From 1b3c32568ab513ea2ba8ac39b0debdd39fd448b7 Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Tue, 7 Dec 2010 12:44:33 +0000 Subject: [PATCH] Update some comments related to use of amd64 full context switch. In exec_linux_setregs(), use locally cached pointer to pcb to set pcb_full_iret. In set_regs(), note that full return is needed when code that sets segment registers is enabled. MFC after: 1 week --- sys/amd64/amd64/machdep.c | 1 + sys/amd64/amd64/vm_machdep.c | 5 ++--- sys/amd64/linux32/linux32_sysvec.c | 4 ++-- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c index d09ae4ad0e6..fe4deb7b4a4 100644 --- a/sys/amd64/amd64/machdep.c +++ b/sys/amd64/amd64/machdep.c @@ -1906,6 +1906,7 @@ set_regs(struct thread *td, struct reg *regs) tp->tf_fs = regs->r_fs; tp->tf_gs = regs->r_gs; tp->tf_flags = TF_HASSEGS; + td->td_pcb->pcb_full_iret = 1; } return (0); } diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c index 2a93bc17bef..b966393b1d4 100644 --- a/sys/amd64/amd64/vm_machdep.c +++ b/sys/amd64/amd64/vm_machdep.c @@ -339,10 +339,9 @@ cpu_set_syscall_retval(struct thread *td, int error) * Reconstruct pc, we know that 'syscall' is 2 bytes, * lcall $X,y is 7 bytes, int 0x80 is 2 bytes. * We saved this in tf_err. - * We have to do a full context restore so that %r10 - * (which was holding the value of %rcx) is restored + * %r10 (which was holding the value of %rcx) is restored * for the next iteration. - * r10 restore is only required for freebsd/amd64 processes, + * %r10 restore is only required for freebsd/amd64 processes, * but shall be innocent for any ia32 ABI. */ td->td_frame->tf_rip -= td->td_frame->tf_err; diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c index 0dbcef4127f..3ebb980f26f 100644 --- a/sys/amd64/linux32/linux32_sysvec.c +++ b/sys/amd64/linux32/linux32_sysvec.c @@ -865,13 +865,13 @@ exec_linux_setregs(struct thread *td, struct image_params *imgp, u_long stack) regs->tf_flags = TF_HASSEGS; regs->tf_cs = _ucode32sel; regs->tf_rbx = imgp->ps_strings; - td->td_pcb->pcb_full_iret = 1; load_cr0(rcr0() | CR0_MP | CR0_TS); fpstate_drop(td); - /* Return via doreti so that we can change to a different %cs */ + /* 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; td->td_retval[1] = 0; }