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Commit 25e13814 authored by Michael Ellerman's avatar Michael Ellerman Committed by Benjamin Herrenschmidt
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powerpc: Apply early paca fixups to boot_paca and the boot cpu's paca 



In commit 466921c5 we added a hack to set the paca data_offset to zero so
that per-cpu accesses would work on the boot cpu prior to per-cpu areas
being setup. This fixed a problem with lockdep touching per-cpu areas
very early in boot.

However if we combine CONFIG_LOCK_STAT=y with any of the PPC_EARLY_DEBUG
options, we can hit the same problem in udbg_early_init(). To avoid that
we need to set the data_offset of the boot_paca also. So factor out the
fixup logic and call it for both the boot_paca, and "the paca of the
boot cpu".

Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
Tested-by: default avatarGeoff Levand <geoff@infradead.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 6a7e4064

arch/powerpc/kernel/setup_64.c

+11 −5
Original line number Diff line number Diff line
@@ -156,6 +156,15 @@ early_param("smt-enabled", early_smt_enabled); 
#define check_smt_enabled()

#endif /* CONFIG_SMP */



/** Fix up paca fields required for the boot cpu */

static void fixup_boot_paca(void)

{

	/* The boot cpu is started */

	get_paca()->cpu_start = 1;

	/* Allow percpu accesses to work until we setup percpu data */

	get_paca()->data_offset = 0;

}



/*

 * Early initialization entry point. This is called by head.S

 * with MMU translation disabled. We rely on the "feature" of
@@ -187,6 +196,7 @@ void __init early_setup(unsigned long dt_ptr) 
	/* Assume we're on cpu 0 for now. Don't write to the paca yet! */

	initialise_paca(&boot_paca, 0);

	setup_paca(&boot_paca);

	fixup_boot_paca();



	/* Initialize lockdep early or else spinlocks will blow */

	lockdep_init();
@@ -207,11 +217,7 @@ void __init early_setup(unsigned long dt_ptr) 


	/* Now we know the logical id of our boot cpu, setup the paca. */

	setup_paca(&paca[boot_cpuid]);



	/* Fix up paca fields required for the boot cpu */

	get_paca()->cpu_start = 1;

	/* Allow percpu accesses to "work" until we setup percpu data */

	get_paca()->data_offset = 0;

	fixup_boot_paca();



	/* Probe the machine type */

	probe_machine();