Commit 519b2e31 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/64: don't set boot CPU's r13 to paca until the structure is set up 



The idea is to get to the point where if r13 is non-zero, then it should
contain a reasonable paca. This can be used in early boot program check
and machine check handlers to avoid running off into the weeds if they
hit before r13 has a paca.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220926055620.2676869-5-npiggin@gmail.com
parent b830c875

arch/powerpc/kernel/setup_64.c

+10 −10
Original line number Diff line number Diff line
@@ -177,10 +177,10 @@ early_param("smt-enabled", early_smt_enabled); 
#endif /* CONFIG_SMP */



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

static void __init fixup_boot_paca(void)

static void __init fixup_boot_paca(struct paca_struct *boot_paca)

{

	/* The boot cpu is started */

	get_paca()->cpu_start = 1;

	boot_paca->cpu_start = 1;

#ifdef CONFIG_PPC_BOOK3S_64

	/*

	 * Give the early boot machine check stack somewhere to use, use
@@ -188,14 +188,14 @@ static void __init fixup_boot_paca(void) 
	 * deep stack usage in early init so shouldn't overflow it or overwrite

	 * things.

	 */

	get_paca()->mc_emergency_sp = (void *)&init_thread_union +

	boot_paca->mc_emergency_sp = (void *)&init_thread_union +

		(THREAD_SIZE/2);

#endif

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

	get_paca()->data_offset = 0;

	boot_paca->data_offset = 0;

	/* Mark interrupts soft and hard disabled in PACA */

	irq_soft_mask_set(IRQS_DISABLED);

	get_paca()->irq_happened = PACA_IRQ_HARD_DIS;

	boot_paca->irq_soft_mask = IRQS_DISABLED;

	boot_paca->irq_happened = PACA_IRQ_HARD_DIS;

	WARN_ON(mfmsr() & MSR_EE);

}
@@ -363,8 +363,8 @@ void __init early_setup(unsigned long dt_ptr) 
	 * what CPU we are on.

	 */

	initialise_paca(&boot_paca, 0);

	setup_paca(&boot_paca);

	fixup_boot_paca();

	fixup_boot_paca(&boot_paca);

	setup_paca(&boot_paca); /* install the paca into registers */



	/* -------- printk is now safe to use ------- */
@@ -393,8 +393,8 @@ void __init early_setup(unsigned long dt_ptr) 
		/* Poison paca_ptrs[0] again if it's not the boot cpu */

		memset(&paca_ptrs[0], 0x88, sizeof(paca_ptrs[0]));

	}

	setup_paca(paca_ptrs[boot_cpuid]);

	fixup_boot_paca();

	fixup_boot_paca(paca_ptrs[boot_cpuid]);

	setup_paca(paca_ptrs[boot_cpuid]); /* install the paca into registers */



	/*

	 * Configure exception handlers. This include setting up trampolines