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From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: alex.bennee@linaro.org, laurent@vivier.eu
Subject: [PATCH v2 10/23] linux-user/i386: Implement setup_sigtramp
Date: Fri, 18 Jun 2021 12:29:38 -0700	[thread overview]
Message-ID: <20210618192951.125651-11-richard.henderson@linaro.org> (raw)
In-Reply-To: <20210618192951.125651-1-richard.henderson@linaro.org>

Create and record the two signal trampolines.
Use them when the guest does not use SA_RESTORER.
Note that x86_64 does not use this code.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/i386/target_signal.h   |  2 ++
 linux-user/x86_64/target_signal.h |  3 +++
 linux-user/i386/signal.c          | 42 ++++++++++++++++++-------------
 3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/linux-user/i386/target_signal.h b/linux-user/i386/target_signal.h
index 50361af874..64d09f2e75 100644
--- a/linux-user/i386/target_signal.h
+++ b/linux-user/i386/target_signal.h
@@ -22,4 +22,6 @@ typedef struct target_sigaltstack {
 #include "../generic/signal.h"
 
 #define TARGET_ARCH_HAS_SETUP_FRAME
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
+
 #endif /* I386_TARGET_SIGNAL_H */
diff --git a/linux-user/x86_64/target_signal.h b/linux-user/x86_64/target_signal.h
index 4ea74f20dd..4673c5a886 100644
--- a/linux-user/x86_64/target_signal.h
+++ b/linux-user/x86_64/target_signal.h
@@ -21,4 +21,7 @@ typedef struct target_sigaltstack {
 
 #include "../generic/signal.h"
 
+/* For x86_64, use of SA_RESTORER is mandatory. */
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 0
+
 #endif /* X86_64_TARGET_SIGNAL_H */
diff --git a/linux-user/i386/signal.c b/linux-user/i386/signal.c
index 8701774e37..a83ecba54f 100644
--- a/linux-user/i386/signal.c
+++ b/linux-user/i386/signal.c
@@ -337,16 +337,7 @@ void setup_frame(int sig, struct target_sigaction *ka,
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         __put_user(ka->sa_restorer, &frame->pretcode);
     } else {
-        uint16_t val16;
-        abi_ulong retcode_addr;
-        retcode_addr = frame_addr + offsetof(struct sigframe, retcode);
-        __put_user(retcode_addr, &frame->pretcode);
-        /* This is popl %eax ; movl $,%eax ; int $0x80 */
-        val16 = 0xb858;
-        __put_user(val16, (uint16_t *)(frame->retcode+0));
-        __put_user(TARGET_NR_sigreturn, (int *)(frame->retcode+2));
-        val16 = 0x80cd;
-        __put_user(val16, (uint16_t *)(frame->retcode+6));
+        __put_user(default_sigreturn, &frame->pretcode);
     }
 
     /* Set up registers for signal handler */
@@ -415,14 +406,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         __put_user(ka->sa_restorer, &frame->pretcode);
     } else {
-        uint16_t val16;
-        addr = frame_addr + offsetof(struct rt_sigframe, retcode);
-        __put_user(addr, &frame->pretcode);
-        /* This is movl $,%eax ; int $0x80 */
-        __put_user(0xb8, (char *)(frame->retcode+0));
-        __put_user(TARGET_NR_rt_sigreturn, (int *)(frame->retcode+1));
-        val16 = 0x80cd;
-        __put_user(val16, (uint16_t *)(frame->retcode+5));
+        __put_user(default_rt_sigreturn, &frame->pretcode);
     }
 #else
     /* XXX: Would be slightly better to return -EFAULT here if test fails
@@ -591,3 +575,25 @@ badframe:
     force_sig(TARGET_SIGSEGV);
     return -TARGET_QEMU_ESIGRETURN;
 }
+
+#ifndef TARGET_X86_64
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
+    assert(tramp != NULL);
+
+    default_sigreturn = sigtramp_page;
+    /* This is popl %eax ; movl $,%eax ; int $0x80 */
+    __put_user(0xb858, (uint16_t *)(tramp + 0));
+    __put_user(TARGET_NR_sigreturn, (int *)(tramp + 2));
+    __put_user(0x80cd, (uint16_t *)(tramp + 6));
+
+    default_rt_sigreturn = sigtramp_page + 8;
+    /* This is movl $,%eax ; int $0x80 */
+    __put_user(0xb8, (char *)(tramp + 8));
+    __put_user(TARGET_NR_rt_sigreturn, (int *)(tramp + 9));
+    __put_user(0x80cd, (uint16_t *)(tramp + 13));
+
+    unlock_user(tramp, sigtramp_page, 2 * 8);
+}
+#endif
-- 
2.25.1



  parent reply	other threads:[~2021-06-18 19:38 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-18 19:29 [PATCH v2 00/23] linux-user: Move signal trampolines to new page Richard Henderson
2021-06-18 19:29 ` [PATCH v2 01/23] linux-user: Add infrastructure for a signal trampoline page Richard Henderson
2021-06-19  9:33   ` Philippe Mathieu-Daudé
2021-06-29 13:30   ` Peter Maydell
2021-06-18 19:29 ` [PATCH v2 02/23] linux-user/aarch64: Implement setup_sigtramp Richard Henderson
2021-06-29 13:36   ` Peter Maydell
2021-07-01 19:27     ` Richard Henderson
2021-06-18 19:29 ` [PATCH v2 03/23] linux-user/arm: Split out v2_frame Richard Henderson
2021-06-29 13:53   ` Peter Maydell
2021-06-29 14:30     ` Richard Henderson
2021-06-18 19:29 ` [PATCH v2 04/23] linux-user/arm: Force v2 frames for fdpic Richard Henderson
2021-06-29 13:54   ` Peter Maydell
2021-06-18 19:29 ` [PATCH v2 05/23] linux-user/arm: Implement setup_sigtramp Richard Henderson
2021-06-29 14:09   ` Peter Maydell
2021-06-29 18:32     ` Richard Henderson
2021-06-18 19:29 ` [PATCH v2 06/23] linux-user/alpha: " Richard Henderson
2021-06-18 19:29 ` [PATCH v2 07/23] linux-user/cris: " Richard Henderson
2021-06-19  9:33   ` Philippe Mathieu-Daudé
2021-06-19 12:55     ` Richard Henderson
2021-06-19 14:17       ` Philippe Mathieu-Daudé
2021-06-18 19:29 ` [PATCH v2 08/23] linux-user/hexagon: " Richard Henderson
2021-06-19  9:31   ` Philippe Mathieu-Daudé
2021-06-18 19:29 ` [PATCH v2 09/23] linux-user/hppa: Document non-use of setup_sigtramp Richard Henderson
2021-06-18 19:29 ` Richard Henderson [this message]
2021-06-29 14:40   ` [PATCH v2 10/23] linux-user/i386: Implement setup_sigtramp Peter Maydell
2021-06-29 18:30     ` Richard Henderson
2021-06-18 19:29 ` [PATCH v2 11/23] linux-user/m68k: " Richard Henderson
2021-06-18 19:29 ` [PATCH v2 12/23] linux-user/microblaze: " Richard Henderson
2021-06-18 19:29 ` [PATCH v2 13/23] linux-user/mips: Tidy install_sigtramp Richard Henderson
2021-06-19  9:29   ` Philippe Mathieu-Daudé
2021-06-18 19:29 ` [PATCH v2 14/23] linux-user/mips: Implement setup_sigtramp Richard Henderson
2021-06-18 19:29 ` [PATCH v2 15/23] linux-user/nios2: Document non-use of setup_sigtramp Richard Henderson
2021-06-19  9:35   ` Philippe Mathieu-Daudé
2021-06-18 19:29 ` [PATCH v2 16/23] linux-user/openrisc: Implement setup_sigtramp Richard Henderson
2021-06-18 19:29 ` [PATCH v2 17/23] linux-user/ppc: " Richard Henderson
2021-06-29 14:52   ` Peter Maydell
2021-06-18 19:29 ` [PATCH v2 18/23] linux-user/riscv: " Richard Henderson
2021-06-18 19:29 ` [PATCH v2 19/23] linux-user/s390x: " Richard Henderson
2021-06-18 19:29 ` [PATCH v2 20/23] linux-user/sh4: " Richard Henderson
2021-06-18 19:29 ` [PATCH v2 21/23] linux-user/sparc: " Richard Henderson
2021-07-02  9:05   ` Philippe Mathieu-Daudé
2021-06-18 19:29 ` [PATCH v2 22/23] linux-user/xtensa: " Richard Henderson
2021-06-18 19:29 ` [PATCH v2 23/23] linux-user: Remove default for TARGET_ARCH_HAS_SIGTRAMP_PAGE Richard Henderson

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