From 6d03a247468059b0e59c821ef39e6762d4d6fc30 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 19 Jun 2024 23:00:51 +0200 Subject: Merging upstream version 6.9.2. Signed-off-by: Daniel Baumann --- arch/loongarch/kernel/unwind_orc.c | 528 +++++++++++++++++++++++++++++++++++++ 1 file changed, 528 insertions(+) create mode 100644 arch/loongarch/kernel/unwind_orc.c (limited to 'arch/loongarch/kernel/unwind_orc.c') diff --git a/arch/loongarch/kernel/unwind_orc.c b/arch/loongarch/kernel/unwind_orc.c new file mode 100644 index 0000000000..b257228763 --- /dev/null +++ b/arch/loongarch/kernel/unwind_orc.c @@ -0,0 +1,528 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +ORC_HEADER; + +#define orc_warn(fmt, ...) \ + printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__) + +extern int __start_orc_unwind_ip[]; +extern int __stop_orc_unwind_ip[]; +extern struct orc_entry __start_orc_unwind[]; +extern struct orc_entry __stop_orc_unwind[]; + +static bool orc_init __ro_after_init; +static unsigned int lookup_num_blocks __ro_after_init; + +/* Fake frame pointer entry -- used as a fallback for generated code */ +static struct orc_entry orc_fp_entry = { + .sp_reg = ORC_REG_FP, + .sp_offset = 16, + .fp_reg = ORC_REG_PREV_SP, + .fp_offset = -16, + .ra_reg = ORC_REG_PREV_SP, + .ra_offset = -8, + .type = ORC_TYPE_CALL +}; + +/* + * If we crash with IP==0, the last successfully executed instruction + * was probably an indirect function call with a NULL function pointer, + * and we don't have unwind information for NULL. + * This hardcoded ORC entry for IP==0 allows us to unwind from a NULL function + * pointer into its parent and then continue normally from there. + */ +static struct orc_entry orc_null_entry = { + .sp_reg = ORC_REG_SP, + .sp_offset = sizeof(long), + .fp_reg = ORC_REG_UNDEFINED, + .type = ORC_TYPE_CALL +}; + +static inline unsigned long orc_ip(const int *ip) +{ + return (unsigned long)ip + *ip; +} + +static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table, + unsigned int num_entries, unsigned long ip) +{ + int *first = ip_table; + int *mid = first, *found = first; + int *last = ip_table + num_entries - 1; + + if (!num_entries) + return NULL; + + /* + * Do a binary range search to find the rightmost duplicate of a given + * starting address. Some entries are section terminators which are + * "weak" entries for ensuring there are no gaps. They should be + * ignored when they conflict with a real entry. + */ + while (first <= last) { + mid = first + ((last - first) / 2); + + if (orc_ip(mid) <= ip) { + found = mid; + first = mid + 1; + } else + last = mid - 1; + } + + return u_table + (found - ip_table); +} + +#ifdef CONFIG_MODULES +static struct orc_entry *orc_module_find(unsigned long ip) +{ + struct module *mod; + + mod = __module_address(ip); + if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip) + return NULL; + + return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind, mod->arch.num_orcs, ip); +} +#else +static struct orc_entry *orc_module_find(unsigned long ip) +{ + return NULL; +} +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE +static struct orc_entry *orc_find(unsigned long ip); + +/* + * Ftrace dynamic trampolines do not have orc entries of their own. + * But they are copies of the ftrace entries that are static and + * defined in ftrace_*.S, which do have orc entries. + * + * If the unwinder comes across a ftrace trampoline, then find the + * ftrace function that was used to create it, and use that ftrace + * function's orc entry, as the placement of the return code in + * the stack will be identical. + */ +static struct orc_entry *orc_ftrace_find(unsigned long ip) +{ + struct ftrace_ops *ops; + unsigned long tramp_addr, offset; + + ops = ftrace_ops_trampoline(ip); + if (!ops) + return NULL; + + /* Set tramp_addr to the start of the code copied by the trampoline */ + if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) + tramp_addr = (unsigned long)ftrace_regs_caller; + else + tramp_addr = (unsigned long)ftrace_caller; + + /* Now place tramp_addr to the location within the trampoline ip is at */ + offset = ip - ops->trampoline; + tramp_addr += offset; + + /* Prevent unlikely recursion */ + if (ip == tramp_addr) + return NULL; + + return orc_find(tramp_addr); +} +#else +static struct orc_entry *orc_ftrace_find(unsigned long ip) +{ + return NULL; +} +#endif + +static struct orc_entry *orc_find(unsigned long ip) +{ + static struct orc_entry *orc; + + if (ip == 0) + return &orc_null_entry; + + /* For non-init vmlinux addresses, use the fast lookup table: */ + if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) { + unsigned int idx, start, stop; + + idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE; + + if (unlikely((idx >= lookup_num_blocks-1))) { + orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%pB\n", + idx, lookup_num_blocks, (void *)ip); + return NULL; + } + + start = orc_lookup[idx]; + stop = orc_lookup[idx + 1] + 1; + + if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) || + (__start_orc_unwind + stop > __stop_orc_unwind))) { + orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%pB\n", + idx, lookup_num_blocks, start, stop, (void *)ip); + return NULL; + } + + return __orc_find(__start_orc_unwind_ip + start, + __start_orc_unwind + start, stop - start, ip); + } + + /* vmlinux .init slow lookup: */ + if (is_kernel_inittext(ip)) + return __orc_find(__start_orc_unwind_ip, __start_orc_unwind, + __stop_orc_unwind_ip - __start_orc_unwind_ip, ip); + + /* Module lookup: */ + orc = orc_module_find(ip); + if (orc) + return orc; + + return orc_ftrace_find(ip); +} + +#ifdef CONFIG_MODULES + +static DEFINE_MUTEX(sort_mutex); +static int *cur_orc_ip_table = __start_orc_unwind_ip; +static struct orc_entry *cur_orc_table = __start_orc_unwind; + +static void orc_sort_swap(void *_a, void *_b, int size) +{ + int delta = _b - _a; + int *a = _a, *b = _b, tmp; + struct orc_entry *orc_a, *orc_b; + + /* Swap the .orc_unwind_ip entries: */ + tmp = *a; + *a = *b + delta; + *b = tmp - delta; + + /* Swap the corresponding .orc_unwind entries: */ + orc_a = cur_orc_table + (a - cur_orc_ip_table); + orc_b = cur_orc_table + (b - cur_orc_ip_table); + swap(*orc_a, *orc_b); +} + +static int orc_sort_cmp(const void *_a, const void *_b) +{ + const int *a = _a, *b = _b; + unsigned long a_val = orc_ip(a); + unsigned long b_val = orc_ip(b); + struct orc_entry *orc_a; + + if (a_val > b_val) + return 1; + if (a_val < b_val) + return -1; + + /* + * The "weak" section terminator entries need to always be first + * to ensure the lookup code skips them in favor of real entries. + * These terminator entries exist to handle any gaps created by + * whitelisted .o files which didn't get objtool generation. + */ + orc_a = cur_orc_table + (a - cur_orc_ip_table); + + return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1; +} + +void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size, + void *_orc, size_t orc_size) +{ + int *orc_ip = _orc_ip; + struct orc_entry *orc = _orc; + unsigned int num_entries = orc_ip_size / sizeof(int); + + WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 || + orc_size % sizeof(*orc) != 0 || + num_entries != orc_size / sizeof(*orc)); + + /* + * The 'cur_orc_*' globals allow the orc_sort_swap() callback to + * associate an .orc_unwind_ip table entry with its corresponding + * .orc_unwind entry so they can both be swapped. + */ + mutex_lock(&sort_mutex); + cur_orc_ip_table = orc_ip; + cur_orc_table = orc; + sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap); + mutex_unlock(&sort_mutex); + + mod->arch.orc_unwind_ip = orc_ip; + mod->arch.orc_unwind = orc; + mod->arch.num_orcs = num_entries; +} +#endif + +void __init unwind_init(void) +{ + int i; + size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind; + size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip; + size_t num_entries = orc_ip_size / sizeof(int); + struct orc_entry *orc; + + if (!num_entries || orc_ip_size % sizeof(int) != 0 || + orc_size % sizeof(struct orc_entry) != 0 || + num_entries != orc_size / sizeof(struct orc_entry)) { + orc_warn("WARNING: Bad or missing .orc_unwind table. Disabling unwinder.\n"); + return; + } + + /* + * Note, the orc_unwind and orc_unwind_ip tables were already + * sorted at build time via the 'sorttable' tool. + * It's ready for binary search straight away, no need to sort it. + */ + + /* Initialize the fast lookup table: */ + lookup_num_blocks = orc_lookup_end - orc_lookup; + for (i = 0; i < lookup_num_blocks-1; i++) { + orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, + num_entries, LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i)); + if (!orc) { + orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n"); + return; + } + + orc_lookup[i] = orc - __start_orc_unwind; + } + + /* Initialize the ending block: */ + orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries, LOOKUP_STOP_IP); + if (!orc) { + orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n"); + return; + } + orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind; + + orc_init = true; +} + +static inline bool on_stack(struct stack_info *info, unsigned long addr, size_t len) +{ + unsigned long begin = info->begin; + unsigned long end = info->end; + + return (info->type != STACK_TYPE_UNKNOWN && + addr >= begin && addr < end && addr + len > begin && addr + len <= end); +} + +static bool stack_access_ok(struct unwind_state *state, unsigned long addr, size_t len) +{ + struct stack_info *info = &state->stack_info; + + if (on_stack(info, addr, len)) + return true; + + return !get_stack_info(addr, state->task, info) && on_stack(info, addr, len); +} + +unsigned long unwind_get_return_address(struct unwind_state *state) +{ + return __unwind_get_return_address(state); +} +EXPORT_SYMBOL_GPL(unwind_get_return_address); + +void unwind_start(struct unwind_state *state, struct task_struct *task, + struct pt_regs *regs) +{ + __unwind_start(state, task, regs); + state->type = UNWINDER_ORC; + if (!unwind_done(state) && !__kernel_text_address(state->pc)) + unwind_next_frame(state); +} +EXPORT_SYMBOL_GPL(unwind_start); + +static bool is_entry_func(unsigned long addr) +{ + extern u32 kernel_entry; + extern u32 kernel_entry_end; + + return addr >= (unsigned long)&kernel_entry && addr < (unsigned long)&kernel_entry_end; +} + +static inline unsigned long bt_address(unsigned long ra) +{ + extern unsigned long eentry; + + if (__kernel_text_address(ra)) + return ra; + + if (__module_text_address(ra)) + return ra; + + if (ra >= eentry && ra < eentry + EXCCODE_INT_END * VECSIZE) { + unsigned long func; + unsigned long type = (ra - eentry) / VECSIZE; + unsigned long offset = (ra - eentry) % VECSIZE; + + switch (type) { + case 0 ... EXCCODE_INT_START - 1: + func = (unsigned long)exception_table[type]; + break; + case EXCCODE_INT_START ... EXCCODE_INT_END: + func = (unsigned long)handle_vint; + break; + default: + func = (unsigned long)handle_reserved; + break; + } + + return func + offset; + } + + return ra; +} + +bool unwind_next_frame(struct unwind_state *state) +{ + unsigned long *p, pc; + struct pt_regs *regs; + struct orc_entry *orc; + struct stack_info *info = &state->stack_info; + + if (unwind_done(state)) + return false; + + /* Don't let modules unload while we're reading their ORC data. */ + preempt_disable(); + + if (is_entry_func(state->pc)) + goto end; + + orc = orc_find(state->pc); + if (!orc) { + /* + * As a fallback, try to assume this code uses a frame pointer. + * This is useful for generated code, like BPF, which ORC + * doesn't know about. This is just a guess, so the rest of + * the unwind is no longer considered reliable. + */ + orc = &orc_fp_entry; + state->error = true; + } else { + if (orc->type == ORC_TYPE_UNDEFINED) + goto err; + + if (orc->type == ORC_TYPE_END_OF_STACK) + goto end; + } + + switch (orc->sp_reg) { + case ORC_REG_SP: + if (info->type == STACK_TYPE_IRQ && state->sp == info->end) + orc->type = ORC_TYPE_REGS; + else + state->sp = state->sp + orc->sp_offset; + break; + case ORC_REG_FP: + state->sp = state->fp; + break; + default: + orc_warn("unknown SP base reg %d at %pB\n", orc->sp_reg, (void *)state->pc); + goto err; + } + + switch (orc->fp_reg) { + case ORC_REG_PREV_SP: + p = (unsigned long *)(state->sp + orc->fp_offset); + if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long))) + goto err; + + state->fp = *p; + break; + case ORC_REG_UNDEFINED: + /* Nothing. */ + break; + default: + orc_warn("unknown FP base reg %d at %pB\n", orc->fp_reg, (void *)state->pc); + goto err; + } + + switch (orc->type) { + case ORC_TYPE_CALL: + if (orc->ra_reg == ORC_REG_PREV_SP) { + p = (unsigned long *)(state->sp + orc->ra_offset); + if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long))) + goto err; + + pc = unwind_graph_addr(state, *p, state->sp); + pc -= LOONGARCH_INSN_SIZE; + } else if (orc->ra_reg == ORC_REG_UNDEFINED) { + if (!state->ra || state->ra == state->pc) + goto err; + + pc = unwind_graph_addr(state, state->ra, state->sp); + pc -= LOONGARCH_INSN_SIZE; + state->ra = 0; + } else { + orc_warn("unknown ra base reg %d at %pB\n", orc->ra_reg, (void *)state->pc); + goto err; + } + break; + case ORC_TYPE_REGS: + if (info->type == STACK_TYPE_IRQ && state->sp == info->end) + regs = (struct pt_regs *)info->next_sp; + else + regs = (struct pt_regs *)state->sp; + + if (!stack_access_ok(state, (unsigned long)regs, sizeof(*regs))) + goto err; + + if ((info->end == (unsigned long)regs + sizeof(*regs)) && + !regs->regs[3] && !regs->regs[1]) + goto end; + + if (user_mode(regs)) + goto end; + + pc = regs->csr_era; + if (!__kernel_text_address(pc)) + goto err; + + state->sp = regs->regs[3]; + state->ra = regs->regs[1]; + state->fp = regs->regs[22]; + get_stack_info(state->sp, state->task, info); + + break; + default: + orc_warn("unknown .orc_unwind entry type %d at %pB\n", orc->type, (void *)state->pc); + goto err; + } + + state->pc = bt_address(pc); + if (!state->pc) { + pr_err("cannot find unwind pc at %pK\n", (void *)pc); + goto err; + } + + if (!__kernel_text_address(state->pc)) + goto err; + + preempt_enable(); + return true; + +err: + state->error = true; + +end: + preempt_enable(); + state->stack_info.type = STACK_TYPE_UNKNOWN; + return false; +} +EXPORT_SYMBOL_GPL(unwind_next_frame); -- cgit v1.2.3