1 // SPDX-License-Identifier: GPL-2.0 2 3 #include "lkdtm.h" 4 #include <linux/slab.h> 5 #include <linux/vmalloc.h> 6 #include <asm/mmu.h> 7 8 /* Inserts new slb entries */ 9 static void insert_slb_entry(unsigned long p, int ssize, int page_size) 10 { 11 unsigned long flags; 12 13 flags = SLB_VSID_KERNEL | mmu_psize_defs[page_size].sllp; 14 preempt_disable(); 15 16 asm volatile("slbmte %0,%1" : 17 : "r" (mk_vsid_data(p, ssize, flags)), 18 "r" (mk_esid_data(p, ssize, SLB_NUM_BOLTED)) 19 : "memory"); 20 21 asm volatile("slbmte %0,%1" : 22 : "r" (mk_vsid_data(p, ssize, flags)), 23 "r" (mk_esid_data(p, ssize, SLB_NUM_BOLTED + 1)) 24 : "memory"); 25 preempt_enable(); 26 } 27 28 /* Inject slb multihit on vmalloc-ed address i.e 0xD00... */ 29 static int inject_vmalloc_slb_multihit(void) 30 { 31 char *p; 32 33 p = vmalloc(PAGE_SIZE); 34 if (!p) 35 return -ENOMEM; 36 37 insert_slb_entry((unsigned long)p, MMU_SEGSIZE_1T, mmu_vmalloc_psize); 38 /* 39 * This triggers exception, If handled correctly we must recover 40 * from this error. 41 */ 42 p[0] = '!'; 43 vfree(p); 44 return 0; 45 } 46 47 /* Inject slb multihit on kmalloc-ed address i.e 0xC00... */ 48 static int inject_kmalloc_slb_multihit(void) 49 { 50 char *p; 51 52 p = kmalloc(2048, GFP_KERNEL); 53 if (!p) 54 return -ENOMEM; 55 56 insert_slb_entry((unsigned long)p, MMU_SEGSIZE_1T, mmu_linear_psize); 57 /* 58 * This triggers exception, If handled correctly we must recover 59 * from this error. 60 */ 61 p[0] = '!'; 62 kfree(p); 63 return 0; 64 } 65 66 /* 67 * Few initial SLB entries are bolted. Add a test to inject 68 * multihit in bolted entry 0. 69 */ 70 static void insert_dup_slb_entry_0(void) 71 { 72 unsigned long test_address = PAGE_OFFSET, *test_ptr; 73 unsigned long esid, vsid; 74 unsigned long i = 0; 75 76 test_ptr = (unsigned long *)test_address; 77 preempt_disable(); 78 79 asm volatile("slbmfee %0,%1" : "=r" (esid) : "r" (i)); 80 asm volatile("slbmfev %0,%1" : "=r" (vsid) : "r" (i)); 81 82 /* for i !=0 we would need to mask out the old entry number */ 83 asm volatile("slbmte %0,%1" : 84 : "r" (vsid), 85 "r" (esid | SLB_NUM_BOLTED) 86 : "memory"); 87 88 asm volatile("slbmfee %0,%1" : "=r" (esid) : "r" (i)); 89 asm volatile("slbmfev %0,%1" : "=r" (vsid) : "r" (i)); 90 91 /* for i !=0 we would need to mask out the old entry number */ 92 asm volatile("slbmte %0,%1" : 93 : "r" (vsid), 94 "r" (esid | (SLB_NUM_BOLTED + 1)) 95 : "memory"); 96 97 pr_info("%s accessing test address 0x%lx: 0x%lx\n", 98 __func__, test_address, *test_ptr); 99 100 preempt_enable(); 101 } 102 103 void lkdtm_PPC_SLB_MULTIHIT(void) 104 { 105 if (!radix_enabled()) { 106 pr_info("Injecting SLB multihit errors\n"); 107 /* 108 * These need not be separate tests, And they do pretty 109 * much same thing. In any case we must recover from the 110 * errors introduced by these functions, machine would not 111 * survive these tests in case of failure to handle. 112 */ 113 inject_vmalloc_slb_multihit(); 114 inject_kmalloc_slb_multihit(); 115 insert_dup_slb_entry_0(); 116 pr_info("Recovered from SLB multihit errors\n"); 117 } else { 118 pr_err("XFAIL: This test is for ppc64 and with hash mode MMU only\n"); 119 } 120 } 121