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From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: qemu-riscv@nongnu.org, alex.bennee@linaro.org, laurent@vivier.eu
Subject: [PATCH 16/21] linux-user/riscv: Implement setup_sigtramp
Date: Tue, 15 Jun 2021 18:12:04 -0700	[thread overview]
Message-ID: <20210616011209.1446045-17-richard.henderson@linaro.org> (raw)
In-Reply-To: <20210616011209.1446045-1-richard.henderson@linaro.org>

Create and record the rt signal trampoline.

This fixes a bug wrt libgcc fallback unwinding.  It expects
the stack pointer to point to the siginfo_t, whereas we had
inexplicably placed our private signal trampoline at the start
of the signal frame instead of the end.  Now moot because we
have removed it from the stack frame entirely.

Cc: qemu-riscv@nongnu.org
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/riscv/target_signal.h |  2 ++
 linux-user/riscv/signal.c        | 22 +++++++++++++---------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/linux-user/riscv/target_signal.h b/linux-user/riscv/target_signal.h
index f113ba9a55..3e36fddc9d 100644
--- a/linux-user/riscv/target_signal.h
+++ b/linux-user/riscv/target_signal.h
@@ -15,4 +15,6 @@ typedef struct target_sigaltstack {
 
 #include "../generic/signal.h"
 
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
+
 #endif /* RISCV_TARGET_SIGNAL_H */
diff --git a/linux-user/riscv/signal.c b/linux-user/riscv/signal.c
index 9405c7fd9a..4086dfa5d5 100644
--- a/linux-user/riscv/signal.c
+++ b/linux-user/riscv/signal.c
@@ -46,7 +46,6 @@ struct target_ucontext {
 };
 
 struct target_rt_sigframe {
-    uint32_t tramp[2]; /* not in kernel, which uses VDSO instead */
     struct target_siginfo info;
     struct target_ucontext uc;
 };
@@ -104,12 +103,6 @@ static void setup_ucontext(struct target_ucontext *uc,
     setup_sigcontext(&uc->uc_mcontext, env);
 }
 
-static inline void install_sigtramp(uint32_t *tramp)
-{
-    __put_user(0x08b00893, tramp + 0);  /* li a7, 139 = __NR_rt_sigreturn */
-    __put_user(0x00000073, tramp + 1);  /* ecall */
-}
-
 void setup_rt_frame(int sig, struct target_sigaction *ka,
                     target_siginfo_t *info,
                     target_sigset_t *set, CPURISCVState *env)
@@ -126,14 +119,13 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
 
     setup_ucontext(&frame->uc, env, set);
     tswap_siginfo(&frame->info, info);
-    install_sigtramp(frame->tramp);
 
     env->pc = ka->_sa_handler;
     env->gpr[xSP] = frame_addr;
     env->gpr[xA0] = sig;
     env->gpr[xA1] = frame_addr + offsetof(struct target_rt_sigframe, info);
     env->gpr[xA2] = frame_addr + offsetof(struct target_rt_sigframe, uc);
-    env->gpr[xRA] = frame_addr + offsetof(struct target_rt_sigframe, tramp);
+    env->gpr[xRA] = default_rt_sigreturn;
 
     return;
 
@@ -202,3 +194,15 @@ badframe:
     force_sig(TARGET_SIGSEGV);
     return 0;
 }
+
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0);
+    assert(tramp != NULL);
+
+    __put_user(0x08b00893, tramp + 0);  /* li a7, 139 = __NR_rt_sigreturn */
+    __put_user(0x00000073, tramp + 1);  /* ecall */
+
+    default_rt_sigreturn = sigtramp_page;
+    unlock_user(tramp, sigtramp_page, 8);
+}
-- 
2.25.1



  parent reply	other threads:[~2021-06-16  1:23 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16  1:11 [PATCH 00/21] linux-user: Move signal trampolines to new page Richard Henderson
2021-06-16  1:11 ` [PATCH 01/21] linux-user: Add infrastructure for a signal trampoline page Richard Henderson
2021-06-16 13:36   ` Max Filippov
2021-06-16  1:11 ` [PATCH 02/21] linux-user/aarch64: Implement setup_sigtramp Richard Henderson
2021-06-16 17:00   ` Philippe Mathieu-Daudé
2021-06-16  1:11 ` [PATCH 03/21] linux-user/arm: Force v2 frames for fdpic Richard Henderson
2021-06-16 17:01   ` Philippe Mathieu-Daudé
2021-06-16  1:11 ` [PATCH 04/21] linux-user/arm: Implement setup_sigtramp Richard Henderson
2021-06-16 13:46   ` Alex Bennée
2021-06-16 13:49     ` Alex Bennée
2021-06-16 17:40       ` Richard Henderson
2021-06-16  1:11 ` [PATCH 05/21] linux-user/alpha: " Richard Henderson
2021-06-16 16:56   ` Philippe Mathieu-Daudé
2021-06-16  1:11 ` [PATCH 06/21] linux-user/cris: " Richard Henderson
2021-06-16 16:37   ` Philippe Mathieu-Daudé
2021-06-16  1:11 ` [PATCH 07/21] linux-user/hexagon: " Richard Henderson
2021-06-16  8:07   ` Taylor Simpson
2021-06-16 15:05     ` Richard Henderson
2021-06-16 15:50       ` Richard Henderson
2021-06-16 21:37         ` Taylor Simpson
2021-06-16 23:15           ` Richard Henderson
2021-06-16  1:11 ` [PATCH 08/21] linux-user/hppa: Document non-use of setup_sigtramp Richard Henderson
2021-06-16 10:46   ` Philippe Mathieu-Daudé
2021-06-16 21:16   ` Alex Bennée
2021-06-16  1:11 ` [PATCH 09/21] linux-user/i386: Implement setup_sigtramp Richard Henderson
2021-06-16  1:11 ` [PATCH 10/21] linux-user/m68k: " Richard Henderson
2021-06-16 16:42   ` Philippe Mathieu-Daudé
2021-06-16  1:11 ` [PATCH 11/21] linux-user/microblaze: " Richard Henderson
2021-06-16 16:43   ` Philippe Mathieu-Daudé
2021-06-16  1:12 ` [PATCH 12/21] linux-user/mips: " Richard Henderson
2021-06-16 16:48   ` Philippe Mathieu-Daudé
2021-06-16  1:12 ` [PATCH 13/21] linux-user/nios2: Document non-use of setup_sigtramp Richard Henderson
2021-06-16  1:12 ` [PATCH 14/21] linux-user/openrisc: Implement setup_sigtramp Richard Henderson
2021-06-16 16:49   ` Philippe Mathieu-Daudé
2021-06-17  0:24   ` Stafford Horne
2021-06-16  1:12 ` [PATCH 15/21] linux-user/ppc: " Richard Henderson
2021-06-16  1:12 ` Richard Henderson [this message]
2021-06-16 16:50   ` [PATCH 16/21] linux-user/riscv: " Philippe Mathieu-Daudé
2021-06-18  1:29   ` Alistair Francis
2021-06-16  1:12 ` [PATCH 17/21] linux-user/s390x: " Richard Henderson
2021-06-16 16:52   ` Philippe Mathieu-Daudé
2021-06-16  1:12 ` [PATCH 18/21] linux-user/sh4: " Richard Henderson
2021-06-16 16:53   ` Philippe Mathieu-Daudé
2021-06-16  1:12 ` [PATCH 19/21] linux-user/sparc: " Richard Henderson
2021-06-16  1:12 ` [PATCH 20/21] linux-user/xtensa: " Richard Henderson
2021-06-16 13:35   ` Max Filippov
2021-06-16  1:12 ` [PATCH 21/21] linux-user: Remove default for TARGET_ARCH_HAS_SIGTRAMP_PAGE Richard Henderson
2021-06-16 16:54   ` Philippe Mathieu-Daudé
2021-06-16 15:05 ` [PATCH 00/21] linux-user: Move signal trampolines to new page Alex Bennée
2021-06-16 15:09   ` Richard Henderson

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