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From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org,
	"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
	laurent@vivier.eu, "Max Filippov" <jcmvbkbc@gmail.com>
Subject: [PATCH v4 24/25] linux-user/xtensa: Implement setup_sigtramp
Date: Mon, 27 Sep 2021 22:00:38 -0400	[thread overview]
Message-ID: <20210928020039.184412-25-richard.henderson@linaro.org> (raw)
In-Reply-To: <20210928020039.184412-1-richard.henderson@linaro.org>

Create and record the rt signal trampoline.
Use it when the guest does not use SA_RESTORER.

Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/xtensa/target_signal.h |  2 ++
 linux-user/xtensa/signal.c        | 56 ++++++++++++++++++++-----------
 2 files changed, 38 insertions(+), 20 deletions(-)

diff --git a/linux-user/xtensa/target_signal.h b/linux-user/xtensa/target_signal.h
index c60bf656f6..1c7ee73154 100644
--- a/linux-user/xtensa/target_signal.h
+++ b/linux-user/xtensa/target_signal.h
@@ -20,4 +20,6 @@ typedef struct target_sigaltstack {
 
 #include "../generic/signal.h"
 
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
+
 #endif
diff --git a/linux-user/xtensa/signal.c b/linux-user/xtensa/signal.c
index 7a3bfb92ca..81572a5fc7 100644
--- a/linux-user/xtensa/signal.c
+++ b/linux-user/xtensa/signal.c
@@ -128,6 +128,29 @@ static int setup_sigcontext(struct target_rt_sigframe *frame,
     return 1;
 }
 
+static void install_sigtramp(uint8_t *tramp)
+{
+#ifdef TARGET_WORDS_BIGENDIAN
+    /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
+    __put_user(0x22, &tramp[0]);
+    __put_user(0x0a, &tramp[1]);
+    __put_user(TARGET_NR_rt_sigreturn, &tramp[2]);
+    /* Generate instruction:  SYSCALL */
+    __put_user(0x00, &tramp[3]);
+    __put_user(0x05, &tramp[4]);
+    __put_user(0x00, &tramp[5]);
+#else
+    /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
+    __put_user(0x22, &tramp[0]);
+    __put_user(0xa0, &tramp[1]);
+    __put_user(TARGET_NR_rt_sigreturn, &tramp[2]);
+    /* Generate instruction:  SYSCALL */
+    __put_user(0x00, &tramp[3]);
+    __put_user(0x50, &tramp[4]);
+    __put_user(0x00, &tramp[5]);
+#endif
+}
+
 void setup_rt_frame(int sig, struct target_sigaction *ka,
                     target_siginfo_t *info,
                     target_sigset_t *set, CPUXtensaState *env)
@@ -164,26 +187,9 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         ra = ka->sa_restorer;
     } else {
-        ra = frame_addr + offsetof(struct target_rt_sigframe, retcode);
-#ifdef TARGET_WORDS_BIGENDIAN
-        /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
-        __put_user(0x22, &frame->retcode[0]);
-        __put_user(0x0a, &frame->retcode[1]);
-        __put_user(TARGET_NR_rt_sigreturn, &frame->retcode[2]);
-        /* Generate instruction:  SYSCALL */
-        __put_user(0x00, &frame->retcode[3]);
-        __put_user(0x05, &frame->retcode[4]);
-        __put_user(0x00, &frame->retcode[5]);
-#else
-        /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
-        __put_user(0x22, &frame->retcode[0]);
-        __put_user(0xa0, &frame->retcode[1]);
-        __put_user(TARGET_NR_rt_sigreturn, &frame->retcode[2]);
-        /* Generate instruction:  SYSCALL */
-        __put_user(0x00, &frame->retcode[3]);
-        __put_user(0x50, &frame->retcode[4]);
-        __put_user(0x00, &frame->retcode[5]);
-#endif
+        /* Not used, but retain for ABI compatibility. */
+        install_sigtramp(frame->retcode);
+        ra = default_rt_sigreturn;
     }
     memset(env->regs, 0, sizeof(env->regs));
     env->pc = ka->_sa_handler;
@@ -264,3 +270,13 @@ badframe:
     force_sig(TARGET_SIGSEGV);
     return -TARGET_QEMU_ESIGRETURN;
 }
+
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint8_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 6, 0);
+    assert(tramp != NULL);
+
+    default_rt_sigreturn = sigtramp_page;
+    install_sigtramp(tramp);
+    unlock_user(tramp, sigtramp_page, 6);
+}
-- 
2.25.1



  parent reply	other threads:[~2021-09-28  2:27 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-28  2:00 [PATCH v4 00/25] linux-user: Move signal trampolines to new page Richard Henderson
2021-09-28  2:00 ` [PATCH v4 01/25] linux-user: Add infrastructure for a signal trampoline page Richard Henderson
2021-09-28  2:00 ` [PATCH v4 02/25] linux-user/aarch64: Implement setup_sigtramp Richard Henderson
2021-09-28  2:00 ` [PATCH v4 03/25] linux-user/arm: Drop v1 signal frames Richard Henderson
2021-09-28  2:00 ` [PATCH v4 04/25] linux-user/arm: Drop "_v2" from symbols in signal.c Richard Henderson
2021-09-28  2:00 ` [PATCH v4 05/25] linux-user/arm: Implement setup_sigtramp Richard Henderson
2021-09-28  9:31   ` Peter Maydell
2021-09-28 12:28     ` Richard Henderson
2021-09-28  2:00 ` [PATCH v4 06/25] linux-user/alpha: " Richard Henderson
2021-09-28  2:00 ` [PATCH v4 07/25] linux-user/cris: " Richard Henderson
2021-09-28  2:00 ` [PATCH v4 08/25] linux-user/hexagon: " Richard Henderson
2021-09-28  2:00 ` [PATCH v4 09/25] linux-user/hppa: Document non-use of setup_sigtramp Richard Henderson
2021-09-28  2:00 ` [PATCH v4 10/25] linux-user/i386: Implement setup_sigtramp Richard Henderson
2021-09-28  6:51   ` Philippe Mathieu-Daudé
2021-09-28  2:00 ` [PATCH v4 11/25] linux-user/x86_64: Raise SIGSEGV if SA_RESTORER not set Richard Henderson
2021-09-28  2:00 ` [PATCH v4 12/25] linux-user/m68k: Implement setup_sigtramp Richard Henderson
2021-09-28  2:00 ` [PATCH v4 13/25] linux-user/microblaze: " Richard Henderson
2021-09-28  2:00 ` [PATCH v4 14/25] linux-user/mips: Tidy install_sigtramp Richard Henderson
2021-09-28  2:00 ` [PATCH v4 15/25] linux-user/mips: Implement setup_sigtramp Richard Henderson
2021-09-28  2:00 ` [PATCH v4 16/25] linux-user/nios2: Document non-use of setup_sigtramp Richard Henderson
2021-09-28  9:24   ` Peter Maydell
2021-09-28  2:00 ` [PATCH v4 17/25] linux-user/openrisc: Implement setup_sigtramp Richard Henderson
2021-09-28  2:00 ` [PATCH v4 18/25] linux-user/ppc: Simplify encode_trampoline Richard Henderson
2021-09-28  2:00 ` [PATCH v4 19/25] linux-user/ppc: Implement setup_sigtramp Richard Henderson
2021-09-28  2:00 ` [PATCH v4 20/25] linux-user/riscv: " Richard Henderson
2021-09-28  2:00 ` [PATCH v4 21/25] linux-user/s390x: " Richard Henderson
2021-09-28  2:00 ` [PATCH v4 22/25] linux-user/sh4: " Richard Henderson
2021-09-28  2:00 ` [PATCH v4 23/25] linux-user/sparc: " Richard Henderson
2021-09-28  6:54   ` Philippe Mathieu-Daudé
2021-09-29  7:17   ` Mark Cave-Ayland
2021-09-28  2:00 ` Richard Henderson [this message]
2021-09-28  2:00 ` [PATCH v4 25/25] linux-user: Remove default for TARGET_ARCH_HAS_SIGTRAMP_PAGE Richard Henderson

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