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linux/arch/s390/kernel/vdso64/clock_getres.S

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s390: kernel: add SPDX identifiers to the remaining files It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the arch/s390/kernel/ files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-24 22:00:32 +08:00
/* SPDX-License-Identifier: GPL-2.0 */
[S390] introduce vdso on s390 Add a vdso to speed up gettimeofday and clock_getres/clock_gettime for CLOCK_REALTIME/CLOCK_MONOTONIC. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 20:38:36 +08:00
/*
* Userland implementation of clock_getres() for 64 bits processes in a
* s390 kernel for use in the vDSO
*
* Copyright IBM Corp. 2008
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
*/
#include <asm/vdso.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
s390/kernel: emit CFI data in .debug_frame and discard .eh_frame sections Using perf probe and libdw on kernel modules failed to find CFI data for symbols. The CFI data is stored in the .eh_frame section. The elfutils libdw is not able to extract the CFI data correctly, because the .eh_frame section requires "non-simple" relocations for kernel modules. The suggestion is to avoid these "non-simple" relocations by emitting the CFI data in the .debug_frame section. Let gcc emit respective directives by specifying the -fno-asynchronous-unwind-tables option. Using the .debug_frame section for CFI data, the .eh_frame section becomes unused and, thus, discard it for kernel and modules builds The vDSO requires the .eh_frame section and, hence, emit the CFI data in both, the .eh_frame and .debug_frame sections. See also discussion on elfutils/libdw bugzilla: https://sourceware.org/bugzilla/show_bug.cgi?id=22452 Suggested-by: Mark Wielaard <mark@klomp.org> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-20 18:41:07 +08:00
#include <asm/dwarf.h>
[S390] introduce vdso on s390 Add a vdso to speed up gettimeofday and clock_getres/clock_gettime for CLOCK_REALTIME/CLOCK_MONOTONIC. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 20:38:36 +08:00
.text
.align 4
.globl __kernel_clock_getres
.type __kernel_clock_getres,@function
__kernel_clock_getres:
s390/vdso: revise CFI annotations of vDSO functions Revise and add CFI CFA and register rule annotations to the vDSO functions for proper stack unwinding and debugging. Because glibc might call the vDSO in special ways, the vDSO code does not rely on a stack frame created by the caller. The TOD clock value can be therefore not stored in the pre-allocated stack area and additional stack space is required. To correctly annotate these situations with CFI, the .cfi_val_offset directive is required to create relative offsets on the value of the stack register %r15. Because the .cfi_val_offset directive is available with recent GNU assembler versions only, additional checks are necessary. Note that if the vDSO is assembled with an older assembler version, stack unwinding and debugging from within the vDSO code might not be possible. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-20 18:46:13 +08:00
CFI_STARTPROC
s390/vdso: add vdso support for coarse clocks Add CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE optimization to the 64-bit and 31-bit vdso. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-08-29 18:31:45 +08:00
larl %r1,4f
cghi %r2,__CLOCK_REALTIME_COARSE
je 0f
cghi %r2,__CLOCK_MONOTONIC_COARSE
je 0f
larl %r1,3f
[S390] vdso: get rid of redefinition warnings The CLOCK_* defines in asm-offsets.c are only used for the vdso code however in the meantime they cause other trouble. Just rename them to get permanently rid of this: In file included from /home2/heicarst/linux-2.6/arch/s390/include/asm/asm-offsets.h:1:0, from arch/s390/mm/fault.c:33: include/generated/asm-offsets.h:53:0: warning: "CLOCK_REALTIME" redefined include/linux/time.h:286:0: note: this is the location of the previous definition include/generated/asm-offsets.h:54:0: warning: "CLOCK_MONOTONIC" redefined include/linux/time.h:287:0: note: this is the location of the previous definition Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-29 22:50:41 +08:00
cghi %r2,__CLOCK_REALTIME
[S390] introduce vdso on s390 Add a vdso to speed up gettimeofday and clock_getres/clock_gettime for CLOCK_REALTIME/CLOCK_MONOTONIC. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 20:38:36 +08:00
je 0f
[S390] vdso: get rid of redefinition warnings The CLOCK_* defines in asm-offsets.c are only used for the vdso code however in the meantime they cause other trouble. Just rename them to get permanently rid of this: In file included from /home2/heicarst/linux-2.6/arch/s390/include/asm/asm-offsets.h:1:0, from arch/s390/mm/fault.c:33: include/generated/asm-offsets.h:53:0: warning: "CLOCK_REALTIME" redefined include/linux/time.h:286:0: note: this is the location of the previous definition include/generated/asm-offsets.h:54:0: warning: "CLOCK_MONOTONIC" redefined include/linux/time.h:287:0: note: this is the location of the previous definition Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-29 22:50:41 +08:00
cghi %r2,__CLOCK_MONOTONIC
[PATCH] fast vdso implementation for CLOCK_THREAD_CPUTIME_ID The extract cpu time instruction (ectg) instruction allows the user process to get the current thread cputime without calling into the kernel. The code that uses the instruction needs to switch to the access registers mode to get access to the per-cpu info page that contains the two base values that are needed to calculate the current cputime from the CPU timer with the ectg instruction. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31 22:11:42 +08:00
je 0f
s390/vdso: ectg gettime support for CLOCK_THREAD_CPUTIME_ID The code to use the ECTG instruction to calculate the cputime for the current thread is currently used only for the per-thread CPU-clock with the clockid -2 (PID=0, VIRT=1). Use the same code for the clockid CLOCK_THREAD_CPUTIME_ID to speed up the more common clockid as well. Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-12-02 21:54:56 +08:00
cghi %r2,__CLOCK_THREAD_CPUTIME_ID
je 0f
cghi %r2,-2 /* Per-thread CPUCLOCK with PID=0, VIRT=1 */
[S390] introduce vdso on s390 Add a vdso to speed up gettimeofday and clock_getres/clock_gettime for CLOCK_REALTIME/CLOCK_MONOTONIC. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 20:38:36 +08:00
jne 2f
[PATCH] fast vdso implementation for CLOCK_THREAD_CPUTIME_ID The extract cpu time instruction (ectg) instruction allows the user process to get the current thread cputime without calling into the kernel. The code that uses the instruction needs to switch to the access registers mode to get access to the per-cpu info page that contains the two base values that are needed to calculate the current cputime from the CPU timer with the ectg instruction. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31 22:11:42 +08:00
larl %r5,_vdso_data
icm %r0,15,__LC_ECTG_OK(%r5)
jz 2f
[S390] introduce vdso on s390 Add a vdso to speed up gettimeofday and clock_getres/clock_gettime for CLOCK_REALTIME/CLOCK_MONOTONIC. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 20:38:36 +08:00
0: ltgr %r3,%r3
jz 1f /* res == NULL */
lg %r0,0(%r1)
xc 0(8,%r3),0(%r3) /* set tp->tv_sec to zero */
stg %r0,8(%r3) /* store tp->tv_usec */
1: lghi %r2,0
br %r14
2: lghi %r1,__NR_clock_getres /* fallback to svc */
svc 0
br %r14
s390/vdso: revise CFI annotations of vDSO functions Revise and add CFI CFA and register rule annotations to the vDSO functions for proper stack unwinding and debugging. Because glibc might call the vDSO in special ways, the vDSO code does not rely on a stack frame created by the caller. The TOD clock value can be therefore not stored in the pre-allocated stack area and additional stack space is required. To correctly annotate these situations with CFI, the .cfi_val_offset directive is required to create relative offsets on the value of the stack register %r15. Because the .cfi_val_offset directive is available with recent GNU assembler versions only, additional checks are necessary. Note that if the vDSO is assembled with an older assembler version, stack unwinding and debugging from within the vDSO code might not be possible. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-20 18:46:13 +08:00
CFI_ENDPROC
[S390] vdso: get rid of redefinition warnings The CLOCK_* defines in asm-offsets.c are only used for the vdso code however in the meantime they cause other trouble. Just rename them to get permanently rid of this: In file included from /home2/heicarst/linux-2.6/arch/s390/include/asm/asm-offsets.h:1:0, from arch/s390/mm/fault.c:33: include/generated/asm-offsets.h:53:0: warning: "CLOCK_REALTIME" redefined include/linux/time.h:286:0: note: this is the location of the previous definition include/generated/asm-offsets.h:54:0: warning: "CLOCK_MONOTONIC" redefined include/linux/time.h:287:0: note: this is the location of the previous definition Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-29 22:50:41 +08:00
3: .quad __CLOCK_REALTIME_RES
s390/vdso: add vdso support for coarse clocks Add CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE optimization to the 64-bit and 31-bit vdso. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-08-29 18:31:45 +08:00
4: .quad __CLOCK_COARSE_RES
[S390] introduce vdso on s390 Add a vdso to speed up gettimeofday and clock_getres/clock_gettime for CLOCK_REALTIME/CLOCK_MONOTONIC. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 20:38:36 +08:00
.size __kernel_clock_getres,.-__kernel_clock_getres