Improve PCB flags handling and make it more robust. Add two new functions

for manipulating pcb_flags.  These inline functions are very similar to
atomic_set_char(9) and atomic_clear_char(9) but without unnecessary LOCK
prefix for SMP.  Add comments about the rationale[1].  Use these functions
wherever possible.  Although there are some places where it is not strictly
necessary (e.g., a PCB is copied to create a new PCB), it is done across
the board for sake of consistency.  Turn pcb_full_iret into a PCB flag as
it is safe now.  Move rarely used fields before pcb_flags and reduce size
of pcb_flags to one byte.  Fix some style(9) nits in pcb.h while I am in
the neighborhood.

Reviewed by:	kib
Submitted by:	kib[1]
MFC after:	2 months

1 files changed, 6 insertions, 7 deletions

diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
index 3ebb980f26f3..674a286e1e33 100644
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -422,7 +422,7 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	regs->tf_fs = _ufssel;
 	regs->tf_gs = _ugssel;
 	regs->tf_flags = TF_HASSEGS;
-	td->td_pcb->pcb_full_iret = 1;
+	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
 	PROC_LOCK(p);
 	mtx_lock(&psp->ps_mtx);
 }
@@ -545,7 +545,7 @@ linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	regs->tf_fs = _ufssel;
 	regs->tf_gs = _ugssel;
 	regs->tf_flags = TF_HASSEGS;
-	td->td_pcb->pcb_full_iret = 1;
+	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
 	PROC_LOCK(p);
 	mtx_lock(&psp->ps_mtx);
 }
@@ -643,7 +643,7 @@ linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 	regs->tf_rflags = eflags;
 	regs->tf_rsp    = frame.sf_sc.sc_esp_at_signal;
 	regs->tf_ss     = frame.sf_sc.sc_ss;
-	td->td_pcb->pcb_full_iret = 1;
+	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
 
 	return (EJUSTRETURN);
 }
@@ -742,7 +742,7 @@ linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
 	regs->tf_rflags = eflags;
 	regs->tf_rsp    = context->sc_esp_at_signal;
 	regs->tf_ss     = context->sc_ss;
-	td->td_pcb->pcb_full_iret = 1;
+	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
 
 	/*
 	 * call sigaltstack & ignore results..
@@ -869,9 +869,8 @@ exec_linux_setregs(struct thread *td, struct image_params *imgp, u_long stack)
 	fpstate_drop(td);
 
 	/* Do full restore on return so that we can change to a different %cs */
-	pcb->pcb_flags |= PCB_32BIT;
-	pcb->pcb_flags &= ~PCB_GS32BIT;
-	pcb->pcb_full_iret = 1;
+	set_pcb_flags(pcb, PCB_32BIT | PCB_FULL_IRET);
+	clear_pcb_flags(pcb, PCB_GS32BIT);
 	td->td_retval[1] = 0;
 }