From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Tue, 12 Feb 2013 11:50:10 +0000 (+0100)
Subject: Remove old kernel hacks for architectures which require new kernels
X-Git-Tag: v4.8~174
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d27809c978f3c8c3271f7d726dc92dd0eefa8a0f;p=strace

Remove old kernel hacks for architectures which require new kernels

* defs.h: Do not define TCB_WAITEXECVE for AVR32, BFIN and TILE.
* util.c (change_syscall): For AVR32, BFIN and TILE, replace code
with dummy "return 0" and a comment explaining why that is ok
for these architectures.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---

diff --git a/defs.h b/defs.h
index 78df638a..50620b3f 100644
--- a/defs.h
+++ b/defs.h
@@ -118,8 +118,8 @@ extern char *stpcpy(char *dst, const char *src);
 #ifndef DEFAULT_SORTBY
 # define DEFAULT_SORTBY "time"
 #endif
-
-/* Experimental code using PTRACE_SEIZE can be enabled here.
+/*
+ * Experimental code using PTRACE_SEIZE can be enabled here.
  * This needs Linux kernel 3.4.x or later to work.
  */
 #define USE_SEIZE 1
@@ -427,15 +427,23 @@ struct tcb {
 #define TCB_REPRINT	00200	/* We should reprint this syscall on exit */
 #define TCB_FILTERED	00400	/* This system call has been filtered out */
 /* x86 does not need TCB_WAITEXECVE.
- * It can detect SIGTRAP by looking at eax/rax.
- * See "not a syscall entry (eax = %ld)\n" message
- * in syscall_fixup_on_sysenter().
+ * It can detect post-execve SIGTRAP by looking at eax/rax.
+ * See "not a syscall entry (eax = %ld)\n" message.
+ *
+ * Note! On new kernels (about 2.5.46+), we use PTRACE_O_TRACEEXEC, which
+ * suppresses post-execve SIGTRAP. If you are adding a new arch which is
+ * only supported by newer kernels, you most likely don't need to define
+ * TCB_WAITEXECVE!
  */
-#if defined(ALPHA) || defined(AVR32) || defined(SPARC) || defined(SPARC64) \
-  || defined(POWERPC) || defined(IA64) || defined(HPPA) \
-  || defined(SH) || defined(SH64) || defined(S390) || defined(S390X) \
-  || defined(ARM) || defined(AARCH64) || defined(MIPS) || defined(BFIN) \
-  || defined(TILE)
+#if defined(ALPHA) \
+ || defined(SPARC) || defined(SPARC64) \
+ || defined(POWERPC) \
+ || defined(IA64) \
+ || defined(HPPA) \
+ || defined(SH) || defined(SH64) \
+ || defined(S390) || defined(S390X) \
+ || defined(ARM) || defined(AARCH64) \
+ || defined(MIPS)
 /* This tracee has entered into execve syscall. Expect post-execve SIGTRAP
  * to happen. (When it is detected, tracee is continued and this bit is cleared.)
  */
diff --git a/util.c b/util.c
index 93a98f64..ae90c348 100644
--- a/util.c
+++ b/util.c
@@ -966,6 +966,13 @@ upeek(struct tcb *tcp, long off, long *res)
 	return 0;
 }
 
+/* Note! On new kernels (about 2.5.46+), we use PTRACE_O_TRACECLONE
+ * and PTRACE_O_TRACE[V]FORK for tracing children.
+ * If you are adding a new arch which is only supported by newer kernels,
+ * you most likely don't need to add any code below
+ * beside a dummy "return 0" block in change_syscall().
+ */
+
 /*
  * These #if's are huge, please indent them correctly.
  * It's easy to get confused otherwise.
@@ -1118,9 +1125,6 @@ typedef struct pt_regs arg_setup_state;
 # elif defined(ALPHA) || defined(MIPS)
 #  define arg0_offset	REG_A0
 #  define arg1_offset	(REG_A0+1)
-# elif defined(AVR32)
-#  define arg0_offset	(REG_R12)
-#  define arg1_offset	(REG_R11)
 # elif defined(POWERPC)
 #  define arg0_offset	(sizeof(unsigned long)*PT_R3)
 #  define arg1_offset	(sizeof(unsigned long)*PT_R4)
@@ -1146,11 +1150,6 @@ typedef struct pt_regs arg_setup_state;
 #  define restore_arg1(tcp, state, val) 0
 #  define arg0_index	1
 #  define arg1_index	0
-# elif defined TILE
-#  define arg0_offset   PTREGS_OFFSET_REG(0)
-#  define arg1_offset   PTREGS_OFFSET_REG(1)
-#  define restore_arg0(tcp, state, val) 0
-#  define restore_arg1(tcp, state, val) 0
 # else
 #  define arg0_offset	0
 #  define arg1_offset	4
@@ -1229,12 +1228,12 @@ change_syscall(struct tcb *tcp, arg_setup_state *state, int new)
 		return -1;
 	return 0;
 #elif defined(AVR32)
-	if (ptrace(PTRACE_POKEUSER, tcp->pid, (char*)(REG_R8), new) < 0)
-		return -1;
+	/* setbpt/clearbpt never used: */
+	/* AVR32 is only supported since about linux-2.6.19 */
 	return 0;
 #elif defined(BFIN)
-	if (ptrace(PTRACE_POKEUSER, tcp->pid, (char*)(REG_P0), new) < 0)
-		return -1;
+	/* setbpt/clearbpt never used: */
+	/* Blackfin is only supported since about linux-2.6.23 */
 	return 0;
 #elif defined(IA64)
 	if (ia32) {
@@ -1282,10 +1281,8 @@ change_syscall(struct tcb *tcp, arg_setup_state *state, int new)
 		return -1;
 	return 0;
 #elif defined(TILE)
-	if (ptrace(PTRACE_POKEUSER, tcp->pid,
-		   (char*)PTREGS_OFFSET_REG(0),
-		   new) != 0)
-		return -1;
+	/* setbpt/clearbpt never used: */
+	/* Tilera CPUs are only supported since about linux-2.6.34 */
 	return 0;
 #elif defined(MICROBLAZE)
 	if (ptrace(PTRACE_POKEUSER, tcp->pid, (char*)(PT_GPR(0)), new) < 0)