From: Ammar Faizi <ammarfaizi2@gnuweeb.org>
To: "H. Peter Anvin" <hpa@zytor.com>, x86 Mailing List <x86@kernel.org>
Cc: Ammar Faizi <ammarfaizi2@gnuweeb.org>,
Dave Hansen <dave.hansen@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Xin Li <xin3.li@intel.com>, Thomas Gleixner <tglx@linutronix.de>,
Andrew Cooper <Andrew.Cooper3@citrix.com>,
Brian Gerst <brgerst@gmail.com>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Shuah Khan <shuah@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Linux Kselftest Mailing List <linux-kselftest@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [RFC PATCH v3 1/2] selftests/x86: sysret_rip: Handle syscall in a FRED system
Date: Tue, 24 Jan 2023 17:09:24 +0700 [thread overview]
Message-ID: <20230124100926.637335-2-ammarfaizi2@gnuweeb.org> (raw)
In-Reply-To: <20230124100926.637335-1-ammarfaizi2@gnuweeb.org>
From: Ammar Faizi <ammarfaizi2@gnuweeb.org>
The current selftest asserts %r11 == %rflags after the 'syscall'
returns to user. Such an assertion doesn't apply to a FRED system
because in a FRED system the 'syscall' instruction does not set
%r11=%rflags and %rcx=%rip.
Handle the FRED case. Now, test that:
- "syscall" in a FRED system doesn't clobber %rcx and %r11.
- "syscall" in a non-FRED system sets %rcx=%rip and %r11=%rflags.
The 'raise()' function from libc can't be used to control those
registers. Therefore, create a syscall wrapper in inline Assembly to
fully control them.
Fixes: 660602140103 ("selftests/x86: Add a selftest for SYSRET to noncanonical addresses")
Link: https://lore.kernel.org/lkml/25b96960-a07e-a952-5c23-786b55054126@zytor.com
Reported-by: Xin Li <xin3.li@intel.com>
Co-developed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
---
tools/testing/selftests/x86/sysret_rip.c | 111 ++++++++++++++++++++++-
1 file changed, 110 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/x86/sysret_rip.c b/tools/testing/selftests/x86/sysret_rip.c
index 84d74be1d90207ab..b0d271c19ddd7834 100644
--- a/tools/testing/selftests/x86/sysret_rip.c
+++ b/tools/testing/selftests/x86/sysret_rip.c
@@ -39,6 +39,110 @@ asm (
extern const char test_page[];
static void const *current_test_page_addr = test_page;
+/* Arbitrary values */
+static const unsigned long r11_sentinel = 0xfeedfacedeadbeef;
+static const unsigned long rcx_sentinel = 0x5ca1ab1e0b57ac1e;
+
+/* An arbitrary *valid* RFLAGS value */
+static const unsigned long rflags_sentinel = 0x200a93;
+
+enum regs_ok {
+ REGS_UNDEFINED = -2, /* For init value checker, never returned */
+ REGS_ERROR = -1, /* Invalid register contents */
+ REGS_SAVED = 0, /* Registers properly preserved */
+ REGS_SYSRET = 1 /* Registers match syscall/sysret */
+};
+
+static enum regs_ok regs_ok_state = REGS_UNDEFINED;
+
+/*
+ * Returns:
+ * 0 = %rcx and %r11 preserved.
+ * 1 = %rcx and %r11 set to %rflags and %rip.
+ * -1 = %rcx and/or %r11 set to any other values.
+ *
+ * Note that check_regs_syscall() sets %rbx to the syscall return %rip.
+ */
+static enum regs_ok check_regs_result(unsigned long r11, unsigned long rcx,
+ unsigned long rbx)
+{
+ if (r11 == r11_sentinel && rcx == rcx_sentinel) {
+ return REGS_SAVED;
+ } else if (r11 == rflags_sentinel && rcx == rbx) {
+ return REGS_SYSRET;
+ } else {
+ printf("[FAIL] check_regs_result\n");
+ printf(" r11_sentinel = %#lx; %%r11 = %#lx;\n", r11_sentinel, r11);
+ printf(" rcx_sentinel = %#lx; %%rcx = %#lx;\n", rcx_sentinel, rcx);
+ printf(" rflags_sentinel = %#lx\n", rflags_sentinel);
+ return REGS_ERROR;
+ }
+}
+
+static long do_syscall(long nr_syscall, unsigned long arg1, unsigned long arg2,
+ unsigned long arg3, unsigned long arg4,
+ unsigned long arg5, unsigned long arg6)
+{
+ register unsigned long r11 asm("%r11");
+ register unsigned long r10 asm("%r10");
+ register unsigned long r8 asm("%r8");
+ register unsigned long r9 asm("%r9");
+ register void *rsp asm("%rsp");
+ unsigned long rcx, rbx;
+ enum regs_ok ret;
+
+ r11 = r11_sentinel;
+ rcx = rcx_sentinel;
+ r10 = arg4;
+ r8 = arg5;
+ r9 = arg6;
+
+ asm volatile (
+ "pushq %[rflags_sentinel]\n\t"
+ "popf\n\t"
+ "leaq 1f(%%rip), %[rbx]\n\t"
+ "syscall\n"
+ "1:"
+
+ : "+a" (nr_syscall),
+ "+r" (r11),
+ "+c" (rcx),
+ [rbx] "=b" (rbx),
+ "+r" (rsp) /* Clobber the redzone */
+
+ : [rflags_sentinel] "g" (rflags_sentinel),
+ "D" (arg1), /* %rdi */
+ "S" (arg2), /* %rsi */
+ "d" (arg3), /* %rdx */
+ "r" (r10),
+ "r" (r8),
+ "r" (r9)
+
+ : "memory"
+ );
+
+ /*
+ * Test that:
+ *
+ * - "syscall" in a FRED system doesn't clobber %rcx and %r11.
+ * - "syscall" in a non-FRED system sets %rcx=%rip and %r11=%rflags.
+ *
+ */
+ ret = check_regs_result(r11, rcx, rbx);
+ assert(ret != REGS_ERROR);
+
+ /*
+ * Test that we don't get a mix of REGS_SAVED and REGS_SYSRET.
+ * Need at least 2 times 'syscall' invoked from this function.
+ */
+ if (regs_ok_state == REGS_UNDEFINED)
+ regs_ok_state = ret;
+ else
+ assert(ret == regs_ok_state);
+
+ return nr_syscall;
+}
+
static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
int flags)
{
@@ -101,11 +205,16 @@ static void sigusr1(int sig, siginfo_t *info, void *ctx_void)
return;
}
+static void __raise(int sig)
+{
+ do_syscall(__NR_kill, getpid(), sig, 0, 0, 0, 0);
+}
+
static void test_sigreturn_to(unsigned long ip)
{
rip = ip;
printf("[RUN]\tsigreturn to 0x%lx\n", ip);
- raise(SIGUSR1);
+ __raise(SIGUSR1);
}
static jmp_buf jmpbuf;
--
Ammar Faizi
next prev parent reply other threads:[~2023-01-24 10:09 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <SA1PR11MB6734FA9139B9C9F6CC2ED123A8C59@SA1PR11MB6734.namprd11.prod.outlook.com>
2023-01-20 17:45 ` the x86 sysret_rip test fails on the Intel FRED architecture Dave Hansen
[not found] ` <eb81f7f2-d266-d999-b41a-e6eae086e731@citrix.com>
2023-01-20 20:50 ` H. Peter Anvin
2023-01-20 21:10 ` Andrew Cooper
2023-01-20 21:17 ` H. Peter Anvin
2023-01-20 21:29 ` Andrew Cooper
2023-01-21 4:59 ` H. Peter Anvin
2023-01-21 16:46 ` Dave Hansen
2023-01-21 21:47 ` Brian Gerst
2023-01-22 3:01 ` Li, Xin3
2023-01-22 3:28 ` H. Peter Anvin
2023-01-22 3:38 ` Li, Xin3
2023-01-22 4:34 ` Dave Hansen
2023-01-22 4:44 ` H. Peter Anvin
2023-01-22 8:22 ` Li, Xin3
2023-01-22 8:54 ` Ammar Faizi
2023-01-22 9:40 ` H. Peter Anvin
2023-01-22 23:45 ` H. Peter Anvin
2023-01-23 9:02 ` Ammar Faizi
2023-01-23 19:43 ` H. Peter Anvin
2023-01-23 23:43 ` Ammar Faizi
2023-01-23 23:58 ` H. Peter Anvin
2023-01-24 0:26 ` [RFC PATCH v1 0/2] selftests/x86: sysret_rip update for FRED system Ammar Faizi
2023-01-24 0:26 ` [RFC PATCH v1 1/2] selftests/x86: sysret_rip: Handle syscall in a " Ammar Faizi
2023-01-24 1:40 ` H. Peter Anvin
2023-01-24 2:31 ` Ammar Faizi
2023-01-26 20:08 ` Ammar Faizi
2023-02-15 9:17 ` Andrew Cooper
2023-02-15 10:29 ` Andrew Cooper
2023-02-15 10:44 ` Ammar Faizi
2023-02-15 10:42 ` Ammar Faizi
2023-01-26 20:16 ` Ammar Faizi
2023-01-24 0:26 ` [RFC PATCH v1 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-23 23:53 ` the x86 sysret_rip test fails on the Intel FRED architecture Andrew Cooper
2023-01-24 0:01 ` H. Peter Anvin
2023-01-24 2:27 ` [RFC PATCH v2 0/2] selftests/x86: sysret_rip update for FRED system Ammar Faizi
2023-01-24 2:27 ` [RFC PATCH v2 1/2] selftests/x86: sysret_rip: Handle syscall in a " Ammar Faizi
2023-01-24 5:44 ` H. Peter Anvin
2023-01-24 2:27 ` [RFC PATCH v2 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-24 6:16 ` H. Peter Anvin
2023-01-24 6:41 ` Ammar Faizi
2023-01-24 6:47 ` Ammar Faizi
2023-01-24 9:07 ` H. Peter Anvin
2023-01-24 9:12 ` Ammar Faizi
2023-01-24 10:09 ` [RFC PATCH v3 0/2] selftests/x86: sysret_rip update for FRED system Ammar Faizi
2023-01-24 10:09 ` Ammar Faizi [this message]
2023-01-24 10:09 ` [RFC PATCH v3 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-24 20:59 ` H. Peter Anvin
2023-01-25 3:29 ` Ammar Faizi
2023-01-24 21:32 ` [RFC PATCH v3 0/2] selftests/x86: sysret_rip update for FRED system Li, Xin3
2023-01-24 21:37 ` H. Peter Anvin
2023-01-24 23:20 ` Li, Xin3
2023-01-25 3:27 ` Ammar Faizi
2023-01-24 21:51 ` Andrew Cooper
2023-01-24 23:58 ` Li, Xin3
2023-01-25 3:22 ` [RFC PATCH v4 0/2] sysret_rip update for the Intel FRED architecture Ammar Faizi
2023-01-25 3:22 ` [RFC PATCH v4 1/2] selftests/x86: sysret_rip: Handle syscall in a FRED system Ammar Faizi
2023-01-25 3:37 ` Ammar Faizi
2023-01-25 3:44 ` Ammar Faizi
2023-01-25 3:22 ` [RFC PATCH v4 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-25 3:49 ` [RFC PATCH v5 0/2] sysret_rip update for the Intel FRED architecture Ammar Faizi
2023-01-25 3:49 ` [RFC PATCH v5 1/2] selftests/x86: sysret_rip: Handle syscall in a FRED system Ammar Faizi
2023-01-25 8:39 ` H. Peter Anvin
2023-01-25 8:53 ` Ammar Faizi
2023-01-25 9:57 ` Ammar Faizi
2023-01-25 10:01 ` Ammar Faizi
2023-01-25 10:17 ` H. Peter Anvin
2023-01-25 11:37 ` Ammar Faizi
2023-01-25 17:25 ` H. Peter Anvin
2023-01-25 3:49 ` [RFC PATCH v5 2/2] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-25 8:22 ` [RFC PATCH v5 0/2] sysret_rip update for the Intel FRED architecture Li, Xin3
2023-01-25 8:32 ` Ammar Faizi
2023-01-25 17:07 ` Li, Xin3
2023-01-25 17:24 ` H. Peter Anvin
2023-01-25 17:41 ` Ammar Faizi
2023-01-25 17:48 ` Li, Xin3
2023-02-15 7:42 ` Li, Xin3
2023-02-15 7:51 ` Ammar Faizi
2023-02-18 4:27 ` Ammar Faizi
2023-02-18 4:51 ` H. Peter Anvin
2023-01-25 21:17 ` [RFC PATCH v6 0/3] " Ammar Faizi
2023-01-25 21:17 ` [RFC PATCH v6 1/3] selftests/x86: sysret_rip: Handle syscall in a FRED system Ammar Faizi
2023-01-25 23:01 ` Ammar Faizi
2023-01-25 21:17 ` [RFC PATCH v6 2/3] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-25 21:17 ` [RFC PATCH v6 3/3] selftests/x86: sysret_rip: Test opportunistic SYSRET Ammar Faizi
2023-01-25 23:24 ` [RFC PATCH v7 0/3] sysret_rip update for the Intel FRED architecture Ammar Faizi
2023-01-25 23:24 ` [RFC PATCH v7 1/3] selftests/x86: sysret_rip: Handle syscall in a FRED system Ammar Faizi
2023-01-25 23:24 ` [RFC PATCH v7 2/3] selftests/x86: sysret_rip: Add more syscall tests with respect to `%rcx` and `%r11` Ammar Faizi
2023-01-25 23:24 ` [RFC PATCH v7 3/3] selftests/x86: sysret_rip: Test SYSRET with a signal handler Ammar Faizi
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