Re: [PATCH v2 19/28] linux-user/i386: Fix -mregparm=3 for signal delivery

[Paolo Bonzini]

On 4/9/24 07:02, Richard Henderson wrote:

Since v2.6.19, the kernel has supported -mregparm=3.

Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
  linux-user/i386/signal.c | 20 +++++++++-----------
  1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/linux-user/i386/signal.c b/linux-user/i386/signal.c
index 559b63c25b..f8cc0cff07 100644
--- a/linux-user/i386/signal.c
+++ b/linux-user/i386/signal.c
@@ -427,6 +427,11 @@ void setup_frame(int sig, struct target_sigaction *ka,
      env->regs[R_ESP] = frame_addr;
      env->eip = ka->_sa_handler;

+ /* Make -mregparm=3 work */

+    env->regs[R_EAX] = sig;
+    env->regs[R_EDX] = 0;
+    env->regs[R_ECX] = 0;

Perhaps also move here the

    __put_user(sig, &frame->sig);

from above, for consistency with setup_rt_frame?

Paolo

      cpu_x86_load_seg(env, R_DS, __USER_DS);
      cpu_x86_load_seg(env, R_ES, __USER_DS);
      cpu_x86_load_seg(env, R_SS, __USER_DS);
@@ -448,9 +453,6 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
                      target_sigset_t *set, CPUX86State *env)
  {
      abi_ulong frame_addr;
-#ifndef TARGET_X86_64
-    abi_ulong addr;
-#endif
      struct rt_sigframe *frame;
      int i;

@@ -460,14 +462,6 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,

      if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
          goto give_sigsegv;

- /* These fields are only in rt_sigframe on 32 bit */

-#ifndef TARGET_X86_64
-    __put_user(sig, &frame->sig);
-    addr = frame_addr + offsetof(struct rt_sigframe, info);
-    __put_user(addr, &frame->pinfo);
-    addr = frame_addr + offsetof(struct rt_sigframe, uc);
-    __put_user(addr, &frame->puc);
-#endif
      if (ka->sa_flags & TARGET_SA_SIGINFO) {
          frame->info = *info;
      }
@@ -507,9 +501,13 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
      env->eip = ka->_sa_handler;

#ifndef TARGET_X86_64

+    /* Store arguments for both -mregparm=3 and standard. */
      env->regs[R_EAX] = sig;
+    __put_user(sig, &frame->sig);
      env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, info);
+    __put_user(env->regs[R_EDX], &frame->pinfo);
      env->regs[R_ECX] = frame_addr + offsetof(struct rt_sigframe, uc);
+    __put_user(env->regs[R_ECX], &frame->puc);
  #else
      env->regs[R_EAX] = 0;
      env->regs[R_EDI] = sig;