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Commit ce22e1d3 authored by David S. Miller's avatar David S. Miller
Browse files

[SPARC64]: Fix booting on non-zero cpu. 



The early per-cpu handling needs a slight tweak to work when booting
on a non-zero cpu.

We got away with this for a long time, but can't any longer as now
even printk() calls functions (cpu_clock() for example) that thus make
early references to per-cpu variables.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 488b5ec8

arch/sparc64/kernel/head.S

+25 −0
Original line number Diff line number Diff line
@@ -632,11 +632,36 @@ tlb_fixup_done: 
	/* Not reached... */



1:

	/* If we boot on a non-zero cpu, all of the per-cpu

	 * variable references we make before setting up the

	 * per-cpu areas will use a bogus offset.  Put a

	 * compensating factor into __per_cpu_base to handle

	 * this cleanly.

	 *

	 * What the per-cpu code calculates is:

	 *

	 *	__per_cpu_base + (cpu << __per_cpu_shift)

	 *

	 * These two variables are zero initially, so to

	 * make it all cancel out to zero we need to put

	 * "0 - (cpu << 0)" into __per_cpu_base so that the

	 * above formula evaluates to zero.

	 *

	 * We cannot even perform a printk() until this stuff

	 * is setup as that calls cpu_clock() which uses

	 * per-cpu variables.

	 */

	sub	%g0, %o0, %o1

	sethi	%hi(__per_cpu_base), %o2

	stx	%o1, [%o2 + %lo(__per_cpu_base)]

#else

	mov	0, %o0

#endif

	sth	%o0, [%g6 + TI_CPU]



	call	prom_init_report

	 nop



	/* Off we go.... */

	call	start_kernel

	 nop

arch/sparc64/prom/init.c

+3 −0
Original line number Diff line number Diff line
@@ -48,7 +48,10 @@ void __init prom_init(void *cif_handler, void *cif_stack) 
	prom_getstring(node, "version", prom_version, sizeof(prom_version));



	prom_printf("\n");

}



void __init prom_init_report(void)

{

	printk("PROMLIB: Sun IEEE Boot Prom '%s'\n", prom_version);

	printk("PROMLIB: Root node compatible: %s\n", prom_root_compatible);

}