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linux/arch/powerpc/kernel/vdso/gettimeofday.S

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Userland implementation of gettimeofday() for processes
* for use in the vDSO
*
* Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org,
* IBM Corp.
*/
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/vdso.h>
#include <asm/vdso_datapage.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
/*
* The macro sets two stack frames, one for the caller and one for the callee
* because there are no requirement for the caller to set a stack frame when
* calling VDSO so it may have omitted to set one, especially on PPC64
*/
.macro cvdso_call funct call_time=0
.cfi_startproc
PPC_STLU r1, -PPC_MIN_STKFRM(r1)
powerpc/vdso: Fix incorrect CFI in gettimeofday.S As reported by Alan, the CFI (Call Frame Information) in the VDSO time routines is incorrect since commit ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation."). DWARF has a concept called the CFA (Canonical Frame Address), which on powerpc is calculated as an offset from the stack pointer (r1). That means when the stack pointer is changed there must be a corresponding CFI directive to update the calculation of the CFA. The current code is missing those directives for the changes to r1, which prevents gdb from being able to generate a backtrace from inside VDSO functions, eg: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x00007fffffffd960 in ?? () #3 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 Backtrace stopped: frame did not save the PC Alan helpfully describes some rules for correctly maintaining the CFI information: 1) Every adjustment to the current frame address reg (ie. r1) must be described, and exactly at the instruction where r1 changes. Why? Because stack unwinding might want to access previous frames. 2) If a function changes LR or any non-volatile register, the save location for those regs must be given. The CFI can be at any instruction after the saves up to the point that the reg is changed. (Exception: LR save should be described before a bl. not after) 3) If asychronous unwind info is needed then restores of LR and non-volatile regs must also be described. The CFI can be at any instruction after the reg is restored up to the point where the save location is (potentially) trashed. Fix the inability to backtrace by adding CFI directives describing the changes to r1, ie. satisfying rule 1. Also change the information for LR to point to the copy saved on the stack, not the value in r0 that will be overwritten by the function call. Finally, add CFI directives describing the save/restore of r2. With the fix gdb can correctly back trace and navigate up and down the stack: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x0000000100015b60 in gettime () #3 0x000000010000c8bc in print_long_format () #4 0x000000010000d180 in print_current_files () #5 0x00000001000054ac in main () (gdb) up #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #2 0x0000000100015b60 in gettime () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #4 0x000000010000d180 in print_current_files () (gdb) #5 0x00000001000054ac in main () (gdb) Initial frame selected; you cannot go up. (gdb) down #4 0x000000010000d180 in print_current_files () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #2 0x0000000100015b60 in gettime () (gdb) #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #0 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) Fixes: ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation.") Cc: stable@vger.kernel.org # v5.11+ Reported-by: Alan Modra <amodra@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Link: https://lore.kernel.org/r/20220502125010.1319370-1-mpe@ellerman.id.au
2022-05-02 22:50:10 +10:00
.cfi_adjust_cfa_offset PPC_MIN_STKFRM
mflr r0
PPC_STLU r1, -PPC_MIN_STKFRM(r1)
powerpc/vdso: Fix incorrect CFI in gettimeofday.S As reported by Alan, the CFI (Call Frame Information) in the VDSO time routines is incorrect since commit ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation."). DWARF has a concept called the CFA (Canonical Frame Address), which on powerpc is calculated as an offset from the stack pointer (r1). That means when the stack pointer is changed there must be a corresponding CFI directive to update the calculation of the CFA. The current code is missing those directives for the changes to r1, which prevents gdb from being able to generate a backtrace from inside VDSO functions, eg: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x00007fffffffd960 in ?? () #3 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 Backtrace stopped: frame did not save the PC Alan helpfully describes some rules for correctly maintaining the CFI information: 1) Every adjustment to the current frame address reg (ie. r1) must be described, and exactly at the instruction where r1 changes. Why? Because stack unwinding might want to access previous frames. 2) If a function changes LR or any non-volatile register, the save location for those regs must be given. The CFI can be at any instruction after the saves up to the point that the reg is changed. (Exception: LR save should be described before a bl. not after) 3) If asychronous unwind info is needed then restores of LR and non-volatile regs must also be described. The CFI can be at any instruction after the reg is restored up to the point where the save location is (potentially) trashed. Fix the inability to backtrace by adding CFI directives describing the changes to r1, ie. satisfying rule 1. Also change the information for LR to point to the copy saved on the stack, not the value in r0 that will be overwritten by the function call. Finally, add CFI directives describing the save/restore of r2. With the fix gdb can correctly back trace and navigate up and down the stack: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x0000000100015b60 in gettime () #3 0x000000010000c8bc in print_long_format () #4 0x000000010000d180 in print_current_files () #5 0x00000001000054ac in main () (gdb) up #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #2 0x0000000100015b60 in gettime () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #4 0x000000010000d180 in print_current_files () (gdb) #5 0x00000001000054ac in main () (gdb) Initial frame selected; you cannot go up. (gdb) down #4 0x000000010000d180 in print_current_files () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #2 0x0000000100015b60 in gettime () (gdb) #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #0 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) Fixes: ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation.") Cc: stable@vger.kernel.org # v5.11+ Reported-by: Alan Modra <amodra@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Link: https://lore.kernel.org/r/20220502125010.1319370-1-mpe@ellerman.id.au
2022-05-02 22:50:10 +10:00
.cfi_adjust_cfa_offset PPC_MIN_STKFRM
PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
powerpc/vdso: Fix incorrect CFI in gettimeofday.S As reported by Alan, the CFI (Call Frame Information) in the VDSO time routines is incorrect since commit ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation."). DWARF has a concept called the CFA (Canonical Frame Address), which on powerpc is calculated as an offset from the stack pointer (r1). That means when the stack pointer is changed there must be a corresponding CFI directive to update the calculation of the CFA. The current code is missing those directives for the changes to r1, which prevents gdb from being able to generate a backtrace from inside VDSO functions, eg: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x00007fffffffd960 in ?? () #3 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 Backtrace stopped: frame did not save the PC Alan helpfully describes some rules for correctly maintaining the CFI information: 1) Every adjustment to the current frame address reg (ie. r1) must be described, and exactly at the instruction where r1 changes. Why? Because stack unwinding might want to access previous frames. 2) If a function changes LR or any non-volatile register, the save location for those regs must be given. The CFI can be at any instruction after the saves up to the point that the reg is changed. (Exception: LR save should be described before a bl. not after) 3) If asychronous unwind info is needed then restores of LR and non-volatile regs must also be described. The CFI can be at any instruction after the reg is restored up to the point where the save location is (potentially) trashed. Fix the inability to backtrace by adding CFI directives describing the changes to r1, ie. satisfying rule 1. Also change the information for LR to point to the copy saved on the stack, not the value in r0 that will be overwritten by the function call. Finally, add CFI directives describing the save/restore of r2. With the fix gdb can correctly back trace and navigate up and down the stack: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x0000000100015b60 in gettime () #3 0x000000010000c8bc in print_long_format () #4 0x000000010000d180 in print_current_files () #5 0x00000001000054ac in main () (gdb) up #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #2 0x0000000100015b60 in gettime () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #4 0x000000010000d180 in print_current_files () (gdb) #5 0x00000001000054ac in main () (gdb) Initial frame selected; you cannot go up. (gdb) down #4 0x000000010000d180 in print_current_files () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #2 0x0000000100015b60 in gettime () (gdb) #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #0 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) Fixes: ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation.") Cc: stable@vger.kernel.org # v5.11+ Reported-by: Alan Modra <amodra@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Link: https://lore.kernel.org/r/20220502125010.1319370-1-mpe@ellerman.id.au
2022-05-02 22:50:10 +10:00
.cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF
#ifdef __powerpc64__
PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1)
powerpc/vdso: Fix incorrect CFI in gettimeofday.S As reported by Alan, the CFI (Call Frame Information) in the VDSO time routines is incorrect since commit ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation."). DWARF has a concept called the CFA (Canonical Frame Address), which on powerpc is calculated as an offset from the stack pointer (r1). That means when the stack pointer is changed there must be a corresponding CFI directive to update the calculation of the CFA. The current code is missing those directives for the changes to r1, which prevents gdb from being able to generate a backtrace from inside VDSO functions, eg: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x00007fffffffd960 in ?? () #3 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 Backtrace stopped: frame did not save the PC Alan helpfully describes some rules for correctly maintaining the CFI information: 1) Every adjustment to the current frame address reg (ie. r1) must be described, and exactly at the instruction where r1 changes. Why? Because stack unwinding might want to access previous frames. 2) If a function changes LR or any non-volatile register, the save location for those regs must be given. The CFI can be at any instruction after the saves up to the point that the reg is changed. (Exception: LR save should be described before a bl. not after) 3) If asychronous unwind info is needed then restores of LR and non-volatile regs must also be described. The CFI can be at any instruction after the reg is restored up to the point where the save location is (potentially) trashed. Fix the inability to backtrace by adding CFI directives describing the changes to r1, ie. satisfying rule 1. Also change the information for LR to point to the copy saved on the stack, not the value in r0 that will be overwritten by the function call. Finally, add CFI directives describing the save/restore of r2. With the fix gdb can correctly back trace and navigate up and down the stack: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x0000000100015b60 in gettime () #3 0x000000010000c8bc in print_long_format () #4 0x000000010000d180 in print_current_files () #5 0x00000001000054ac in main () (gdb) up #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #2 0x0000000100015b60 in gettime () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #4 0x000000010000d180 in print_current_files () (gdb) #5 0x00000001000054ac in main () (gdb) Initial frame selected; you cannot go up. (gdb) down #4 0x000000010000d180 in print_current_files () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #2 0x0000000100015b60 in gettime () (gdb) #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #0 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) Fixes: ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation.") Cc: stable@vger.kernel.org # v5.11+ Reported-by: Alan Modra <amodra@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Link: https://lore.kernel.org/r/20220502125010.1319370-1-mpe@ellerman.id.au
2022-05-02 22:50:10 +10:00
.cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
#endif
get_datapage r5
.ifeq \call_time
addi r5, r5, VDSO_DATA_OFFSET
.else
addi r4, r5, VDSO_DATA_OFFSET
.endif
bl DOTSYM(\funct)
PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
#ifdef __powerpc64__
PPC_LL r2, PPC_MIN_STKFRM + STK_GOT(r1)
powerpc/vdso: Fix incorrect CFI in gettimeofday.S As reported by Alan, the CFI (Call Frame Information) in the VDSO time routines is incorrect since commit ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation."). DWARF has a concept called the CFA (Canonical Frame Address), which on powerpc is calculated as an offset from the stack pointer (r1). That means when the stack pointer is changed there must be a corresponding CFI directive to update the calculation of the CFA. The current code is missing those directives for the changes to r1, which prevents gdb from being able to generate a backtrace from inside VDSO functions, eg: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x00007fffffffd960 in ?? () #3 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 Backtrace stopped: frame did not save the PC Alan helpfully describes some rules for correctly maintaining the CFI information: 1) Every adjustment to the current frame address reg (ie. r1) must be described, and exactly at the instruction where r1 changes. Why? Because stack unwinding might want to access previous frames. 2) If a function changes LR or any non-volatile register, the save location for those regs must be given. The CFI can be at any instruction after the saves up to the point that the reg is changed. (Exception: LR save should be described before a bl. not after) 3) If asychronous unwind info is needed then restores of LR and non-volatile regs must also be described. The CFI can be at any instruction after the reg is restored up to the point where the save location is (potentially) trashed. Fix the inability to backtrace by adding CFI directives describing the changes to r1, ie. satisfying rule 1. Also change the information for LR to point to the copy saved on the stack, not the value in r0 that will be overwritten by the function call. Finally, add CFI directives describing the save/restore of r2. With the fix gdb can correctly back trace and navigate up and down the stack: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x0000000100015b60 in gettime () #3 0x000000010000c8bc in print_long_format () #4 0x000000010000d180 in print_current_files () #5 0x00000001000054ac in main () (gdb) up #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #2 0x0000000100015b60 in gettime () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #4 0x000000010000d180 in print_current_files () (gdb) #5 0x00000001000054ac in main () (gdb) Initial frame selected; you cannot go up. (gdb) down #4 0x000000010000d180 in print_current_files () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #2 0x0000000100015b60 in gettime () (gdb) #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #0 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) Fixes: ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation.") Cc: stable@vger.kernel.org # v5.11+ Reported-by: Alan Modra <amodra@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Link: https://lore.kernel.org/r/20220502125010.1319370-1-mpe@ellerman.id.au
2022-05-02 22:50:10 +10:00
.cfi_restore r2
#endif
.ifeq \call_time
cmpwi r3, 0
.endif
mtlr r0
addi r1, r1, 2 * PPC_MIN_STKFRM
powerpc/vdso: Fix incorrect CFI in gettimeofday.S As reported by Alan, the CFI (Call Frame Information) in the VDSO time routines is incorrect since commit ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation."). DWARF has a concept called the CFA (Canonical Frame Address), which on powerpc is calculated as an offset from the stack pointer (r1). That means when the stack pointer is changed there must be a corresponding CFI directive to update the calculation of the CFA. The current code is missing those directives for the changes to r1, which prevents gdb from being able to generate a backtrace from inside VDSO functions, eg: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x00007fffffffd960 in ?? () #3 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 Backtrace stopped: frame did not save the PC Alan helpfully describes some rules for correctly maintaining the CFI information: 1) Every adjustment to the current frame address reg (ie. r1) must be described, and exactly at the instruction where r1 changes. Why? Because stack unwinding might want to access previous frames. 2) If a function changes LR or any non-volatile register, the save location for those regs must be given. The CFI can be at any instruction after the saves up to the point that the reg is changed. (Exception: LR save should be described before a bl. not after) 3) If asychronous unwind info is needed then restores of LR and non-volatile regs must also be described. The CFI can be at any instruction after the reg is restored up to the point where the save location is (potentially) trashed. Fix the inability to backtrace by adding CFI directives describing the changes to r1, ie. satisfying rule 1. Also change the information for LR to point to the copy saved on the stack, not the value in r0 that will be overwritten by the function call. Finally, add CFI directives describing the save/restore of r2. With the fix gdb can correctly back trace and navigate up and down the stack: Breakpoint 1, 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) bt #0 0x00007ffff7f804dc in __kernel_clock_gettime () #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 #2 0x0000000100015b60 in gettime () #3 0x000000010000c8bc in print_long_format () #4 0x000000010000d180 in print_current_files () #5 0x00000001000054ac in main () (gdb) up #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #2 0x0000000100015b60 in gettime () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #4 0x000000010000d180 in print_current_files () (gdb) #5 0x00000001000054ac in main () (gdb) Initial frame selected; you cannot go up. (gdb) down #4 0x000000010000d180 in print_current_files () (gdb) #3 0x000000010000c8bc in print_long_format () (gdb) #2 0x0000000100015b60 in gettime () (gdb) #1 0x00007ffff7d8872c in clock_gettime@@GLIBC_2.17 () from /lib64/libc.so.6 (gdb) #0 0x00007ffff7f804dc in __kernel_clock_gettime () (gdb) Fixes: ce7d8056e38b ("powerpc/vdso: Prepare for switching VDSO to generic C implementation.") Cc: stable@vger.kernel.org # v5.11+ Reported-by: Alan Modra <amodra@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Link: https://lore.kernel.org/r/20220502125010.1319370-1-mpe@ellerman.id.au
2022-05-02 22:50:10 +10:00
.cfi_restore lr
.cfi_def_cfa_offset 0
crclr so
.ifeq \call_time
beqlr+
crset so
neg r3, r3
.endif
blr
.cfi_endproc
.endm
.text
/*
* Exact prototype of gettimeofday
*
* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz);
*
*/
V_FUNCTION_BEGIN(__kernel_gettimeofday)
powerpc/vdso: Switch VDSO to generic C implementation. With the C VDSO, the performance is slightly lower, but it is worth it as it will ease maintenance and evolution, and also brings clocks that are not supported with the ASM VDSO. On an 8xx at 132 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 828 nsec/call clock-getres-realtime-coarse: vdso: 391 nsec/call clock-gettime-realtime-coarse: vdso: 614 nsec/call clock-getres-realtime: vdso: 460 nsec/call clock-gettime-realtime: vdso: 876 nsec/call clock-getres-monotonic-coarse: vdso: 399 nsec/call clock-gettime-monotonic-coarse: vdso: 691 nsec/call clock-getres-monotonic: vdso: 460 nsec/call clock-gettime-monotonic: vdso: 1026 nsec/call On an 8xx at 132 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 955 nsec/call clock-getres-realtime-coarse: vdso: 545 nsec/call clock-gettime-realtime-coarse: vdso: 592 nsec/call clock-getres-realtime: vdso: 545 nsec/call clock-gettime-realtime: vdso: 941 nsec/call clock-getres-monotonic-coarse: vdso: 545 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call clock-getres-monotonic: vdso: 545 nsec/call clock-gettime-monotonic: vdso: 940 nsec/call It is even better for gettime with monotonic clocks. Unsupported clocks with ASM VDSO: clock-gettime-boottime: vdso: 3851 nsec/call clock-gettime-tai: vdso: 3852 nsec/call clock-gettime-monotonic-raw: vdso: 3396 nsec/call Same clocks with C VDSO: clock-gettime-tai: vdso: 941 nsec/call clock-gettime-monotonic-raw: vdso: 1001 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call On an 8321E at 333 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 220 nsec/call clock-getres-realtime-coarse: vdso: 102 nsec/call clock-gettime-realtime-coarse: vdso: 178 nsec/call clock-getres-realtime: vdso: 129 nsec/call clock-gettime-realtime: vdso: 235 nsec/call clock-getres-monotonic-coarse: vdso: 105 nsec/call clock-gettime-monotonic-coarse: vdso: 208 nsec/call clock-getres-monotonic: vdso: 129 nsec/call clock-gettime-monotonic: vdso: 274 nsec/call On an 8321E at 333 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 272 nsec/call clock-getres-realtime-coarse: vdso: 160 nsec/call clock-gettime-realtime-coarse: vdso: 184 nsec/call clock-getres-realtime: vdso: 166 nsec/call clock-gettime-realtime: vdso: 281 nsec/call clock-getres-monotonic-coarse: vdso: 160 nsec/call clock-gettime-monotonic-coarse: vdso: 184 nsec/call clock-getres-monotonic: vdso: 169 nsec/call clock-gettime-monotonic: vdso: 275 nsec/call On a Power9 Nimbus DD2.2 at 3.8GHz, with the ASM VDSO: clock-gettime-monotonic: vdso: 35 nsec/call clock-getres-monotonic: vdso: 16 nsec/call clock-gettime-monotonic-coarse: vdso: 18 nsec/call clock-getres-monotonic-coarse: vdso: 522 nsec/call clock-gettime-monotonic-raw: vdso: 598 nsec/call clock-getres-monotonic-raw: vdso: 520 nsec/call clock-gettime-realtime: vdso: 34 nsec/call clock-getres-realtime: vdso: 16 nsec/call clock-gettime-realtime-coarse: vdso: 18 nsec/call clock-getres-realtime-coarse: vdso: 517 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 25 nsec/call And with the C VDSO: clock-gettime-monotonic: vdso: 37 nsec/call clock-getres-monotonic: vdso: 20 nsec/call clock-gettime-monotonic-coarse: vdso: 21 nsec/call clock-getres-monotonic-coarse: vdso: 19 nsec/call clock-gettime-monotonic-raw: vdso: 38 nsec/call clock-getres-monotonic-raw: vdso: 20 nsec/call clock-gettime-realtime: vdso: 37 nsec/call clock-getres-realtime: vdso: 20 nsec/call clock-gettime-realtime-coarse: vdso: 20 nsec/call clock-getres-realtime-coarse: vdso: 19 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 28 nsec/call Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201126131006.2431205-8-mpe@ellerman.id.au
2020-11-27 00:10:05 +11:00
cvdso_call __c_kernel_gettimeofday
V_FUNCTION_END(__kernel_gettimeofday)
/*
* Exact prototype of clock_gettime()
*
* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp);
*
*/
V_FUNCTION_BEGIN(__kernel_clock_gettime)
powerpc/vdso: Switch VDSO to generic C implementation. With the C VDSO, the performance is slightly lower, but it is worth it as it will ease maintenance and evolution, and also brings clocks that are not supported with the ASM VDSO. On an 8xx at 132 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 828 nsec/call clock-getres-realtime-coarse: vdso: 391 nsec/call clock-gettime-realtime-coarse: vdso: 614 nsec/call clock-getres-realtime: vdso: 460 nsec/call clock-gettime-realtime: vdso: 876 nsec/call clock-getres-monotonic-coarse: vdso: 399 nsec/call clock-gettime-monotonic-coarse: vdso: 691 nsec/call clock-getres-monotonic: vdso: 460 nsec/call clock-gettime-monotonic: vdso: 1026 nsec/call On an 8xx at 132 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 955 nsec/call clock-getres-realtime-coarse: vdso: 545 nsec/call clock-gettime-realtime-coarse: vdso: 592 nsec/call clock-getres-realtime: vdso: 545 nsec/call clock-gettime-realtime: vdso: 941 nsec/call clock-getres-monotonic-coarse: vdso: 545 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call clock-getres-monotonic: vdso: 545 nsec/call clock-gettime-monotonic: vdso: 940 nsec/call It is even better for gettime with monotonic clocks. Unsupported clocks with ASM VDSO: clock-gettime-boottime: vdso: 3851 nsec/call clock-gettime-tai: vdso: 3852 nsec/call clock-gettime-monotonic-raw: vdso: 3396 nsec/call Same clocks with C VDSO: clock-gettime-tai: vdso: 941 nsec/call clock-gettime-monotonic-raw: vdso: 1001 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call On an 8321E at 333 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 220 nsec/call clock-getres-realtime-coarse: vdso: 102 nsec/call clock-gettime-realtime-coarse: vdso: 178 nsec/call clock-getres-realtime: vdso: 129 nsec/call clock-gettime-realtime: vdso: 235 nsec/call clock-getres-monotonic-coarse: vdso: 105 nsec/call clock-gettime-monotonic-coarse: vdso: 208 nsec/call clock-getres-monotonic: vdso: 129 nsec/call clock-gettime-monotonic: vdso: 274 nsec/call On an 8321E at 333 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 272 nsec/call clock-getres-realtime-coarse: vdso: 160 nsec/call clock-gettime-realtime-coarse: vdso: 184 nsec/call clock-getres-realtime: vdso: 166 nsec/call clock-gettime-realtime: vdso: 281 nsec/call clock-getres-monotonic-coarse: vdso: 160 nsec/call clock-gettime-monotonic-coarse: vdso: 184 nsec/call clock-getres-monotonic: vdso: 169 nsec/call clock-gettime-monotonic: vdso: 275 nsec/call On a Power9 Nimbus DD2.2 at 3.8GHz, with the ASM VDSO: clock-gettime-monotonic: vdso: 35 nsec/call clock-getres-monotonic: vdso: 16 nsec/call clock-gettime-monotonic-coarse: vdso: 18 nsec/call clock-getres-monotonic-coarse: vdso: 522 nsec/call clock-gettime-monotonic-raw: vdso: 598 nsec/call clock-getres-monotonic-raw: vdso: 520 nsec/call clock-gettime-realtime: vdso: 34 nsec/call clock-getres-realtime: vdso: 16 nsec/call clock-gettime-realtime-coarse: vdso: 18 nsec/call clock-getres-realtime-coarse: vdso: 517 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 25 nsec/call And with the C VDSO: clock-gettime-monotonic: vdso: 37 nsec/call clock-getres-monotonic: vdso: 20 nsec/call clock-gettime-monotonic-coarse: vdso: 21 nsec/call clock-getres-monotonic-coarse: vdso: 19 nsec/call clock-gettime-monotonic-raw: vdso: 38 nsec/call clock-getres-monotonic-raw: vdso: 20 nsec/call clock-gettime-realtime: vdso: 37 nsec/call clock-getres-realtime: vdso: 20 nsec/call clock-gettime-realtime-coarse: vdso: 20 nsec/call clock-getres-realtime-coarse: vdso: 19 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 28 nsec/call Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201126131006.2431205-8-mpe@ellerman.id.au
2020-11-27 00:10:05 +11:00
cvdso_call __c_kernel_clock_gettime
V_FUNCTION_END(__kernel_clock_gettime)
/*
* Exact prototype of clock_gettime64()
*
* int __kernel_clock_gettime64(clockid_t clock_id, struct __timespec64 *ts);
*
*/
#ifndef __powerpc64__
V_FUNCTION_BEGIN(__kernel_clock_gettime64)
cvdso_call __c_kernel_clock_gettime64
V_FUNCTION_END(__kernel_clock_gettime64)
#endif
/*
* Exact prototype of clock_getres()
*
* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
*
*/
V_FUNCTION_BEGIN(__kernel_clock_getres)
powerpc/vdso: Switch VDSO to generic C implementation. With the C VDSO, the performance is slightly lower, but it is worth it as it will ease maintenance and evolution, and also brings clocks that are not supported with the ASM VDSO. On an 8xx at 132 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 828 nsec/call clock-getres-realtime-coarse: vdso: 391 nsec/call clock-gettime-realtime-coarse: vdso: 614 nsec/call clock-getres-realtime: vdso: 460 nsec/call clock-gettime-realtime: vdso: 876 nsec/call clock-getres-monotonic-coarse: vdso: 399 nsec/call clock-gettime-monotonic-coarse: vdso: 691 nsec/call clock-getres-monotonic: vdso: 460 nsec/call clock-gettime-monotonic: vdso: 1026 nsec/call On an 8xx at 132 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 955 nsec/call clock-getres-realtime-coarse: vdso: 545 nsec/call clock-gettime-realtime-coarse: vdso: 592 nsec/call clock-getres-realtime: vdso: 545 nsec/call clock-gettime-realtime: vdso: 941 nsec/call clock-getres-monotonic-coarse: vdso: 545 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call clock-getres-monotonic: vdso: 545 nsec/call clock-gettime-monotonic: vdso: 940 nsec/call It is even better for gettime with monotonic clocks. Unsupported clocks with ASM VDSO: clock-gettime-boottime: vdso: 3851 nsec/call clock-gettime-tai: vdso: 3852 nsec/call clock-gettime-monotonic-raw: vdso: 3396 nsec/call Same clocks with C VDSO: clock-gettime-tai: vdso: 941 nsec/call clock-gettime-monotonic-raw: vdso: 1001 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call On an 8321E at 333 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 220 nsec/call clock-getres-realtime-coarse: vdso: 102 nsec/call clock-gettime-realtime-coarse: vdso: 178 nsec/call clock-getres-realtime: vdso: 129 nsec/call clock-gettime-realtime: vdso: 235 nsec/call clock-getres-monotonic-coarse: vdso: 105 nsec/call clock-gettime-monotonic-coarse: vdso: 208 nsec/call clock-getres-monotonic: vdso: 129 nsec/call clock-gettime-monotonic: vdso: 274 nsec/call On an 8321E at 333 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 272 nsec/call clock-getres-realtime-coarse: vdso: 160 nsec/call clock-gettime-realtime-coarse: vdso: 184 nsec/call clock-getres-realtime: vdso: 166 nsec/call clock-gettime-realtime: vdso: 281 nsec/call clock-getres-monotonic-coarse: vdso: 160 nsec/call clock-gettime-monotonic-coarse: vdso: 184 nsec/call clock-getres-monotonic: vdso: 169 nsec/call clock-gettime-monotonic: vdso: 275 nsec/call On a Power9 Nimbus DD2.2 at 3.8GHz, with the ASM VDSO: clock-gettime-monotonic: vdso: 35 nsec/call clock-getres-monotonic: vdso: 16 nsec/call clock-gettime-monotonic-coarse: vdso: 18 nsec/call clock-getres-monotonic-coarse: vdso: 522 nsec/call clock-gettime-monotonic-raw: vdso: 598 nsec/call clock-getres-monotonic-raw: vdso: 520 nsec/call clock-gettime-realtime: vdso: 34 nsec/call clock-getres-realtime: vdso: 16 nsec/call clock-gettime-realtime-coarse: vdso: 18 nsec/call clock-getres-realtime-coarse: vdso: 517 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 25 nsec/call And with the C VDSO: clock-gettime-monotonic: vdso: 37 nsec/call clock-getres-monotonic: vdso: 20 nsec/call clock-gettime-monotonic-coarse: vdso: 21 nsec/call clock-getres-monotonic-coarse: vdso: 19 nsec/call clock-gettime-monotonic-raw: vdso: 38 nsec/call clock-getres-monotonic-raw: vdso: 20 nsec/call clock-gettime-realtime: vdso: 37 nsec/call clock-getres-realtime: vdso: 20 nsec/call clock-gettime-realtime-coarse: vdso: 20 nsec/call clock-getres-realtime-coarse: vdso: 19 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 28 nsec/call Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201126131006.2431205-8-mpe@ellerman.id.au
2020-11-27 00:10:05 +11:00
cvdso_call __c_kernel_clock_getres
V_FUNCTION_END(__kernel_clock_getres)
/*
* Exact prototype of time()
*
* time_t time(time *t);
*
*/
V_FUNCTION_BEGIN(__kernel_time)
cvdso_call __c_kernel_time call_time=1
V_FUNCTION_END(__kernel_time)
/* Routines for restoring integer registers, called by the compiler. */
/* Called with r11 pointing to the stack header word of the caller of the */
/* function, just beyond the end of the integer restore area. */
#ifndef __powerpc64__
_GLOBAL(_restgpr_31_x)
_GLOBAL(_rest32gpr_31_x)
lwz r0,4(r11)
lwz r31,-4(r11)
mtlr r0
mr r1,r11
blr
#endif