From 26d16c8adeaaddbd7fd6eb52a16c0a31e59267e6 Mon Sep 17 00:00:00 2001
From: "Dmitry V. Levin" <ldv@altlinux.org>
Date: Wed, 4 Mar 2015 22:27:35 +0000
Subject: [PATCH] arm: simplify sigreturn decoding

* signal.c (sys_sigreturn) [ARM]: Do not define sigcontext and ucontext
structures, fetch signal mask only, use print_sigset_addr_len.
---
 signal.c | 45 ++++++---------------------------------------
 1 file changed, 6 insertions(+), 39 deletions(-)

diff --git a/signal.c b/signal.c
index 3437f02d..bc78379c 100644
--- a/signal.c
+++ b/signal.c
@@ -692,49 +692,16 @@ sys_sigreturn(struct tcb *tcp)
 {
 #if defined(ARM)
 	if (entering(tcp)) {
-		struct arm_sigcontext {
-			unsigned long trap_no;
-			unsigned long error_code;
-			unsigned long oldmask;
-			unsigned long arm_r0;
-			unsigned long arm_r1;
-			unsigned long arm_r2;
-			unsigned long arm_r3;
-			unsigned long arm_r4;
-			unsigned long arm_r5;
-			unsigned long arm_r6;
-			unsigned long arm_r7;
-			unsigned long arm_r8;
-			unsigned long arm_r9;
-			unsigned long arm_r10;
-			unsigned long arm_fp;
-			unsigned long arm_ip;
-			unsigned long arm_sp;
-			unsigned long arm_lr;
-			unsigned long arm_pc;
-			unsigned long arm_cpsr;
-			unsigned long fault_address;
-		};
-		struct arm_ucontext {
-			unsigned long uc_flags;
-			unsigned long uc_link;  /* struct ucontext* */
-			/* The next three members comprise stack_t struct: */
-			unsigned long ss_sp;    /* void*   */
-			unsigned long ss_flags; /* int     */
-			unsigned long ss_size;  /* size_t  */
-			struct arm_sigcontext sc;
-			/* These two members are sigset_t: */
-			unsigned long uc_sigmask[2];
-			/* more fields follow, which we aren't interested in */
-		};
-		struct arm_ucontext uc;
-		if (umove(tcp, arm_regs.ARM_sp, &uc) < 0)
-			return 0;
 		/*
 		 * Kernel fills out uc.sc.oldmask too when it sets up signal stack,
 		 * but for sigmask restore, sigreturn syscall uses uc.uc_sigmask instead.
 		 */
-		tprintsigmask_addr(") (mask ", uc.uc_sigmask);
+# define SIZEOF_STRUCT_SIGCONTEXT (21 * 4)
+# define OFFSETOF_STRUCT_UCONTEXT_UC_SIGMASK (5 * 4 + SIZEOF_STRUCT_SIGCONTEXT)
+		const long addr = arm_regs.ARM_sp +
+			OFFSETOF_STRUCT_UCONTEXT_UC_SIGMASK;
+		tprints(") (mask ");
+		print_sigset_addr_len(tcp, addr, NSIG / 8);
 	}
 #elif defined(S390) || defined(S390X)
 	if (entering(tcp)) {
-- 
2.40.0