The following commit has been merged into the x86/apic branch of tip:
Commit-ID: 058df195c23403f91acc028e39ca2ad599d0af52
Gitweb:
https://git.kernel.org/tip/058df195c23403f91acc028e39ca2ad599d0af52
Author: Thomas Gleixner <[email protected]>
AuthorDate: Thu, 10 Dec 2020 21:15:04 +01:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Thu, 10 Dec 2020 23:02:31 +01:00
x86/ioapic: Cleanup the timer_works() irqflags mess
Mark tripped over the creative irqflags handling in the IO-APIC timer
delivery check which ends up doing:
local_irq_save(flags);
local_irq_enable();
local_irq_restore(flags);
which triggered a new consistency check he's working on required for
replacing the POPF based restore with a conditional STI.
That code is a historical mess and none of this is needed. Make it
straightforward use local_irq_disable()/enable() as that's all what is
required. It is invoked from interrupt enabled code nowadays.
Reported-by: Mark Rutland <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Mark Rutland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/kernel/apic/io_apic.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 089e755..e4ab480 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1620,21 +1620,16 @@ static void __init delay_without_tsc(void)
static int __init timer_irq_works(void)
{
unsigned long t1 = jiffies;
- unsigned long flags;
if (no_timer_check)
return 1;
- local_save_flags(flags);
local_irq_enable();
-
if (boot_cpu_has(X86_FEATURE_TSC))
delay_with_tsc();
else
delay_without_tsc();
- local_irq_restore(flags);
-
/*
* Expect a few ticks at least, to be sure some possible
* glue logic does not lock up after one or two first
@@ -1643,10 +1638,10 @@ static int __init timer_irq_works(void)
* least one tick may be lost due to delays.
*/
- /* jiffies wrap? */
- if (time_after(jiffies, t1 + 4))
- return 1;
- return 0;
+ local_irq_disable();
+
+ /* Did jiffies advance? */
+ return time_after(jiffies, t1 + 4);
}
/*
@@ -2163,13 +2158,12 @@ static inline void __init check_timer(void)
struct irq_cfg *cfg = irqd_cfg(irq_data);
int node = cpu_to_node(0);
int apic1, pin1, apic2, pin2;
- unsigned long flags;
int no_pin1 = 0;
if (!global_clock_event)
return;
- local_irq_save(flags);
+ local_irq_disable();
/*
* get/set the timer IRQ vector:
@@ -2237,7 +2231,6 @@ static inline void __init check_timer(void)
goto out;
}
panic_if_irq_remap("timer doesn't work through
Interrupt-remapped IO-APIC");
- local_irq_disable();
clear_IO_APIC_pin(apic1, pin1);
if (!no_pin1)
apic_printk(APIC_QUIET, KERN_ERR "..MP-BIOS bug: "
@@ -2261,7 +2254,6 @@ static inline void __init check_timer(void)
/*
* Cleanup, just in case ...
*/
- local_irq_disable();
legacy_pic->mask(0);
clear_IO_APIC_pin(apic2, pin2);
apic_printk(APIC_QUIET, KERN_INFO "....... failed.\n");
@@ -2278,7 +2270,6 @@ static inline void __init check_timer(void)
apic_printk(APIC_QUIET, KERN_INFO "..... works.\n");
goto out;
}
- local_irq_disable();
legacy_pic->mask(0);
apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_FIXED | cfg->vector);
apic_printk(APIC_QUIET, KERN_INFO "..... failed.\n");
@@ -2297,7 +2288,6 @@ static inline void __init check_timer(void)
apic_printk(APIC_QUIET, KERN_INFO "..... works.\n");
goto out;
}
- local_irq_disable();
apic_printk(APIC_QUIET, KERN_INFO "..... failed :(.\n");
if (apic_is_x2apic_enabled())
apic_printk(APIC_QUIET, KERN_INFO
@@ -2306,7 +2296,7 @@ static inline void __init check_timer(void)
panic("IO-APIC + timer doesn't work! Boot with apic=debug and send a "
"report. Then try booting with the 'noapic' option.\n");
out:
- local_irq_restore(flags);
+ local_irq_enable();
}
/*
