the secure computing check first */
         secure_computing_strict(regs->regs[2]);
 
@@ -570,6 +573,13 @@ out:
  */
 asmlinkage void syscall_trace_leave(struct pt_regs *regs)
 {
+        /*
+         * We may come here right after calling schedule_user()
+         * or do_notify_resume(), in which case we can be in RCU
+         * user mode.
+         */
+        user_exit();
+
         audit_syscall_exit(regs);
 
         if (!(current->ptrace & PT_PTRACED))
@@ -592,4 +602,6 @@ asmlinkage void syscall_trace_leave(struct pt_regs *regs)
                 send_sig(current->exit_code, current, 1);
                 current->exit_code = 0;
         }
+
+        user_enter();
 }
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index fd3ef2c2afbc..2f285abc76d5 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -8,6 +8,7 @@
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  */
 #include <linux/cache.h>
+#include <linux/context_tracking.h>
 #include <linux/irqflags.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
@@ -573,6 +574,8 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 {
         local_irq_enable();
 
+        user_exit();
+
         /* deal with pending signal delivery */
         if (thread_info_flags & _TIF_SIGPENDING)
                 do_signal(regs);
@@ -581,6 +584,8 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
                 clear_thread_flag(TIF_NOTIFY_RESUME);
                 tracehook_notify_resume(regs);
         }
+
+        user_enter();
 }
 
 #ifdef CONFIG_SMP
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index a75ae40184aa..beba1e616b6e 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -13,6 +13,7 @@
  */
 #include <linux/bug.h>
 #include <linux/compiler.h>
+#include <linux/context_tracking.h>
 #include <linux/kexec.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -423,7 +424,9 @@ asmlinkage void do_be(struct pt_regs *regs)
         const struct exception_table_entry *fixup = NULL;
         int data = regs->cp0_cause & 4;
         int action = MIPS_BE_FATAL;
+        enum ctx_state prev_state;
 
+        prev_state = exception_enter();
         /* XXX For now.  Fixme, this searches the wrong table ...  */
         if (data && !user_mode(regs))
                 fixup = search_dbe_tables(exception_epc(regs));
@@ -436,11 +439,11 @@ asmlinkage void do_be(struct pt_regs *regs)
 
         switch (action) {
         case MIPS_BE_DISCARD:
-                return;
+                goto out;
         case MIPS_BE_FIXUP:
                 if (fixup) {
                         regs->cp0_epc = fixup->nextinsn;
-                        return;
+                        goto out;
                 }
                 break;
         default:
@@ -455,10 +458,13 @@ asmlinkage void do_be(struct pt_regs *regs)
                field, regs->cp0_epc, field, regs->regs[31]);
         if (notify_die(DIE_OOPS, "bus error", regs, 0, regs_to_trapnr(regs), SIGBUS)
             == NOTIFY_STOP)
-                return;
+                goto out;
 
         die_if_kernel("Oops", regs);
         force_sig(SIGBUS, current);
+
+out:
+        exception_exit(prev_state);
 }
 
 /*
@@ -673,8 +679,10 @@ static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
 
 asmlinkage void do_ov(struct pt_regs *regs)
 {
+        enum ctx_state prev_state;
         siginfo_t info;
 
+        prev_state = exception_enter();
         die_if_kernel("Integer overflow", regs);
 
         info.si_code = FPE_INTOVF;
@@ -682,6 +690,7 @@ asmlinkage void do_ov(struct pt_regs *regs)
         info.si_errno = 0;
         info.si_addr = (void __user *) regs->cp0_epc;
         force_sig_info(SIGFPE, &info, current);
+        exception_exit(prev_state);
 }
 
 int process_fpemu_return(int sig, void __user *fault_addr)
@@ -713,11 +722,13 @@ int process_fpemu_return(int sig, void __user *fault_addr)
  */
 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 {
+        enum ctx_state prev_state;
         siginfo_t info = {0};
 
+        prev_state = exception_enter();
         if (notify_die(DIE_FP, "FP exception", regs, 0, regs_to_trapnr(regs), SIGFPE)
             == NOTIFY_STOP)
-                return;
+                goto out;
         die_if_kernel("FP exception in kernel code", regs);
 
         if (fcr31 & FPU_CSR_UNI_X) {
@@ -753,7 +764,7 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
                 /* If something went wrong, signal */
                 process_fpemu_return(sig, fault_addr);
 
-                return;
+                goto out;
         } else if (fcr31 & FPU_CSR_INV_X)
                 info.si_code = FPE_FLTINV;
         else if (fcr31 & FPU_CSR_DIV_X)
@@ -770,6 +781,9 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
         info.si_errno = 0;
         info.si_addr = (void __user *) regs->cp0_epc;
         force_sig_info(SIGFPE, &info, current);
+
+out:
+        exception_exit(prev_state);
 }
 
 static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
@@ -835,9 +849,11 @@ static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
 asmlinkage void do_bp(struct pt_regs *regs)
 {
         unsigned int opcode, bcode;
+        enum ctx_state prev_state;
         unsigned long epc;
         u16 instr[2];
 
+        prev_state = exception_enter();
         if (get_isa16_mode(regs->cp0_epc)) {
                 /* Calculate EPC. */
                 epc = exception_epc(regs);
@@ -852,7 +868,7 @@ asmlinkage void do_bp(struct pt_regs *regs)
                                 goto out_sigsegv;
                     bcode = (instr[0] >> 6) & 0x3f;
                     do_trap_or_bp(regs, bcode, "Break");
-                    return;
+                    goto out;
                 }
         } else {
                 if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
@@ -876,12 +892,12 @@ asmlinkage void do_bp(struct pt_regs *regs)
         switch (bcode) {
         case BRK_KPROBE_BP:
                 if (notify_die(DIE_BREAK, "debug", regs, bcode, regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
-                        return;
+                        goto out;
                 else
                         break;
         case BRK_KPROBE_SSTEPBP:
                 if (notify_die(DIE_SSTEPBP, "single_step", regs, bcode, regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
-                        return;
+                        goto out;
                 else
                         break;
         default:
@@ -889,18 +905,24 @@ asmlinkage void do_bp(struct pt_regs *regs)
         }
 
         do_trap_or_bp(regs, bcode, "Break");
+
+out:
+        exception_exit(prev_state);
         return;
 
 out_sigsegv:
         force_sig(SIGSEGV, current);
+        goto out;
 }
 
 asmlinkage void do_tr(struct pt_regs *regs)
 {
         u32 opcode, tcode = 0;
+        enum ctx_state prev_state;
         u16 instr[2];
         unsigned long epc = msk_isa16_mode(exception_epc(regs));
 
+        prev_state = exception_enter();
         if (get_isa16_mode(regs->cp0_epc)) {
                 if (__get_user(instr[0], (u16 __user *)(epc + 0)) ||
                     __get_user(instr[1], (u16 __user *)(epc + 2)))
@@ -918,10 +940,14 @@ asmlinkage void do_tr(struct pt_regs *regs)
         }
 
         do_trap_or_bp(regs, tcode, "Trap");
+
+out:
+        exception_exit(prev_state);
         return;
 
 out_sigsegv:
         force_sig(SIGSEGV, current);
+        goto out;
 }
 
 asmlinkage void do_ri(struct pt_regs *regs)
@@ -929,17 +955,19 @@ asmlinkage void do_ri(struct pt_regs *regs)
         unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
         unsigned long old_epc = regs->cp0_epc;
         unsigned long old31 = regs->regs[31];
+        enum ctx_state prev_state;
         unsigned int opcode = 0;
         int status = -1;
 
+        prev_state = exception_enter();
         if (notify_die(DIE_RI, "RI Fault", regs, 0, regs_to_trapnr(regs), SIGILL)
             == NOTIFY_STOP)
-                return;
+                goto out;
 
         die_if_kernel("Reserved instruction in kernel code", regs);
 
         if (unlikely(compute_return_epc(regs) < 0))
-                return;
+                goto out;
 
         if (get_isa16_mode(regs->cp0_epc)) {
                 unsigned short mmop[2] = { 0 };
@@ -974,6 +1002,9 @@ asmlinkage void do_ri(struct pt_regs *regs)
                 regs->regs[31] = old31;
                 force_sig(status, current);
         }
+
+out:
+        exception_exit(prev_state);
 }
 
 /*
@@ -1040,6 +1071,7 @@ static int default_cu2_call(struct notifier_block *nfb, unsigned long action,
 
 asmlinkage void do_cpu(struct pt_regs *regs)
 {
+        enum ctx_state prev_state;
         unsigned int __user *epc;
         unsigned long old_epc, old31;
         unsigned int opcode;
@@ -1047,6 +1079,7 @@ asmlinkage void do_cpu(struct pt_regs *regs)
         int status;
         unsigned long __maybe_unused flags;
 
+        prev_state = exception_enter();
         die_if_kernel("do_cpu invoked from kernel context!", regs);
 
         cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
@@ -1060,7 +1093,7 @@ asmlinkage void do_cpu(struct pt_regs *regs)
                 status = -1;
 
                 if (unlikely(compute_return_epc(regs) < 0))
-                        return;
+                        goto out;
 
                 if (get_isa16_mode(regs->cp0_epc)) {
                         unsigned short mmop[2] = { 0 };
@@ -1093,7 +1126,7 @@ asmlinkage void do_cpu(struct pt_regs *regs)
                         force_sig(status, current);
                 }
 
-                return;
+                goto out;
 
         case 3:
                 /*
@@ -1131,19 +1164,26 @@ asmlinkage void do_cpu(struct pt_regs *regs)
                                 mt_ase_fp_affinity();
                 }
 
-                return;
+                goto out;
 
         case 2:
                 raw_notifier_call_chain(&cu2_chain, CU2_EXCEPTION, regs);
-                return;
+                goto out;
         }
 
         force_sig(SIGILL, current);
+
+out:
+        exception_exit(prev_state);
 }
 
 asmlinkage void do_mdmx(struct pt_regs *regs)
 {
+        enum ctx_state prev_state;
+
+        prev_state = exception_enter();
         force_sig(SIGILL, current);
+        exception_exit(prev_state);
 }
 
 /*
@@ -1151,8 +1191,10 @@ asmlinkage void do_mdmx(struct pt_regs *regs)
  */
 asmlinkage void do_watch(struct pt_regs *regs)
 {
+        enum ctx_state prev_state;
         u32 cause;
 
+        prev_state = exception_enter();
         /*
          * Clear WP (bit 22) bit of cause register so we don't loop
          * forever.
@@ -1174,13 +1216,16 @@ asmlinkage void do_watch(struct pt_regs *regs)
                 mips_clear_watch_registers();
                 local_irq_enable();
         }
+        exception_exit(prev_state);
 }
 
 asmlinkage void do_mcheck(struct pt_regs *regs)
 {
         const int field = 2 * sizeof(unsigned long);
         int multi_match = regs->cp0_status & ST0_TS;
+        enum ctx_state prev_state;
 
+        prev_state = exception_enter();
         show_regs(regs);
 
         if (multi_match) {
@@ -1202,6 +1247,7 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
         panic("Caught Machine Check exception - %scaused by multiple "
               "matching entries in the TLB.",
               (multi_match) ? "" : "not ");
+        exception_exit(prev_state);
 }
 
 asmlinkage void do_mt(struct pt_regs *regs)
diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
index 203d8857070d..3eaa02aa8ae0 100644
--- a/arch/mips/kernel/unaligned.c
+++ b/arch/mips/kernel/unaligned.c
@@ -72,6 +72,7 @@
  *       A store crossing a page boundary might be executed only partially.
  *       Undo the partial store in this case.
  */
+#include <linux/context_tracking.h>
 #include <linux/mm.h>
 #include <linux/signal.h>
 #include <linux/smp.h>
@@ -1550,9 +1551,11 @@ sigill:
 }
 asmlinkage void do_ade(struct pt_regs *regs)
 {
+        enum ctx_state prev_state;
         unsigned int __user *pc;
         mm_segment_t seg;
 
+        prev_state = exception_enter();
         perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS,
                         1, regs, regs->cp0_badvaddr);
         /*
@@ -1628,6 +1631,7 @@ sigbus:
         /*
          * XXX On return from the signal handler we should advance the epc
          */
+        exception_exit(prev_state);
 }
 
 #ifdef CONFIG_DEBUG_FS