vx32

commit d2d43ccb6890cbd0afaaa45a24db7b8d6b05129c
parent e353c388b738920a4b17c7630c3ddc597e2c09d5
Author: Russ Cox <rsc@swtch.com>
Date:   Sun, 29 Jun 2008 21:33:11 -0400

[merge]

Diffstat:
src/9vx/vx32.c
 | 
5
+----
src/libvx32/linux.c
 | 
6
+++++-

2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/src/9vx/vx32.c b/src/9vx/vx32.c
@@ -260,10 +260,7 @@ touser(void *initsp)
 		if(rc == VXTRAP_PAGEFAULT){
 			int read;
 			nfaults++;
-			if(vp->cpu->traperr == 0xffffffff)
-				read = -1;
-			else
-				read = !(vp->cpu->traperr & 2);
+			read = !(vp->cpu->traperr & 2);
 			addr = (uchar*)vp->cpu->trapva;
 			if(traceprocs)
 				print("fault %p read=%d\n", addr, read);
diff --git a/src/libvx32/linux.c b/src/libvx32/linux.c
@@ -320,7 +320,11 @@ int vx32_sighandler(int signo, siginfo_t *si, void *v)
 		if (emu->trapenv == NULL)
 			return 0;
 		emu->cpu.traperr = ctx->err;
-		emu->cpu.trapva = ctx->cr2;
+		// Usually, ctx->cr2 == si->si_addr.
+		// But on a segmentation fault (as opposed to a paging fault),
+		// cr2 is not updated and the kernel sends an si_addr == 0.
+		// Be sure to use si_addr, not cr2.
+		emu->cpu.trapva = (uint32_t)si->si_addr;
 		memmove(mc->gregs, emu->trapenv->gregs, 19*4);
 		return 1;
 	}