Commit 57892847 authored by Alexander Gordeev's avatar Alexander Gordeev Committed by Vasily Gorbik
Browse files

s390/smp: reallocate IPL CPU lowcore 



The lowcore for IPL CPU is special. It is allocated early
in the boot process using memblock and never freed since.
The reason is pcpu_alloc_lowcore() and pcpu_free_lowcore()
routines use page allocator which is not available when
the IPL CPU is getting initialized.

Similar problem is already addressed for stacks - once the
virtual memory is available the early boot stacks get re-
allocated. Doing the same for lowcore will allow freeing
the IPL CPU lowcore and make no difference between the
boot and secondary CPUs.

Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent bdb8c935

arch/s390/kernel/setup.c

+0 −21
Original line number Diff line number Diff line
@@ -341,27 +341,6 @@ int __init arch_early_irq_init(void) 
	return 0;

}



static int __init stack_realloc(void)

{

	unsigned long old, new;



	old = S390_lowcore.async_stack - STACK_INIT_OFFSET;

	new = stack_alloc();

	if (!new)

		panic("Couldn't allocate async stack");

	WRITE_ONCE(S390_lowcore.async_stack, new + STACK_INIT_OFFSET);

	free_pages(old, THREAD_SIZE_ORDER);



	old = S390_lowcore.mcck_stack - STACK_INIT_OFFSET;

	new = stack_alloc();

	if (!new)

		panic("Couldn't allocate machine check stack");

	WRITE_ONCE(S390_lowcore.mcck_stack, new + STACK_INIT_OFFSET);

	memblock_free_late(old, THREAD_SIZE);

	return 0;

}

early_initcall(stack_realloc);



void __init arch_call_rest_init(void)

{

	unsigned long stack;

arch/s390/kernel/smp.c

+52 −0
Original line number Diff line number Diff line
@@ -1234,3 +1234,55 @@ static int __init s390_smp_init(void) 
	return rc;

}

subsys_initcall(s390_smp_init);



static __always_inline void set_new_lowcore(struct lowcore *lc)

{

	struct lowcore *old_lc = &S390_lowcore;

	struct lowcore *new_lc = lc;

	u32 pfx;

	register struct lowcore *reg2 asm ("2") = new_lc;

	register unsigned long	 reg3 asm ("3") = sizeof(*reg2);

	register struct lowcore *reg4 asm ("4") = old_lc;

	register unsigned long	 reg5 asm ("5") = sizeof(*reg4);



	asm volatile(

		"	st	2,%[pfx]\n"

		"	mvcl	2,4\n"

		"	spx	%[pfx]\n"

		: "+&d" (reg2), "+&d" (reg3),

		  "+&d" (reg4), "+&d" (reg5), [pfx] "=Q" (pfx)

		: : "memory", "cc");

}



static int __init smp_reinit_ipl_cpu(void)

{

	unsigned long async_stack, nodat_stack, mcck_stack;

	struct lowcore *lc, *lc_ipl;

	unsigned long flags;



	lc_ipl = lowcore_ptr[0];

	lc = (struct lowcore *)	__get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);

	nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);

	async_stack = stack_alloc();

	mcck_stack = stack_alloc();

	if (!lc || !nodat_stack || !async_stack || !mcck_stack)

		panic("Couldn't allocate memory");



	local_irq_save(flags);

	local_mcck_disable();

	set_new_lowcore(lc);

	S390_lowcore.nodat_stack = nodat_stack + STACK_INIT_OFFSET;

	S390_lowcore.async_stack = async_stack + STACK_INIT_OFFSET;

	S390_lowcore.mcck_stack = mcck_stack + STACK_INIT_OFFSET;

	lowcore_ptr[0] = lc;

	pcpu_devices[0].lowcore = lc;

	local_mcck_enable();

	local_irq_restore(flags);



	free_pages(lc_ipl->async_stack - STACK_INIT_OFFSET, THREAD_SIZE_ORDER);

	memblock_free_late(lc_ipl->mcck_stack - STACK_INIT_OFFSET, THREAD_SIZE);

	memblock_free_late((unsigned long) lc_ipl, sizeof(*lc_ipl));



	return 0;

}

early_initcall(smp_reinit_ipl_cpu);