Commit d9e1831a authored by Scott Wood's avatar Scott Wood
Browse files

powerpc/85xx: Load all early TLB entries at once 



Use an AS=1 trampoline TLB entry to allow all normal TLB1 entries to
be loaded at once.  This avoids the need to keep the translation that
code is executing from in the same TLB entry in the final TLB
configuration as during early boot, which in turn is helpful for
relocatable kernels (e.g. kdump) where the kernel is not running from
what would be the first TLB entry.

On e6500, we limit map_mem_in_cams() to the primary hwthread of a
core (the boot cpu is always considered primary, as a kdump kernel
can be entered on any cpu).  Each TLB only needs to be set up once,
and when we do, we don't want another thread to be running when we
create a temporary trampoline TLB1 entry.

Signed-off-by: default avatarScott Wood <scottwood@freescale.com>
parent 1930bb5c

arch/powerpc/kernel/setup_64.c

+8 −0
Original line number Diff line number Diff line
@@ -108,6 +108,14 @@ static void setup_tlb_core_data(void) 
	for_each_possible_cpu(cpu) {

		int first = cpu_first_thread_sibling(cpu);



		/*

		 * If we boot via kdump on a non-primary thread,

		 * make sure we point at the thread that actually

		 * set up this TLB.

		 */

		if (cpu_first_thread_sibling(boot_cpuid) == first)

			first = boot_cpuid;



		paca[cpu].tcd_ptr = &paca[first].tcd;



		/*

arch/powerpc/mm/fsl_booke_mmu.c

+2 −2
Original line number Diff line number Diff line
@@ -141,8 +141,6 @@ static void settlbcam(int index, unsigned long virt, phys_addr_t phys, 
	tlbcam_addrs[index].start = virt;

	tlbcam_addrs[index].limit = virt + size - 1;

	tlbcam_addrs[index].phys = phys;



	loadcam_entry(index);

}



unsigned long calc_cam_sz(unsigned long ram, unsigned long virt,
@@ -188,6 +186,8 @@ static unsigned long map_mem_in_cams_addr(phys_addr_t phys, unsigned long virt, 
		virt += cam_sz;

		phys += cam_sz;

	}



	loadcam_multi(0, i, max_cam_idx);

	tlbcam_index = i;



#ifdef CONFIG_PPC64

arch/powerpc/mm/mmu_decl.h

+1 −0
Original line number Diff line number Diff line
@@ -152,6 +152,7 @@ extern int switch_to_as1(void); 
extern void restore_to_as0(int esel, int offset, void *dt_ptr, int bootcpu);

#endif

extern void loadcam_entry(unsigned int index);

extern void loadcam_multi(int first_idx, int num, int tmp_idx);



struct tlbcam {

	u32	MAS0;

arch/powerpc/mm/tlb_nohash.c

+18 −1
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#include <asm/tlbflush.h>

#include <asm/tlb.h>

#include <asm/code-patching.h>

#include <asm/cputhreads.h>

#include <asm/hugetlb.h>

#include <asm/paca.h>
@@ -628,10 +629,26 @@ static void early_init_this_mmu(void) 
#ifdef CONFIG_PPC_FSL_BOOK3E

	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {

		unsigned int num_cams;

		int __maybe_unused cpu = smp_processor_id();

		bool map = true;



		/* use a quarter of the TLBCAM for bolted linear map */

		num_cams = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) / 4;

		linear_map_top = map_mem_in_cams(linear_map_top, num_cams);



		/*

		 * Only do the mapping once per core, or else the

		 * transient mapping would cause problems.

		 */

#ifdef CONFIG_SMP

		if (cpu != boot_cpuid &&

		    (cpu != cpu_first_thread_sibling(cpu) ||

		     cpu == cpu_first_thread_sibling(boot_cpuid)))

			map = false;

#endif



		if (map)

			linear_map_top = map_mem_in_cams(linear_map_top,

							 num_cams);

	}

#endif

arch/powerpc/mm/tlb_nohash_low.S

+63 −0
Original line number Diff line number Diff line
@@ -400,6 +400,7 @@ _GLOBAL(set_context) 
 * extern void loadcam_entry(unsigned int index)

 *

 * Load TLBCAM[index] entry in to the L2 CAM MMU

 * Must preserve r7, r8, r9, and r10

 */

_GLOBAL(loadcam_entry)

	mflr	r5
@@ -423,4 +424,66 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_BIG_PHYS) 
	tlbwe

	isync

	blr



/*

 * Load multiple TLB entries at once, using an alternate-space

 * trampoline so that we don't have to care about whether the same

 * TLB entry maps us before and after.

 *

 * r3 = first entry to write

 * r4 = number of entries to write

 * r5 = temporary tlb entry

 */

_GLOBAL(loadcam_multi)

	mflr	r8



	/*

	 * Set up temporary TLB entry that is the same as what we're

	 * running from, but in AS=1.

	 */

	bl	1f

1:	mflr	r6

	tlbsx	0,r8

	mfspr	r6,SPRN_MAS1

	ori	r6,r6,MAS1_TS

	mtspr	SPRN_MAS1,r6

	mfspr	r6,SPRN_MAS0

	rlwimi	r6,r5,MAS0_ESEL_SHIFT,MAS0_ESEL_MASK

	mr	r7,r5

	mtspr	SPRN_MAS0,r6

	isync

	tlbwe

	isync



	/* Switch to AS=1 */

	mfmsr	r6

	ori	r6,r6,MSR_IS|MSR_DS

	mtmsr	r6

	isync



	mr	r9,r3

	add	r10,r3,r4

2:	bl	loadcam_entry

	addi	r9,r9,1

	cmpw	r9,r10

	mr	r3,r9

	blt	2b



	/* Return to AS=0 and clear the temporary entry */

	mfmsr	r6

	rlwinm.	r6,r6,0,~(MSR_IS|MSR_DS)

	mtmsr	r6

	isync



	li	r6,0

	mtspr	SPRN_MAS1,r6

	rlwinm	r6,r7,MAS0_ESEL_SHIFT,MAS0_ESEL_MASK

	oris	r6,r6,MAS0_TLBSEL(1)@h

	mtspr	SPRN_MAS0,r6

	isync

	tlbwe

	isync



	mtlr	r8

	blr

#endif

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