Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3) #include <linux/sched/task.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4) #include <linux/sched/task_stack.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5) #include <linux/interrupt.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) #include <asm/sections.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include <asm/ptrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <asm/bitops.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <asm/stacktrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <asm/unwind.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #define FRAME_HEADER_SIZE (sizeof(long) * 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) unsigned long unwind_get_return_address(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) 	if (unwind_done(state))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 	return __kernel_text_address(state->ip) ? state->ip : 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) EXPORT_SYMBOL_GPL(unwind_get_return_address);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 	if (unwind_done(state))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	return state->regs ? &state->regs->ip : state->bp + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) static void unwind_dump(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	static bool dumped_before = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	bool prev_zero, zero = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	unsigned long word, *sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	struct stack_info stack_info = {0};
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 	unsigned long visit_mask = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 	if (dumped_before)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	dumped_before = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	printk_deferred("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 			state->stack_info.type, state->stack_info.next_sp,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 			state->stack_mask, state->graph_idx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	for (sp = PTR_ALIGN(state->orig_sp, sizeof(long)); sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	     sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 		if (get_stack_info(sp, state->task, &stack_info, &visit_mask))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 		for (; sp < stack_info.end; sp++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 			word = READ_ONCE_NOCHECK(*sp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 			prev_zero = zero;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 			zero = word == 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 			if (zero) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 				if (!prev_zero)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 					printk_deferred("%p: %0*x ...\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 							sp, BITS_PER_LONG/4, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 				continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 			printk_deferred("%p: %0*lx (%pB)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 					sp, BITS_PER_LONG/4, word, (void *)word);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) static bool in_entry_code(unsigned long ip)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	char *addr = (char *)ip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	return addr >= __entry_text_start && addr < __entry_text_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) static inline unsigned long *last_frame(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	return (unsigned long *)task_pt_regs(state->task) - 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) static bool is_last_frame(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	return state->bp == last_frame(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) #ifdef CONFIG_X86_32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) #define GCC_REALIGN_WORDS 3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) #define GCC_REALIGN_WORDS 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) static inline unsigned long *last_aligned_frame(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	return last_frame(state) - GCC_REALIGN_WORDS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) static bool is_last_aligned_frame(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 	unsigned long *last_bp = last_frame(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	unsigned long *aligned_bp = last_aligned_frame(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	 * GCC can occasionally decide to realign the stack pointer and change
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	 * the offset of the stack frame in the prologue of a function called
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	 * by head/entry code.  Examples:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	 * <start_secondary>:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	 *      push   %edi
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	 *      lea    0x8(%esp),%edi
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	 *      and    $0xfffffff8,%esp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	 *      pushl  -0x4(%edi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	 *      push   %ebp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	 *      mov    %esp,%ebp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	 * <x86_64_start_kernel>:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	 *      lea    0x8(%rsp),%r10
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	 *      and    $0xfffffffffffffff0,%rsp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	 *      pushq  -0x8(%r10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	 *      push   %rbp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	 *      mov    %rsp,%rbp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	 * After aligning the stack, it pushes a duplicate copy of the return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	 * address before pushing the frame pointer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	return (state->bp == aligned_bp && *(aligned_bp + 1) == *(last_bp + 1));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) static bool is_last_ftrace_frame(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	unsigned long *last_bp = last_frame(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	unsigned long *last_ftrace_bp = last_bp - 3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	 * When unwinding from an ftrace handler of a function called by entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	 * code, the stack layout of the last frame is:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	 *   bp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	 *   parent ret addr
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	 *   bp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	 *   function ret addr
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 	 *   parent ret addr
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	 *   pt_regs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	 *   -----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	return (state->bp == last_ftrace_bp &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 		*state->bp == *(state->bp + 2) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 		*(state->bp + 1) == *(state->bp + 4));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) static bool is_last_task_frame(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	return is_last_frame(state) || is_last_aligned_frame(state) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	       is_last_ftrace_frame(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161)  * This determines if the frame pointer actually contains an encoded pointer to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162)  * pt_regs on the stack.  See ENCODE_FRAME_POINTER.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) #ifdef CONFIG_X86_64
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) static struct pt_regs *decode_frame_pointer(unsigned long *bp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	unsigned long regs = (unsigned long)bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	if (!(regs & 0x1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	return (struct pt_regs *)(regs & ~0x1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) static struct pt_regs *decode_frame_pointer(unsigned long *bp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	unsigned long regs = (unsigned long)bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	if (regs & 0x80000000)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	return (struct pt_regs *)(regs | 0x80000000);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) static bool update_stack_state(struct unwind_state *state,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 			       unsigned long *next_bp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	struct stack_info *info = &state->stack_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	enum stack_type prev_type = info->type;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	struct pt_regs *regs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	unsigned long *frame, *prev_frame_end, *addr_p, addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	size_t len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	if (state->regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 		prev_frame_end = (void *)state->regs + sizeof(*state->regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 		prev_frame_end = (void *)state->bp + FRAME_HEADER_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	/* Is the next frame pointer an encoded pointer to pt_regs? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	regs = decode_frame_pointer(next_bp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	if (regs) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 		frame = (unsigned long *)regs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 		len = sizeof(*regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		state->got_irq = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 		frame = next_bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 		len = FRAME_HEADER_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	 * If the next bp isn't on the current stack, switch to the next one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	 * We may have to traverse multiple stacks to deal with the possibility
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	 * that info->next_sp could point to an empty stack and the next bp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 	 * could be on a subsequent stack.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	while (!on_stack(info, frame, len))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 		if (get_stack_info(info->next_sp, state->task, info,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 				   &state->stack_mask))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 			return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	/* Make sure it only unwinds up and doesn't overlap the prev frame: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	if (state->orig_sp && state->stack_info.type == prev_type &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	    frame < prev_frame_end)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 	/* Move state to the next frame: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 	if (regs) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 		state->regs = regs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 		state->bp = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 		state->bp = next_bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 		state->regs = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 	/* Save the return address: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 	if (state->regs && user_mode(state->regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 		state->ip = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 		addr_p = unwind_get_return_address_ptr(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 		addr = READ_ONCE_TASK_STACK(state->task, *addr_p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 		state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 						  addr, addr_p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	/* Save the original stack pointer for unwind_dump(): */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	if (!state->orig_sp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 		state->orig_sp = frame;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) bool unwind_next_frame(struct unwind_state *state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	struct pt_regs *regs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	unsigned long *next_bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	if (unwind_done(state))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	/* Have we reached the end? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	if (state->regs && user_mode(state->regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 		goto the_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 	if (is_last_task_frame(state)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 		regs = task_pt_regs(state->task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 		 * kthreads (other than the boot CPU's idle thread) have some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 		 * partial regs at the end of their stack which were placed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 		 * there by copy_thread().  But the regs don't have any
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 		 * useful information, so we can skip them.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 		 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 		 * This user_mode() check is slightly broader than a PF_KTHREAD
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 		 * check because it also catches the awkward situation where a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 		 * newly forked kthread transitions into a user task by calling
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 		 * kernel_execve(), which eventually clears PF_KTHREAD.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 		if (!user_mode(regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 			goto the_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 		 * We're almost at the end, but not quite: there's still the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 		 * syscall regs frame.  Entry code doesn't encode the regs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 		 * pointer for syscalls, so we have to set it manually.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 		state->regs = regs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 		state->bp = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 		state->ip = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 	/* Get the next frame pointer: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	if (state->next_bp) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 		next_bp = state->next_bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 		state->next_bp = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 	} else if (state->regs) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 		next_bp = (unsigned long *)state->regs->bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 		next_bp = (unsigned long *)READ_ONCE_TASK_STACK(state->task, *state->bp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 	/* Move to the next frame if it's safe: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 	if (!update_stack_state(state, next_bp))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 		goto bad_address;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) bad_address:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 	state->error = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 	 * When unwinding a non-current task, the task might actually be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 	 * running on another CPU, in which case it could be modifying its
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	 * stack while we're reading it.  This is generally not a problem and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	 * can be ignored as long as the caller understands that unwinding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 	 * another task will not always succeed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 	if (state->task != current)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 		goto the_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 	 * Don't warn if the unwinder got lost due to an interrupt in entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 	 * code or in the C handler before the first frame pointer got set up:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	if (state->got_irq && in_entry_code(state->ip))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 		goto the_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 	if (state->regs &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	    state->regs->sp >= (unsigned long)last_aligned_frame(state) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 	    state->regs->sp < (unsigned long)task_pt_regs(state->task))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 		goto the_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 	 * There are some known frame pointer issues on 32-bit.  Disable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 	 * unwinder warnings on 32-bit until it gets objtool support.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 	if (IS_ENABLED(CONFIG_X86_32))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 		goto the_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 	if (state->task != current)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 		goto the_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 	if (state->regs) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 		printk_deferred_once(KERN_WARNING
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 			"WARNING: kernel stack regs at %p in %s:%d has bad 'bp' value %p\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 			state->regs, state->task->comm,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 			state->task->pid, next_bp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 		unwind_dump(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 		printk_deferred_once(KERN_WARNING
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 			"WARNING: kernel stack frame pointer at %p in %s:%d has bad value %p\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 			state->bp, state->task->comm,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 			state->task->pid, next_bp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 		unwind_dump(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) the_end:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 	state->stack_info.type = STACK_TYPE_UNKNOWN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 	return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) EXPORT_SYMBOL_GPL(unwind_next_frame);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) void __unwind_start(struct unwind_state *state, struct task_struct *task,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 		    struct pt_regs *regs, unsigned long *first_frame)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 	unsigned long *bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) 	memset(state, 0, sizeof(*state));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) 	state->task = task;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) 	state->got_irq = (regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 	/* Don't even attempt to start from user mode regs: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 	if (regs && user_mode(regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 		state->stack_info.type = STACK_TYPE_UNKNOWN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) 	bp = get_frame_pointer(task, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) 	 * If we crash with IP==0, the last successfully executed instruction
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) 	 * was probably an indirect function call with a NULL function pointer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) 	 * That means that SP points into the middle of an incomplete frame:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) 	 * *SP is a return pointer, and *(SP-sizeof(unsigned long)) is where we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) 	 * would have written a frame pointer if we hadn't crashed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) 	 * Pretend that the frame is complete and that BP points to it, but save
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) 	 * the real BP so that we can use it when looking for the next frame.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 	if (regs && regs->ip == 0 && (unsigned long *)regs->sp >= first_frame) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) 		state->next_bp = bp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) 		bp = ((unsigned long *)regs->sp) - 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) 	/* Initialize stack info and make sure the frame data is accessible: */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) 	get_stack_info(bp, state->task, &state->stack_info,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) 		       &state->stack_mask);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) 	update_stack_state(state, bp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) 	 * The caller can provide the address of the first frame directly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) 	 * (first_frame) or indirectly (regs->sp) to indicate which stack frame
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) 	 * to start unwinding at.  Skip ahead until we reach it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) 	while (!unwind_done(state) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) 	       (!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) 			(state->next_bp == NULL && state->bp < first_frame)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) 		unwind_next_frame(state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) EXPORT_SYMBOL_GPL(__unwind_start);