On Tue, 23 Apr 2024 09:10:04 +0100 Peter Hoyes peter.hoyes@arm.com wrote:
Hi,
From: Peter Hoyes Peter.Hoyes@arm.com
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 Peter.Hoyes@arm.com
Looks alright to me, and the memory barrier for wfe looks justified.
For the records: we couldn't come up with a reason why "sev" would need one as well, so even while the kernel has this, this seems to be more a copy&paste incident rather than something intentional.
Reviewed-by: Andre Przywara andre.przywara@arm.com
Cheers, Andre
arch/arm/include/asm/system.h | 9 +++++++++ arch/arm/mach-exynos/include/mach/system.h | 19 ------------------- 2 files changed, 9 insertions(+), 19 deletions(-)
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index 43f7503571..51123c2968 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 diff --git a/arch/arm/mach-exynos/include/mach/system.h b/arch/arm/mach-exynos/include/mach/system.h index 5d0bebac57..0aed4c3e2b 100644 --- a/arch/arm/mach-exynos/include/mach/system.h +++ b/arch/arm/mach-exynos/include/mach/system.h @@ -36,25 +36,6 @@ struct exynos5_sysreg {
#define USB20_PHY_CFG_HOST_LINK_EN (1 << 0)
-/*
- This instruction causes an event to be signaled to all cores
- within a multiprocessor system. If SEV is implemented,
- WFE must also be implemented.
- */
-#define sev() __asm__ __volatile__ ("sev\n\t" : : ); -/*
- If the Event Register is not set, WFE suspends execution until
- one of the following events occurs:
- an IRQ interrupt, unless masked by the CPSR I-bit
- an FIQ interrupt, unless masked by the CPSR F-bit
- an Imprecise Data abort, unless masked by the CPSR A-bit
- a Debug Entry request, if Debug is enabled
- an Event signaled by another processor using the SEV instruction.
- If the Event Register is set, WFE clears it and returns immediately.
- If WFE is implemented, SEV must also be implemented.
- */
-#define wfe() __asm__ __volatile__ ("wfe\n\t" : : );
/* Move 0xd3 value to CPSR register to enable SVC mode */ #define svc32_mode_en() __asm__ __volatile__ \ ("@ I&F disable, Mode: 0x13 - SVC\n\t" \