svn commit: r366665 - in head: sys/arm64/arm64 tests/sys/vm

[Andrew Turner]

Author: andrew
Date: Tue Oct 13 10:26:15 2020
New Revision: 366665
URL: https://svnweb.freebsd.org/changeset/base/366665

Log:
  Fix write only mappings on arm64
  
  When trapping on a wrote access to a buffer the kernel has mapped as write
  only we should only pass the VM_PROT_WRITE flag. Previously the call to
  vm_fault_trap as the VM_PROT_READ flag was unexpected.
  
  Reported by:	manu
  Sponsored by:	Innovate UK

Modified:
  head/sys/arm64/arm64/trap.c
  head/tests/sys/vm/mmap_test.c

Modified: head/sys/arm64/arm64/trap.c
==============================================================================
--- head/sys/arm64/arm64/trap.c	Tue Oct 13 08:14:33 2020	(r366664)
+++ head/sys/arm64/arm64/trap.c	Tue Oct 13 10:26:15 2020	(r366665)
@@ -301,7 +301,7 @@ data_abort(struct thread *td, struct trapframe *frame,
 		break;
 	default:
 		ftype = (esr & ISS_DATA_WnR) == 0 ? VM_PROT_READ :
-		    VM_PROT_READ | VM_PROT_WRITE;
+		    VM_PROT_WRITE;
 		break;
 	}
 

Modified: head/tests/sys/vm/mmap_test.c
==============================================================================
--- head/tests/sys/vm/mmap_test.c	Tue Oct 13 08:14:33 2020	(r366664)
+++ head/tests/sys/vm/mmap_test.c	Tue Oct 13 10:26:15 2020	(r366665)
@@ -259,6 +259,21 @@ ATF_TC_BODY(mmap__dev_zero_shared, tc)
 	close(fd);
 }
 
+ATF_TC_WITHOUT_HEAD(mmap__write_only);
+ATF_TC_BODY(mmap__write_only, tc)
+{
+	void *p;
+	int pagesize;
+
+	ATF_REQUIRE((pagesize = getpagesize()) > 0);
+	p = mmap(NULL, pagesize, PROT_WRITE, MAP_ANON, -1, 0);
+	ATF_REQUIRE(p != MAP_FAILED);
+
+	*(volatile uint32_t *)p = 0x12345678;
+
+	munmap(p, pagesize);
+}
+
 ATF_TP_ADD_TCS(tp)
 {
 
@@ -266,6 +281,7 @@ ATF_TP_ADD_TCS(tp)
 	ATF_TP_ADD_TC(tp, mmap__bad_arguments);
 	ATF_TP_ADD_TC(tp, mmap__dev_zero_private);
 	ATF_TP_ADD_TC(tp, mmap__dev_zero_shared);
+	ATF_TP_ADD_TC(tp, mmap__write_only);
 
 	return (atf_no_error());
 }