---

yaml
---
r: 190503
b: refs/heads/master
c: 1ec5632
h: refs/heads/master
i:
  190501: 000ebec
  190499: 9400a75
  190495: 33b36c9
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3be6022c27ace1e3b4ba963e7ffd2e3b60cecd8a
+refs/heads/master: 1ec56329ff939aba29291c0dec1a28ceed660162

trunk/arch/mips/mm/tlbex.c

@@ -31,6 +31,16 @@
 #include <asm/war.h>
 #include <asm/uasm.h>
 
+/*
+ * TLB load/store/modify handlers.
+ *
+ * Only the fastpath gets synthesized at runtime, the slowpath for
+ * do_page_fault remains normal asm.
+ */
+extern void tlb_do_page_fault_0(void);
+extern void tlb_do_page_fault_1(void);
+
+
 static inline int r45k_bvahwbug(void)
 {
 	/* XXX: We should probe for the presence of this bug, but we don't. */
@@ -83,6 +93,7 @@ enum label_id {
 	label_nopage_tlbm,
 	label_smp_pgtable_change,
 	label_r3000_write_probe_fail,
+	label_large_segbits_fault,
 #ifdef CONFIG_HUGETLB_PAGE
 	label_tlb_huge_update,
 #endif
@@ -101,6 +112,7 @@ UASM_L_LA(_nopage_tlbs)
 UASM_L_LA(_nopage_tlbm)
 UASM_L_LA(_smp_pgtable_change)
 UASM_L_LA(_r3000_write_probe_fail)
+UASM_L_LA(_large_segbits_fault)
 #ifdef CONFIG_HUGETLB_PAGE
 UASM_L_LA(_tlb_huge_update)
 #endif
@@ -157,6 +169,10 @@ static u32 tlb_handler[128] __cpuinitdata;
 static struct uasm_label labels[128] __cpuinitdata;
 static struct uasm_reloc relocs[128] __cpuinitdata;
 
+#ifdef CONFIG_64BIT
+static int check_for_high_segbits __cpuinitdata;
+#endif
+
 #ifndef CONFIG_MIPS_PGD_C0_CONTEXT
 /*
  * CONFIG_MIPS_PGD_C0_CONTEXT implies 64 bit and lack of pgd_current,
@@ -532,7 +548,24 @@ build_get_pmde64(u32 **p, struct uasm_label **l, struct uasm_reloc **r,
 	 * The vmalloc handling is not in the hotpath.
 	 */
 	uasm_i_dmfc0(p, tmp, C0_BADVADDR);
-	uasm_il_bltz(p, r, tmp, label_vmalloc);
+
+	if (check_for_high_segbits) {
+		/*
+		 * The kernel currently implicitely assumes that the
+		 * MIPS SEGBITS parameter for the processor is
+		 * (PGDIR_SHIFT+PGDIR_BITS) or less, and will never
+		 * allocate virtual addresses outside the maximum
+		 * range for SEGBITS = (PGDIR_SHIFT+PGDIR_BITS). But
+		 * that doesn't prevent user code from accessing the
+		 * higher xuseg addresses.  Here, we make sure that
+		 * everything but the lower xuseg addresses goes down
+		 * the module_alloc/vmalloc path.
+		 */
+		uasm_i_dsrl_safe(p, ptr, tmp, PGDIR_SHIFT + PGD_ORDER + PAGE_SHIFT - 3);
+		uasm_il_bnez(p, r, ptr, label_vmalloc);
+	} else {
+		uasm_il_bltz(p, r, tmp, label_vmalloc);
+	}
 	/* No uasm_i_nop needed here, since the next insn doesn't touch TMP. */
 
 #ifdef CONFIG_MIPS_PGD_C0_CONTEXT
@@ -583,28 +616,64 @@ build_get_pmde64(u32 **p, struct uasm_label **l, struct uasm_reloc **r,
 #endif
 }
 
+enum vmalloc64_mode {not_refill, refill};
 /*
  * BVADDR is the faulting address, PTR is scratch.
  * PTR will hold the pgd for vmalloc.
  */
 static void __cpuinit
 build_get_pgd_vmalloc64(u32 **p, struct uasm_label **l, struct uasm_reloc **r,
-			unsigned int bvaddr, unsigned int ptr)
+			unsigned int bvaddr, unsigned int ptr,
+			enum vmalloc64_mode mode)
 {
 	long swpd = (long)swapper_pg_dir;
+	int single_insn_swpd;
+	int did_vmalloc_branch = 0;
+
+	single_insn_swpd = uasm_in_compat_space_p(swpd) && !uasm_rel_lo(swpd);
 
 	uasm_l_vmalloc(l, *p);
 
-	if (uasm_in_compat_space_p(swpd) && !uasm_rel_lo(swpd)) {
-		uasm_il_b(p, r, label_vmalloc_done);
-		uasm_i_lui(p, ptr, uasm_rel_hi(swpd));
-	} else {
-		UASM_i_LA_mostly(p, ptr, swpd);
-		uasm_il_b(p, r, label_vmalloc_done);
-		if (uasm_in_compat_space_p(swpd))
-			uasm_i_addiu(p, ptr, ptr, uasm_rel_lo(swpd));
-		else
-			uasm_i_daddiu(p, ptr, ptr, uasm_rel_lo(swpd));
+	if (mode == refill && check_for_high_segbits) {
+		if (single_insn_swpd) {
+			uasm_il_bltz(p, r, bvaddr, label_vmalloc_done);
+			uasm_i_lui(p, ptr, uasm_rel_hi(swpd));
+			did_vmalloc_branch = 1;
+			/* fall through */
+		} else {
+			uasm_il_bgez(p, r, bvaddr, label_large_segbits_fault);
+		}
+	}
+	if (!did_vmalloc_branch) {
+		if (uasm_in_compat_space_p(swpd) && !uasm_rel_lo(swpd)) {
+			uasm_il_b(p, r, label_vmalloc_done);
+			uasm_i_lui(p, ptr, uasm_rel_hi(swpd));
+		} else {
+			UASM_i_LA_mostly(p, ptr, swpd);
+			uasm_il_b(p, r, label_vmalloc_done);
+			if (uasm_in_compat_space_p(swpd))
+				uasm_i_addiu(p, ptr, ptr, uasm_rel_lo(swpd));
+			else
+				uasm_i_daddiu(p, ptr, ptr, uasm_rel_lo(swpd));
+		}
+	}
+	if (mode == refill && check_for_high_segbits) {
+		uasm_l_large_segbits_fault(l, *p);
+		/*
+		 * We get here if we are an xsseg address, or if we are
+		 * an xuseg address above (PGDIR_SHIFT+PGDIR_BITS) boundary.
+		 *
+		 * Ignoring xsseg (assume disabled so would generate
+		 * (address errors?), the only remaining possibility
+		 * is the upper xuseg addresses.  On processors with
+		 * TLB_SEGBITS <= PGDIR_SHIFT+PGDIR_BITS, these
+		 * addresses would have taken an address error. We try
+		 * to mimic that here by taking a load/istream page
+		 * fault.
+		 */
+		UASM_i_LA(p, ptr, (unsigned long)tlb_do_page_fault_0);
+		uasm_i_jr(p, ptr);
+		uasm_i_nop(p);
 	}
 }
 
@@ -823,7 +892,7 @@ static void __cpuinit build_r4000_tlb_refill_handler(void)
 #endif
 
 #ifdef CONFIG_64BIT
-	build_get_pgd_vmalloc64(&p, &l, &r, K0, K1);
+	build_get_pgd_vmalloc64(&p, &l, &r, K0, K1, refill);
 #endif
 
 	/*
@@ -932,15 +1001,6 @@ static void __cpuinit build_r4000_tlb_refill_handler(void)
 	dump_handler((u32 *)ebase, 64);
 }
 
-/*
- * TLB load/store/modify handlers.
- *
- * Only the fastpath gets synthesized at runtime, the slowpath for
- * do_page_fault remains normal asm.
- */
-extern void tlb_do_page_fault_0(void);
-extern void tlb_do_page_fault_1(void);
-
 /*
  * 128 instructions for the fastpath handler is generous and should
  * never be exceeded.
@@ -1300,7 +1360,7 @@ build_r4000_tlbchange_handler_tail(u32 **p, struct uasm_label **l,
 	uasm_i_eret(p); /* return from trap */
 
 #ifdef CONFIG_64BIT
-	build_get_pgd_vmalloc64(p, l, r, tmp, ptr);
+	build_get_pgd_vmalloc64(p, l, r, tmp, ptr, not_refill);
 #endif
 }
 
@@ -1524,6 +1584,10 @@ void __cpuinit build_tlb_refill_handler(void)
 	 */
 	static int run_once = 0;
 
+#ifdef CONFIG_64BIT
+	check_for_high_segbits = current_cpu_data.vmbits > (PGDIR_SHIFT + PGD_ORDER + PAGE_SHIFT - 3);
+#endif
+
 	switch (current_cpu_type()) {
 	case CPU_R2000:
 	case CPU_R3000: