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Commit 02a54177 authored by Ralf Baechle's avatar Ralf Baechle
Browse files

MIPS: tlbex: Deal with re-definition of label 



The microassembler used in tlbex.c does not notice if a label is redefined
resulting in relocations against such labels silently missrelocated.
The issues exists since commit add6eb04776db4189ea89f596cbcde31b899be9d
[Synthesize TLB exception handlers at runtime.] in 2.6.10 and went unnoticed
for so long because the relocations for the affected branches got computed
to do something *almost* sensible.

The issue affects R4000, R4400, QED/IDT RM5230, RM5231, RM5260, RM5261,
RM5270 and RM5271 processors.

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 5210edcd

arch/mips/mm/tlbex.c

+34 −7
Original line number Diff line number Diff line
@@ -148,8 +148,8 @@ enum label_id { 
	label_leave,

	label_vmalloc,

	label_vmalloc_done,

	label_tlbw_hazard,

	label_split,

	label_tlbw_hazard_0,

	label_split = label_tlbw_hazard_0 + 8,

	label_tlbl_goaround1,

	label_tlbl_goaround2,

	label_nopage_tlbl,
@@ -167,7 +167,7 @@ UASM_L_LA(_second_part) 
UASM_L_LA(_leave)

UASM_L_LA(_vmalloc)

UASM_L_LA(_vmalloc_done)

UASM_L_LA(_tlbw_hazard)

/* _tlbw_hazard_x is handled differently.  */

UASM_L_LA(_split)

UASM_L_LA(_tlbl_goaround1)

UASM_L_LA(_tlbl_goaround2)
@@ -181,6 +181,30 @@ UASM_L_LA(_large_segbits_fault) 
UASM_L_LA(_tlb_huge_update)

#endif



static int __cpuinitdata hazard_instance;



static void uasm_bgezl_hazard(u32 **p, struct uasm_reloc **r, int instance)

{

	switch (instance) {

	case 0 ... 7:

		uasm_il_bgezl(p, r, 0, label_tlbw_hazard_0 + instance);

		return;

	default:

		BUG();

	}

}



static void uasm_bgezl_label(struct uasm_label **l, u32 **p, int instance)

{

	switch (instance) {

	case 0 ... 7:

		uasm_build_label(l, *p, label_tlbw_hazard_0 + instance);

		break;

	default:

		BUG();

	}

}



/*

 * For debug purposes.

 */
@@ -478,9 +502,10 @@ static void __cpuinit build_tlb_write_entry(u32 **p, struct uasm_label **l, 
		 * This branch uses up a mtc0 hazard nop slot and saves

		 * two nops after the tlbw instruction.

		 */

		uasm_il_bgezl(p, r, 0, label_tlbw_hazard);

		uasm_bgezl_hazard(p, r, hazard_instance);

		tlbw(p);

		uasm_l_tlbw_hazard(l, *p);

		uasm_bgezl_label(l, p, hazard_instance);

		hazard_instance++;

		uasm_i_nop(p);

		break;
@@ -527,14 +552,16 @@ static void __cpuinit build_tlb_write_entry(u32 **p, struct uasm_label **l, 
		break;



	case CPU_NEVADA:

		uasm_i_nop(p); /* QED specifies 2 nops hazard */

		uasm_i_nop(p); /* QED specifies 2 nops hazard */

		/*

		 * This branch uses up a mtc0 hazard nop slot and saves

		 * a nop after the tlbw instruction.

		 */

		uasm_il_bgezl(p, r, 0, label_tlbw_hazard);

		uasm_bgezl_hazard(p, r, hazard_instance);

		tlbw(p);

		uasm_l_tlbw_hazard(l, *p);

		uasm_bgezl_label(l, p, hazard_instance);

		hazard_instance++;

		break;



	case CPU_RM7000: