Merge tag 'for-v4.6-rc/omap-fixes-a' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending into omap-for-v4.6/fixes

ARM: OMAP2+: first hwmod fix for v4.6-rc

Fix a longstanding bug in the hwmod code that could cause
hardware SYSCONFIG register values to not match the kernel's
idea of what they should be, and that could result in lower
performance during IP block idle entry.

Basic build, boot, and PM test logs are available here:

http://www.pwsan.com/omap/testlogs/omap-hwmod-fixes-a-for-v4.6-rc/20160326231727/

1 files changed, 53 insertions, 53 deletions

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 03663740c866..e79d93d44ecd 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -26,6 +26,7 @@
 #include <asm/traps.h>
 #include <asm/vdso.h>
 #include <asm/uaccess.h>
+#include <asm/cpufeature.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/syscalls.h>
@@ -44,6 +45,8 @@ __visible void enter_from_user_mode(void)
 	CT_WARN_ON(ct_state() != CONTEXT_USER);
 	user_exit();
 }
+#else
+static inline void enter_from_user_mode(void) {}
 #endif
 
 static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
@@ -84,17 +87,6 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
 
 	work = ACCESS_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY;
 
-#ifdef CONFIG_CONTEXT_TRACKING
-	/*
-	 * If TIF_NOHZ is set, we are required to call user_exit() before
-	 * doing anything that could touch RCU.
-	 */
-	if (work & _TIF_NOHZ) {
-		enter_from_user_mode();
-		work &= ~_TIF_NOHZ;
-	}
-#endif
-
 #ifdef CONFIG_SECCOMP
 	/*
 	 * Do seccomp first -- it should minimize exposure of other
@@ -171,16 +163,6 @@ long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
 	if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
 		BUG_ON(regs != task_pt_regs(current));
 
-	/*
-	 * If we stepped into a sysenter/syscall insn, it trapped in
-	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
-	 * If user-mode had set TF itself, then it's still clear from
-	 * do_debug() and we need to set it again to restore the user
-	 * state.  If we entered on the slow path, TF was already set.
-	 */
-	if (work & _TIF_SINGLESTEP)
-		regs->flags |= X86_EFLAGS_TF;
-
 #ifdef CONFIG_SECCOMP
 	/*
 	 * Call seccomp_phase2 before running the other hooks so that
@@ -268,6 +250,7 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
 /* Called with IRQs disabled. */
 __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
 {
+	struct thread_info *ti = pt_regs_to_thread_info(regs);
 	u32 cached_flags;
 
 	if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled()))
@@ -275,12 +258,22 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
 
 	lockdep_sys_exit();
 
-	cached_flags =
-		READ_ONCE(pt_regs_to_thread_info(regs)->flags);
+	cached_flags = READ_ONCE(ti->flags);
 
 	if (unlikely(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS))
 		exit_to_usermode_loop(regs, cached_flags);
 
+#ifdef CONFIG_COMPAT
+	/*
+	 * Compat syscalls set TS_COMPAT.  Make sure we clear it before
+	 * returning to user mode.  We need to clear it *after* signal
+	 * handling, because syscall restart has a fixup for compat
+	 * syscalls.  The fixup is exercised by the ptrace_syscall_32
+	 * selftest.
+	 */
+	ti->status &= ~TS_COMPAT;
+#endif
+
 	user_enter();
 }
 
@@ -332,33 +325,45 @@ __visible inline void syscall_return_slowpath(struct pt_regs *regs)
 	if (unlikely(cached_flags & SYSCALL_EXIT_WORK_FLAGS))
 		syscall_slow_exit_work(regs, cached_flags);
 
-#ifdef CONFIG_COMPAT
+	local_irq_disable();
+	prepare_exit_to_usermode(regs);
+}
+
+#ifdef CONFIG_X86_64
+__visible void do_syscall_64(struct pt_regs *regs)
+{
+	struct thread_info *ti = pt_regs_to_thread_info(regs);
+	unsigned long nr = regs->orig_ax;
+
+	enter_from_user_mode();
+	local_irq_enable();
+
+	if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY)
+		nr = syscall_trace_enter(regs);
+
 	/*
-	 * Compat syscalls set TS_COMPAT.  Make sure we clear it before
-	 * returning to user mode.
+	 * NB: Native and x32 syscalls are dispatched from the same
+	 * table.  The only functional difference is the x32 bit in
+	 * regs->orig_ax, which changes the behavior of some syscalls.
 	 */
-	ti->status &= ~TS_COMPAT;
-#endif
+	if (likely((nr & __SYSCALL_MASK) < NR_syscalls)) {
+		regs->ax = sys_call_table[nr & __SYSCALL_MASK](
+			regs->di, regs->si, regs->dx,
+			regs->r10, regs->r8, regs->r9);
+	}
 
-	local_irq_disable();
-	prepare_exit_to_usermode(regs);
+	syscall_return_slowpath(regs);
 }
+#endif
 
 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 /*
- * Does a 32-bit syscall.  Called with IRQs on and does all entry and
- * exit work and returns with IRQs off.  This function is extremely hot
- * in workloads that use it, and it's usually called from
+ * Does a 32-bit syscall.  Called with IRQs on in CONTEXT_KERNEL.  Does
+ * all entry and exit work and returns with IRQs off.  This function is
+ * extremely hot in workloads that use it, and it's usually called from
  * do_fast_syscall_32, so forcibly inline it to improve performance.
  */
-#ifdef CONFIG_X86_32
-/* 32-bit kernels use a trap gate for INT80, and the asm code calls here. */
-__visible
-#else
-/* 64-bit kernels use do_syscall_32_irqs_off() instead. */
-static
-#endif
-__always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
+static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
 {
 	struct thread_info *ti = pt_regs_to_thread_info(regs);
 	unsigned int nr = (unsigned int)regs->orig_ax;
@@ -393,14 +398,13 @@ __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
 	syscall_return_slowpath(regs);
 }
 
-#ifdef CONFIG_X86_64
-/* Handles INT80 on 64-bit kernels */
-__visible void do_syscall_32_irqs_off(struct pt_regs *regs)
+/* Handles int $0x80 */
+__visible void do_int80_syscall_32(struct pt_regs *regs)
 {
+	enter_from_user_mode();
 	local_irq_enable();
 	do_syscall_32_irqs_on(regs);
 }
-#endif
 
 /* Returns 0 to return using IRET or 1 to return using SYSEXIT/SYSRETL. */
 __visible long do_fast_syscall_32(struct pt_regs *regs)
@@ -420,12 +424,11 @@ __visible long do_fast_syscall_32(struct pt_regs *regs)
 	 */
 	regs->ip = landing_pad;
 
-	/*
-	 * Fetch EBP from where the vDSO stashed it.
-	 *
-	 * WARNING: We are in CONTEXT_USER and RCU isn't paying attention!
-	 */
+	enter_from_user_mode();
+
 	local_irq_enable();
+
+	/* Fetch EBP from where the vDSO stashed it. */
 	if (
 #ifdef CONFIG_X86_64
 		/*
@@ -443,9 +446,6 @@ __visible long do_fast_syscall_32(struct pt_regs *regs)
 		/* User code screwed up. */
 		local_irq_disable();
 		regs->ax = -EFAULT;
-#ifdef CONFIG_CONTEXT_TRACKING
-		enter_from_user_mode();
-#endif
 		prepare_exit_to_usermode(regs);
 		return 0;	/* Keep it simple: use IRET. */
 	}