[PATCH 1/3] um: Drop own definition of PTRACE_SYSEMU/_SINGLESTEP

[PATCH 1/3] um: Drop own definition of PTRACE_SYSEMU/_SINGLESTEP

[Richard Weinberger]

32bit UML used to define PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP
own its own because many years ago not all libcs had these request codes
in their UAPI.
These days PTRACE_SYSEMU/_SINGLESTEP is well known and part of glibc
and our own define becomes problematic.

With change c48831d0eebf ("linux/x86: sync sys/ptrace.h with Linux 4.14
[BZ #22433]") glibc turned PTRACE_SYSEMU/_SINGLESTEP into a enum and
UML failed to build.

Let's drop our define and rely on the fact that every libc has
PTRACE_SYSEMU/_SINGLESTEP.

Cc: <stable@vger.kernel.org>
Cc: Ritesh Raj Sarraf <rrs@researchut.com>
Reported-and-tested-by: Ritesh Raj Sarraf <rrs@researchut.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
 arch/x86/um/shared/sysdep/ptrace_32.h | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/arch/x86/um/shared/sysdep/ptrace_32.h b/arch/x86/um/shared/sysdep/ptrace_32.h
index b94a108de1dc..ae00d22bce02 100644
--- a/arch/x86/um/shared/sysdep/ptrace_32.h
+++ b/arch/x86/um/shared/sysdep/ptrace_32.h
@@ -10,20 +10,10 @@
 
 static inline void update_debugregs(int seq) {}
 
-/* syscall emulation path in ptrace */
-
-#ifndef PTRACE_SYSEMU
-#define PTRACE_SYSEMU 31
-#endif
-
 void set_using_sysemu(int value);
 int get_using_sysemu(void);
 extern int sysemu_supported;
 
-#ifndef PTRACE_SYSEMU_SINGLESTEP
-#define PTRACE_SYSEMU_SINGLESTEP 32
-#endif
-
 #define UPT_SYSCALL_ARG1(r) UPT_BX(r)
 #define UPT_SYSCALL_ARG2(r) UPT_CX(r)
 #define UPT_SYSCALL_ARG3(r) UPT_DX(r)
-- 
2.13.6

[PATCH 2/3] um: Remove update_debugregs()

[Richard Weinberger]

This function is nowhere used, let's get rid of it.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 arch/x86/um/shared/sysdep/ptrace_32.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/x86/um/shared/sysdep/ptrace_32.h b/arch/x86/um/shared/sysdep/ptrace_32.h
index ae00d22bce02..db8478a83a09 100644
--- a/arch/x86/um/shared/sysdep/ptrace_32.h
+++ b/arch/x86/um/shared/sysdep/ptrace_32.h
@@ -8,8 +8,6 @@
 
 #define MAX_FP_NR HOST_FPX_SIZE
 
-static inline void update_debugregs(int seq) {}
-
 void set_using_sysemu(int value);
 int get_using_sysemu(void);
 extern int sysemu_supported;
-- 
2.13.6

[PATCH 3/3] um: Give start_idle_thread() a return code

[Richard Weinberger]

Fixes:
arch/um/os-Linux/skas/process.c:613:1: warning: control reaches end of
non-void function [-Wreturn-type]

longjmp() never returns but gcc still warns that the end of the function
can be reached.
Add a return code and debug aid to detect this impossible case.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 arch/um/os-Linux/skas/process.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index c94c3bd70ccd..df4a985716eb 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -610,6 +610,11 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
 		fatal_sigsegv();
 	}
 	longjmp(*switch_buf, 1);
+
+	/* unreachable */
+	printk(UM_KERN_ERR "impossible long jump!");
+	fatal_sigsegv();
+	return 0;
 }
 
 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
-- 
2.13.6


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