Commit 1aaf179d authored by Michael Holzheu's avatar Michael Holzheu Committed by Martin Schwidefsky
Browse files

[S390] hibernate: Do real CPU swap at resume time 



Currently, when the physical resume CPU is not equal to the physical suspend
CPU, we swap the CPUs logically, by modifying the logical/physical CPU mapping.
This has two major drawbacks: First the change is visible from user space (e.g.
CPU sysfs files) and second it is hard to ensure that nowhere in the kernel
the physical CPU ID is stored before suspend.
To fix this, we now really swap the physical CPUs, if the resume CPU is not
the pysical suspend CPU. We restart the suspend CPU and stop the resume CPU
using SIGP restart and SIGP stop. If the suspend CPU is no longer available,
we write a message and load a disabled wait PSW.

Signed-off-by: default avatarMichael Holzheu <michael.holzheu@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 68d1e5f0

arch/s390/include/asm/lowcore.h

+1 −0
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ 
#define __LC_PGM_OLD_PSW		0x0150

#define __LC_MCK_OLD_PSW		0x0160

#define __LC_IO_OLD_PSW			0x0170

#define __LC_RESTART_PSW		0x01a0

#define __LC_EXT_NEW_PSW		0x01b0

#define __LC_SVC_NEW_PSW		0x01c0

#define __LC_PGM_NEW_PSW		0x01d0

arch/s390/kernel/asm-offsets.c

+6 −1
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/sched.h>

#include <linux/kbuild.h>

#include <asm/vdso.h>

#include <asm/sigp.h>



int main(void)

{
@@ -59,6 +60,10 @@ int main(void) 
	DEFINE(CLOCK_REALTIME, CLOCK_REALTIME);

	DEFINE(CLOCK_MONOTONIC, CLOCK_MONOTONIC);

	DEFINE(CLOCK_REALTIME_RES, MONOTONIC_RES_NSEC);



	/* constants for SIGP */

	DEFINE(__SIGP_STOP, sigp_stop);

	DEFINE(__SIGP_RESTART, sigp_restart);

	DEFINE(__SIGP_SENSE, sigp_sense);

	DEFINE(__SIGP_INITIAL_CPU_RESET, sigp_initial_cpu_reset);

	return 0;

}

arch/s390/kernel/sclp.S

+1 −4
Original line number Diff line number Diff line
@@ -24,8 +24,6 @@ LC_EXT_INT_CODE = 0x86 # addr of ext int code 
#   R3	= external interruption parameter if R2=0

#



.section ".init.text","ax"



_sclp_wait_int:

	stm	%r6,%r15,24(%r15)		# save registers

	basr	%r13,0				# get base register
@@ -318,9 +316,8 @@ _sclp_print_early: 
	.long	_sclp_work_area

.Lascebc:

	.long	_ascebc

.previous



.section ".init.data","a"

.section .data,"aw",@progbits

	.balign 4096

_sclp_work_area:

	.fill	4096

arch/s390/kernel/smp.c

+0 −36
Original line number Diff line number Diff line
@@ -1041,42 +1041,6 @@ out: 
static SYSDEV_CLASS_ATTR(dispatching, 0644, dispatching_show,

			 dispatching_store);



/*

 * If the resume kernel runs on another cpu than the suspended kernel,

 * we have to switch the cpu IDs in the logical map.

 */

void smp_switch_boot_cpu_in_resume(u32 resume_phys_cpu_id,

				   struct _lowcore *suspend_lowcore)

{

	int cpu, suspend_cpu_id, resume_cpu_id;

	u32 suspend_phys_cpu_id;



	suspend_phys_cpu_id = __cpu_logical_map[suspend_lowcore->cpu_nr];

	suspend_cpu_id = suspend_lowcore->cpu_nr;



	for_each_present_cpu(cpu) {

		if (__cpu_logical_map[cpu] == resume_phys_cpu_id) {

			resume_cpu_id = cpu;

			goto found;

		}

	}

	panic("Could not find resume cpu in logical map.\n");



found:

	printk("Resume  cpu ID: %i/%i\n", resume_phys_cpu_id, resume_cpu_id);

	printk("Suspend cpu ID: %i/%i\n", suspend_phys_cpu_id, suspend_cpu_id);



	__cpu_logical_map[resume_cpu_id] = suspend_phys_cpu_id;

	__cpu_logical_map[suspend_cpu_id] = resume_phys_cpu_id;



	lowcore_ptr[suspend_cpu_id]->cpu_addr = resume_phys_cpu_id;

}



u32 smp_get_phys_cpu_id(void)

{

	return __cpu_logical_map[smp_processor_id()];

}



static int __init topology_init(void)

{

	int cpu;

arch/s390/kernel/swsusp_asm64.S

+63 −28
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 


#include <asm/page.h>

#include <asm/ptrace.h>

#include <asm/thread_info.h>

#include <asm/asm-offsets.h>



/*
@@ -41,6 +42,9 @@ swsusp_arch_suspend: 
	/* Get pointer to save area */

	lghi	%r1,0x1000



	/* Save CPU address */

	stap	__LC_CPU_ADDRESS(%r1)



	/* Store registers */

	mvc	0x318(4,%r1),__SF_EMPTY(%r15)	/* move prefix to lowcore */

	stfpc	0x31c(%r1)			/* store fpu control */
@@ -105,12 +109,7 @@ swsusp_arch_resume: 
	/* Make all free pages stable */

	lghi	%r2,1

	brasl	%r14,arch_set_page_states

#ifdef CONFIG_SMP

	/* Save boot cpu number */

	brasl	%r14,smp_get_phys_cpu_id

	larl	%r1,saved_cpu_id

	st	%r2,0(%r1)

#endif



	/* Deactivate DAT */

	stnsm	__SF_EMPTY(%r15),0xfb
@@ -139,12 +138,10 @@ swsusp_arch_resume: 


	/* Reset System */

	larl	%r1,restart_entry

	larl	%r2,restart_psw

	larl	%r2,.Lrestart_diag308_psw

	og	%r1,0(%r2)

	stg	%r1,0(%r0)

	larl	%r1,saved_pgm_check_psw

	mvc	0(16,%r1),__LC_PGM_NEW_PSW(%r0)

	larl	%r1,new_pgm_check_psw

	larl	%r1,.Lnew_pgm_check_psw

	epsw	%r2,%r3

	stm	%r2,%r3,0(%r1)

	mvc	__LC_PGM_NEW_PSW(16,%r0),0(%r1)
@@ -154,12 +151,54 @@ restart_entry: 
	lhi	%r1,1

	sigp	%r1,%r0,0x12

	sam64

	larl	%r1,new_pgm_check_psw

	larl	%r1,.Lnew_pgm_check_psw

	lpswe	0(%r1)

pgm_check_entry:

	larl	%r1,saved_pgm_check_psw

	mvc	__LC_PGM_NEW_PSW(16,%r0),0(%r1)



	/* Switch to original suspend CPU */

	larl	%r1,.Lresume_cpu		/* Resume CPU address: r2 */

	stap	0(%r1)

	llgh	%r2,0(%r1)

	lghi	%r3,0x1000

	llgh	%r1,__LC_CPU_ADDRESS(%r3)	/* Suspend CPU address: r1 */

	cgr	%r1,%r2

	je	restore_registers		/* r1 = r2 -> nothing to do */

	larl	%r4,.Lrestart_suspend_psw	/* Set new restart PSW */

	mvc	__LC_RESTART_PSW(16,%r0),0(%r4)

3:

	sigp	%r9,%r1,__SIGP_INITIAL_CPU_RESET

	brc	8,4f	/* accepted */

	brc	2,3b	/* busy, try again */



	/* Suspend CPU not available -> panic */

	larl	%r15,init_thread_union

	ahi	%r15,1<<(PAGE_SHIFT+THREAD_ORDER)

	larl	%r2,.Lpanic_string

	larl	%r3,_sclp_print_early

	lghi	%r1,0

	sam31

	sigp	%r1,%r0,0x12

	basr	%r14,%r3

	larl	%r3,.Ldisabled_wait_31

	lpsw	0(%r3)

4:

	/* Switch to suspend CPU */

	sigp	%r9,%r1,__SIGP_RESTART	/* start suspend CPU */

	brc	2,4b			/* busy, try again */

5:

	sigp	%r9,%r2,__SIGP_STOP	/* stop resume (current) CPU */

6:	j	6b



restart_suspend:

	larl	%r1,.Lresume_cpu

	llgh	%r2,0(%r1)

7:

	sigp	%r9,%r2,__SIGP_SENSE	/* Wait for resume CPU */

	brc	2,7b			/* busy, try again */

	tmll	%r9,0x40		/* Test if resume CPU is stopped */

	jz	7b



restore_registers:

	/* Restore registers */

	lghi	%r13,0x1000		/* %r1 = pointer to save arae */
@@ -193,13 +232,6 @@ pgm_check_entry: 
	/* Pointer to save area */

	lghi	%r13,0x1000



#ifdef CONFIG_SMP

	/* Switch CPUs */

	larl	%r1,saved_cpu_id

	llgf	%r2,0(%r1)

	llgf	%r3,0x318(%r13)

	brasl	%r14,smp_switch_boot_cpu_in_resume

#endif

	/* Restore prefix register */

	spx	0x318(%r13)
@@ -217,13 +249,16 @@ pgm_check_entry: 


	.section .data.nosave,"aw",@progbits

	.align	8

restart_psw:

.Ldisabled_wait_31:

	.long  0x000a0000,0x00000000

.Lpanic_string:

	.asciz	"Resume not possible because suspend CPU is no longer available"

	.align	8

.Lrestart_diag308_psw:

	.long	0x00080000,0x80000000

new_pgm_check_psw:

.Lrestart_suspend_psw:

	.quad	0x0000000180000000,restart_suspend

.Lnew_pgm_check_psw:

	.quad	0,pgm_check_entry

saved_pgm_check_psw:

	.quad	0,0

#ifdef CONFIG_SMP

saved_cpu_id:

	.long	0

#endif
 
.Lresume_cpu:

	.byte	0,0

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