diff mbox series

[v2,08/23] linux-user/hexagon: Implement setup_sigtramp

Message ID 20210618192951.125651-9-richard.henderson@linaro.org
State Superseded
Headers show
Series linux-user: Move signal trampolines to new page | expand

Commit Message

Richard Henderson June 18, 2021, 7:29 p.m. UTC 
Continue to initialize the words on the stack, as documented.
However, use the off-stack trampoline.

Cc: Taylor Simpson <tsimpson@quicinc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 linux-user/hexagon/target_signal.h |  2 ++
 linux-user/hexagon/signal.c        | 19 +++++++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

-- 
2.25.1

Comments

Philippe Mathieu-Daudé June 19, 2021, 9:31 a.m. UTC | #1 
On 6/18/21 9:29 PM, Richard Henderson wrote:
> Continue to initialize the words on the stack, as documented.

> However, use the off-stack trampoline.

> 

> Cc: Taylor Simpson <tsimpson@quicinc.com>

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  linux-user/hexagon/target_signal.h |  2 ++

>  linux-user/hexagon/signal.c        | 19 +++++++++++++++++--

>  2 files changed, 19 insertions(+), 2 deletions(-)


Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
diff mbox series

Patch

diff --git a/linux-user/hexagon/target_signal.h b/linux-user/hexagon/target_signal.h
index 345cf1cbb8..9e0223d322 100644
--- a/linux-user/hexagon/target_signal.h
+++ b/linux-user/hexagon/target_signal.h
@@ -31,4 +31,6 @@  typedef struct target_sigaltstack {
 
 #include "../generic/signal.h"
 
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1
+
 #endif /* TARGET_SIGNAL_H */
diff --git a/linux-user/hexagon/signal.c b/linux-user/hexagon/signal.c
index 85eab5e943..bd0f9b1c85 100644
--- a/linux-user/hexagon/signal.c
+++ b/linux-user/hexagon/signal.c
@@ -161,6 +161,11 @@  void setup_rt_frame(int sig, struct target_sigaction *ka,
 
     setup_ucontext(&frame->uc, env, set);
     tswap_siginfo(&frame->info, info);
+    /*
+     * The on-stack signal trampoline is no longer executed;
+     * however, the libgcc signal frame unwinding code checks
+     * for the presence of these two numeric magic values.
+     */
     install_sigtramp(frame->tramp);
 
     env->gpr[HEX_REG_PC] = ka->_sa_handler;
@@ -170,8 +175,7 @@  void setup_rt_frame(int sig, struct target_sigaction *ka,
         frame_addr + offsetof(struct target_rt_sigframe, info);
     env->gpr[HEX_REG_R02] =
         frame_addr + offsetof(struct target_rt_sigframe, uc);
-    env->gpr[HEX_REG_LR] =
-        frame_addr + offsetof(struct target_rt_sigframe, tramp);
+    env->gpr[HEX_REG_LR] = default_rt_sigreturn;
 
     return;
 
@@ -270,3 +274,14 @@  badframe:
     force_sig(TARGET_SIGSEGV);
     return 0;
 }
+
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 4 * 2, 0);
+    assert(tramp != NULL);
+
+    default_rt_sigreturn = sigtramp_page;
+    install_sigtramp(tramp);
+
+    unlock_user(tramp, sigtramp_page, 4 * 2);
+}