On 13/08/2019 17:26, Dave Martin wrote:

On Fri, Aug 02, 2019 at 06:02:58PM +0100, Cristian Marussi wrote:

quoted

Added a simple fake_sigreturn testcase which builds a ucontext_t

Add

Ok

quoted

with an anomalous additional fpsimd_context and place it onto the stack.
Expects a SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 .../arm64/signal/testcases/.gitignore         |  1 +
 .../fake_sigreturn_duplicated_fpsimd.c        | 62 +++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c

diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore
index 17d1c5e73319..94f9baaf638c 100644
--- a/tools/testing/selftests/arm64/signal/testcases/.gitignore
+++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore

@@ -7,3 +7,4 @@ mangle_pstate_ssbs_regs
 fake_sigreturn_bad_magic
 fake_sigreturn_bad_size_for_magic0
 fake_sigreturn_missing_fpsimd
+fake_sigreturn_duplicated_fpsimd

diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c
new file mode 100644
index 000000000000..09af7a0f8776
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c

@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 ARM Limited */
+

signal.h?

Ok

quoted

+#include <stdio.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+
+static int fake_sigreturn_duplicated_fpsimd_run(struct tdescr *td,
+						siginfo_t *si, ucontext_t *uc)
+{
+	size_t resv_sz, offset;
+	struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;
+
+	/* just to fill the ucontext_t with something real */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	resv_sz = GET_SF_RESV_SIZE(sf);
+	/*
+	 * find the terminator, preserving existing headers
+	 * and verify amount of spare room in __reserved area.
+	 */
+	head = get_terminator(shead, resv_sz, &offset);
+	/*
+	 * try stripping extra_context header when low on space:
+	 * we need at least space for one additional fpsimd_context
+	 */
+	if (head && resv_sz - offset < sizeof(struct fpsimd_context)) {
+		fprintf(stderr, "Low on space:%zd. Discarding extra_context.\n",
+			resv_sz - offset);
+		head = get_header(shead, EXTRA_MAGIC, resv_sz, &offset);
+	}
+
+	/* just give up and timeout if still not enough space */
+	if (head &&
+	    resv_sz - offset >= sizeof(struct fpsimd_context) + HDR_SZ) {
+		fprintf(stderr, "Mangling template header. Spare space:%zd\n",
+			resv_sz - offset);
+		/* Add a spurios fpsimd_context */
+		head->magic = FPSIMD_MAGIC;
+		head->size = sizeof(struct fpsimd_context);
+		/* and terminate */
+		write_terminator_record(GET_RESV_NEXT_HEAD(head));
+
+		ASSERT_BAD_CONTEXT(&sf.uc);
+		fake_sigreturn(&sf, sizeof(sf), 16);
+	}
+
+	return 1;
+}

I'll convert to use new helper get_starting_head() to make space in __reserved.

Cheers

Cristian

[...]

Otherwise looks ok.

Cheers
---Dave

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