diff options
Diffstat (limited to 'arch/mips/oprofile/backtrace.c')
| -rw-r--r-- | arch/mips/oprofile/backtrace.c | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/arch/mips/oprofile/backtrace.c b/arch/mips/oprofile/backtrace.c deleted file mode 100644 index 07d98ba7f49e..000000000000 --- a/arch/mips/oprofile/backtrace.c +++ /dev/null @@ -1,177 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -#include <linux/oprofile.h> -#include <linux/sched.h> -#include <linux/mm.h> -#include <linux/uaccess.h> -#include <asm/ptrace.h> -#include <asm/stacktrace.h> -#include <linux/stacktrace.h> -#include <linux/kernel.h> -#include <asm/sections.h> -#include <asm/inst.h> - -struct stackframe { - unsigned long sp; - unsigned long pc; - unsigned long ra; -}; - -static inline int get_mem(unsigned long addr, unsigned long *result) -{ - unsigned long *address = (unsigned long *) addr; - if (!access_ok(address, sizeof(unsigned long))) - return -1; - if (__copy_from_user_inatomic(result, address, sizeof(unsigned long))) - return -3; - return 0; -} - -/* - * These two instruction helpers were taken from process.c - */ -static inline int is_ra_save_ins(union mips_instruction *ip) -{ - /* sw / sd $ra, offset($sp) */ - return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) - && ip->i_format.rs == 29 && ip->i_format.rt == 31; -} - -static inline int is_sp_move_ins(union mips_instruction *ip) -{ - /* addiu/daddiu sp,sp,-imm */ - if (ip->i_format.rs != 29 || ip->i_format.rt != 29) - return 0; - if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) - return 1; - return 0; -} - -/* - * Looks for specific instructions that mark the end of a function. - * This usually means we ran into the code area of the previous function. - */ -static inline int is_end_of_function_marker(union mips_instruction *ip) -{ - /* jr ra */ - if (ip->r_format.func == jr_op && ip->r_format.rs == 31) - return 1; - /* lui gp */ - if (ip->i_format.opcode == lui_op && ip->i_format.rt == 28) - return 1; - return 0; -} - -/* - * TODO for userspace stack unwinding: - * - handle cases where the stack is adjusted inside a function - * (generally doesn't happen) - * - find optimal value for max_instr_check - * - try to find a better way to handle leaf functions - */ - -static inline int unwind_user_frame(struct stackframe *old_frame, - const unsigned int max_instr_check) -{ - struct stackframe new_frame = *old_frame; - off_t ra_offset = 0; - size_t stack_size = 0; - unsigned long addr; - - if (old_frame->pc == 0 || old_frame->sp == 0 || old_frame->ra == 0) - return -9; - - for (addr = new_frame.pc; (addr + max_instr_check > new_frame.pc) - && (!ra_offset || !stack_size); --addr) { - union mips_instruction ip; - - if (get_mem(addr, (unsigned long *) &ip)) - return -11; - - if (is_sp_move_ins(&ip)) { - int stack_adjustment = ip.i_format.simmediate; - if (stack_adjustment > 0) - /* This marks the end of the previous function, - which means we overran. */ - break; - stack_size = (unsigned long) stack_adjustment; - } else if (is_ra_save_ins(&ip)) { - int ra_slot = ip.i_format.simmediate; - if (ra_slot < 0) - /* This shouldn't happen. */ - break; - ra_offset = ra_slot; - } else if (is_end_of_function_marker(&ip)) - break; - } - - if (!ra_offset || !stack_size) - goto done; - - if (ra_offset) { - new_frame.ra = old_frame->sp + ra_offset; - if (get_mem(new_frame.ra, &(new_frame.ra))) - return -13; - } - - if (stack_size) { - new_frame.sp = old_frame->sp + stack_size; - if (get_mem(new_frame.sp, &(new_frame.sp))) - return -14; - } - - if (new_frame.sp > old_frame->sp) - return -2; - -done: - new_frame.pc = old_frame->ra; - *old_frame = new_frame; - - return 0; -} - -static inline void do_user_backtrace(unsigned long low_addr, - struct stackframe *frame, - unsigned int depth) -{ - const unsigned int max_instr_check = 512; - const unsigned long high_addr = low_addr + THREAD_SIZE; - - while (depth-- && !unwind_user_frame(frame, max_instr_check)) { - oprofile_add_trace(frame->ra); - if (frame->sp < low_addr || frame->sp > high_addr) - break; - } -} - -#ifndef CONFIG_KALLSYMS -static inline void do_kernel_backtrace(unsigned long low_addr, - struct stackframe *frame, - unsigned int depth) { } -#else -static inline void do_kernel_backtrace(unsigned long low_addr, - struct stackframe *frame, - unsigned int depth) -{ - while (depth-- && frame->pc) { - frame->pc = unwind_stack_by_address(low_addr, - &(frame->sp), - frame->pc, - &(frame->ra)); - oprofile_add_trace(frame->ra); - } -} -#endif - -void notrace op_mips_backtrace(struct pt_regs *const regs, unsigned int depth) -{ - struct stackframe frame = { .sp = regs->regs[29], - .pc = regs->cp0_epc, - .ra = regs->regs[31] }; - const int userspace = user_mode(regs); - const unsigned long low_addr = ALIGN(frame.sp, THREAD_SIZE); - - if (userspace) - do_user_backtrace(low_addr, &frame, depth); - else - do_kernel_backtrace(low_addr, &frame, depth); -} |