Files
linux-stable-mirror/arch/s390/kernel/asm-offsets.c
T
Heiko CarstensandAlexander Gordeev 670e057744 s390/idle: Provide arch specific kcpustat_field_idle()/kcpustat_field_iowait()
The former s390 specific arch_cpu_idle_time() implementation was
removed, since its implementation was racy and reported idle time
could go backwards [1].

However this removal was not necessary, since independently of the s390
architecture specific races there exists the iowait counter update race,
which can also lead to reported idle time going backwards [2].

With Frederic Weisbecker's recent cpu idle time accounting refactoring
kernel_cpustat got a sequence counter. Use this to implement s390 specific
variants of kcpustat_field_idle() and kcpustat_field_iowait(). This is
logically a revert of [1] and moves cpu idle time accounting back into s390
architecture code, which is also more precise than the dyntick idle time
accounting by nohz/scheduler.

For comparing cross cpu time stamps it is necessary to use the stcke
instead of the stckf instruction in irq entry path. Furthermore this
open-codes a sequence lock in assembler and C code, which is required to
update the irq entry time stamp to the per cpu idle_data structure in a
race free manner.

[1] commit be76ea6144 ("s390/idle: remove arch_cpu_idle_time() and corresponding code")
[2] commit ead70b7523 ("timers/nohz: Add a comment about broken iowait counter update race")

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2026-06-15 16:33:40 +02:00

196 lines
8.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Generate definitions needed by assembly language modules.
* This code generates raw asm output which is post-processed to extract
* and format the required data.
*/
#define COMPILE_OFFSETS
#include <linux/kbuild.h>
#include <linux/sched.h>
#include <linux/purgatory.h>
#include <linux/pgtable.h>
#include <linux/ftrace_regs.h>
#include <linux/kernel_stat.h>
#include <asm/kvm_host_types.h>
#include <asm/stacktrace.h>
#include <asm/ptrace.h>
#include <asm/idle.h>
int main(void)
{
/* task struct offsets */
OFFSET(__TASK_stack, task_struct, stack);
OFFSET(__TASK_thread, task_struct, thread);
OFFSET(__TASK_pid, task_struct, pid);
#ifdef CONFIG_STACKPROTECTOR
OFFSET(__TASK_stack_canary, task_struct, stack_canary);
#endif
BLANK();
/* thread struct offsets */
OFFSET(__THREAD_ksp, thread_struct, ksp);
BLANK();
/* thread info offsets */
OFFSET(__TI_flags, task_struct, thread_info.flags);
OFFSET(__TI_sie, task_struct, thread_info.sie);
BLANK();
/* pt_regs offsets */
OFFSET(__PT_PSW, pt_regs, psw);
OFFSET(__PT_GPRS, pt_regs, gprs);
OFFSET(__PT_R0, pt_regs, gprs[0]);
OFFSET(__PT_R1, pt_regs, gprs[1]);
OFFSET(__PT_R2, pt_regs, gprs[2]);
OFFSET(__PT_R3, pt_regs, gprs[3]);
OFFSET(__PT_R4, pt_regs, gprs[4]);
OFFSET(__PT_R5, pt_regs, gprs[5]);
OFFSET(__PT_R6, pt_regs, gprs[6]);
OFFSET(__PT_R7, pt_regs, gprs[7]);
OFFSET(__PT_R8, pt_regs, gprs[8]);
OFFSET(__PT_R9, pt_regs, gprs[9]);
OFFSET(__PT_R10, pt_regs, gprs[10]);
OFFSET(__PT_R11, pt_regs, gprs[11]);
OFFSET(__PT_R12, pt_regs, gprs[12]);
OFFSET(__PT_R13, pt_regs, gprs[13]);
OFFSET(__PT_R14, pt_regs, gprs[14]);
OFFSET(__PT_R15, pt_regs, gprs[15]);
OFFSET(__PT_ORIG_GPR2, pt_regs, orig_gpr2);
OFFSET(__PT_INT_CODE, pt_regs, int_code);
OFFSET(__PT_FLAGS, pt_regs, flags);
OFFSET(__PT_LAST_BREAK, pt_regs, last_break);
DEFINE(__PT_SIZE, sizeof(struct pt_regs));
BLANK();
/* stack_frame offsets */
OFFSET(__SF_BACKCHAIN, stack_frame, back_chain);
OFFSET(__SF_GPRS, stack_frame, gprs);
OFFSET(__SF_EMPTY, stack_frame, empty[0]);
OFFSET(__SF_SIE_CONTROL, stack_frame, sie_control_block);
OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea);
OFFSET(__SF_SIE_RETURN, stack_frame, sie_return);
OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags);
OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);
OFFSET(__SF_SIE_GUEST_ASCE, stack_frame, sie_guest_asce);
OFFSET(__SF_SIE_IRQ, stack_frame, sie_irq);
DEFINE(STACK_FRAME_OVERHEAD, sizeof(struct stack_frame));
BLANK();
OFFSET(__SFUSER_BACKCHAIN, stack_frame_user, back_chain);
DEFINE(STACK_FRAME_USER_OVERHEAD, sizeof(struct stack_frame_user));
OFFSET(__SFVDSO_RETURN_ADDRESS, stack_frame_vdso_wrapper, return_address);
DEFINE(STACK_FRAME_VDSO_OVERHEAD, sizeof(struct stack_frame_vdso_wrapper));
BLANK();
/* hardware defined lowcore locations 0x000 - 0x1ff */
OFFSET(__LC_EXT_PARAMS, lowcore, ext_params);
OFFSET(__LC_EXT_CPU_ADDR, lowcore, ext_cpu_addr);
OFFSET(__LC_EXT_INT_CODE, lowcore, ext_int_code);
OFFSET(__LC_PGM_ILC, lowcore, pgm_ilc);
OFFSET(__LC_PGM_CODE, lowcore, pgm_code);
OFFSET(__LC_PGM_INT_CODE, lowcore, pgm_int_code);
OFFSET(__LC_DATA_EXC_CODE, lowcore, data_exc_code);
OFFSET(__LC_MON_CLASS_NR, lowcore, mon_class_num);
OFFSET(__LC_PER_CODE, lowcore, per_code);
OFFSET(__LC_PER_ATMID, lowcore, per_atmid);
OFFSET(__LC_PER_ADDRESS, lowcore, per_address);
OFFSET(__LC_EXC_ACCESS_ID, lowcore, exc_access_id);
OFFSET(__LC_PER_ACCESS_ID, lowcore, per_access_id);
OFFSET(__LC_OP_ACCESS_ID, lowcore, op_access_id);
OFFSET(__LC_AR_MODE_ID, lowcore, ar_mode_id);
OFFSET(__LC_TRANS_EXC_CODE, lowcore, trans_exc_code);
OFFSET(__LC_MON_CODE, lowcore, monitor_code);
OFFSET(__LC_SUBCHANNEL_ID, lowcore, subchannel_id);
OFFSET(__LC_SUBCHANNEL_NR, lowcore, subchannel_nr);
OFFSET(__LC_IO_INT_PARM, lowcore, io_int_parm);
OFFSET(__LC_IO_INT_WORD, lowcore, io_int_word);
OFFSET(__LC_MCCK_CODE, lowcore, mcck_interruption_code);
OFFSET(__LC_EXT_DAMAGE_CODE, lowcore, external_damage_code);
OFFSET(__LC_MCCK_FAIL_STOR_ADDR, lowcore, failing_storage_address);
OFFSET(__LC_PGM_LAST_BREAK, lowcore, pgm_last_break);
OFFSET(__LC_RETURN_LPSWE, lowcore, return_lpswe);
OFFSET(__LC_RETURN_MCCK_LPSWE, lowcore, return_mcck_lpswe);
OFFSET(__LC_RST_OLD_PSW, lowcore, restart_old_psw);
OFFSET(__LC_EXT_OLD_PSW, lowcore, external_old_psw);
OFFSET(__LC_SVC_OLD_PSW, lowcore, svc_old_psw);
OFFSET(__LC_PGM_OLD_PSW, lowcore, program_old_psw);
OFFSET(__LC_MCK_OLD_PSW, lowcore, mcck_old_psw);
OFFSET(__LC_IO_OLD_PSW, lowcore, io_old_psw);
OFFSET(__LC_RST_NEW_PSW, lowcore, restart_psw);
OFFSET(__LC_EXT_NEW_PSW, lowcore, external_new_psw);
OFFSET(__LC_SVC_NEW_PSW, lowcore, svc_new_psw);
OFFSET(__LC_PGM_NEW_PSW, lowcore, program_new_psw);
OFFSET(__LC_MCK_NEW_PSW, lowcore, mcck_new_psw);
OFFSET(__LC_IO_NEW_PSW, lowcore, io_new_psw);
/* software defined lowcore locations 0x200 - 0xdff*/
OFFSET(__LC_SAVE_AREA, lowcore, save_area);
OFFSET(__LC_SAVE_AREA_RESTART, lowcore, save_area_restart);
OFFSET(__LC_PCPU, lowcore, pcpu);
OFFSET(__LC_RETURN_PSW, lowcore, return_psw);
OFFSET(__LC_RETURN_MCCK_PSW, lowcore, return_mcck_psw);
OFFSET(__LC_SYS_ENTER_TIMER, lowcore, sys_enter_timer);
OFFSET(__LC_MCCK_ENTER_TIMER, lowcore, mcck_enter_timer);
OFFSET(__LC_EXIT_TIMER, lowcore, exit_timer);
OFFSET(__LC_LAST_UPDATE_TIMER, lowcore, last_update_timer);
OFFSET(__LC_LAST_UPDATE_CLOCK, lowcore, last_update_clock);
OFFSET(__LC_INT_CLOCK, lowcore, int_clock);
OFFSET(__LC_CURRENT, lowcore, current_task);
OFFSET(__LC_PERCPU_OFFSET, lowcore, percpu_offset);
OFFSET(__LC_KERNEL_STACK, lowcore, kernel_stack);
OFFSET(__LC_ASYNC_STACK, lowcore, async_stack);
OFFSET(__LC_NODAT_STACK, lowcore, nodat_stack);
OFFSET(__LC_RESTART_STACK, lowcore, restart_stack);
OFFSET(__LC_MCCK_STACK, lowcore, mcck_stack);
OFFSET(__LC_RESTART_FN, lowcore, restart_fn);
OFFSET(__LC_RESTART_DATA, lowcore, restart_data);
OFFSET(__LC_RESTART_SOURCE, lowcore, restart_source);
OFFSET(__LC_RESTART_FLAGS, lowcore, restart_flags);
OFFSET(__LC_KERNEL_ASCE, lowcore, kernel_asce);
OFFSET(__LC_USER_ASCE, lowcore, user_asce);
OFFSET(__LC_LPP, lowcore, lpp);
OFFSET(__LC_CURRENT_PID, lowcore, current_pid);
OFFSET(__LC_LAST_BREAK, lowcore, last_break);
/* software defined ABI-relevant lowcore locations 0xe00 - 0xe20 */
OFFSET(__LC_STACK_CANARY, lowcore, stack_canary);
OFFSET(__LC_DUMP_REIPL, lowcore, ipib);
OFFSET(__LC_VMCORE_INFO, lowcore, vmcore_info);
OFFSET(__LC_OS_INFO, lowcore, os_info);
/* hardware defined lowcore locations 0x1000 - 0x18ff */
OFFSET(__LC_MCESAD, lowcore, mcesad);
OFFSET(__LC_EXT_PARAMS2, lowcore, ext_params2);
OFFSET(__LC_FPREGS_SAVE_AREA, lowcore, floating_pt_save_area);
OFFSET(__LC_GPREGS_SAVE_AREA, lowcore, gpregs_save_area);
OFFSET(__LC_PSW_SAVE_AREA, lowcore, psw_save_area);
OFFSET(__LC_PREFIX_SAVE_AREA, lowcore, prefixreg_save_area);
OFFSET(__LC_FP_CREG_SAVE_AREA, lowcore, fpt_creg_save_area);
OFFSET(__LC_TOD_PROGREG_SAVE_AREA, lowcore, tod_progreg_save_area);
OFFSET(__LC_CPU_TIMER_SAVE_AREA, lowcore, cpu_timer_save_area);
OFFSET(__LC_CLOCK_COMP_SAVE_AREA, lowcore, clock_comp_save_area);
OFFSET(__LC_LAST_BREAK_SAVE_AREA, lowcore, last_break_save_area);
OFFSET(__LC_AREGS_SAVE_AREA, lowcore, access_regs_save_area);
OFFSET(__LC_CREGS_SAVE_AREA, lowcore, cregs_save_area);
OFFSET(__LC_PGM_TDB, lowcore, pgm_tdb);
BLANK();
/* gmap/sie offsets */
OFFSET(__SIE_PROG0C, kvm_s390_sie_block, prog0c);
OFFSET(__SIE_PROG20, kvm_s390_sie_block, prog20);
/* kexec_sha_region */
OFFSET(__KEXEC_SHA_REGION_START, kexec_sha_region, start);
OFFSET(__KEXEC_SHA_REGION_LEN, kexec_sha_region, len);
DEFINE(__KEXEC_SHA_REGION_SIZE, sizeof(struct kexec_sha_region));
/* sizeof kernel parameter area */
DEFINE(__PARMAREA_SIZE, sizeof(struct parmarea));
/* kernel parameter area offsets */
DEFINE(IPL_DEVICE, PARMAREA + offsetof(struct parmarea, ipl_device));
DEFINE(INITRD_START, PARMAREA + offsetof(struct parmarea, initrd_start));
DEFINE(INITRD_SIZE, PARMAREA + offsetof(struct parmarea, initrd_size));
DEFINE(OLDMEM_BASE, PARMAREA + offsetof(struct parmarea, oldmem_base));
DEFINE(OLDMEM_SIZE, PARMAREA + offsetof(struct parmarea, oldmem_size));
DEFINE(COMMAND_LINE, PARMAREA + offsetof(struct parmarea, command_line));
DEFINE(MAX_COMMAND_LINE_SIZE, PARMAREA + offsetof(struct parmarea, max_command_line_size));
OFFSET(__IDLE_CLOCK_EXIT, s390_idle_data, clock_idle_exit);
#ifdef CONFIG_NO_HZ_COMMON
OFFSET(__KCPUSTAT_SEQUENCE, kernel_cpustat, idle_sleeptime_seq);
#endif
OFFSET(__FTRACE_REGS_PT_REGS, __arch_ftrace_regs, regs);
DEFINE(__FTRACE_REGS_SIZE, sizeof(struct __arch_ftrace_regs));
OFFSET(__PCPU_FLAGS, pcpu, flags);
return 0;
}