[PATCH v2 20/28] um: Move faultinfo extraction into userspace routine

[benjamin at sipsolutions.net]

From: Benjamin Berg <benjamin at sipsolutions.net>

The segv handler is called slightly differently depending on whether
PTRACE_FULL_FAULTINFO is set or not (32bit vs. 64bit). The only
difference is that we don't try to pass the registers and instruction
pointer to the segv handler.

It would be good to either document or remove the difference, but I do
not know why this difference exists.

Signed-off-by: Benjamin Berg <benjamin at sipsolutions.net>
---
 arch/um/os-Linux/skas/process.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 1e1c378588ba..1bc7e5aa2fc1 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -171,12 +171,6 @@ static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux
 	}
 }
 
-static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
-{
-	get_skas_faultinfo(pid, &regs->faultinfo, aux_fp_regs);
-	segv(regs->faultinfo, 0, 1, NULL);
-}
-
 static void handle_trap(int pid, struct uml_pt_regs *regs)
 {
 	if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END))
@@ -422,13 +416,15 @@ void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
 
 			switch (sig) {
 			case SIGSEGV:
-				if (PTRACE_FULL_FAULTINFO) {
-					get_skas_faultinfo(pid,
-							   &regs->faultinfo, aux_fp_regs);
+				get_skas_faultinfo(pid,
+						   &regs->faultinfo, aux_fp_regs);
+
+				if (PTRACE_FULL_FAULTINFO)
 					(*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
 							     regs);
-				}
-				else handle_segv(pid, regs, aux_fp_regs);
+				else
+					segv(regs->faultinfo, 0, 1, NULL);
+
 				break;
 			case SIGTRAP + 0x80:
 				handle_trap(pid, regs);
-- 
2.38.1