diff options
| -rw-r--r-- | sys/ia64/ia64/machdep.c | 75 |
1 files changed, 30 insertions, 45 deletions
diff --git a/sys/ia64/ia64/machdep.c b/sys/ia64/ia64/machdep.c index 00cab57..1779341 100644 --- a/sys/ia64/ia64/machdep.c +++ b/sys/ia64/ia64/machdep.c @@ -1112,9 +1112,15 @@ set_mcontext(struct thread *td, const mcontext_t *mc) struct trapframe *tf; tf = td->td_frame; + + KASSERT((tf->tf_special.ndirty & ~PAGE_MASK) == 0, + ("Whoa there! We have more than 8KB of dirty registers!")); + s = mc->mc_special; /* Only copy the user mask from the new context. */ s.psr = (s.psr & 0x1f) | (tf->tf_special.psr & ~0x1f); + /* We don't have any dirty registers of the new context. */ + s.ndirty = 0; if (mc->mc_flags & _MC_FLAGS_ASYNC_CONTEXT) { tf->tf_scratch = mc->mc_scratch; tf->tf_scratch_fp = mc->mc_scratch_fp; @@ -1171,67 +1177,46 @@ void exec_setregs(struct thread *td, u_long entry, u_long stack, u_long ps_strings) { struct trapframe *tf; - uint64_t bspst, kstack, ndirty; - size_t rssz; + uint64_t *ksttop, *kst; tf = td->td_frame; - kstack = td->td_kstack; + ksttop = (uint64_t*)(td->td_kstack + tf->tf_special.ndirty); /* - * RSE magic: We have ndirty registers of the process on the kernel - * stack which don't belong to the new image. Discard them. Note - * that for the "legacy" syscall support we need to keep 3 registers - * worth of dirty bytes. These 3 registers are the initial arguments - * to the newly executing program. - * However, we cannot discard all the ndirty registers by simply - * moving the kernel related registers to the bottom of the kernel - * stack and lowering the current bspstore, because we get into - * trouble with the NaT collections. We need to keep that in sync - * with the registers. Hence, we can only copy a multiple of 512 - * bytes. Consequently, we may end up with some registers of the - * previous image on the kernel stack. This we ignore by making - * sure we mask-off the lower 9 bits of the bspstore value just - * prior to saving it in ar.k6. + * We can ignore up to 8KB of dirty registers by masking off the + * lower 13 bits in exception_restore() or epc_syscall(). This + * should be enough for a couple of years, but if there are more + * than 8KB of dirty registers, we lose track of the bottom of + * the kernel stack. The solution is to copy the active part of + * the kernel stack down 1 page (or 2, but not more than that) + * so that we always have less than 8KB of dirty registers. */ - ndirty = tf->tf_special.ndirty & ~0x1ff; - if (ndirty > 0) { - __asm __volatile("mov ar.rsc=0;;"); - __asm __volatile("mov %0=ar.bspstore" : "=r"(bspst)); - /* - * Make sure we have all the user registers written out. - * We're doing culculations with ndirty and ar.bspstore - * and we better make sure ar.bspstore >= ndirty. - */ - rssz = bspst - kstack; - if (rssz < ndirty) { - __asm __volatile("flushrs;;"); - __asm __volatile("mov %0=ar.bspstore" : "=r"(bspst)); - rssz = bspst - kstack; - } - bcopy((void*)(kstack + ndirty), (void*)kstack, rssz - ndirty); - bspst -= ndirty; - __asm __volatile("mov ar.bspstore=%0;;" :: "r"(bspst)); - __asm __volatile("mov ar.rsc=3"); - tf->tf_special.ndirty -= ndirty; - } - ndirty = tf->tf_special.ndirty; + KASSERT((tf->tf_special.ndirty & ~PAGE_MASK) == 0, + ("Whoa there! We have more than 8KB of dirty registers!")); bzero(&tf->tf_special, sizeof(tf->tf_special)); - if ((tf->tf_flags & FRAME_SYSCALL) == 0) { /* break syscalls. */ bzero(&tf->tf_scratch, sizeof(tf->tf_scratch)); bzero(&tf->tf_scratch_fp, sizeof(tf->tf_scratch_fp)); tf->tf_special.iip = entry; tf->tf_special.cfm = (1UL<<63) | (3UL<<7) | 3UL; tf->tf_special.bspstore = td->td_md.md_bspstore; - tf->tf_special.ndirty = 24; /* * Copy the arguments onto the kernel register stack so that - * they get loaded by the loadrs instruction. + * they get loaded by the loadrs instruction. Skip over the + * NaT collection points. */ - *(uint64_t*)(kstack + ndirty - 24) = stack; - *(uint64_t*)(kstack + ndirty - 16) = ps_strings; - *(uint64_t*)(kstack + ndirty - 8) = 0; + kst = ksttop - 1; + if (((uintptr_t)kst & 0x1ff) == 0x1f8) + *kst-- = 0; + *kst-- = 0; + if (((uintptr_t)kst & 0x1ff) == 0x1f8) + *kst-- = 0; + *kst-- = ps_strings; + if (((uintptr_t)kst & 0x1ff) == 0x1f8) + *kst-- = 0; + *kst = stack; + tf->tf_special.ndirty = (ksttop - kst) << 3; } else { /* epc syscalls (default). */ tf->tf_special.rp = entry; tf->tf_special.pfs = (3UL<<62) | (3UL<<7) | 3UL; |
