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Commit 465ccab9 authored by will schmidt's avatar will schmidt Committed by Paul Mackerras
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[POWERPC] Fix switch_slb handling of 1T ESID values 



Now that we have 1TB segment size support, we need to be using the
GET_ESID_1T macro when comparing ESID values for pc, stack, and
unmapped_base within switch_slb().   A new helper function called
esids_match() contains the logic for deciding when to call GET_ESID
and GET_ESID_1T.

This fixes a duplicate-slb-entry inspired machine-check exception I
was seeing when trying to run java on a power6 partition.

Tested on power6 and power5.

Signed-off-by: default avatarWill Schmidt <will_schmidt@vnet.ibm.com>
Acked-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent e7bda183

arch/powerpc/mm/slb.c

+31 −3
Original line number Diff line number Diff line
@@ -149,6 +149,35 @@ void slb_vmalloc_update(void) 
	slb_flush_and_rebolt();

}



/* Helper function to compare esids.  There are four cases to handle.

 * 1. The system is not 1T segment size capable.  Use the GET_ESID compare.

 * 2. The system is 1T capable, both addresses are < 1T, use the GET_ESID compare.

 * 3. The system is 1T capable, only one of the two addresses is > 1T.  This is not a match.

 * 4. The system is 1T capable, both addresses are > 1T, use the GET_ESID_1T macro to compare.

 */

static inline int esids_match(unsigned long addr1, unsigned long addr2)

{

	int esid_1t_count;



	/* System is not 1T segment size capable. */

	if (!cpu_has_feature(CPU_FTR_1T_SEGMENT))

		return (GET_ESID(addr1) == GET_ESID(addr2));



	esid_1t_count = (((addr1 >> SID_SHIFT_1T) != 0) +

				((addr2 >> SID_SHIFT_1T) != 0));



	/* both addresses are < 1T */

	if (esid_1t_count == 0)

		return (GET_ESID(addr1) == GET_ESID(addr2));



	/* One address < 1T, the other > 1T.  Not a match */

	if (esid_1t_count == 1)

		return 0;



	/* Both addresses are > 1T. */

	return (GET_ESID_1T(addr1) == GET_ESID_1T(addr2));

}



/* Flush all user entries from the segment table of the current processor. */

void switch_slb(struct task_struct *tsk, struct mm_struct *mm)

{
@@ -194,15 +223,14 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm) 
		return;

	slb_allocate(pc);



	if (GET_ESID(pc) == GET_ESID(stack))

	if (esids_match(pc,stack))

		return;



	if (is_kernel_addr(stack))

		return;

	slb_allocate(stack);



	if ((GET_ESID(pc) == GET_ESID(unmapped_base))

	    || (GET_ESID(stack) == GET_ESID(unmapped_base)))

	if (esids_match(pc,unmapped_base) || esids_match(stack,unmapped_base))

		return;



	if (is_kernel_addr(unmapped_base))