[PATCH] hwasan: Check if Intel LAM_U57 is enabled

["H.J. Lu" <hjl.tools@gmail.com>]

When -fsanitize=hwaddress is used, libhwasan will try to enable LAM_U57
in the startup code.  Update the target check to enable hwaddress tests
if LAM_U57 is enabled.  Also compile hwaddress tests with -mlam=u57 on
x86-64 since hwasan requires LAM_U57 on x86-64.

	* lib/hwasan-dg.exp (check_effective_target_hwaddress_exec):
	Return 1 if Intel LAM_U57 is enabled.
	(hwasan_init): Add -mlam=u57 on x86-64.
---
 gcc/testsuite/lib/hwasan-dg.exp | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/gcc/testsuite/lib/hwasan-dg.exp b/gcc/testsuite/lib/hwasan-dg.exp
index e9c5ef6524d..76057502ee6 100644
--- a/gcc/testsuite/lib/hwasan-dg.exp
+++ b/gcc/testsuite/lib/hwasan-dg.exp
@@ -44,11 +44,25 @@ proc check_effective_target_hwaddress_exec {} {
 	#ifdef __cplusplus
 	extern "C" {
 	#endif
+	extern int arch_prctl (int, unsigned long int *);
 	extern int prctl(int, unsigned long, unsigned long, unsigned long, unsigned long);
 	#ifdef __cplusplus
 	}
 	#endif
 	int main (void) {
+	#ifdef __x86_64__
+	# ifdef __LP64__
+	#  define ARCH_GET_UNTAG_MASK 0x4001
+	#  define LAM_U57_MASK (0x3fULL << 57)
+	  unsigned long mask = 0;
+	  if (arch_prctl(ARCH_GET_UNTAG_MASK, &mask) != 0)
+	    return 1;
+	  if (mask != ~LAM_U57_MASK)
+	    return 1;
+	  return 0;
+	# endif
+	  return 1;
+	#else
 	#define PR_SET_TAGGED_ADDR_CTRL 55
 	#define PR_GET_TAGGED_ADDR_CTRL 56
 	#define PR_TAGGED_ADDR_ENABLE (1UL << 0)
@@ -58,6 +72,7 @@ proc check_effective_target_hwaddress_exec {} {
 	      || !prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0))
 	    return 1;
 	  return 0;
+	#endif
 	}
     }] {
 	return 0;
@@ -102,6 +117,10 @@ proc hwasan_init { args } {
 
     setenv HWASAN_OPTIONS "random_tags=0"
 
+    if [istarget x86_64-*-*] {
+      set target_hwasan_flags "-mlam=u57"
+    }
+
     set link_flags ""
     if ![is_remote host] {
 	if [info exists TOOL_OPTIONS] {
@@ -119,12 +138,12 @@ proc hwasan_init { args } {
     if [info exists ALWAYS_CXXFLAGS] {
 	set hwasan_saved_ALWAYS_CXXFLAGS $ALWAYS_CXXFLAGS
 	set ALWAYS_CXXFLAGS [concat "{ldflags=$link_flags}" $ALWAYS_CXXFLAGS]
-	set ALWAYS_CXXFLAGS [concat "{additional_flags=-fsanitize=hwaddress --param hwasan-random-frame-tag=0 -g $include_flags}" $ALWAYS_CXXFLAGS]
+	set ALWAYS_CXXFLAGS [concat "{additional_flags=-fsanitize=hwaddress $target_hwasan_flags --param hwasan-random-frame-tag=0 -g $include_flags}" $ALWAYS_CXXFLAGS]
     } else {
 	if [info exists TEST_ALWAYS_FLAGS] {
-	    set TEST_ALWAYS_FLAGS "$link_flags -fsanitize=hwaddress --param hwasan-random-frame-tag=0 -g $include_flags $TEST_ALWAYS_FLAGS"
+	    set TEST_ALWAYS_FLAGS "$link_flags -fsanitize=hwaddress $target_hwasan_flags --param hwasan-random-frame-tag=0 -g $include_flags $TEST_ALWAYS_FLAGS"
 	} else {
-	    set TEST_ALWAYS_FLAGS "$link_flags -fsanitize=hwaddress --param hwasan-random-frame-tag=0 -g $include_flags"
+	    set TEST_ALWAYS_FLAGS "$link_flags -fsanitize=hwaddress $target_hwasan_flags --param hwasan-random-frame-tag=0 -g $include_flags"
 	}
     }
 }
-- 
2.43.0