setup: Move unmask of async interrupts after possible earlycon setup

The kernel wants to enable reporting of asynchronous interrupts (i.e. System Errors) as early as possible. But if this happens too early then a pending System Error on initial entry into the kernel will never be reported where a user can see it (instead it will remain in the kernel ring buffer and be visible only via hardware debug). Therefore, move the enabling of asynchronous interrupts to after parsing any possible earlycon parameters setting up earlycon.

Signed-off-by Jon Masters <[email protected]>

---
 arch/arm64/kernel/setup.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

arch/arm64/kernel/setup.c +6 -6

index f6f0ccf..f849b88 100644
@@ -362,11 +362,6 @@ u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID };
 
 void __init setup_arch(char **cmdline_p)
 {
-       /*
-        * Unmask asynchronous aborts early to catch possible system errors.
-        */
-       local_async_enable();
-
        setup_processor();
 
        setup_machine_fdt(__fdt_pointer);

@@ -382,6 +377,12 @@ void __init setup_arch(char **cmdline_p)
 
        parse_early_param();
 
+       /*
+        *  Unmask asynchronous aborts after bringing up possible earlycon.
+        * (Report possible System Errors once we can report this occurred)
+        */
+       local_async_enable();
+
        efi_init();
        arm64_memblock_init();
 
--

1.8.3.1

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Quoted 8 lines · Jon Masters

The kernel wants to enable reporting of asynchronous interrupts (i.e. System Errors) as early as possible. But if this happens too early then a pending System Error on initial entry into the kernel will never be reported where a user can see it (instead it will remain in the kernel ring buffer and be visible only via hardware debug). Therefore, move the enabling of asynchronous interrupts to after parsing any possible earlycon parameters setting up earlycon.

Quoted 1 line

Signed-off-by Jon Masters <[email protected]>

That sounds wrong. Why aren't early log messages getting flushed out when the console shows up?

Hi Grant,

Quoted 9 lines · Grant Likely

Quoted 8 lines · Jon Masters

The kernel wants to enable reporting of asynchronous interrupts (i.e. System Errors) as early as possible. But if this happens too early then a pending System Error on initial entry into the kernel will never be reported where a user can see it (instead it will remain in the kernel ring buffer and be visible only via hardware debug). Therefore, move the enabling of asynchronous interrupts to after parsing any possible earlycon parameters setting up earlycon.

Quoted 4 lines

Quoted 1 line

Signed-off-by Jon Masters <[email protected]>

That sounds wrong. Why aren't early log messages getting flushed out when the console shows up?

The problem is that when such an error occurs, we immediately panic. And we've not setup the earlycon yet so there's no way to ever see it. I wasted a bunch of time last week so it's worth saving someone else.

Quoted 14 lines · Jon Masters

Hi Grant,

Quoted 11 lines · Grant Likely

Quoted 9 lines · Jon Masters

The kernel wants to enable reporting of asynchronous interrupts (i.e. System Errors) as early as possible. But if this happens too early then a pending System Error on initial entry into the kernel will never be reported where a user can see it (instead it will remain in the kernel ring buffer and be visible only via hardware debug). Therefore, move the enabling of asynchronous interrupts to after parsing any possible earlycon parameters setting up earlycon.

Signed-off-by Jon Masters <[email protected]>

Quoted 6 lines

Quoted 2 lines

That sounds wrong. Why aren't early log messages getting flushed out when the console shows up?

The problem is that when such an error occurs, we immediately panic. And we've not setup the earlycon yet so there's no way to ever see it. I wasted a bunch of time last week so it's worth saving someone else.

Reasonable reason. Perhaps put that in the patch description.

Hi Grant,

Quoted 9 lines · Grant Likely

Quoted 8 lines · Jon Masters

The kernel wants to enable reporting of asynchronous interrupts (i.e. System Errors) as early as possible. But if this happens too early then a pending System Error on initial entry into the kernel will never be reported where a user can see it (instead it will remain in the kernel ring buffer and be visible only via hardware debug). Therefore, move the enabling of asynchronous interrupts to after parsing any possible earlycon parameters setting up earlycon.

Quoted 4 lines

Quoted 1 line

Signed-off-by Jon Masters <[email protected]>

That sounds wrong. Why aren't early log messages getting flushed out when the console shows up?

The problem is that when such an error occurs, we immediately panic. And we've not setup the earlycon yet so there's no way to ever see it. I wasted a bunch of time last week so it's worth saving someone else.