From: Warner Losh <imp@bsdimp.com>

The trap number for a page fault on BSD systems is T_PAGEFLT not 0xe. 0xe is
used by Linux and represents the intel hardware trap vector. The BSD kernels,
however, translate this to T_PAGEFLT in their Xpage, Xtrap0e, Xtrap14, etc fault
handlers. This is true for i386 and x86_64, though the name of the trap hanlder
can very on the flavor of BSD. As far as I can tell, Linux doesn't provide a
define for this value. Invent a new one (PAGE_FAULT_TRAP) and use it instead to
avoid uglier ifdefs.

Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Signed-off-by: Juergen Lock <nox@FreeBSD.org>
[ Rework to avoid ifdefs and expand it to i386 ]
Signed-off-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20210506173826.72832-1-imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/user-exec.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index fb2d43e6a9..d2acf6e82c 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -259,6 +259,7 @@ void *probe_access(CPUArchState *env, target_ulong addr, int size,
 #define TRAP_sig(context)    ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
 #define ERROR_sig(context)   ((context)->uc_mcontext.__gregs[_REG_ERR])
 #define MASK_sig(context)    ((context)->uc_sigmask)
+#define PAGE_FAULT_TRAP      T_PAGEFLT
 #elif defined(__FreeBSD__) || defined(__DragonFly__)
 #include <ucontext.h>
 
@@ -266,16 +267,19 @@ void *probe_access(CPUArchState *env, target_ulong addr, int size,
 #define TRAP_sig(context)    ((context)->uc_mcontext.mc_trapno)
 #define ERROR_sig(context)   ((context)->uc_mcontext.mc_err)
 #define MASK_sig(context)    ((context)->uc_sigmask)
+#define PAGE_FAULT_TRAP      T_PAGEFLT
 #elif defined(__OpenBSD__)
 #define EIP_sig(context)     ((context)->sc_eip)
 #define TRAP_sig(context)    ((context)->sc_trapno)
 #define ERROR_sig(context)   ((context)->sc_err)
 #define MASK_sig(context)    ((context)->sc_mask)
+#define PAGE_FAULT_TRAP      T_PAGEFLT
 #else
 #define EIP_sig(context)     ((context)->uc_mcontext.gregs[REG_EIP])
 #define TRAP_sig(context)    ((context)->uc_mcontext.gregs[REG_TRAPNO])
 #define ERROR_sig(context)   ((context)->uc_mcontext.gregs[REG_ERR])
 #define MASK_sig(context)    ((context)->uc_sigmask)
+#define PAGE_FAULT_TRAP      0xe
 #endif
 
 int cpu_signal_handler(int host_signum, void *pinfo,
@@ -301,7 +305,8 @@ int cpu_signal_handler(int host_signum, void *pinfo,
     pc = EIP_sig(uc);
     trapno = TRAP_sig(uc);
     return handle_cpu_signal(pc, info,
-                             trapno == 0xe ? (ERROR_sig(uc) >> 1) & 1 : 0,
+                             trapno == PAGE_FAULT_TRAP ?
+                             (ERROR_sig(uc) >> 1) & 1 : 0,
                              &MASK_sig(uc));
 }
 
@@ -312,11 +317,13 @@ int cpu_signal_handler(int host_signum, void *pinfo,
 #define TRAP_sig(context)     ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
 #define ERROR_sig(context)    ((context)->uc_mcontext.__gregs[_REG_ERR])
 #define MASK_sig(context)     ((context)->uc_sigmask)
+#define PAGE_FAULT_TRAP       T_PAGEFLT
 #elif defined(__OpenBSD__)
 #define PC_sig(context)       ((context)->sc_rip)
 #define TRAP_sig(context)     ((context)->sc_trapno)
 #define ERROR_sig(context)    ((context)->sc_err)
 #define MASK_sig(context)     ((context)->sc_mask)
+#define PAGE_FAULT_TRAP       T_PAGEFLT
 #elif defined(__FreeBSD__) || defined(__DragonFly__)
 #include <ucontext.h>
 
@@ -324,11 +331,13 @@ int cpu_signal_handler(int host_signum, void *pinfo,
 #define TRAP_sig(context)     ((context)->uc_mcontext.mc_trapno)
 #define ERROR_sig(context)    ((context)->uc_mcontext.mc_err)
 #define MASK_sig(context)     ((context)->uc_sigmask)
+#define PAGE_FAULT_TRAP       T_PAGEFLT
 #else
 #define PC_sig(context)       ((context)->uc_mcontext.gregs[REG_RIP])
 #define TRAP_sig(context)     ((context)->uc_mcontext.gregs[REG_TRAPNO])
 #define ERROR_sig(context)    ((context)->uc_mcontext.gregs[REG_ERR])
 #define MASK_sig(context)     ((context)->uc_sigmask)
+#define PAGE_FAULT_TRAP       0xe
 #endif
 
 int cpu_signal_handler(int host_signum, void *pinfo,
@@ -346,7 +355,8 @@ int cpu_signal_handler(int host_signum, void *pinfo,
 
     pc = PC_sig(uc);
     return handle_cpu_signal(pc, info,
-                             TRAP_sig(uc) == 0xe ? (ERROR_sig(uc) >> 1) & 1 : 0,
+                             TRAP_sig(uc) == PAGE_FAULT_TRAP ?
+                             (ERROR_sig(uc) >> 1) & 1 : 0,
                              &MASK_sig(uc));
 }
 
-- 
2.25.1