From b18a3c183d20812933d192d4b0d622b11ef2bf29 Mon Sep 17 00:00:00 2001 From: Peter Hoyes Date: Wed, 1 May 2024 09:16:32 +0100 Subject: arm: Move sev() and wfe() definitions to common Arm header file The sev() and wfe() asm macros are currently defined only for mach-exynos. As these are common Arm instructions, move them to the common asm/system.h header file, for both Armv7 and Armv8, so they can be used by other machines. wfe may theoretically trigger a context switch if an interrupt occurs so add a memory barrier to this call. Signed-off-by: Peter Hoyes Reviewed-by: Andre Przywara --- arch/arm/include/asm/system.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/arm/include/asm/system.h') diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index 43f7503571d..51123c29684 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -154,6 +154,13 @@ enum dcache_option { "wfi" : : : "memory"); \ }) +#define wfe() \ + ({asm volatile( \ + "wfe" : : : "memory"); \ + }) + +#define sev() asm volatile("sev") + static inline unsigned int current_el(void) { unsigned long el; @@ -369,6 +376,8 @@ void switch_to_hypervisor_ret(void); #ifdef __ARM_ARCH_7A__ #define wfi() __asm__ __volatile__ ("wfi" : : : "memory") +#define wfe() __asm__ __volatile__ ("wfe" : : : "memory") +#define sev() __asm__ __volatile__ ("sev") #else #define wfi() #endif -- cgit v1.2.3 From ebc84d7b60c1ed3398e9f600fe3dc8406500bd35 Mon Sep 17 00:00:00 2001 From: Peter Hoyes Date: Wed, 1 May 2024 09:16:33 +0100 Subject: armv8: generic_timer: Use event stream for udelay Polling cntpct_el0 in a tight loop for delays is inefficient. This is particularly apparent on Arm FVPs, which do not simulate real time, meaning that a 1s sleep can take a couple of orders of magnitude longer to execute in wall time. If running at EL2 or above (where CNTHCTL_EL2 is available), enable the cntpct_el0 event stream temporarily and use wfe to implement the delay more efficiently. The event period is chosen as a trade-off between efficiency and the fact that Arm FVPs do not typically simulate real time. This is only implemented for Armv8 boards, where an architectural timer exists, and only enabled by default for the ARCH_VEXPRESS64 board family. Signed-off-by: Peter Hoyes Reviewed-by: Andre Przywara --- arch/arm/include/asm/system.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'arch/arm/include/asm/system.h') diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index 51123c29684..7e30cac32a0 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -69,8 +69,10 @@ /* * CNTHCTL_EL2 bits definitions */ -#define CNTHCTL_EL2_EL1PCEN_EN (1 << 1) /* Physical timer regs accessible */ -#define CNTHCTL_EL2_EL1PCTEN_EN (1 << 0) /* Physical counter accessible */ +#define CNTHCTL_EL2_EVNT_EN BIT(2) /* Enable the event stream */ +#define CNTHCTL_EL2_EVNT_I(val) ((val) << 4) /* Event stream trigger bits */ +#define CNTHCTL_EL2_EL1PCEN_EN (1 << 1) /* Physical timer regs accessible */ +#define CNTHCTL_EL2_EL1PCTEN_EN (1 << 0) /* Physical counter accessible */ /* * HCR_EL2 bits definitions -- cgit v1.2.3