On 03/05/19 13:13, nadav.amit@xxxxxxxxx wrote:
> From: Nadav Amit <nadav.amit@xxxxxxxxx>
>
> There is no guarantee that a self-IPI would be delivered immediately.
> In eventinj, io_delay() is called after self-IPI is generated but does
> nothing.
>
> In general, there is mess in regard to delay() and io_delay(). There are
> two definitions of delay() and they do not really look on the timestamp
> counter and instead count invocations of "pause" (or even "nop"), which
> might be different on different CPUs/setups, for example due to
> different pause-loop-exiting configurations.
>
> To address these issues change io_delay() to really do a delay, based on
> timestamp counter, and move common functions into delay.[hc].
>
> Cc: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
> Signed-off-by: Nadav Amit <nadav.amit@xxxxxxxxx>
Queued; there is another io_delay instance in taskswitch2.c, so I
removed it too.
Paolo
> ---
> lib/x86/delay.c | 9 ++++++---
> lib/x86/delay.h | 7 +++++++
> x86/eventinj.c | 5 +----
> x86/ioapic.c | 8 +-------
> 4 files changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/lib/x86/delay.c b/lib/x86/delay.c
> index 595ad24..e7d2717 100644
> --- a/lib/x86/delay.c
> +++ b/lib/x86/delay.c
> @@ -1,8 +1,11 @@
> #include "delay.h"
> +#include "processor.h"
>
> void delay(u64 count)
> {
> - while (count--)
> - asm volatile("pause");
> -}
> + u64 start = rdtsc();
>
> + do {
> + pause();
> + } while (rdtsc() - start < count);
> +}
> diff --git a/lib/x86/delay.h b/lib/x86/delay.h
> index a9bf894..a51eb34 100644
> --- a/lib/x86/delay.h
> +++ b/lib/x86/delay.h
> @@ -3,6 +3,13 @@
>
> #include "libcflat.h"
>
> +#define IPI_DELAY 1000000
> +
> void delay(u64 count);
>
> +static inline void io_delay(void)
> +{
> + delay(IPI_DELAY);
> +}
> +
> #endif
> diff --git a/x86/eventinj.c b/x86/eventinj.c
> index d2dfc40..901b9db 100644
> --- a/x86/eventinj.c
> +++ b/x86/eventinj.c
> @@ -7,6 +7,7 @@
> #include "apic-defs.h"
> #include "vmalloc.h"
> #include "alloc_page.h"
> +#include "delay.h"
>
> #ifdef __x86_64__
> # define R "r"
> @@ -16,10 +17,6 @@
>
> void do_pf_tss(void);
>
> -static inline void io_delay(void)
> -{
> -}
> -
> static void apic_self_ipi(u8 v)
> {
> apic_icr_write(APIC_DEST_SELF | APIC_DEST_PHYSICAL | APIC_DM_FIXED |
> diff --git a/x86/ioapic.c b/x86/ioapic.c
> index 2ac4ac6..c32dabd 100644
> --- a/x86/ioapic.c
> +++ b/x86/ioapic.c
> @@ -4,6 +4,7 @@
> #include "smp.h"
> #include "desc.h"
> #include "isr.h"
> +#include "delay.h"
>
> static void toggle_irq_line(unsigned line)
> {
> @@ -165,13 +166,6 @@ static void test_ioapic_level_tmr(bool expected_tmr_before)
> expected_tmr_before ? "true" : "false");
> }
>
> -#define IPI_DELAY 1000000
> -
> -static void delay(int count)
> -{
> - while(count--) asm("");
> -}
> -
> static void toggle_irq_line_0x0e(void *data)
> {
> irq_disable();
>
