Module Name: src
Committed By: thorpej
Date: Tue Nov 23 18:45:53 UTC 2021
Modified Files:
src/lib/libc/arch/arm: genassym.cf
src/lib/libc/arch/arm/sys: __sigtramp2.S
Log Message:
Decorate the ARM signal trampoline with the appropriate .cfi
directives to allow exception unwind / backtrace across a signal
handler.
To generate a diff of this commit:
cvs rdiff -u -r1.3 -r1.4 src/lib/libc/arch/arm/genassym.cf
cvs rdiff -u -r1.3 -r1.4 src/lib/libc/arch/arm/sys/__sigtramp2.S
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/arch/arm/genassym.cf
diff -u src/lib/libc/arch/arm/genassym.cf:1.3 src/lib/libc/arch/arm/genassym.cf:1.4
--- src/lib/libc/arch/arm/genassym.cf:1.3 Sat Oct 24 07:03:11 2020
+++ src/lib/libc/arch/arm/genassym.cf Tue Nov 23 18:45:53 2021
@@ -1,4 +1,4 @@
-# $NetBSD: genassym.cf,v 1.3 2020/10/24 07:03:11 skrll Exp $
+# $NetBSD: genassym.cf,v 1.4 2021/11/23 18:45:53 thorpej Exp $
#
# Copyright (c) 2012 The NetBSD Foundation, Inc.
@@ -30,21 +30,30 @@
#
include <sys/types.h>
+include <signal.h>
include <ucontext.h>
+define _UC_GREGS offsetof(ucontext_t, uc_mcontext.__gregs[0])
define _UC_REGS_R0 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R0])
-define _UC_REGS_R1 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R1])
-define _UC_REGS_R2 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R2])
-define _UC_REGS_R3 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R3])
-define _UC_REGS_R4 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R4])
-define _UC_REGS_R5 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R5])
-define _UC_REGS_R6 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R6])
-define _UC_REGS_R7 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R7])
-define _UC_REGS_R8 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R8])
-define _UC_REGS_R9 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R9])
-define _UC_REGS_R10 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R10])
-define _UC_REGS_R11 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R11])
-define _UC_REGS_R12 offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R12])
define _UC_REGS_SP offsetof(ucontext_t, uc_mcontext.__gregs[_REG_SP])
-define _UC_REGS_LR offsetof(ucontext_t, uc_mcontext.__gregs[_REG_LR])
define _UC_REGS_PC offsetof(ucontext_t, uc_mcontext.__gregs[_REG_PC])
+
+define SIZEOF_SIGINFO sizeof(siginfo_t)
+
+define _REG_R0 _REG_R0
+define _REG_R1 _REG_R1
+define _REG_R2 _REG_R2
+define _REG_R3 _REG_R3
+define _REG_R4 _REG_R4
+define _REG_R5 _REG_R5
+define _REG_R6 _REG_R6
+define _REG_R7 _REG_R7
+define _REG_R8 _REG_R8
+define _REG_R9 _REG_R9
+define _REG_R10 _REG_R10
+define _REG_R11 _REG_R11
+define _REG_R12 _REG_R12
+define _REG_R13 _REG_R13
+define _REG_R14 _REG_R14
+define _REG_R15 _REG_R15
+define _REG_SP _REG_SP
Index: src/lib/libc/arch/arm/sys/__sigtramp2.S
diff -u src/lib/libc/arch/arm/sys/__sigtramp2.S:1.3 src/lib/libc/arch/arm/sys/__sigtramp2.S:1.4
--- src/lib/libc/arch/arm/sys/__sigtramp2.S:1.3 Fri Aug 16 23:20:59 2013
+++ src/lib/libc/arch/arm/sys/__sigtramp2.S Tue Nov 23 18:45:53 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: __sigtramp2.S,v 1.3 2013/08/16 23:20:59 matt Exp $ */
+/* $NetBSD: __sigtramp2.S,v 1.4 2021/11/23 18:45:53 thorpej Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -30,6 +30,7 @@
*/
#include "SYS.h"
+#include "assym.h"
/*
* The ARM signal trampoline is invoked only to return from
@@ -39,12 +40,46 @@
*
* ucontext structure
* sp-> siginfo structure
- * and r5 points to the ucontext
+ * and r5 points to the ucontext
*/
+
+#define CFI_OFFSET(r) .cfi_offset r, r * 4
+
+ _TEXT_SECTION
+ .cfi_startproc
+ .cfi_signal_frame
+ .cfi_def_cfa _REG_SP, SIZEOF_SIGINFO + _UC_GREGS
+ CFI_OFFSET(_REG_R0)
+ CFI_OFFSET(_REG_R1)
+ CFI_OFFSET(_REG_R2)
+ CFI_OFFSET(_REG_R3)
+ CFI_OFFSET(_REG_R4)
+ CFI_OFFSET(_REG_R5)
+ CFI_OFFSET(_REG_R6)
+ CFI_OFFSET(_REG_R7)
+ CFI_OFFSET(_REG_R8)
+ CFI_OFFSET(_REG_R9)
+ CFI_OFFSET(_REG_R10)
+ CFI_OFFSET(_REG_R11)
+ CFI_OFFSET(_REG_R12)
+ CFI_OFFSET(_REG_R13) /* a.k.a. _REG_SP */
+ CFI_OFFSET(_REG_R14) /* a.k.a. _REG_LR */
+ .cfi_return_column _REG_R15
+ CFI_OFFSET(_REG_R15) /* a.k.a. _REG_PC */
+
+/*
+ * The unwind entry includes the one instruction prior to the trampoline
+ * because the unwinder will look up (return PC - 1) while unwinding.
+ * Normally this would be the jump / branch, but since there isn't one in
+ * this case, we place an explicit nop there instead.
+ */
+ nop
+
ENTRY_NP(__sigtramp_siginfo_2)
mov r0, r5 /* set the arg */
SYSTRAP(setcontext) /* and call setcontext */
/* If that failed, exit with the error code. */
SYSTRAP(exit)
+ .cfi_endproc
END(__sigtramp_siginfo_2)
