CVS commit: src/sys/arch/i386

["Manuel Bouyer" <bouyer%netbsd.org@localhost>]

Module Name:    src
Committed By:   bouyer
Date:           Sat Jan 17 10:59:10 UTC 2026

Modified Files:
        src/sys/arch/i386/i386: i386_trap.S locore.S spl.S
        src/sys/arch/i386/include: frameasm.h

Log Message:
Port amd64 fix for PR port-xen/58561 to i386, with one extra fix:
with recent Xen (maybe since pvshim), traps handlers are called with
interrupts enabled, so adjust the i386 assembly code for this.
updating curcup()->ci_vcpu->evtchn_upcall_mask requires 2 intructions, e.g.
movl CPUVAR(VCPU),reg
movb $1,EVTCHN_UPCALL_MASK(reg)
With preemption enabled we may be moved to another CPU between the
2 intructions and we end up updating the evtchn_upcall_mask of another VCPU
than the one we're now running on.
Fix for Xen/i386:
- Add a CLI2 macro, which disables preemtion before the above sequence.
  Use it instead of CLI where preemtion may be enabled
- Add DIAGNOSTIC code to check that preemtion is disabled in CLI
- Add DIAGNOSTIC code to check that interrupts are disabled when calling STI     and STIC
- rename PUSHF to PUSHFCLI and change it to both read and disable
  EVTCHN_UPCALL_MASK with preemption disabled
- remove the XENPVHVM version of STIC which is unused


To generate a diff of this commit:
cvs rdiff -u -r1.24 -r1.25 src/sys/arch/i386/i386/i386_trap.S
cvs rdiff -u -r1.205 -r1.206 src/sys/arch/i386/i386/locore.S
cvs rdiff -u -r1.58 -r1.59 src/sys/arch/i386/i386/spl.S
cvs rdiff -u -r1.35 -r1.36 src/sys/arch/i386/include/frameasm.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.