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[COMMITTED] ada: Adjust QNX Ada priorities to match QNX system priorities

Message ID 20230615080413.939627-1-poulhies@adacore.com
State Committed
Commit b36be75b29d7fc5c6ab3c48229f9521ae91c6a2c
Headers
Series [COMMITTED] ada: Adjust QNX Ada priorities to match QNX system priorities |

Checks

Context Check Description
linaro-tcwg-bot/tcwg_gcc_check--master-aarch64 fail Patch failed to apply
linaro-tcwg-bot/tcwg_gcc_build--master-arm fail Patch failed to apply
linaro-tcwg-bot/tcwg_gcc_build--master-aarch64 fail Patch failed to apply
linaro-tcwg-bot/tcwg_gcc_check--master-arm success Testing passed

Commit Message

Marc Poulhiès June 15, 2023, 8:04 a.m. UTC 
  From: Johannes Kliemann <kliemann@adacore.com>

The Ada priority range of the QNX runtime started from 0, differing from
the QNX system priorities range starting from 1. As this may cause
confusion, especially if used in a mixed language environment, the Ada
priority range now starts at 1.

The default priority of Ada tasks as mandated is the middle of the
priority range. On QNX this means the default priority of Ada tasks is
30. This is much higher than the default QNX priority of 10 and may
cause unexpected system interruptions when Ada tasks take a lot of CPU time.

gcc/ada/

	* libgnarl/s-osinte__qnx.adb: Adjust priority conversion function.
	* libgnat/system-qnx-arm.ads: Adjust priority range and default
	priority.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/libgnarl/s-osinte__qnx.adb |  2 +-
 gcc/ada/libgnat/system-qnx-arm.ads | 14 ++++++--------
 2 files changed, 7 insertions(+), 9 deletions(-)
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Patch

diff --git a/gcc/ada/libgnarl/s-osinte__qnx.adb b/gcc/ada/libgnarl/s-osinte__qnx.adb
index bf08ecbf4dd..127d1795a35 100644
--- a/gcc/ada/libgnarl/s-osinte__qnx.adb
+++ b/gcc/ada/libgnarl/s-osinte__qnx.adb
@@ -87,7 +87,7 @@  package body System.OS_Interface is
      (Prio : System.Any_Priority) return Interfaces.C.int
    is
    begin
-      return Interfaces.C.int (Prio) + 1;
+      return Interfaces.C.int (Prio);
    end To_Target_Priority;
 
    -----------------
diff --git a/gcc/ada/libgnat/system-qnx-arm.ads b/gcc/ada/libgnat/system-qnx-arm.ads
index 344bd6168f3..1dd1a2228e9 100644
--- a/gcc/ada/libgnat/system-qnx-arm.ads
+++ b/gcc/ada/libgnat/system-qnx-arm.ads
@@ -95,22 +95,20 @@  package System is
 
    --  Priority-related Declarations (RM D.1)
 
-   --  System priority is Ada priority + 1, so lies in the range 1 .. 63.
-   --
    --  If the scheduling policy is SCHED_FIFO or SCHED_RR the runtime makes use
    --  of the entire range provided by the system.
    --
    --  If the scheduling policy is SCHED_OTHER the only valid system priority
    --  is 1 and other values are simply ignored.
 
-   Max_Priority           : constant Positive := 61;
-   Max_Interrupt_Priority : constant Positive := 62;
+   Max_Priority           : constant Positive := 62;
+   Max_Interrupt_Priority : constant Positive := 63;
 
-   subtype Any_Priority       is Integer      range  0 .. 62;
-   subtype Priority           is Any_Priority range  0 .. 61;
-   subtype Interrupt_Priority is Any_Priority range 62 .. 62;
+   subtype Any_Priority       is Integer      range  1 .. 63;
+   subtype Priority           is Any_Priority range  1 .. 62;
+   subtype Interrupt_Priority is Any_Priority range 63 .. 63;
 
-   Default_Priority : constant Priority := 30;
+   Default_Priority : constant Priority := 10;
 
 private