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Commit 71c04fdf authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Greg Kroah-Hartman
Browse files

selftests/rseq: Introduce thread pointer getters 



commit 886ddfba933f5ce9d76c278165d834d114ba4ffc upstream.

This is done in preparation for the selftest uplift to become compatible
with glibc-2.35.

glibc-2.35 exposes the rseq per-thread data in the TCB, accessible
at an offset from the thread pointer.

The toolchains do not implement accessing the thread pointer on all
architectures. Provide thread pointer getters for ppc and x86 which
lack (or lacked until recently) toolchain support.

Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220124171253.22072-7-mathieu.desnoyers@efficios.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f491e073

tools/testing/selftests/rseq/rseq-generic-thread-pointer.h

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+25 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: LGPL-2.1-only OR MIT */

/*

 * rseq-generic-thread-pointer.h

 *

 * (C) Copyright 2021 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 */



#ifndef _RSEQ_GENERIC_THREAD_POINTER

#define _RSEQ_GENERIC_THREAD_POINTER



#ifdef __cplusplus

extern "C" {

#endif



/* Use gcc builtin thread pointer. */

static inline void *rseq_thread_pointer(void)

{

	return __builtin_thread_pointer();

}



#ifdef __cplusplus

}

#endif



#endif

tools/testing/selftests/rseq/rseq-ppc-thread-pointer.h

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Original line number Diff line number Diff line 
/* SPDX-License-Identifier: LGPL-2.1-only OR MIT */

/*

 * rseq-ppc-thread-pointer.h

 *

 * (C) Copyright 2021 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 */



#ifndef _RSEQ_PPC_THREAD_POINTER

#define _RSEQ_PPC_THREAD_POINTER



#ifdef __cplusplus

extern "C" {

#endif



static inline void *rseq_thread_pointer(void)

{

#ifdef __powerpc64__

	register void *__result asm ("r13");

#else

	register void *__result asm ("r2");

#endif

	asm ("" : "=r" (__result));

	return __result;

}



#ifdef __cplusplus

}

#endif



#endif

tools/testing/selftests/rseq/rseq-thread-pointer.h

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Original line number Diff line number Diff line 
/* SPDX-License-Identifier: LGPL-2.1-only OR MIT */

/*

 * rseq-thread-pointer.h

 *

 * (C) Copyright 2021 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 */



#ifndef _RSEQ_THREAD_POINTER

#define _RSEQ_THREAD_POINTER



#if defined(__x86_64__) || defined(__i386__)

#include "rseq-x86-thread-pointer.h"

#elif defined(__PPC__)

#include "rseq-ppc-thread-pointer.h"

#else

#include "rseq-generic-thread-pointer.h"

#endif



#endif

tools/testing/selftests/rseq/rseq-x86-thread-pointer.h

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Original line number Diff line number Diff line 
/* SPDX-License-Identifier: LGPL-2.1-only OR MIT */

/*

 * rseq-x86-thread-pointer.h

 *

 * (C) Copyright 2021 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 */



#ifndef _RSEQ_X86_THREAD_POINTER

#define _RSEQ_X86_THREAD_POINTER



#include <features.h>



#ifdef __cplusplus

extern "C" {

#endif



#if __GNUC_PREREQ (11, 1)

static inline void *rseq_thread_pointer(void)

{

	return __builtin_thread_pointer();

}

#else

static inline void *rseq_thread_pointer(void)

{

	void *__result;



# ifdef __x86_64__

	__asm__ ("mov %%fs:0, %0" : "=r" (__result));

# else

	__asm__ ("mov %%gs:0, %0" : "=r" (__result));

# endif

	return __result;

}

#endif /* !GCC 11 */



#ifdef __cplusplus

}

#endif



#endif