1 files changed, 81 insertions, 10 deletions

diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c
index 4177f9507bbe..4e4aa006004c 100644
--- a/tools/testing/selftests/rseq/rseq.c
+++ b/tools/testing/selftests/rseq/rseq.c
@@ -28,6 +28,8 @@
 #include <limits.h>
 #include <dlfcn.h>
 #include <stddef.h>
+#include <sys/auxv.h>
+#include <linux/auxvec.h>
 
 #include "../kselftest.h"
 #include "rseq.h"
@@ -36,20 +38,38 @@ static const ptrdiff_t *libc_rseq_offset_p;
 static const unsigned int *libc_rseq_size_p;
 static const unsigned int *libc_rseq_flags_p;
 
-/* Offset from the thread pointer to the rseq area.  */
+/* Offset from the thread pointer to the rseq area. */
 ptrdiff_t rseq_offset;
 
-/* Size of the registered rseq area.  0 if the registration was
-   unsuccessful.  */
+/*
+ * Size of the registered rseq area. 0 if the registration was
+ * unsuccessful.
+ */
 unsigned int rseq_size = -1U;
 
 /* Flags used during rseq registration.  */
 unsigned int rseq_flags;
 
+/*
+ * rseq feature size supported by the kernel. 0 if the registration was
+ * unsuccessful.
+ */
+unsigned int rseq_feature_size = -1U;
+
 static int rseq_ownership;
+static int rseq_reg_success;	/* At least one rseq registration has succeded. */
+
+/* Allocate a large area for the TLS. */
+#define RSEQ_THREAD_AREA_ALLOC_SIZE	1024
+
+/* Original struct rseq feature size is 20 bytes. */
+#define ORIG_RSEQ_FEATURE_SIZE		20
+
+/* Original struct rseq allocation size is 32 bytes. */
+#define ORIG_RSEQ_ALLOC_SIZE		32
 
 static
-__thread struct rseq_abi __rseq_abi __attribute__((tls_model("initial-exec"))) = {
+__thread struct rseq_abi __rseq_abi __attribute__((tls_model("initial-exec"), aligned(RSEQ_THREAD_AREA_ALLOC_SIZE))) = {
 	.cpu_id = RSEQ_ABI_CPU_ID_UNINITIALIZED,
 };
 
@@ -59,6 +79,11 @@ static int sys_rseq(struct rseq_abi *rseq_abi, uint32_t rseq_len,
 	return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
 }
 
+static int sys_getcpu(unsigned *cpu, unsigned *node)
+{
+	return syscall(__NR_getcpu, cpu, node, NULL);
+}
+
 int rseq_available(void)
 {
 	int rc;
@@ -84,10 +109,16 @@ int rseq_register_current_thread(void)
 		/* Treat libc's ownership as a successful registration. */
 		return 0;
 	}
-	rc = sys_rseq(&__rseq_abi, sizeof(struct rseq_abi), 0, RSEQ_SIG);
-	if (rc)
+	rc = sys_rseq(&__rseq_abi, rseq_size, 0, RSEQ_SIG);
+	if (rc) {
+		if (RSEQ_READ_ONCE(rseq_reg_success)) {
+			/* Incoherent success/failure within process. */
+			abort();
+		}
 		return -1;
+	}
 	assert(rseq_current_cpu_raw() >= 0);
+	RSEQ_WRITE_ONCE(rseq_reg_success, 1);
 	return 0;
 }
 
@@ -99,12 +130,28 @@ int rseq_unregister_current_thread(void)
 		/* Treat libc's ownership as a successful unregistration. */
 		return 0;
 	}
-	rc = sys_rseq(&__rseq_abi, sizeof(struct rseq_abi), RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
+	rc = sys_rseq(&__rseq_abi, rseq_size, RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
 	if (rc)
 		return -1;
 	return 0;
 }
 
+static
+unsigned int get_rseq_feature_size(void)
+{
+	unsigned long auxv_rseq_feature_size, auxv_rseq_align;
+
+	auxv_rseq_align = getauxval(AT_RSEQ_ALIGN);
+	assert(!auxv_rseq_align || auxv_rseq_align <= RSEQ_THREAD_AREA_ALLOC_SIZE);
+
+	auxv_rseq_feature_size = getauxval(AT_RSEQ_FEATURE_SIZE);
+	assert(!auxv_rseq_feature_size || auxv_rseq_feature_size <= RSEQ_THREAD_AREA_ALLOC_SIZE);
+	if (auxv_rseq_feature_size)
+		return auxv_rseq_feature_size;
+	else
+		return ORIG_RSEQ_FEATURE_SIZE;
+}
+
 static __attribute__((constructor))
 void rseq_init(void)
 {
@@ -117,14 +164,24 @@ void rseq_init(void)
 		rseq_offset = *libc_rseq_offset_p;
 		rseq_size = *libc_rseq_size_p;
 		rseq_flags = *libc_rseq_flags_p;
+		rseq_feature_size = get_rseq_feature_size();
+		if (rseq_feature_size > rseq_size)
+			rseq_feature_size = rseq_size;
 		return;
 	}
-	if (!rseq_available())
-		return;
 	rseq_ownership = 1;
+	if (!rseq_available()) {
+		rseq_size = 0;
+		rseq_feature_size = 0;
+		return;
+	}
 	rseq_offset = (void *)&__rseq_abi - rseq_thread_pointer();
-	rseq_size = sizeof(struct rseq_abi);
 	rseq_flags = 0;
+	rseq_feature_size = get_rseq_feature_size();
+	if (rseq_feature_size == ORIG_RSEQ_FEATURE_SIZE)
+		rseq_size = ORIG_RSEQ_ALLOC_SIZE;
+	else
+		rseq_size = RSEQ_THREAD_AREA_ALLOC_SIZE;
 }
 
 static __attribute__((destructor))
@@ -134,6 +191,7 @@ void rseq_exit(void)
 		return;
 	rseq_offset = 0;
 	rseq_size = -1U;
+	rseq_feature_size = -1U;
 	rseq_ownership = 0;
 }
 
@@ -148,3 +206,16 @@ int32_t rseq_fallback_current_cpu(void)
 	}
 	return cpu;
 }
+
+int32_t rseq_fallback_current_node(void)
+{
+	uint32_t cpu_id, node_id;
+	int ret;
+
+	ret = sys_getcpu(&cpu_id, &node_id);
+	if (ret) {
+		perror("sys_getcpu()");
+		return ret;
+	}
+	return (int32_t) node_id;
+}