diff options
Diffstat (limited to 'kernel/unwind.c')
| -rw-r--r-- | kernel/unwind.c | 318 |
1 files changed, 279 insertions, 39 deletions
diff --git a/kernel/unwind.c b/kernel/unwind.c index 2e2368607aa..f7e50d16dbf 100644 --- a/kernel/unwind.c +++ b/kernel/unwind.c @@ -11,13 +11,15 @@ #include <linux/unwind.h> #include <linux/module.h> -#include <linux/delay.h> +#include <linux/bootmem.h> +#include <linux/sort.h> #include <linux/stop_machine.h> #include <asm/sections.h> #include <asm/uaccess.h> #include <asm/unaligned.h> extern char __start_unwind[], __end_unwind[]; +extern const u8 __start_unwind_hdr[], __end_unwind_hdr[]; #define MAX_STACK_DEPTH 8 @@ -100,6 +102,8 @@ static struct unwind_table { } core, init; const void *address; unsigned long size; + const unsigned char *header; + unsigned long hdrsz; struct unwind_table *link; const char *name; } root_table; @@ -145,6 +149,10 @@ static struct unwind_table *find_table(unsigned long pc) return table; } +static unsigned long read_pointer(const u8 **pLoc, + const void *end, + signed ptrType); + static void init_unwind_table(struct unwind_table *table, const char *name, const void *core_start, @@ -152,14 +160,30 @@ static void init_unwind_table(struct unwind_table *table, const void *init_start, unsigned long init_size, const void *table_start, - unsigned long table_size) + unsigned long table_size, + const u8 *header_start, + unsigned long header_size) { + const u8 *ptr = header_start + 4; + const u8 *end = header_start + header_size; + table->core.pc = (unsigned long)core_start; table->core.range = core_size; table->init.pc = (unsigned long)init_start; table->init.range = init_size; table->address = table_start; table->size = table_size; + /* 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) + header_start = NULL; + table->hdrsz = header_size; + smp_wmb(); + table->header = header_start; table->link = NULL; table->name = name; } @@ -169,7 +193,143 @@ void __init unwind_init(void) init_unwind_table(&root_table, "kernel", _text, _end - _text, NULL, 0, - __start_unwind, __end_unwind - __start_unwind); + __start_unwind, __end_unwind - __start_unwind, + __start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr); +} + +static const u32 bad_cie, not_fde; +static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *); +static signed fde_pointer_type(const u32 *cie); + +struct eh_frame_hdr_table_entry { + unsigned long start, fde; +}; + +static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2) +{ + const struct eh_frame_hdr_table_entry *e1 = p1; + const struct eh_frame_hdr_table_entry *e2 = p2; + + return (e1->start > e2->start) - (e1->start < e2->start); +} + +static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size) +{ + struct eh_frame_hdr_table_entry *e1 = p1; + struct eh_frame_hdr_table_entry *e2 = p2; + unsigned long v; + + v = e1->start; + e1->start = e2->start; + e2->start = v; + v = e1->fde; + e1->fde = e2->fde; + e2->fde = v; +} + +static void __init setup_unwind_table(struct unwind_table *table, + void *(*alloc)(unsigned long)) +{ + const u8 *ptr; + unsigned long tableSize = table->size, hdrSize; + unsigned n; + const u32 *fde; + struct { + u8 version; + u8 eh_frame_ptr_enc; + u8 fde_count_enc; + u8 table_enc; + unsigned long eh_frame_ptr; + unsigned int fde_count; + struct eh_frame_hdr_table_entry table[]; + } __attribute__((__packed__)) *header; + + if (table->header) + return; + + if (table->hdrsz) + printk(KERN_WARNING ".eh_frame_hdr for '%s' present but unusable\n", + table->name); + + if (tableSize & (sizeof(*fde) - 1)) + return; + + for (fde = table->address, n = 0; + tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde; + tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { + const u32 *cie = cie_for_fde(fde, table); + signed ptrType; + + if (cie == ¬_fde) + continue; + if (cie == NULL + || cie == &bad_cie + || (ptrType = fde_pointer_type(cie)) < 0) + return; + ptr = (const u8 *)(fde + 2); + if (!read_pointer(&ptr, + (const u8 *)(fde + 1) + *fde, + ptrType)) + return; + ++n; + } + + if (tableSize || !n) + return; + + hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int) + + 2 * n * sizeof(unsigned long); + header = alloc(hdrSize); + if (!header) + return; + header->version = 1; + header->eh_frame_ptr_enc = DW_EH_PE_abs|DW_EH_PE_native; + header->fde_count_enc = DW_EH_PE_abs|DW_EH_PE_data4; + header->table_enc = DW_EH_PE_abs|DW_EH_PE_native; + put_unaligned((unsigned long)table->address, &header->eh_frame_ptr); + BUILD_BUG_ON(offsetof(typeof(*header), fde_count) + % __alignof(typeof(header->fde_count))); + header->fde_count = n; + + BUILD_BUG_ON(offsetof(typeof(*header), table) + % __alignof(typeof(*header->table))); + for (fde = table->address, tableSize = table->size, n = 0; + tableSize; + tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { + const u32 *cie = fde + 1 - fde[1] / sizeof(*fde); + + if (!fde[1]) + continue; /* this is a CIE */ + ptr = (const u8 *)(fde + 2); + header->table[n].start = read_pointer(&ptr, + (const u8 *)(fde + 1) + *fde, + fde_pointer_type(cie)); + header->table[n].fde = (unsigned long)fde; + ++n; + } + WARN_ON(n != header->fde_count); + + sort(header->table, + n, + sizeof(*header->table), + cmp_eh_frame_hdr_table_entries, + swap_eh_frame_hdr_table_entries); + + table->hdrsz = hdrSize; + smp_wmb(); + table->header = (const void *)header; +} + +static void *__init balloc(unsigned long sz) +{ + return __alloc_bootmem_nopanic(sz, + sizeof(unsigned int), + __pa(MAX_DMA_ADDRESS)); +} + +void __init unwind_setup(void) +{ + setup_unwind_table(&root_table, balloc); } #ifdef CONFIG_MODULES @@ -193,7 +353,8 @@ void *unwind_add_table(struct module *module, init_unwind_table(table, module->name, module->module_core, module->core_size, module->module_init, module->init_size, - table_start, table_size); + table_start, table_size, + NULL, 0); if (last_table) last_table->link = table; @@ -303,6 +464,26 @@ static sleb128_t get_sleb128(const u8 **pcur, const u8 *end) return value; } +static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table) +{ + const u32 *cie; + + if (!*fde || (*fde & (sizeof(*fde) - 1))) + return &bad_cie; + if (!fde[1]) + return ¬_fde; /* this is a CIE */ + if ((fde[1] & (sizeof(*fde) - 1)) + || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address) + return NULL; /* this is not a valid FDE */ + cie = fde + 1 - fde[1] / sizeof(*fde); + if (*cie <= sizeof(*cie) + 4 + || *cie >= fde[1] - sizeof(*fde) + || (*cie & (sizeof(*cie) - 1)) + || cie[1]) + return NULL; /* this is not a (valid) CIE */ + return cie; +} + static unsigned long read_pointer(const u8 **pLoc, const void *end, signed ptrType) @@ -610,49 +791,108 @@ int unwind(struct unwind_frame_info *frame) unsigned i; signed ptrType = -1; uleb128_t retAddrReg = 0; - struct unwind_table *table; + const struct unwind_table *table; struct unwind_state state; if (UNW_PC(frame) == 0) return -EINVAL; if ((table = find_table(pc)) != NULL && !(table->size & (sizeof(*fde) - 1))) { - unsigned long tableSize = table->size; - - for (fde = table->address; - tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde; - tableSize -= sizeof(*fde) + *fde, - fde += 1 + *fde / sizeof(*fde)) { - if (!*fde || (*fde & (sizeof(*fde) - 1))) - break; - if (!fde[1]) - continue; /* this is a CIE */ - if ((fde[1] & (sizeof(*fde) - 1)) - || fde[1] > (unsigned long)(fde + 1) - - (unsigned long)table->address) - continue; /* this is not a valid FDE */ - cie = fde + 1 - fde[1] / sizeof(*fde); - if (*cie <= sizeof(*cie) + 4 - || *cie >= fde[1] - sizeof(*fde) - || (*cie & (sizeof(*cie) - 1)) - || cie[1] - || (ptrType = fde_pointer_type(cie)) < 0) { - cie = NULL; /* this is not a (valid) CIE */ - continue; + const u8 *hdr = table->header; + unsigned long tableSize; + + smp_rmb(); + if (hdr && hdr[0] == 1) { + switch(hdr[3] & DW_EH_PE_FORM) { + case DW_EH_PE_native: tableSize = sizeof(unsigned long); break; + case DW_EH_PE_data2: tableSize = 2; break; + case DW_EH_PE_data4: tableSize = 4; break; + case DW_EH_PE_data8: tableSize = 8; break; + default: tableSize = 0; break; + } + ptr = hdr + 4; + end = hdr + table->hdrsz; + if (tableSize + && read_pointer(&ptr, end, hdr[1]) + == (unsigned long)table->address + && (i = read_pointer(&ptr, end, hdr[2])) > 0 + && i == (end - ptr) / (2 * tableSize) + && !((end - ptr) % (2 * tableSize))) { + do { + const u8 *cur = ptr + (i / 2) * (2 * tableSize); + + startLoc = read_pointer(&cur, + cur + tableSize, + hdr[3]); + if (pc < startLoc) + i /= 2; + else { + ptr = cur - tableSize; + i = (i + 1) / 2; + } + } while (startLoc && i > 1); + if (i == 1 + && (startLoc = read_pointer(&ptr, + ptr + tableSize, + hdr[3])) != 0 + && pc >= startLoc) + fde = (void *)read_pointer(&ptr, + ptr + tableSize, + hdr[3]); } + } + + if (fde != NULL) { + cie = cie_for_fde(fde, table); ptr = (const u8 *)(fde + 2); - startLoc = read_pointer(&ptr, - (const u8 *)(fde + 1) + *fde, - ptrType); - endLoc = startLoc - + read_pointer(&ptr, - (const u8 *)(fde + 1) + *fde, - ptrType & DW_EH_PE_indirect - ? ptrType - : ptrType & (DW_EH_PE_FORM|DW_EH_PE_signed)); - if (pc >= startLoc && pc < endLoc) - break; - cie = NULL; + if(cie != NULL + && cie != &bad_cie + && cie != ¬_fde + && (ptrType = fde_pointer_type(cie)) >= 0 + && read_pointer(&ptr, + (const u8 *)(fde + 1) + *fde, + ptrType) == 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); + if(pc >= endLoc) + fde = NULL; + } else + fde = NULL; + } + if (fde == NULL) { + for (fde = table->address, tableSize = table->size; + cie = NULL, tableSize > sizeof(*fde) + && tableSize - sizeof(*fde) >= *fde; + tableSize -= sizeof(*fde) + *fde, + fde += 1 + *fde / sizeof(*fde)) { + cie = cie_for_fde(fde, table); + if (cie == &bad_cie) { + cie = NULL; + break; + } + if (cie == NULL + || cie == ¬_fde + || (ptrType = fde_pointer_type(cie)) < 0) + continue; + ptr = (const u8 *)(fde + 2); + startLoc = read_pointer(&ptr, + (const u8 *)(fde + 1) + *fde, + ptrType); + if (!startLoc) + continue; + 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); + if (pc >= startLoc && pc < endLoc) + break; + } } } if (cie != NULL) { |