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Commit 40bd587a authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

powerpc: Rename slb0_limit() to safe_stack_limit() and add Book3E support 



slb0_limit() wasn't a very descriptive name. This changes it along with
a comment explaining what it's used for, and provides a 64-bit BookE
implementation.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 77eafe10

arch/powerpc/include/asm/mmu-book3e.h

+4 −0
Original line number Diff line number Diff line
@@ -245,6 +245,10 @@ extern struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT]; 
extern int mmu_linear_psize;

extern int mmu_vmemmap_psize;



#ifdef CONFIG_PPC64

extern unsigned long linear_map_top;

#endif



#endif /* !__ASSEMBLY__ */



#endif /* _ASM_POWERPC_MMU_BOOK3E_H_ */

arch/powerpc/kernel/setup_64.c

+18 −5
Original line number Diff line number Diff line
@@ -434,17 +434,30 @@ void __init setup_system(void) 
	DBG(" <- setup_system()\n");

}



static u64 slb0_limit(void)

/* This returns the limit below which memory accesses to the linear

 * mapping are guarnateed not to cause a TLB or SLB miss. This is

 * used to allocate interrupt or emergency stacks for which our

 * exception entry path doesn't deal with being interrupted.

 */

static u64 safe_stack_limit(void)

{

	if (mmu_has_feature(MMU_FTR_1T_SEGMENT)) {

#ifdef CONFIG_PPC_BOOK3E

	/* Freescale BookE bolts the entire linear mapping */

	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E))

		return linear_map_top;

	/* Other BookE, we assume the first GB is bolted */

	return 1ul << 30;

#else

	/* BookS, the first segment is bolted */

	if (mmu_has_feature(MMU_FTR_1T_SEGMENT))

		return 1UL << SID_SHIFT_1T;

	}

	return 1UL << SID_SHIFT;

#endif

}



static void __init irqstack_early_init(void)

{

	u64 limit = slb0_limit();

	u64 limit = safe_stack_limit();

	unsigned int i;



	/*
@@ -497,7 +510,7 @@ static void __init emergency_stack_init(void) 
	 * bringup, we need to get at them in real mode. This means they

	 * must also be within the RMO region.

	 */

	limit = min(slb0_limit(), ppc64_rma_size);

	limit = min(safe_stack_limit(), ppc64_rma_size);



	for_each_possible_cpu(i) {

		unsigned long sp;