Fix gdb issue where the i-cache was not being updated when a breakpoint

was written into a user's address space. The fix is to modify uiomove_fromphys
to sync the icache when an executable user-space page is written into.

Alan Cox suggested that there should probably be a higher-level interface
to this in the ptrace code, but agreed that this is an OK short-term solution.

Files changed:

pmap.h - declaration of pmap_page_executable()
pmap_dispatch.c - pass through the page_executable call to the mmu object
mmu_oea.c - implement the page_executable method by examining the PTE_EXEC
 field in the vm_page_t
uio_machdep.c - in uiomove_fromphys(), if the op was a UIO_WRITE to user-space,
 and if the page is executable, sync the icache since this is at the least
 a breakpoint-write from gdb.

Reported by:	marcel
Tested by:	marcel, grehan on g3+g4
Discussed with:	alc
MFC after:	2 weeks

1 files changed, 5 insertions, 1 deletions

diff --git a/sys/powerpc/aim/uio_machdep.c b/sys/powerpc/aim/uio_machdep.c
index bd2f1b4..a52f729 100644
--- a/sys/powerpc/aim/uio_machdep.c
+++ b/sys/powerpc/aim/uio_machdep.c
@@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$");
 #include <vm/vm.h>
 #include <vm/vm_page.h>
 
+#include <machine/cpu.h>
 #include <machine/vmparam.h>
 
 /*
@@ -92,10 +93,13 @@ uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
 				uio_yield();
 			if (uio->uio_rw == UIO_READ)
 				error = copyout(cp, iov->iov_base, cnt);
-			else
+			else 
 				error = copyin(iov->iov_base, cp, cnt);
 			if (error)
 				goto out;
+			if (uio->uio_rw == UIO_WRITE &&
+			    pmap_page_executable(ma[offset >> PAGE_SHIFT]))
+				__syncicache(cp, cnt);
 			break;
 		case UIO_SYSSPACE:
 			if (uio->uio_rw == UIO_READ)