Hi Catalin,

On 27/08/13 12:19, Catalin Marinas wrote:

On Fri, Aug 23, 2013 at 05:19:07PM +0100, Sudeep KarkadaNagesha wrote:

quoted

diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index 00b09d0..0f57158 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h

@@ -97,21 +97,53 @@ static inline u32 arch_timer_get_cntfrq(void)
 	return val;
 }
 
-static inline void arch_counter_set_user_access(void)
+static inline u32 arch_timer_get_cntkctl(void)
 {
 	u32 cntkctl;
-
 	asm volatile("mrs	%0, cntkctl_el1" : "=r" (cntkctl));
+	return cntkctl;
+}
+
+static inline void arch_timer_set_cntkctl(u32 cntkctl)
+{
+	asm volatile("msr	cntkctl_el1, %0" : : "r" (cntkctl));
+}
+
+static inline void arch_counter_set_user_access(void)
+{
+	u32 cntkctl = arch_timer_get_cntkctl();
 
 	/* Disable user access to the timers and the physical counter. */
 	cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
 			| ARCH_TIMER_USR_VT_ACCESS_EN
 			| ARCH_TIMER_USR_PCT_ACCESS_EN);
 
-	/* Enable user access to the virtual counter. */
+	/* Enable user access to the virtual counter */

This change isn't needed here. Just move it to the first patch which
adds the comment.

It's a mistake, accidentally removed leading '.'
I will remove this.

quoted

 	cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
 
-	asm volatile("msr	cntkctl_el1, %0" : : "r" (cntkctl));
+	arch_timer_set_cntkctl(cntkctl);
+}
+
+static inline void arch_timer_evtstrm_config(bool enable, int divider)
+{
+	u32 cntkctl = arch_timer_get_cntkctl();
+	if (enable) {
+		cntkctl &= ~ARCH_TIMER_EVT_TRIGGER_MASK;
+		/* Set the divider and enable virtual event stream */
+		cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
+				| ARCH_TIMER_VIRT_EVT_EN;
+	} else {
+		cntkctl &= ~ARCH_TIMER_VIRT_EVT_EN; /* disable event stream */
+	}
+	arch_timer_set_cntkctl(cntkctl);
+}
+
+static inline void arch_timer_set_hwcap_evtstrm(void)
+{
+	elf_hwcap |= HWCAP_EVTSTRM;
+#ifdef CONFIG_COMPAT
+	compat_dyn_elf_hwcap |= COMPAT_HWCAP_EVTSTRM;
+#endif
 }
 
 static inline u64 arch_counter_get_cntvct(void)

diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 6d4482f..022d771 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h

@@ -30,6 +30,7 @@
 #define COMPAT_HWCAP_IDIVA	(1 << 17)
 #define COMPAT_HWCAP_IDIVT	(1 << 18)
 #define COMPAT_HWCAP_IDIV	(COMPAT_HWCAP_IDIVA|COMPAT_HWCAP_IDIVT)
+#define COMPAT_HWCAP_EVTSTRM	(1 << 21)
 
 #ifndef __ASSEMBLY__
 /*

@@ -37,11 +38,15 @@
  * instruction set this cpu supports.
  */
 #define ELF_HWCAP		(elf_hwcap)
+#ifdef CONFIG_COMPAT
 #define COMPAT_ELF_HWCAP	(COMPAT_HWCAP_HALF|COMPAT_HWCAP_THUMB|\
 				 COMPAT_HWCAP_FAST_MULT|COMPAT_HWCAP_EDSP|\
 				 COMPAT_HWCAP_TLS|COMPAT_HWCAP_VFP|\
 				 COMPAT_HWCAP_VFPv3|COMPAT_HWCAP_VFPv4|\
-				 COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV)
+				 COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV|\
+				 compat_dyn_elf_hwcap)
+extern unsigned int compat_dyn_elf_hwcap;
+#endif

Can we just have a compat_elf_hwcap which is initialised to all the
above and avoid compat_dyn_elf_hwcap?

It was Will's suggestion(https://lkml.org/lkml/2013/8/20/425)
Moreover with config option now it makes more sense to retain it.
It avoids having conditional definition. Let me know your opinion.

Regards,
Sudeep