Merge master.kernel.org:/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw
[pandora-kernel.git] / kernel / unwind.c
index ed0a21d..09c2613 100644 (file)
 #include <linux/bootmem.h>
 #include <linux/sort.h>
 #include <linux/stop_machine.h>
+#include <linux/uaccess.h>
 #include <asm/sections.h>
 #include <asm/uaccess.h>
 #include <asm/unaligned.h>
 
-extern char __start_unwind[], __end_unwind[];
+extern const char __start_unwind[], __end_unwind[];
 extern const u8 __start_unwind_hdr[], __end_unwind_hdr[];
 
 #define MAX_STACK_DEPTH 8
@@ -94,6 +95,7 @@ static const struct {
 
 typedef unsigned long uleb128_t;
 typedef   signed long sleb128_t;
+#define sleb128abs __builtin_labs
 
 static struct unwind_table {
        struct {
@@ -135,6 +137,17 @@ struct unwind_state {
 
 static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
 
+static unsigned unwind_debug;
+static int __init unwind_debug_setup(char *s)
+{
+       unwind_debug = simple_strtoul(s, NULL, 0);
+       return 1;
+}
+__setup("unwind_debug=", unwind_debug_setup);
+#define dprintk(lvl, fmt, args...) \
+       ((void)(lvl > unwind_debug \
+        || printk(KERN_DEBUG "unwind: " fmt "\n", ##args)))
+
 static struct unwind_table *find_table(unsigned long pc)
 {
        struct unwind_table *table;
@@ -151,7 +164,9 @@ static struct unwind_table *find_table(unsigned long pc)
 
 static unsigned long read_pointer(const u8 **pLoc,
                                   const void *end,
-                                  signed ptrType);
+                                  signed ptrType,
+                                  unsigned long text_base,
+                                  unsigned long data_base);
 
 static void init_unwind_table(struct unwind_table *table,
                               const char *name,
@@ -176,10 +191,13 @@ static void init_unwind_table(struct unwind_table *table,
        /* See if the linker provided table looks valid. */
        if (header_size <= 4
            || header_start[0] != 1
-           || (void *)read_pointer(&ptr, end, header_start[1]) != table_start
-           || header_start[2] == DW_EH_PE_omit
-           || read_pointer(&ptr, end, header_start[2]) <= 0
-           || header_start[3] == DW_EH_PE_omit)
+           || (void *)read_pointer(&ptr, end, header_start[1], 0, 0)
+              != table_start
+           || !read_pointer(&ptr, end, header_start[2], 0, 0)
+           || !read_pointer(&ptr, end, header_start[3], 0,
+                            (unsigned long)header_start)
+           || !read_pointer(&ptr, end, header_start[3], 0,
+                            (unsigned long)header_start))
                header_start = NULL;
        table->hdrsz = header_size;
        smp_wmb();
@@ -269,7 +287,7 @@ static void __init setup_unwind_table(struct unwind_table *table,
                ptr = (const u8 *)(fde + 2);
                if (!read_pointer(&ptr,
                                  (const u8 *)(fde + 1) + *fde,
-                                 ptrType))
+                                 ptrType, 0, 0))
                        return;
                ++n;
        }
@@ -279,6 +297,7 @@ static void __init setup_unwind_table(struct unwind_table *table,
 
        hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
                + 2 * n * sizeof(unsigned long);
+       dprintk(2, "Binary lookup table size for %s: %lu bytes", table->name, hdrSize);
        header = alloc(hdrSize);
        if (!header)
                return;
@@ -303,7 +322,7 @@ static void __init setup_unwind_table(struct unwind_table *table,
                ptr = (const u8 *)(fde + 2);
                header->table[n].start = read_pointer(&ptr,
                                                      (const u8 *)(fde + 1) + *fde,
-                                                     fde_pointer_type(cie));
+                                                     fde_pointer_type(cie), 0, 0);
                header->table[n].fde = (unsigned long)fde;
                ++n;
        }
@@ -486,7 +505,9 @@ static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
 
 static unsigned long read_pointer(const u8 **pLoc,
                                   const void *end,
-                                  signed ptrType)
+                                  signed ptrType,
+                                  unsigned long text_base,
+                                  unsigned long data_base)
 {
        unsigned long value = 0;
        union {
@@ -498,13 +519,17 @@ static unsigned long read_pointer(const u8 **pLoc,
                const unsigned long *pul;
        } ptr;
 
-       if (ptrType < 0 || ptrType == DW_EH_PE_omit)
+       if (ptrType < 0 || ptrType == DW_EH_PE_omit) {
+               dprintk(1, "Invalid pointer encoding %02X (%p,%p).", ptrType, *pLoc, end);
                return 0;
+       }
        ptr.p8 = *pLoc;
        switch(ptrType & DW_EH_PE_FORM) {
        case DW_EH_PE_data2:
-               if (end < (const void *)(ptr.p16u + 1))
+               if (end < (const void *)(ptr.p16u + 1)) {
+                       dprintk(1, "Data16 overrun (%p,%p).", ptr.p8, end);
                        return 0;
+               }
                if(ptrType & DW_EH_PE_signed)
                        value = get_unaligned(ptr.p16s++);
                else
@@ -512,8 +537,10 @@ static unsigned long read_pointer(const u8 **pLoc,
                break;
        case DW_EH_PE_data4:
 #ifdef CONFIG_64BIT
-               if (end < (const void *)(ptr.p32u + 1))
+               if (end < (const void *)(ptr.p32u + 1)) {
+                       dprintk(1, "Data32 overrun (%p,%p).", ptr.p8, end);
                        return 0;
+               }
                if(ptrType & DW_EH_PE_signed)
                        value = get_unaligned(ptr.p32s++);
                else
@@ -525,8 +552,10 @@ static unsigned long read_pointer(const u8 **pLoc,
                BUILD_BUG_ON(sizeof(u32) != sizeof(value));
 #endif
        case DW_EH_PE_native:
-               if (end < (const void *)(ptr.pul + 1))
+               if (end < (const void *)(ptr.pul + 1)) {
+                       dprintk(1, "DataUL overrun (%p,%p).", ptr.p8, end);
                        return 0;
+               }
                value = get_unaligned(ptr.pul++);
                break;
        case DW_EH_PE_leb128:
@@ -534,10 +563,14 @@ static unsigned long read_pointer(const u8 **pLoc,
                value = ptrType & DW_EH_PE_signed
                        ? get_sleb128(&ptr.p8, end)
                        : get_uleb128(&ptr.p8, end);
-               if ((const void *)ptr.p8 > end)
+               if ((const void *)ptr.p8 > end) {
+                       dprintk(1, "DataLEB overrun (%p,%p).", ptr.p8, end);
                        return 0;
+               }
                break;
        default:
+               dprintk(2, "Cannot decode pointer type %02X (%p,%p).",
+                       ptrType, ptr.p8, end);
                return 0;
        }
        switch(ptrType & DW_EH_PE_ADJUST) {
@@ -546,12 +579,33 @@ static unsigned long read_pointer(const u8 **pLoc,
        case DW_EH_PE_pcrel:
                value += (unsigned long)*pLoc;
                break;
+       case DW_EH_PE_textrel:
+               if (likely(text_base)) {
+                       value += text_base;
+                       break;
+               }
+               dprintk(2, "Text-relative encoding %02X (%p,%p), but zero text base.",
+                       ptrType, *pLoc, end);
+               return 0;
+       case DW_EH_PE_datarel:
+               if (likely(data_base)) {
+                       value += data_base;
+                       break;
+               }
+               dprintk(2, "Data-relative encoding %02X (%p,%p), but zero data base.",
+                       ptrType, *pLoc, end);
+               return 0;
        default:
+               dprintk(2, "Cannot adjust pointer type %02X (%p,%p).",
+                       ptrType, *pLoc, end);
                return 0;
        }
        if ((ptrType & DW_EH_PE_indirect)
-           && __get_user(value, (unsigned long *)value))
+           && probe_kernel_address((unsigned long *)value, value)) {
+               dprintk(1, "Cannot read indirect value %lx (%p,%p).",
+                       value, *pLoc, end);
                return 0;
+       }
        *pLoc = ptr.p8;
 
        return value;
@@ -594,7 +648,8 @@ static signed fde_pointer_type(const u32 *cie)
                        case 'P': {
                                        signed ptrType = *ptr++;
 
-                                       if (!read_pointer(&ptr, end, ptrType) || ptr > end)
+                                       if (!read_pointer(&ptr, end, ptrType, 0, 0)
+                                           || ptr > end)
                                                return -1;
                                }
                                break;
@@ -654,7 +709,8 @@ static int processCFI(const u8 *start,
                        case DW_CFA_nop:
                                break;
                        case DW_CFA_set_loc:
-                               if ((state->loc = read_pointer(&ptr.p8, end, ptrType)) == 0)
+                               state->loc = read_pointer(&ptr.p8, end, ptrType, 0, 0);
+                               if (state->loc == 0)
                                        result = 0;
                                break;
                        case DW_CFA_advance_loc1:
@@ -700,8 +756,10 @@ static int processCFI(const u8 *start,
                                        state->label = NULL;
                                        return 1;
                                }
-                               if (state->stackDepth >= MAX_STACK_DEPTH)
+                               if (state->stackDepth >= MAX_STACK_DEPTH) {
+                                       dprintk(1, "State stack overflow (%p,%p).", ptr.p8, end);
                                        return 0;
+                               }
                                state->stack[state->stackDepth++] = ptr.p8;
                                break;
                        case DW_CFA_restore_state:
@@ -716,8 +774,10 @@ static int processCFI(const u8 *start,
                                        result = processCFI(start, end, 0, ptrType, state);
                                        state->loc = loc;
                                        state->label = label;
-                               } else
+                               } else {
+                                       dprintk(1, "State stack underflow (%p,%p).", ptr.p8, end);
                                        return 0;
+                               }
                                break;
                        case DW_CFA_def_cfa:
                                state->cfa.reg = get_uleb128(&ptr.p8, end);
@@ -749,6 +809,7 @@ static int processCFI(const u8 *start,
                                break;
                        case DW_CFA_GNU_window_save:
                        default:
+                               dprintk(1, "Unrecognized CFI op %02X (%p,%p).", ptr.p8[-1], ptr.p8 - 1, end);
                                result = 0;
                                break;
                        }
@@ -764,12 +825,17 @@ static int processCFI(const u8 *start,
                        set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
                        break;
                }
-               if (ptr.p8 > end)
+               if (ptr.p8 > end) {
+                       dprintk(1, "Data overrun (%p,%p).", ptr.p8, end);
                        result = 0;
+               }
                if (result && targetLoc != 0 && targetLoc < state->loc)
                        return 1;
        }
 
+       if (result && ptr.p8 < end)
+               dprintk(1, "Data underrun (%p,%p).", ptr.p8, end);
+
        return result
           && ptr.p8 == end
           && (targetLoc == 0
@@ -786,7 +852,7 @@ int unwind(struct unwind_frame_info *frame)
 #define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
        const u32 *fde = NULL, *cie = NULL;
        const u8 *ptr = NULL, *end = NULL;
-       unsigned long pc = UNW_PC(frame) - frame->call_frame;
+       unsigned long pc = UNW_PC(frame) - frame->call_frame, sp;
        unsigned long startLoc = 0, endLoc = 0, cfa;
        unsigned i;
        signed ptrType = -1;
@@ -813,9 +879,9 @@ int unwind(struct unwind_frame_info *frame)
                        ptr = hdr + 4;
                        end = hdr + table->hdrsz;
                        if (tableSize
-                           && read_pointer(&ptr, end, hdr[1])
+                           && read_pointer(&ptr, end, hdr[1], 0, 0)
                               == (unsigned long)table->address
-                           && (i = read_pointer(&ptr, end, hdr[2])) > 0
+                           && (i = read_pointer(&ptr, end, hdr[2], 0, 0)) > 0
                            && i == (end - ptr) / (2 * tableSize)
                            && !((end - ptr) % (2 * tableSize))) {
                                do {
@@ -823,7 +889,8 @@ int unwind(struct unwind_frame_info *frame)
 
                                        startLoc = read_pointer(&cur,
                                                                cur + tableSize,
-                                                               hdr[3]);
+                                                               hdr[3], 0,
+                                                               (unsigned long)hdr);
                                        if (pc < startLoc)
                                                i /= 2;
                                        else {
@@ -834,13 +901,17 @@ int unwind(struct unwind_frame_info *frame)
                                if (i == 1
                                    && (startLoc = read_pointer(&ptr,
                                                                ptr + tableSize,
-                                                               hdr[3])) != 0
+                                                               hdr[3], 0,
+                                                               (unsigned long)hdr)) != 0
                                    && pc >= startLoc)
                                        fde = (void *)read_pointer(&ptr,
                                                                   ptr + tableSize,
-                                                                  hdr[3]);
+                                                                  hdr[3], 0,
+                                                                  (unsigned long)hdr);
                        }
                }
+               if(hdr && !fde)
+                       dprintk(3, "Binary lookup for %lx failed.", pc);
 
                if (fde != NULL) {
                        cie = cie_for_fde(fde, table);
@@ -851,17 +922,19 @@ int unwind(struct unwind_frame_info *frame)
                           && (ptrType = fde_pointer_type(cie)) >= 0
                           && read_pointer(&ptr,
                                           (const u8 *)(fde + 1) + *fde,
-                                          ptrType) == startLoc) {
+                                          ptrType, 0, 0) == startLoc) {
                                if (!(ptrType & DW_EH_PE_indirect))
                                        ptrType &= DW_EH_PE_FORM|DW_EH_PE_signed;
                                endLoc = startLoc
                                         + read_pointer(&ptr,
                                                        (const u8 *)(fde + 1) + *fde,
-                                                       ptrType);
+                                                       ptrType, 0, 0);
                                if(pc >= endLoc)
                                        fde = NULL;
                        } else
                                fde = NULL;
+                       if(!fde)
+                               dprintk(1, "Binary lookup result for %lx discarded.", pc);
                }
                if (fde == NULL) {
                        for (fde = table->address, tableSize = table->size;
@@ -881,7 +954,7 @@ int unwind(struct unwind_frame_info *frame)
                                ptr = (const u8 *)(fde + 2);
                                startLoc = read_pointer(&ptr,
                                                        (const u8 *)(fde + 1) + *fde,
-                                                       ptrType);
+                                                       ptrType, 0, 0);
                                if (!startLoc)
                                        continue;
                                if (!(ptrType & DW_EH_PE_indirect))
@@ -889,10 +962,12 @@ int unwind(struct unwind_frame_info *frame)
                                endLoc = startLoc
                                         + read_pointer(&ptr,
                                                        (const u8 *)(fde + 1) + *fde,
-                                                       ptrType);
+                                                       ptrType, 0, 0);
                                if (pc >= startLoc && pc < endLoc)
                                        break;
                        }
+                       if(!fde)
+                               dprintk(3, "Linear lookup for %lx failed.", pc);
                }
        }
        if (cie != NULL) {
@@ -926,6 +1001,8 @@ int unwind(struct unwind_frame_info *frame)
                        if (ptr >= end || *ptr)
                                cie = NULL;
                }
+               if(!cie)
+                       dprintk(1, "CIE unusable (%p,%p).", ptr, end);
                ++ptr;
        }
        if (cie != NULL) {
@@ -935,7 +1012,12 @@ int unwind(struct unwind_frame_info *frame)
                state.dataAlign = get_sleb128(&ptr, end);
                if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
                        cie = NULL;
-               else {
+               else if (UNW_PC(frame) % state.codeAlign
+                        || UNW_SP(frame) % sleb128abs(state.dataAlign)) {
+                       dprintk(1, "Input pointer(s) misaligned (%lx,%lx).",
+                               UNW_PC(frame), UNW_SP(frame));
+                       return -EPERM;
+               } else {
                        retAddrReg = state.version <= 1 ? *ptr++ : get_uleb128(&ptr, end);
                        /* skip augmentation */
                        if (((const char *)(cie + 2))[1] == 'z') {
@@ -949,6 +1031,8 @@ int unwind(struct unwind_frame_info *frame)
                           || reg_info[retAddrReg].width != sizeof(unsigned long))
                                cie = NULL;
                }
+               if(!cie)
+                       dprintk(1, "CIE validation failed (%p,%p).", ptr, end);
        }
        if (cie != NULL) {
                state.cieStart = ptr;
@@ -962,11 +1046,15 @@ int unwind(struct unwind_frame_info *frame)
                        if ((ptr += augSize) > end)
                                fde = NULL;
                }
+               if(!fde)
+                       dprintk(1, "FDE validation failed (%p,%p).", ptr, end);
        }
        if (cie == NULL || fde == NULL) {
 #ifdef CONFIG_FRAME_POINTER
                unsigned long top, bottom;
 
+               if ((UNW_SP(frame) | UNW_FP(frame)) % sizeof(unsigned long))
+                       return -EPERM;
                top = STACK_TOP(frame->task);
                bottom = STACK_BOTTOM(frame->task);
 # if FRAME_RETADDR_OFFSET < 0
@@ -982,18 +1070,19 @@ int unwind(struct unwind_frame_info *frame)
                        & (sizeof(unsigned long) - 1))) {
                        unsigned long link;
 
-                       if (!__get_user(link,
+                       if (!probe_kernel_address(
                                        (unsigned long *)(UNW_FP(frame)
-                                                         + FRAME_LINK_OFFSET))
+                                                         + FRAME_LINK_OFFSET),
+                                                 link)
 # if FRAME_RETADDR_OFFSET < 0
                           && link > bottom && link < UNW_FP(frame)
 # else
                           && link > UNW_FP(frame) && link < bottom
 # endif
                           && !(link & (sizeof(link) - 1))
-                          && !__get_user(UNW_PC(frame),
+                          && !probe_kernel_address(
                                          (unsigned long *)(UNW_FP(frame)
-                                                           + FRAME_RETADDR_OFFSET))) {
+                                                           + FRAME_RETADDR_OFFSET), UNW_PC(frame))) {
                                UNW_SP(frame) = UNW_FP(frame) + FRAME_RETADDR_OFFSET
 # if FRAME_RETADDR_OFFSET < 0
                                        -
@@ -1016,8 +1105,11 @@ int unwind(struct unwind_frame_info *frame)
           || state.regs[retAddrReg].where == Nowhere
           || state.cfa.reg >= ARRAY_SIZE(reg_info)
           || reg_info[state.cfa.reg].width != sizeof(unsigned long)
-          || state.cfa.offs % sizeof(unsigned long))
+          || FRAME_REG(state.cfa.reg, unsigned long) % sizeof(unsigned long)
+          || state.cfa.offs % sizeof(unsigned long)) {
+               dprintk(1, "Unusable unwind info (%p,%p).", ptr, end);
                return -EIO;
+       }
        /* update frame */
 #ifndef CONFIG_AS_CFI_SIGNAL_FRAME
        if(frame->call_frame
@@ -1036,10 +1128,14 @@ int unwind(struct unwind_frame_info *frame)
 #else
 # define CASES CASE(8); CASE(16); CASE(32); CASE(64)
 #endif
+       pc = UNW_PC(frame);
+       sp = UNW_SP(frame);
        for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
                if (REG_INVALID(i)) {
                        if (state.regs[i].where == Nowhere)
                                continue;
+                       dprintk(1, "Cannot restore register %u (%d).",
+                               i, state.regs[i].where);
                        return -EIO;
                }
                switch(state.regs[i].where) {
@@ -1048,8 +1144,11 @@ int unwind(struct unwind_frame_info *frame)
                case Register:
                        if (state.regs[i].value >= ARRAY_SIZE(reg_info)
                           || REG_INVALID(state.regs[i].value)
-                          || reg_info[i].width > reg_info[state.regs[i].value].width)
+                          || reg_info[i].width > reg_info[state.regs[i].value].width) {
+                               dprintk(1, "Cannot restore register %u from register %lu.",
+                                       i, state.regs[i].value);
                                return -EIO;
+                       }
                        switch(reg_info[state.regs[i].value].width) {
 #define CASE(n) \
                        case sizeof(u##n): \
@@ -1059,6 +1158,9 @@ int unwind(struct unwind_frame_info *frame)
                        CASES;
 #undef CASE
                        default:
+                               dprintk(1, "Unsupported register size %u (%lu).",
+                                       reg_info[state.regs[i].value].width,
+                                       state.regs[i].value);
                                return -EIO;
                        }
                        break;
@@ -1083,12 +1185,17 @@ int unwind(struct unwind_frame_info *frame)
                        CASES;
 #undef CASE
                        default:
+                               dprintk(1, "Unsupported register size %u (%u).",
+                                       reg_info[i].width, i);
                                return -EIO;
                        }
                        break;
                case Value:
-                       if (reg_info[i].width != sizeof(unsigned long))
+                       if (reg_info[i].width != sizeof(unsigned long)) {
+                               dprintk(1, "Unsupported value size %u (%u).",
+                                       reg_info[i].width, i);
                                return -EIO;
+                       }
                        FRAME_REG(i, unsigned long) = cfa + state.regs[i].value
                                                            * state.dataAlign;
                        break;
@@ -1100,15 +1207,20 @@ int unwind(struct unwind_frame_info *frame)
                                    % sizeof(unsigned long)
                                    || addr < startLoc
                                    || addr + sizeof(unsigned long) < addr
-                                   || addr + sizeof(unsigned long) > endLoc)
+                                   || addr + sizeof(unsigned long) > endLoc) {
+                                       dprintk(1, "Bad memory location %lx (%lx).",
+                                               addr, state.regs[i].value);
                                        return -EIO;
+                               }
                                switch(reg_info[i].width) {
 #define CASE(n)     case sizeof(u##n): \
-                                       __get_user(FRAME_REG(i, u##n), (u##n *)addr); \
+                                       probe_kernel_address((u##n *)addr, FRAME_REG(i, u##n)); \
                                        break
                                CASES;
 #undef CASE
                                default:
+                                       dprintk(1, "Unsupported memory size %u (%u).",
+                                               reg_info[i].width, i);
                                        return -EIO;
                                }
                        }
@@ -1116,6 +1228,17 @@ int unwind(struct unwind_frame_info *frame)
                }
        }
 
+       if (UNW_PC(frame) % state.codeAlign
+           || UNW_SP(frame) % sleb128abs(state.dataAlign)) {
+               dprintk(1, "Output pointer(s) misaligned (%lx,%lx).",
+                       UNW_PC(frame), UNW_SP(frame));
+               return -EIO;
+       }
+       if (pc == UNW_PC(frame) && sp == UNW_SP(frame)) {
+               dprintk(1, "No progress (%lx,%lx).", pc, sp);
+               return -EIO;
+       }
+
        return 0;
 #undef CASES
 #undef FRAME_REG