[PATCH 0/1] MR10330: ntdll: Implement syscall emulation on Linux using Syscall User Dispatch.

[Elizabeth Figura (＠zfigura)]

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10330

[PATCH 1/1] ntdll: Implement syscall emulation on Linux using Syscall User Dispatch.

[Elizabeth Figura]

From: Elizabeth Figura <[e-mail]>

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=48921
---
 dlls/ntdll/tests/exception.c    |  1 -
 dlls/ntdll/unix/signal_x86_64.c | 66 ++++++++++++++++++++++++++++++++-
 2 files changed, 64 insertions(+), 3 deletions(-)

diff --git a/dlls/ntdll/tests/exception.c b/dlls/ntdll/tests/exception.c
index b114b82cd4b..5ba23d38d34 100644
--- a/dlls/ntdll/tests/exception.c
+++ b/dlls/ntdll/tests/exception.c
@@ -6237,7 +6237,6 @@ static void test_direct_syscalls(void)
     func = code_mem;
     func(find_syscall_nr("NtSetEvent"), event, NULL);
 
-    todo_wine
     ok(WaitForSingleObject(event, 0) == WAIT_OBJECT_0, "Event not signaled.\n");
     CloseHandle(event);
 }
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 740df80341f..808e0e1f437 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -35,6 +35,9 @@
 #include <sys/types.h>
 #include <sys/mman.h>
 #include <unistd.h>
+#ifdef HAVE_LINK_H
+# include <link.h>
+#endif
 #ifdef HAVE_MACHINE_SYSARCH_H
 # include <machine/sysarch.h>
 #endif
@@ -44,6 +47,9 @@
 #ifdef HAVE_SYS_PARAM_H
 # include <sys/param.h>
 #endif
+#ifdef HAVE_SYS_PRCTL_H
+# include <sys/prctl.h>
+#endif
 #ifdef HAVE_SYSCALL_H
 # include <syscall.h>
 #else
@@ -506,6 +512,7 @@ struct amd64_thread_data
     void                **instrumentation_callback; /* 0330 */
     DWORD                 fs;            /* 0338 WOW TEB selector */
     DWORD                 mxcsr;         /* 033c Unix-side mxcsr register */
+    char                  syscall_dispatch; /* 0340 */
 };
 
 C_ASSERT( sizeof(struct amd64_thread_data) <= sizeof(((struct ntdll_thread_data *)0)->cpu_data) );
@@ -2682,7 +2689,7 @@ static void usr1_handler( int signal, siginfo_t *siginfo, void *sigcontext )
 }
 
 
-#ifdef __APPLE__
+#if defined(__APPLE__) || defined(PR_SET_SYSCALL_USER_DISPATCH)
 /**********************************************************************
  *		sigsys_handler
  *
@@ -2879,7 +2886,7 @@ void signal_init_process(void)
     if (sigaction( SIGSEGV, &sig_act, NULL ) == -1) goto error;
     if (sigaction( SIGILL, &sig_act, NULL ) == -1) goto error;
     if (sigaction( SIGBUS, &sig_act, NULL ) == -1) goto error;
-#ifdef __APPLE__
+#if defined(__APPLE__) || defined(PR_SET_SYSCALL_USER_DISPATCH)
     sig_act.sa_sigaction = sigsys_handler;
     if (sigaction( SIGSYS, &sig_act, NULL ) == -1) goto error;
 #endif
@@ -2891,6 +2898,53 @@ void signal_init_process(void)
 }
 
 
+#ifdef PR_SET_SYSCALL_USER_DISPATCH
+
+struct libc_addr_ctx
+{
+    uintptr_t addr, size;
+};
+
+static int libc_addr_cb(struct dl_phdr_info *info, size_t size, void *arg)
+{
+    struct libc_addr_ctx *ctx = arg;
+    const char *p;
+
+    if ((p = strrchr( info->dlpi_name, '/' )))
+        ++p;
+    else
+        p = info->dlpi_name;
+
+    if (strcmp( p, "libc.so.6" ))
+        return 0;
+
+    ctx->addr = info->dlpi_addr;
+    ctx->size = 0;
+    for (unsigned int i = 0; i < info->dlpi_phnum; ++i)
+        ctx->size = max( ctx->size, info->dlpi_phdr[i].p_vaddr + info->dlpi_phdr[i].p_memsz );
+
+    return 1;
+}
+
+static void init_linux_syscall_dispatch( struct amd64_thread_data *thread_data )
+{
+    struct libc_addr_ctx ctx;
+
+    if (!dl_iterate_phdr( libc_addr_cb, &ctx ))
+    {
+        WARN_(seh)( "could not find libc\n" );
+        return;
+    }
+
+    if (prctl( PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON,
+               ctx.addr, ctx.size, &thread_data->syscall_dispatch ) < 0)
+        WARN_(seh)( "could not enable syscall user dispatch\n" );
+
+    thread_data->syscall_dispatch = SYSCALL_DISPATCH_FILTER_BLOCK;
+}
+#endif
+
+
 /***********************************************************************
  *           init_syscall_frame
  */
@@ -2977,6 +3031,10 @@ void init_syscall_frame( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend,
     }
 
     pthread_sigmask( SIG_UNBLOCK, &server_block_set, NULL );
+
+#ifdef PR_SET_SYSCALL_USER_DISPATCH
+    init_linux_syscall_dispatch( thread_data );
+#endif
 }
 
 
@@ -3115,6 +3173,7 @@ __ASM_GLOBAL_FUNC( __wine_syscall_dispatcher,
                     * (on macOS, signal handlers set gsbase to pthread_teb when on the kernel stack).
                     */
 #ifdef __linux__
+                   "movb $0,0x340(%r13)\n\t"       /* amd64_thread_data()->syscall_dispatch */
                    "movq 0x320(%r13),%rsi\n\t"     /* amd64_thread_data()->pthread_teb */
                    "testq %rsi,%rsi\n\t"
                    "jz 2f\n\t"
@@ -3174,6 +3233,7 @@ __ASM_GLOBAL_FUNC( __wine_syscall_dispatcher,
                    __ASM_CFI_CFA_IS_AT2(rcx, 0xa8, 0x01) /* frame->syscall_cfa */
                    "leaq 0x70(%rcx),%rsp\n\t"      /* %rsp > frame means no longer inside syscall */
 #ifdef __linux__
+                   "movb $1,0x340(%r13)\n\t"       /* amd64_thread_data()->syscall_dispatch */
                    "movw 0x338(%r13),%dx\n"        /* amd64_thread_data()->fs */
                    "testw %dx,%dx\n\t"
                    "jz 1f\n\t"
@@ -3404,6 +3464,7 @@ __ASM_GLOBAL_FUNC( __wine_unix_call_dispatcher,
                    __ASM_CFI(".cfi_undefined %rdi\n\t")
                    __ASM_CFI(".cfi_undefined %rsi\n\t")
 #ifdef __linux__
+                   "movb $0,0x340(%r13)\n\t"       /* amd64_thread_data()->syscall_dispatch */
                    "movq 0x320(%r13),%rsi\n\t"     /* amd64_thread_data()->pthread_teb */
                    "testq %rsi,%rsi\n\t"
                    "jz 2f\n\t"
@@ -3442,6 +3503,7 @@ __ASM_GLOBAL_FUNC( __wine_unix_call_dispatcher,
                    "movq 0x88(%rcx),%rsp\n\t"
                    __ASM_CFI(".cfi_restore_state\n\t")
 #ifdef __linux__
+                   "movb $1,0x340(%r13)\n\t"       /* amd64_thread_data()->syscall_dispatch */
                    "movw 0x338(%r13),%dx\n"        /* amd64_thread_data()->fs */
                    "testw %dx,%dx\n\t"
                    "jz 1f\n\t"
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10330