From e22cf8ca6f75a6c4fccf2d6ee818bdb1205f32e6 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 6 Oct 2015 18:06:15 +0200 Subject: [PATCH] s390/cpumf: rework program parameter setting to detect guest samples The program parameter can be used to mark hardware samples with some token. Previously, it was used to mark guest samples only. Improve the program parameter doubleword by combining two parts, the leftmost LPP part and the rightmost PID part. Set the PID part for processes by using the task PID. To distinguish host and guest samples for the kernel (PID part is zero), the guest must always set the program paramater to a non-zero value. Use the leftmost bit in the LPP part of the program parameter to be able to detect guest kernel samples. [brueckner@linux.vnet.ibm.com]: Split __LC_CURRENT and introduced __LC_LPP. Corrected __LC_CURRENT users and adjusted assembler parts. And updated the commit message accordingly. Signed-off-by: Christian Borntraeger Signed-off-by: Hendrik Brueckner Reviewed-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/lowcore.h | 9 ++++++++- arch/s390/include/asm/setup.h | 3 +++ arch/s390/kernel/asm-offsets.c | 1 + arch/s390/kernel/entry.S | 28 ++++++++++++---------------- arch/s390/kernel/head64.S | 7 ++++++- arch/s390/kernel/perf_cpum_sf.c | 10 ++++++---- arch/s390/kernel/smp.c | 2 ++ arch/s390/mm/fault.c | 4 ++-- 8 files changed, 40 insertions(+), 24 deletions(-) diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h index 663f23e37460..12af453c3c19 100644 --- a/arch/s390/include/asm/lowcore.h +++ b/arch/s390/include/asm/lowcore.h @@ -132,7 +132,14 @@ struct _lowcore { /* Address space pointer. */ __u64 kernel_asce; /* 0x0358 */ __u64 user_asce; /* 0x0360 */ - __u64 current_pid; /* 0x0368 */ + + /* + * The lpp and current_pid fields form a + * 64-bit value that is set as program + * parameter with the LPP instruction. + */ + __u32 lpp; /* 0x0368 */ + __u32 current_pid; /* 0x036c */ /* SMP info area */ __u32 cpu_nr; /* 0x0370 */ diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h index ab015a7f20d0..23537661da0e 100644 --- a/arch/s390/include/asm/setup.h +++ b/arch/s390/include/asm/setup.h @@ -34,6 +34,9 @@ #define MACHINE_FLAG_VX _BITUL(18) #define MACHINE_FLAG_CAD _BITUL(19) +#define LPP_MAGIC _BITUL(31) +#define LPP_PFAULT_PID_MASK _AC(0xffffffff, UL) + #ifndef __ASSEMBLY__ #include diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c index ac857c452be2..9cd248f637c7 100644 --- a/arch/s390/kernel/asm-offsets.c +++ b/arch/s390/kernel/asm-offsets.c @@ -163,6 +163,7 @@ int main(void) OFFSET(__LC_RESTART_DATA, _lowcore, restart_data); OFFSET(__LC_RESTART_SOURCE, _lowcore, restart_source); OFFSET(__LC_USER_ASCE, _lowcore, user_asce); + OFFSET(__LC_LPP, _lowcore, lpp); OFFSET(__LC_CURRENT_PID, _lowcore, current_pid); OFFSET(__LC_PERCPU_OFFSET, _lowcore, percpu_offset); OFFSET(__LC_VDSO_PER_CPU, _lowcore, vdso_per_cpu_data); diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 2444ea7f7ba4..d653a87d66b5 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -187,8 +187,11 @@ ENTRY(__switch_to) stg %r15,__LC_KERNEL_STACK # store end of kernel stack lg %r15,__THREAD_ksp(%r1) # load kernel stack of next lctl %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4 - mvc __LC_CURRENT_PID+4(4,%r0),__TASK_pid(%r3) # store pid of next + mvc __LC_CURRENT_PID(4,%r0),__TASK_pid(%r3) # store pid of next lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task + TSTMSK __LC_MACHINE_FLAGS,MACHINE_FLAG_LPP + bzr %r14 + .insn s,0xb2800000,__LC_LPP # set program parameter br %r14 .L__critical_start: @@ -203,7 +206,7 @@ ENTRY(sie64a) stmg %r6,%r14,__SF_GPRS(%r15) # save kernel registers stg %r2,__SF_EMPTY(%r15) # save control block pointer stg %r3,__SF_EMPTY+8(%r15) # save guest register save area - xc __SF_EMPTY+16(16,%r15),__SF_EMPTY+16(%r15) # host id & reason + xc __SF_EMPTY+16(8,%r15),__SF_EMPTY+16(%r15) # reason code = 0 TSTMSK __LC_CPU_FLAGS,_CIF_FPU # load guest fp/vx registers ? jno .Lsie_load_guest_gprs brasl %r14,load_fpu_regs # load guest fp/vx regs @@ -220,14 +223,7 @@ ENTRY(sie64a) jnz .Lsie_skip TSTMSK __LC_CPU_FLAGS,_CIF_FPU jo .Lsie_skip # exit if fp/vx regs changed - TSTMSK __LC_MACHINE_FLAGS,MACHINE_FLAG_LPP - jz .Lsie_enter - .insn s,0xb2800000,__LC_CURRENT_PID # set guest id to pid -.Lsie_enter: sie 0(%r14) - TSTMSK __LC_MACHINE_FLAGS,MACHINE_FLAG_LPP - jz .Lsie_skip - .insn s,0xb2800000,__SF_EMPTY+16(%r15)# set host id .Lsie_skip: ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE lctlg %c1,%c1,__LC_USER_ASCE # load primary asce @@ -244,11 +240,11 @@ sie_exit: lg %r14,__SF_EMPTY+8(%r15) # load guest register save area stmg %r0,%r13,0(%r14) # save guest gprs 0-13 lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers - lg %r2,__SF_EMPTY+24(%r15) # return exit reason code + lg %r2,__SF_EMPTY+16(%r15) # return exit reason code br %r14 .Lsie_fault: lghi %r14,-EFAULT - stg %r14,__SF_EMPTY+24(%r15) # set exit reason code + stg %r14,__SF_EMPTY+16(%r15) # set exit reason code j sie_exit EX_TABLE(.Lrewind_pad,.Lsie_fault) @@ -938,7 +934,10 @@ ENTRY(mcck_int_handler) # PSW restart interrupt handler # ENTRY(restart_int_handler) - stg %r15,__LC_SAVE_AREA_RESTART + TSTMSK __LC_MACHINE_FLAGS,MACHINE_FLAG_LPP + jz 0f + .insn s,0xb2800000,__LC_LPP +0: stg %r15,__LC_SAVE_AREA_RESTART lg %r15,__LC_RESTART_STACK aghi %r15,-__PT_SIZE # create pt_regs on stack xc 0(__PT_SIZE,%r15),0(%r15) @@ -1042,10 +1041,7 @@ cleanup_critical: .Lcleanup_sie: lg %r9,__SF_EMPTY(%r15) # get control block pointer - TSTMSK __LC_MACHINE_FLAGS,MACHINE_FLAG_LPP - jz 0f - .insn s,0xb2800000,__SF_EMPTY+16(%r15)# set host id -0: ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE + ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE lctlg %c1,%c1,__LC_USER_ASCE # load primary asce larl %r9,sie_exit # skip forward to sie_exit br %r14 diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S index d7c00507568a..58b719fa8067 100644 --- a/arch/s390/kernel/head64.S +++ b/arch/s390/kernel/head64.S @@ -16,7 +16,12 @@ __HEAD ENTRY(startup_continue) - larl %r1,sched_clock_base_cc + tm __LC_STFL_FAC_LIST+6,0x80 # LPP available ? + jz 0f + xc __LC_LPP+1(7,0),__LC_LPP+1 # clear lpp and current_pid + mvi __LC_LPP,0x80 # and set LPP_MAGIC + .insn s,0xb2800000,__LC_LPP # load program parameter +0: larl %r1,sched_clock_base_cc mvc 0(8,%r1),__LC_LAST_UPDATE_CLOCK larl %r13,.LPG1 # get base lctlg %c0,%c15,.Lctl-.LPG1(%r13) # load control registers diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c index b973972f6ba5..3d8da1e742c2 100644 --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -1019,11 +1019,13 @@ static int perf_push_sample(struct perf_event *event, struct sf_raw_sample *sfr) break; } - /* The host-program-parameter (hpp) contains the pid of - * the CPU thread as set by sie64a() in entry.S. - * If non-zero assume a guest sample. + /* + * A non-zero guest program parameter indicates a guest + * sample. + * Note that some early samples might be misaccounted to + * the host. */ - if (sfr->basic.hpp) + if (sfr->basic.gpp) sde_regs->in_guest = 1; overflow = 0; diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index dbd40d448294..9062df575afe 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -262,6 +262,8 @@ static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk) + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); lc->thread_info = (unsigned long) task_thread_info(tsk); lc->current_task = (unsigned long) tsk; + lc->lpp = LPP_MAGIC; + lc->current_pid = tsk->pid; lc->user_timer = ti->user_timer; lc->system_timer = ti->system_timer; lc->steal_timer = 0; diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 77b3938d6bfa..ec1a30d0d11a 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -590,7 +590,7 @@ int pfault_init(void) .reffcode = 0, .refdwlen = 5, .refversn = 2, - .refgaddr = __LC_CURRENT_PID, + .refgaddr = __LC_LPP, .refselmk = 1ULL << 48, .refcmpmk = 1ULL << 48, .reserved = __PF_RES_FIELD }; @@ -649,7 +649,7 @@ static void pfault_interrupt(struct ext_code ext_code, return; inc_irq_stat(IRQEXT_PFL); /* Get the token (= pid of the affected task). */ - pid = param64; + pid = param64 & LPP_PFAULT_PID_MASK; rcu_read_lock(); tsk = find_task_by_pid_ns(pid, &init_pid_ns); if (tsk) -- 2.11.0