Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0d18e171 authored by Mark Salyzyn's avatar Mark Salyzyn Committed by Gagan Malvi
Browse files

FROMLIST: [PATCH v5 03/12] arm: vdso: inline assembler operations to compiler.h 

(cherry picked from commit https://patchwork.kernel.org/patch/10044507/

)

Take an effort to recode the arm64 vdso code from assembler to C
previously submitted by Andrew Pinski <apinski@cavium.com>, rework
it for use in both arm and arm64, overlapping any optimizations
for each architecture. But instead of landing it in arm64, land the
result into lib/vdso and unify both implementations to simplify
future maintenance.

Move compiler-specific code to a local compiler.h file:

- CONFIG_AEABI dependency check.
- System call fallback functions standardized into a
  DEFINE_FALLBACK macro.
- Replace arch_counter_get_cntvct() with arch_vdso_read_counter.
- Deal with architecture specific unresolved references emitted
  by GCC.
- Optimize handling of fallback calls in callers.
- For time functions that always return success, do not waste time
  checking return value for switch to fallback.
- Optimize unlikely nullptr checking in __vdso_gettimeofday,
  if tv null no need to proceed to fallback, as vdso is still
  capable of filling in the tv values.

Signed-off-by: default avatarMark Salyzyn <salyzyn@android.com>
Cc: James Morse <james.morse@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Andrew Pinski <apinski@cavium.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Bug: 63737556
Bug: 20045882
Change-Id: I468e4c32b5136d199982bf25df8967321e384d90

Signed-off-by: default avatarstarlight5234 <ifist2834@gmail.com>
Signed-off-by: default avatarTheSync <repo-sync@outlook.com>
parent 2b09e58a

arch/arm/vdso/compiler.h

0 → 100644
+69 −0
Original line number Diff line number Diff line 
/*

 * Userspace implementations of fallback calls

 *

 * Copyright (C) 2017 Cavium, Inc.

 * Copyright (C) 2012 ARM Limited

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * Author: Will Deacon <will.deacon@arm.com>

 * Rewriten into C by: Andrew Pinski <apinski@cavium.com>

 */



#ifndef __VDSO_COMPILER_H

#define __VDSO_COMPILER_H



#include <asm/arch_timer.h>	/* for arch_counter_get_cntvct()	*/

#include <asm/processor.h>	/* for cpu_relax()			*/

#include <asm/unistd.h>

#include <linux/compiler.h>



#ifndef CONFIG_AEABI

#error This code depends on AEABI system call conventions

#endif



#define DEFINE_FALLBACK(name, type_arg1, name_arg1, type_arg2, name_arg2) \

static notrace long name##_fallback(type_arg1 _##name_arg1,		  \

				    type_arg2 _##name_arg2)		  \

{									  \

	register type_arg1 name_arg1 asm("r0") = _##name_arg1;		  \

	register type_arg2 name_arg2 asm("r1") = _##name_arg2;		  \

	register long ret asm ("r0");					  \

	register long nr asm("r7") = __NR_##name;			  \

									  \

	asm volatile(							  \

	"	swi #0\n"						  \

	: "=r" (ret)							  \

	: "r" (name_arg1), "r" (name_arg2), "r" (nr)			  \

	: "memory");							  \

									  \

	return ret;							  \

}



#define arch_vdso_read_counter() arch_counter_get_cntvct()



/* Avoid unresolved references emitted by GCC */



void __aeabi_unwind_cpp_pr0(void)

{

}



void __aeabi_unwind_cpp_pr1(void)

{

}



void __aeabi_unwind_cpp_pr2(void)

{

}



#endif /* __VDSO_COMPILER_H */

arch/arm/vdso/vgettimeofday.c

+27 −82
Original line number Diff line number Diff line
@@ -22,21 +22,16 @@ 
 * Reworked and rebased over arm version by: Mark Salyzyn <salyzyn@android.com>

 */



#include <linux/compiler.h>

#include <linux/hrtimer.h>

#include <linux/time.h>

#include <asm/arch_timer.h>

#include <asm/barrier.h>

#include <asm/bug.h>

#include <asm/page.h>

#include <asm/unistd.h>



#ifndef CONFIG_AEABI

#error This code depends on AEABI system call conventions

#endif

#include <linux/compiler.h>	/* for notrace				*/

#include <linux/time.h>



#include "compiler.h"

#include "datapage.h"



DEFINE_FALLBACK(gettimeofday, struct timeval *, tv, struct timezone *, tz)

DEFINE_FALLBACK(clock_gettime, clockid_t, clock, struct timespec *, ts)



static notrace u32 vdso_read_begin(const struct vdso_data *vd)

{

	u32 seq;
@@ -63,23 +58,6 @@ static notrace int vdso_read_retry(const struct vdso_data *vd, u32 start) 
	return seq != start;

}



static notrace long clock_gettime_fallback(clockid_t _clkid,

					   struct timespec *_ts)

{

	register struct timespec *ts asm("r1") = _ts;

	register clockid_t clkid asm("r0") = _clkid;

	register long ret asm ("r0");

	register long nr asm("r7") = __NR_clock_gettime;



	asm volatile(

	"	swi #0\n"

	: "=r" (ret)

	: "r" (clkid), "r" (ts), "r" (nr)

	: "memory");



	return ret;

}



static notrace int do_realtime_coarse(const struct vdso_data *vd,

				      struct timespec *ts)

{
@@ -127,7 +105,7 @@ static notrace u64 get_ns(const struct vdso_data *vd) 
	u64 cycle_now;

	u64 nsec;



	cycle_now = arch_counter_get_cntvct();

	cycle_now = arch_vdso_read_counter();



	cycle_delta = (cycle_now - vd->cs_cycle_last) & vd->cs_mask;
@@ -200,85 +178,52 @@ static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts) 


#endif /* CONFIG_ARM_ARCH_TIMER */



notrace int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts)

notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)

{

	int ret = -1;



	const struct vdso_data *vd = __get_datapage();



	switch (clkid) {

	switch (clock) {

	case CLOCK_REALTIME_COARSE:

		ret = do_realtime_coarse(vd, ts);

		do_realtime_coarse(vd, ts);

		break;

	case CLOCK_MONOTONIC_COARSE:

		ret = do_monotonic_coarse(vd, ts);

		do_monotonic_coarse(vd, ts);

		break;

	case CLOCK_REALTIME:

		ret = do_realtime(vd, ts);

		if (do_realtime(vd, ts))

			goto fallback;

		break;

	case CLOCK_MONOTONIC:

		ret = do_monotonic(vd, ts);

		if (do_monotonic(vd, ts))

			goto fallback;

		break;

	default:

		break;

	}



	if (ret)

		ret = clock_gettime_fallback(clkid, ts);



	return ret;

		goto fallback;

	}



static notrace long gettimeofday_fallback(struct timeval *_tv,

					  struct timezone *_tz)

{

	register struct timezone *tz asm("r1") = _tz;

	register struct timeval *tv asm("r0") = _tv;

	register long ret asm ("r0");

	register long nr asm("r7") = __NR_gettimeofday;



	asm volatile(

	"	swi #0\n"

	: "=r" (ret)

	: "r" (tv), "r" (tz), "r" (nr)

	: "memory");



	return ret;

	return 0;

fallback:

	return clock_gettime_fallback(clock, ts);

}



notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)

{

	struct timespec ts;

	int ret;



	const struct vdso_data *vd = __get_datapage();



	ret = do_realtime(vd, &ts);

	if (ret)

	if (likely(tv != NULL)) {

		struct timespec ts;



		if (do_realtime(vd, &ts))

			return gettimeofday_fallback(tv, tz);



	if (tv) {

		tv->tv_sec = ts.tv_sec;

		tv->tv_usec = ts.tv_nsec / 1000;

	}

	if (tz) {



	if (unlikely(tz != NULL)) {

		tz->tz_minuteswest = vd->tz_minuteswest;

		tz->tz_dsttime = vd->tz_dsttime;

	}



	return ret;

}



/* Avoid unresolved references emitted by GCC */



void __aeabi_unwind_cpp_pr0(void)

{

}



void __aeabi_unwind_cpp_pr1(void)

{

}



void __aeabi_unwind_cpp_pr2(void)

{

	return 0;

}