arch_prctl: decode ARCH_GET_XCOMP_SUPP, ARCH_{GET,REQ}_XCOMP{,_GUEST}_PERM

* src/xlat/archvals.in (ARCH_GET_XCOMP_SUPP, ARCH_GET_XCOMP_PERM,
ARCH_REQ_XCOMP_PERM): New constants, introduced by Linux commit
v5.16-rc1~195^2~21.
(ARCH_GET_XCOMP_GUEST_PERM, ARCH_REQ_XCOMP_GUEST_PERM): New constants,
introduced by Linux commit v5.17-rc1~15^2~70.
* src/xlat/x86_xfeature_bits.in: New file.
* src/xlat/x86_xfeatures.in: Likewise.
* src/prctl.c [X86_64 || X32 || I386]: Include
"xlat/x86_xfeature_bits.h", "xlat/x86_xfeatures.h".
* tests/.gitignore: Add arch_prctl, arch_prctl-Xabbrev, arch_prctl-Xraw,
arch_prctl-Xverbose, arch_prctl-success, arch_prctl-success-Xabbrev,
arch_prctl-success-Xraw, and arch_prctl-success-Xverbose.
* tests/Makefile.am (check_PROGRAMS): Add arch_prctl-success,
arch_prctl-success-Xabbrev, arch_prctl-success-Xraw,
and arch_prctl-success-Xverbose.
* tests/arch_prctl.c: New file.
* tests/arch_prctl-Xabbrev.c: Likewise.
* tests/arch_prctl-Xraw.c: Likewise.
* tests/arch_prctl-Xverbose.c: Likewise.
* tests/arch_prctl-success.c: Likewise.
* tests/arch_prctl-success-Xabbrev.c: Likewise.
* tests/arch_prctl-success-Xraw.c: Likewise.
* tests/arch_prctl-success-Xverbose.c: Likewise.
* tests/arch_prctl.sh: Likewise.
* tests/gen_tests.in (arch_prctl, arch_prctl-Xabbrev, arch_prctl-Xraw,
arch_prctl-Xverbose, arch_prctl-success, arch_prctl-success-Xabbrev,
arch_prctl-success-Xraw, arch_prctl-success-Xverbose): New tests.
* tests/prctl-success.sh (PRCTL_SYSCALL, PRCTL_MARKER_RE): New vaiables.
Handle "ARCH_PRCTL_INJECT_RETVALS" in addition to "PRCTL_INJECT_RETVALS",
set PRCTL_SYSCALL and PRCTL_MARKER_RE accordingly;  use $PRCTL_SYSCALL
and $PRCTL_MARKER_RE in run_strace and sed calls.
* tests/pure_executables.list: Add arch_prctl, arch_prctl-Xabbrev,
arch_prctl-Xraw, and arch_prctl-Xverbose.
* NEWS: Mention it.

19 files changed, 506 insertions, 16 deletions

diff --git a/NEWS b/NEWS
index c54f57a7c..5bd64ce02 100644
--- a/NEWS
+++ b/NEWS
@@ -15,7 +15,7 @@ Noteworthy changes in release ?.?? (????-??-??)
     INET_DIAG_PROTOCOL, INET_DIAG_REQ_PROTOCOL, INET_DIAG_SHUTDOWN,
     INET_DIAG_SK_BPF_STORAGES, INET_DIAG_SOCKOPT, and INET_DIAG_ULP_INFO
     NETLINK_SOCK_DIAG netlink attributes.
-  * Enhanced decoding of prctl syscall.
+  * Enhanced decoding of arch_prctl and prctl syscalls.
   * Enhanced siginfo_t decoding.
   * Updated decoding of struct rtnl_link_stats64.
   * Updated lists of DEVCONF_*, FAN_MARK_*, GPIO_V2_LINE_FLAG_*, IORING_*,
diff --git a/src/prctl.c b/src/prctl.c
index cf281d8ae..97f42fe15 100644
--- a/src/prctl.c
+++ b/src/prctl.c
@@ -637,6 +637,8 @@ SYS_FUNC(prctl)
 
 #if defined X86_64 || defined X32 || defined I386
 # include "xlat/archvals.h"
+# include "xlat/x86_xfeature_bits.h"
+# include "xlat/x86_xfeatures.h"
 
 SYS_FUNC(arch_prctl)
 {
@@ -657,6 +659,60 @@ SYS_FUNC(arch_prctl)
 
 	case ARCH_GET_CPUID: /* has no arguments */
 		return RVAL_DECODED;
+
+	case ARCH_GET_XCOMP_SUPP:
+	case ARCH_GET_XCOMP_PERM:
+	case ARCH_GET_XCOMP_GUEST_PERM:
+		if (entering(tcp)) {
+			tprint_arg_next();
+		} else {
+			uint64_t val;
+
+			if (umove_or_printaddr(tcp, addr, &val))
+				return 0;
+
+			/* XFEATURE_MASK_* macros are not publicly exposed */
+			tprint_indirect_begin();
+			printflags_ex(val, "XFEATURE_MASK_???",
+				xlat_verbose(xlat_verbosity) == XLAT_STYLE_RAW
+				      ? XLAT_STYLE_RAW : XLAT_STYLE_VERBOSE,
+				x86_xfeatures, NULL);
+			tprint_indirect_end();
+		}
+
+		return 0;
+
+	case ARCH_REQ_XCOMP_PERM:
+	case ARCH_REQ_XCOMP_GUEST_PERM:
+		if (entering(tcp)) {
+			/* XFEATURE_* enum is not publicly exposed */
+			tprint_arg_next();
+			printxvals_ex(addr, "XFEATURE_???",
+				xlat_verbose(xlat_verbosity) == XLAT_STYLE_RAW
+				      ? XLAT_STYLE_RAW : XLAT_STYLE_VERBOSE,
+				x86_xfeature_bits, NULL);
+		} else {
+			if (tcp->u_rval <= 0)
+				return 0;
+
+			tcp->auxstr = sprintflags_ex("", x86_xfeatures,
+					(kernel_ulong_t) tcp->u_rval, '\0',
+					XLAT_STYLE_DEFAULT | SPFF_AUXSTR_MODE);
+
+			return RVAL_HEX | RVAL_STR;
+		}
+
+		return 0;
+
+	/* default handling: print arg2 in hexadecimal on entering */
+	case ARCH_SET_GS:
+	case ARCH_SET_FS:
+	case ARCH_SET_CPUID:
+	case ARCH_MAP_VDSO_X32:
+	case ARCH_MAP_VDSO_32:
+	case ARCH_MAP_VDSO_64:
+	default:
+		break;
 	}
 
 	tprint_arg_next();
diff --git a/src/xlat/archvals.in b/src/xlat/archvals.in
index 1dbbb8d00..b50ce32d6 100644
--- a/src/xlat/archvals.in
+++ b/src/xlat/archvals.in
@@ -1,9 +1,15 @@
-ARCH_SET_GS	0x1001
-ARCH_SET_FS	0x1002
-ARCH_GET_FS	0x1003
-ARCH_GET_GS	0x1004
-ARCH_GET_CPUID	0x1011
-ARCH_SET_CPUID	0x1012
-ARCH_MAP_VDSO_X32	0x2001
-ARCH_MAP_VDSO_32	0x2002
-ARCH_MAP_VDSO_64	0x2003
+#sorted
+ARCH_SET_GS			0x1001
+ARCH_SET_FS			0x1002
+ARCH_GET_FS			0x1003
+ARCH_GET_GS			0x1004
+ARCH_GET_CPUID			0x1011
+ARCH_SET_CPUID			0x1012
+ARCH_GET_XCOMP_SUPP		0x1021
+ARCH_GET_XCOMP_PERM		0x1022
+ARCH_REQ_XCOMP_PERM		0x1023
+ARCH_GET_XCOMP_GUEST_PERM	0x1024
+ARCH_REQ_XCOMP_GUEST_PERM	0x1025
+ARCH_MAP_VDSO_X32		0x2001
+ARCH_MAP_VDSO_32		0x2002
+ARCH_MAP_VDSO_64		0x2003
diff --git a/src/xlat/x86_xfeature_bits.in b/src/xlat/x86_xfeature_bits.in
new file mode 100644
index 000000000..208a4c33e
--- /dev/null
+++ b/src/xlat/x86_xfeature_bits.in
@@ -0,0 +1,21 @@
+#value_indexed
+/* From arch/x86/include/asm/fpu/types.h */
+XFEATURE_FP				0
+XFEATURE_SSE				1
+XFEATURE_YMM				2
+XFEATURE_BNDREGS			3
+XFEATURE_BNDCSR				4
+XFEATURE_OPMASK				5
+XFEATURE_ZMM_Hi256			6
+XFEATURE_Hi16_ZMM			7
+XFEATURE_PT_UNIMPLEMENTED_SO_FAR	8
+XFEATURE_PKRU				9
+XFEATURE_PASID				10
+/* XFEATURE_RSRVD_COMP_11		11 */
+/* XFEATURE_RSRVD_COMP_12		12 */
+/* XFEATURE_RSRVD_COMP_13		13 */
+/* XFEATURE_RSRVD_COMP_14		14 */
+XFEATURE_LBR				15
+/* XFEATURE_RSRVD_COMP_16		16 */
+XFEATURE_XTILE_CFG			17
+XFEATURE_XTILE_DATA			18
diff --git a/src/xlat/x86_xfeatures.in b/src/xlat/x86_xfeatures.in
new file mode 100644
index 000000000..ef81ff3fb
--- /dev/null
+++ b/src/xlat/x86_xfeatures.in
@@ -0,0 +1,18 @@
+/* From arch/x86/include/asm/fpu/types.h */
+XFEATURE_MASK_FPSSE		(XFEATURE_MASK_FP | XFEATURE_MASK_SSE)
+XFEATURE_MASK_FP		(1 << XFEATURE_FP)
+XFEATURE_MASK_SSE		(1 << XFEATURE_SSE)
+XFEATURE_MASK_YMM		(1 << XFEATURE_YMM)
+XFEATURE_MASK_BNDREGS		(1 << XFEATURE_BNDREGS)
+XFEATURE_MASK_BNDCSR		(1 << XFEATURE_BNDCSR)
+XFEATURE_MASK_AVX512		(XFEATURE_MASK_OPMASK | XFEATURE_MASK_ZMM_Hi256 | XFEATURE_MASK_Hi16_ZMM)
+XFEATURE_MASK_OPMASK		(1 << XFEATURE_OPMASK)
+XFEATURE_MASK_ZMM_Hi256		(1 << XFEATURE_ZMM_Hi256)
+XFEATURE_MASK_Hi16_ZMM		(1 << XFEATURE_Hi16_ZMM)
+XFEATURE_MASK_PT		(1 << XFEATURE_PT_UNIMPLEMENTED_SO_FAR)
+XFEATURE_MASK_PKRU		(1 << XFEATURE_PKRU)
+XFEATURE_MASK_PASID		(1 << XFEATURE_PASID)
+XFEATURE_MASK_LBR		(1 << XFEATURE_LBR)
+XFEATURE_MASK_XTILE		(XFEATURE_MASK_XTILE_DATA | XFEATURE_MASK_XTILE_CFG)
+XFEATURE_MASK_XTILE_CFG		(1 << XFEATURE_XTILE_CFG)
+XFEATURE_MASK_XTILE_DATA	(1 << XFEATURE_XTILE_DATA)
diff --git a/tests/.gitignore b/tests/.gitignore
index 653002ac1..361f74655 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -23,6 +23,14 @@ aio
 aio_pgetevents
 alarm
 answer
+arch_prctl
+arch_prctl-Xabbrev
+arch_prctl-Xraw
+arch_prctl-Xverbose
+arch_prctl-success
+arch_prctl-success-Xabbrev
+arch_prctl-success-Xraw
+arch_prctl-success-Xverbose
 at_fdcwd-pathmax
 attach-f-p
 attach-f-p-cmd
diff --git a/tests/Makefile.am b/tests/Makefile.am
index df5cf6313..7d08c0523 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -99,6 +99,10 @@ check_PROGRAMS = $(PURE_EXECUTABLES) \
 	$(secontext_EXECUTABLES) \
 	_newselect-P \
 	answer \
+	arch_prctl-success \
+	arch_prctl-success-Xabbrev \
+	arch_prctl-success-Xraw \
+	arch_prctl-success-Xverbose \
 	attach-f-p \
 	attach-f-p-cmd \
 	attach-p-cmd-cmd \
@@ -633,6 +637,7 @@ EXTRA_DIST = \
 	GPL-2.0-or-later \
 	PTRACE_SEIZE.sh \
 	accept_compat.h \
+	arch_prctl.sh \
 	attach-p-cmd.h \
 	caps-abbrev.awk \
 	caps.awk \
diff --git a/tests/arch_prctl-Xabbrev.c b/tests/arch_prctl-Xabbrev.c
new file mode 100644
index 000000000..3f4c7626c
--- /dev/null
+++ b/tests/arch_prctl-Xabbrev.c
@@ -0,0 +1,2 @@
+#define XLAT_ABBREV 1
+#include "arch_prctl.c"
diff --git a/tests/arch_prctl-Xraw.c b/tests/arch_prctl-Xraw.c
new file mode 100644
index 000000000..8068cb53c
--- /dev/null
+++ b/tests/arch_prctl-Xraw.c
@@ -0,0 +1,2 @@
+#define XLAT_RAW 1
+#include "arch_prctl.c"
diff --git a/tests/arch_prctl-Xverbose.c b/tests/arch_prctl-Xverbose.c
new file mode 100644
index 000000000..bab799a66
--- /dev/null
+++ b/tests/arch_prctl-Xverbose.c
@@ -0,0 +1,2 @@
+#define XLAT_VERBOSE 1
+#include "arch_prctl.c"
diff --git a/tests/arch_prctl-success-Xabbrev.c b/tests/arch_prctl-success-Xabbrev.c
new file mode 100644
index 000000000..2572ff845
--- /dev/null
+++ b/tests/arch_prctl-success-Xabbrev.c
@@ -0,0 +1,2 @@
+#define XLAT_ABBREV 1
+#include "arch_prctl-success.c"
diff --git a/tests/arch_prctl-success-Xraw.c b/tests/arch_prctl-success-Xraw.c
new file mode 100644
index 000000000..f685c369b
--- /dev/null
+++ b/tests/arch_prctl-success-Xraw.c
@@ -0,0 +1,2 @@
+#define XLAT_RAW 1
+#include "arch_prctl-success.c"
diff --git a/tests/arch_prctl-success-Xverbose.c b/tests/arch_prctl-success-Xverbose.c
new file mode 100644
index 000000000..e8e0afc81
--- /dev/null
+++ b/tests/arch_prctl-success-Xverbose.c
@@ -0,0 +1,2 @@
+#define XLAT_VERBOSE 1
+#include "arch_prctl-success.c"
diff --git a/tests/arch_prctl-success.c b/tests/arch_prctl-success.c
new file mode 100644
index 000000000..02b6e39b0
--- /dev/null
+++ b/tests/arch_prctl-success.c
@@ -0,0 +1,2 @@
+#define INJECT_RETVAL
+#include "arch_prctl.c"
diff --git a/tests/arch_prctl.c b/tests/arch_prctl.c
new file mode 100644
index 000000000..08ba31ac1
--- /dev/null
+++ b/tests/arch_prctl.c
@@ -0,0 +1,323 @@
+/*
+ * Check decoding of arch_prctl syscall.
+ *
+ * Copyright (c) 2021-2022 The strace developers.
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "tests.h"
+#include "scno.h"
+
+#ifdef __NR_arch_prctl
+
+# include <stdio.h>
+# include <stdlib.h>
+# include <unistd.h>
+# include <linux/prctl.h>
+
+# define XLAT_MACROS_ONLY
+#  include "xlat/archvals.h"
+# undef XLAT_MACROS_ONLY
+
+# include "xlat.h"
+# include "xlat/x86_xfeature_bits.h"
+# include "xlat/x86_xfeatures.h"
+
+# ifdef INJECT_RETVAL
+#  define INJ_STR " (INJECTED)\n"
+# else
+#  define INJ_STR "\n"
+# endif
+
+# define ARRAY_END(a_) ((a_) + ARRAY_SIZE(a_))
+
+static long
+sys_arch_prctl(unsigned int cmd, kernel_ulong_t arg)
+{
+	return syscall(__NR_arch_prctl, cmd, arg, (unsigned long) -3U,
+						  (unsigned long) -4U,
+						  (unsigned long) -5U);
+}
+
+static long
+arch_prctl_marker(void)
+{
+	return sys_arch_prctl(-1U, (unsigned long) -2U);
+}
+
+int
+main(int argc, char *argv[])
+{
+	const kernel_ulong_t dummy = (kernel_ulong_t) 0xbadfaceddeadbeefULL;
+	const char *errstr;
+	long rc;
+
+	arch_prctl_marker();
+
+# ifdef INJECT_RETVAL
+	unsigned long num_skip;
+	long inject_retval;
+	bool locked = false;
+
+	if (argc < 3)
+		error_msg_and_fail("Usage: %s NUM_SKIP INJECT_RETVAL", argv[0]);
+
+	num_skip = strtoul(argv[1], NULL, 0);
+	inject_retval = strtol(argv[2], NULL, 0);
+
+	for (size_t i = 0; i < num_skip; i++) {
+		if (arch_prctl_marker() != inject_retval)
+			continue;
+
+		locked = true;
+		break;
+	}
+
+	if (!locked)
+		error_msg_and_fail("Have not locked on arch_prctl(-1, -2)"
+				   " returning %ld", inject_retval);
+# endif /* INJECT_RETVAL */
+
+	TAIL_ALLOC_OBJECT_CONST_PTR(uint64_t, u64_p);
+
+	/* Unknown commands */
+	static const uint32_t unk_cmds[] = {
+		0, 0x1,
+		0x1000, 0x1005,
+		0x1010, 0x1013,
+		0x1020, 0x1026,
+		0x1030, 0x1031,
+		0x1100, 0x1101,
+		0x2000, 0x2004,
+		0x2010, 0x2011,
+		0x2100, 0x2101,
+		0x3000, 0x3001,
+		0xdeadc0de };
+
+	for (size_t i = 0; i < ARRAY_SIZE(unk_cmds); i++) {
+		rc = sys_arch_prctl(unk_cmds[i], 0);
+		printf("arch_prctl(" XLAT_UNKNOWN_FMT("%#x", "ARCH_???")
+		       ", 0) = %s" INJ_STR,
+		       unk_cmds[i], sprintrc(rc));
+
+		rc = sys_arch_prctl(unk_cmds[i], (kernel_ulong_t) dummy);
+		printf("arch_prctl(" XLAT_UNKNOWN_FMT("%#x", "ARCH_???")
+		       ", %#llx) = %s" INJ_STR,
+		       unk_cmds[i], (unsigned long long) dummy, sprintrc(rc));
+
+		rc = sys_arch_prctl(unk_cmds[i], (uintptr_t) u64_p);
+		printf("arch_prctl(" XLAT_UNKNOWN_FMT("%#x", "ARCH_???")
+		       ", %p) = %s" INJ_STR,
+		       unk_cmds[i], u64_p, sprintrc(rc));
+	}
+
+	/* Default decoding */
+	static const struct strval32 def_cmds[] = {
+		{ ARG_XLAT_KNOWN(0x1001, "ARCH_SET_GS") },
+# ifdef INJECT_RETVAL
+		{ ARG_XLAT_KNOWN(0x1002, "ARCH_SET_FS") },
+# endif
+		{ ARG_XLAT_KNOWN(0x1012, "ARCH_SET_CPUID") },
+		{ ARG_XLAT_KNOWN(0x2001, "ARCH_MAP_VDSO_X32") },
+		{ ARG_XLAT_KNOWN(0x2002, "ARCH_MAP_VDSO_32") },
+		{ ARG_XLAT_KNOWN(0x2003, "ARCH_MAP_VDSO_64") },
+	};
+
+	for (const struct strval32 *p = def_cmds; p < ARRAY_END(def_cmds); p++)
+	{
+		rc = sys_arch_prctl(p->val, (kernel_ulong_t) dummy);
+		printf("arch_prctl(%s, %#llx) = %s" INJ_STR,
+		       p->str, (unsigned long long) dummy, sprintrc(rc));
+
+		rc = sys_arch_prctl(p->val, (uintptr_t) u64_p);
+		printf("arch_prctl(%s, %p) = %s" INJ_STR,
+		       p->str, u64_p, sprintrc(rc));
+
+		rc = sys_arch_prctl(p->val, 0);
+		printf("arch_prctl(%s, 0) = %s" INJ_STR, p->str, sprintrc(rc));
+	}
+
+	/* ARCH_GET_GS, ARCH_GET_FS */
+	static const struct strval32 kptr_cmds[] = {
+# ifdef INJECT_RETVAL
+		{ ARG_XLAT_KNOWN(0x1003, "ARCH_GET_FS") },
+# endif
+		{ ARG_XLAT_KNOWN(0x1004, "ARCH_GET_GS") },
+	};
+	TAIL_ALLOC_OBJECT_CONST_PTR(kernel_ulong_t, kulong_p);
+	const kernel_ulong_t ptrs[] = {
+		(kernel_ulong_t) 0xdeadfacecafebeefULL,
+		(uintptr_t) (kulong_p + 1),
+		(uintptr_t) kulong_p ,
+		0
+	};
+
+	for (const struct strval32 *p = kptr_cmds; p < ARRAY_END(kptr_cmds);
+	     p++) {
+		rc = sys_arch_prctl(p->val, 0);
+		printf("arch_prctl(%s, NULL) = %s" INJ_STR,
+		       p->str, sprintrc(rc));
+
+		rc = sys_arch_prctl(p->val, (uintptr_t) (kulong_p + 1));
+		printf("arch_prctl(%s, %p) = %s" INJ_STR,
+		       p->str, kulong_p + 1, sprintrc(rc));
+
+		for (size_t j = 0; j < ARRAY_SIZE(ptrs); j++) {
+			*kulong_p = ptrs[j];
+			uint32_t wr_cmd = p->val == ARCH_GET_GS ? ARCH_SET_GS
+								: ARCH_SET_FS;
+# if !XLAT_RAW
+			const char *wr_str = p->val == ARCH_GET_GS
+						? "ARCH_SET_GS" : "ARCH_SET_FS";
+# endif
+			rc = sys_arch_prctl(wr_cmd, *kulong_p);
+			printf("arch_prctl(" XLAT_FMT ", %#llx) = %s" INJ_STR,
+			       XLAT_SEL(wr_cmd, wr_str),
+			       (unsigned long long) *kulong_p, sprintrc(rc));
+
+			rc = sys_arch_prctl(p->val, (uintptr_t) kulong_p);
+			errstr = sprintrc(rc);
+			printf("arch_prctl(%s, ", p->str);
+			if (rc >= 0) {
+				if (*kulong_p) {
+					printf("[%#llx]",
+					       (unsigned long long) *kulong_p);
+				} else {
+					printf("[NULL]");
+				}
+			} else {
+				printf("%p", kulong_p);
+			}
+			printf(") = %s" INJ_STR, errstr);
+		}
+	}
+
+	/* ARCH_GET_CPUID */
+	rc = sys_arch_prctl(ARCH_GET_CPUID, 0xdeadc0de);
+	printf("arch_prctl(" XLAT_FMT ") = %s" INJ_STR,
+	       XLAT_ARGS(ARCH_GET_CPUID), sprintrc(rc));
+
+	/* xfeature mask get */
+	static const struct strval32 xfget_cmds[] = {
+		{ ARG_XLAT_KNOWN(0x1021, "ARCH_GET_XCOMP_SUPP") },
+		{ ARG_XLAT_KNOWN(0x1022, "ARCH_GET_XCOMP_PERM") },
+		{ ARG_XLAT_KNOWN(0x1024, "ARCH_GET_XCOMP_GUEST_PERM") },
+	};
+	static const struct strval64 xfget_vals[] = {
+		{ ARG_STR(0) },
+		{ ARG_XLAT_UNKNOWN(0x1, "XFEATURE_MASK_FP") },
+		{ ARG_XLAT_UNKNOWN(0x2, "XFEATURE_MASK_SSE") },
+		{ ARG_XLAT_UNKNOWN(0x3, "XFEATURE_MASK_FPSSE") },
+		{ ARG_XLAT_UNKNOWN(0x20, "XFEATURE_MASK_OPMASK") },
+		{ ARG_XLAT_UNKNOWN(0xc0, "XFEATURE_MASK_ZMM_Hi256"
+					 "|XFEATURE_MASK_Hi16_ZMM") },
+		{ ARG_XLAT_UNKNOWN(0xe0, "XFEATURE_MASK_AVX512") },
+		{ ARG_XLAT_UNKNOWN(0x20000, "XFEATURE_MASK_XTILE_CFG") },
+		{ ARG_XLAT_UNKNOWN(0x40000, "XFEATURE_MASK_XTILE_DATA") },
+		{ ARG_XLAT_UNKNOWN(0x60000, "XFEATURE_MASK_XTILE") },
+		{ ARG_XLAT_UNKNOWN(0xbadfaced,
+				   "XFEATURE_MASK_FP|XFEATURE_MASK_YMM"
+				   "|XFEATURE_MASK_BNDREGS|XFEATURE_MASK_AVX512"
+				   "|XFEATURE_MASK_PASID|XFEATURE_MASK_LBR"
+				   "|XFEATURE_MASK_XTILE|0xbad92800") },
+		{ ARG_XLAT_UNKNOWN(0x687ff,
+				   "XFEATURE_MASK_FPSSE|XFEATURE_MASK_YMM"
+				   "|XFEATURE_MASK_BNDREGS|XFEATURE_MASK_BNDCSR"
+				   "|XFEATURE_MASK_AVX512|XFEATURE_MASK_PT"
+				   "|XFEATURE_MASK_PKRU|XFEATURE_MASK_PASID"
+				   "|XFEATURE_MASK_LBR|XFEATURE_MASK_XTILE") },
+		{ ARG_XLAT_UNKNOWN(0xfffffffffff97800, "XFEATURE_MASK_???") },
+	};
+
+	for (const struct strval32 *p = xfget_cmds; p < ARRAY_END(xfget_cmds);
+	     p++) {
+		rc = sys_arch_prctl(p->val, 0);
+		printf("arch_prctl(%s, NULL) = %s" INJ_STR,
+		       p->str, sprintrc(rc));
+
+		rc = sys_arch_prctl(p->val, (uintptr_t) (u64_p + 1));
+		printf("arch_prctl(%s, %p) = %s" INJ_STR,
+		       p->str, u64_p + 1, sprintrc(rc));
+
+		for (const struct strval64 *q = xfget_vals;
+		     q < ARRAY_END(xfget_vals); q++) {
+			*u64_p = q->val;
+			rc = sys_arch_prctl(p->val, (uintptr_t) u64_p);
+			errstr = sprintrc(rc);
+			printf("arch_prctl(%s, ", p->str);
+			if (rc >= 0) {
+# ifdef INJECT_RETVAL
+				printf("[%s]", q->str);
+# else
+				if (*u64_p) {
+					printf("[%#llx" NRAW(" /* "),
+					       (unsigned long long) *u64_p);
+#  if !XLAT_RAW
+					printflags(x86_xfeatures, *u64_p, NULL);
+#  endif
+					printf(NRAW(" */") "]");
+				} else {
+					printf("[0]");
+				}
+# endif
+			} else {
+				printf("%p", u64_p);
+			}
+			printf(") = %s" INJ_STR, errstr);
+		}
+	}
+
+	/* xfeature in arg, xfeature mask in ret */
+	static const struct strval32 xfreq_cmds[] = {
+		{ ARG_XLAT_KNOWN(0x1023, "ARCH_REQ_XCOMP_PERM") },
+		{ ARG_XLAT_KNOWN(0x1025, "ARCH_REQ_XCOMP_GUEST_PERM") },
+	};
+	static const struct strval32 xfreq_vals[] = {
+		{ ARG_XLAT_UNKNOWN(0, "XFEATURE_FP") },
+		{ ARG_XLAT_UNKNOWN(0x8, "XFEATURE_PT_UNIMPLEMENTED_SO_FAR") },
+		{ ARG_XLAT_UNKNOWN(0xb, "XFEATURE_???") },
+		{ ARG_XLAT_UNKNOWN(0xc, "XFEATURE_???") },
+		{ ARG_XLAT_UNKNOWN(0xd, "XFEATURE_???") },
+		{ ARG_XLAT_UNKNOWN(0xe, "XFEATURE_???") },
+		{ ARG_XLAT_UNKNOWN(0xf, "XFEATURE_LBR") },
+		{ ARG_XLAT_UNKNOWN(0x10, "XFEATURE_???") },
+		{ ARG_XLAT_UNKNOWN(0x11, "XFEATURE_XTILE_CFG") },
+		{ ARG_XLAT_UNKNOWN(0x12, "XFEATURE_XTILE_DATA") },
+		{ ARG_XLAT_UNKNOWN(0x13, "XFEATURE_???") },
+		{ ARG_XLAT_UNKNOWN(0xdeadface, "XFEATURE_???") },
+	};
+
+	for (const struct strval32 *p = xfreq_cmds; p < ARRAY_END(xfreq_cmds);
+	     p++) {
+		for (const struct strval32 *q = xfreq_vals;
+		     q < ARRAY_END(xfreq_vals); q++) {
+			rc = sys_arch_prctl(p->val, q->val);
+			errstr = sprintrc(rc);
+			printf("arch_prctl(%s, %s) = ", p->str, q->str);
+			if (rc > 0) {
+				printf("%#lx", rc);
+# if !XLAT_RAW
+				if (rc & x86_xfeatures->flags_mask) {
+					printf(" (");
+					printflags(x86_xfeatures, rc, NULL);
+					printf(")");
+				}
+# endif
+				printf(INJ_STR);
+			} else {
+				printf("%s" INJ_STR, errstr);
+			}
+		}
+	}
+
+	puts("+++ exited with 0 +++");
+	return 0;
+}
+
+#else
+
+SKIP_MAIN_UNDEFINED("__NR_arch_prctl")
+
+#endif
diff --git a/tests/arch_prctl.sh b/tests/arch_prctl.sh
new file mode 100644
index 000000000..ddab7e25a
--- /dev/null
+++ b/tests/arch_prctl.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+#
+# Check arch_prctl syscall decoding.
+#
+# Copyright (c) 20212-2022 The strace developers.
+# All rights reserved.
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+. "${srcdir=.}/init.sh"
+
+check_prog sed
+run_prog > /dev/null
+run_strace -earch_prctl "$@" $args > "$EXP"
+sed '0,/^arch_prctl(0xffffffff\( \/\* ARCH_??? \*\/\)\?, 0xfffffffe)  *= -1 /d' < "$LOG" > "$OUT"
+match_diff "$OUT" "$EXP"
diff --git a/tests/gen_tests.in b/tests/gen_tests.in
index bb21a9d80..4bb63227f 100644
--- a/tests/gen_tests.in
+++ b/tests/gen_tests.in
@@ -20,6 +20,14 @@ adjtimex	-a15
 aio	-a14 -e trace=io_setup,io_submit,io_getevents,io_cancel,io_destroy
 aio_pgetevents	-e trace=io_pgetevents
 alarm	-a10
+arch_prctl			+arch_prctl.sh -a27
+arch_prctl-Xabbrev		+arch_prctl.sh -a27 -Xabbrev
+arch_prctl-Xraw			+arch_prctl.sh -a17 -Xraw
+arch_prctl-Xverbose		+arch_prctl.sh -a32 -Xverbose
+arch_prctl-success		+prctl-success.sh ARCH_PRCTL_INJECT_RETVALS="0 1 2 3 0x20 0xc0 0xdead 0x20000 0x40000 0x60000 0x687ff 0x97800 0x789abcde" -a27
+arch_prctl-success-Xabbrev	+prctl-success.sh ARCH_PRCTL_INJECT_RETVALS="0 1 2 3 0x20 0xc0 0xdead 0x20000 0x40000 0x60000 0x687ff 0x97800 0x789abcde" -a27 -Xabbrev
+arch_prctl-success-Xraw		+prctl-success.sh ARCH_PRCTL_INJECT_RETVALS="0 1 2 3 0x20 0xc0 0xdead 0x20000 0x40000 0x60000 0x687ff 0x97800 0x789abcde" -a17 -Xraw
+arch_prctl-success-Xverbose	+prctl-success.sh ARCH_PRCTL_INJECT_RETVALS="0 1 2 3 0x20 0xc0 0xdead 0x20000 0x40000 0x60000 0x687ff 0x97800 0x789abcde" -a32 -Xverbose
 at_fdcwd-pathmax	-a36 --trace=openat -y -P sample
 bpf	-a20
 bpf-obj_get_info_by_fd	-a20 -y -e trace=bpf
diff --git a/tests/prctl-success.sh b/tests/prctl-success.sh
index 2ab26023c..0d5301501 100644
--- a/tests/prctl-success.sh
+++ b/tests/prctl-success.sh
@@ -12,8 +12,10 @@
 
 . "${srcdir=.}/scno_tampering.sh"
 
-: ${PRCTL_INJECT_START=256}
-: ${PRCTL_INJECT_RETVALS=42}
+: "${PRCTL_INJECT_START=256}"
+: "${PRCTL_INJECT_RETVALS=42}"
+: "${PRCTL_SYSCALL=prctl}"
+: "${PRCTL_MARKER_RE='prctl(0xffffffff\( \/\* PR_??? \*\/\)\?, 0xfffffffe, 0xfffffffd, 0xfffffffc, 0xfffffffb)'}"
 
 check_prog sed
 
@@ -21,7 +23,16 @@ check_prog sed
 # at the beginning of the argument list.
 while [ "$#" -gt 0 ]; do
 	case "$1" in
-	PRCTL_INJECT_RETVALS=*) PRCTL_INJECT_RETVALS="${1#PRCTL_INJECT_RETVALS=}"; ;;
+	ARCH_PRCTL_INJECT_RETVALS=*)
+		PRCTL_INJECT_RETVALS="${1#ARCH_PRCTL_INJECT_RETVALS=}"
+		PRCTL_SYSCALL=arch_prctl
+		PRCTL_MARKER_RE='arch_prctl(0xffffffff\( \/\* ARCH_??? \*\/\)\?, 0xfffffffe)'
+		;;
+	PRCTL_INJECT_RETVALS=*)
+		PRCTL_INJECT_RETVALS="${1#PRCTL_INJECT_RETVALS=}"
+		PRCTL_SYSCALL=prctl
+		PRCTL_MARKER_RE='prctl(0xffffffff\( \/\* PR_??? \*\/\)\?, 0xfffffffe, 0xfffffffd, 0xfffffffc, 0xfffffffb)'
+		;;
 	*) break; ;;
 	esac
 
@@ -48,9 +59,9 @@ for i in $(echo "$PRCTL_INJECT_RETVALS"); do
 		sed_match="-1 ${i#error=}"
 	fi
 
-	run_strace -a80 "$@" -e trace=prctl \
-		-e inject=prctl:"${inj_str}":when="${PRCTL_INJECT_START}+" \
+	run_strace -a80 "$@" -e trace="${PRCTL_SYSCALL}" \
+		-e inject="${PRCTL_SYSCALL}":"${inj_str}":when="${PRCTL_INJECT_START}+" \
 		"../$NAME" "${PRCTL_INJECT_START}" "${ret_val}" > "$EXP.$i"
-	sed '0,/^prctl(0xffffffff\( \/\* PR_??? \*\/\)\?, 0xfffffffe, 0xfffffffd, 0xfffffffc, 0xfffffffb)  *= '"${sed_match}"' /d' < "$LOG" > "$OUT.$i"
+	sed '0,/^'"${PRCTL_MARKER_RE}"'  *= '"${sed_match}"' /d' < "$LOG" > "$OUT.$i"
 	match_diff "$OUT.$i" "$EXP.$i"
 done
diff --git a/tests/pure_executables.list b/tests/pure_executables.list
index 3577499cc..471a97e1e 100755
--- a/tests/pure_executables.list
+++ b/tests/pure_executables.list
@@ -15,6 +15,10 @@ adjtimex
 aio
 aio_pgetevents
 alarm
+arch_prctl
+arch_prctl-Xabbrev
+arch_prctl-Xraw
+arch_prctl-Xverbose
 at_fdcwd-pathmax
 bpf
 bpf-v