diff options
Diffstat (limited to 'arch/mips/kernel/ftrace.c')
| -rw-r--r-- | arch/mips/kernel/ftrace.c | 89 |
1 files changed, 41 insertions, 48 deletions
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index 9d9b8fbae202..b15615b28569 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Code for replacing ftrace calls with jumps. * @@ -36,10 +37,6 @@ void arch_ftrace_update_code(int command) ftrace_modify_all_code(command); } -#endif - -#ifdef CONFIG_DYNAMIC_FTRACE - #define JAL 0x0c000000 /* jump & link: ip --> ra, jump to target */ #define ADDR_MASK 0x03ffffff /* op_code|addr : 31...26|25 ....0 */ #define JUMP_RANGE_MASK ((1UL << 28) - 1) @@ -57,10 +54,20 @@ static inline void ftrace_dyn_arch_init_insns(void) u32 *buf; unsigned int v1; - /* la v1, _mcount */ - v1 = 3; - buf = (u32 *)&insn_la_mcount[0]; - UASM_i_LA(&buf, v1, MCOUNT_ADDR); + /* If we are not in compat space, the number of generated + * instructions will exceed the maximum expected limit of 2. + * To prevent buffer overflow, we avoid generating them. + * insn_la_mcount will not be used later in ftrace_make_call. + */ + if (uasm_in_compat_space_p(MCOUNT_ADDR)) { + /* la v1, _mcount */ + v1 = 3; + buf = (u32 *)&insn_la_mcount[0]; + UASM_i_LA(&buf, v1, MCOUNT_ADDR); + } else { + pr_warn("ftrace: mcount address beyond 32 bits is not supported (%lX)\n", + MCOUNT_ADDR); + } /* jal (ftrace_caller + 8), jump over the first two instruction */ buf = (u32 *)&insn_jal_ftrace_caller; @@ -76,7 +83,6 @@ static inline void ftrace_dyn_arch_init_insns(void) static int ftrace_modify_code(unsigned long ip, unsigned int new_code) { int faulted; - mm_segment_t old_fs; /* *(unsigned int *)ip = new_code; */ safe_store_code(new_code, ip, faulted); @@ -84,10 +90,7 @@ static int ftrace_modify_code(unsigned long ip, unsigned int new_code) if (unlikely(faulted)) return -EFAULT; - old_fs = get_fs(); - set_fs(get_ds()); flush_icache_range(ip, ip + 8); - set_fs(old_fs); return 0; } @@ -97,7 +100,6 @@ static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1, unsigned int new_code2) { int faulted; - mm_segment_t old_fs; safe_store_code(new_code1, ip, faulted); if (unlikely(faulted)) @@ -109,10 +111,7 @@ static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1, return -EFAULT; ip -= 4; - old_fs = get_fs(); - set_fs(get_ds()); flush_icache_range(ip, ip + 8); - set_fs(old_fs); return 0; } @@ -121,7 +120,6 @@ static int ftrace_modify_code_2r(unsigned long ip, unsigned int new_code1, unsigned int new_code2) { int faulted; - mm_segment_t old_fs; ip += 4; safe_store_code(new_code2, ip, faulted); @@ -133,10 +131,7 @@ static int ftrace_modify_code_2r(unsigned long ip, unsigned int new_code1, if (unlikely(faulted)) return -EFAULT; - old_fs = get_fs(); - set_fs(get_ds()); flush_icache_range(ip, ip + 8); - set_fs(old_fs); return 0; } @@ -204,6 +199,13 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) unsigned int new; unsigned long ip = rec->ip; + /* When the code to patch does not belong to the kernel code + * space, we must use insn_la_mcount. However, if MCOUNT_ADDR + * is not in compat space, insn_la_mcount is not usable. + */ + if (!core_kernel_text(ip) && !uasm_in_compat_space_p(MCOUNT_ADDR)) + return -EFAULT; + new = core_kernel_text(ip) ? insn_jal_ftrace_caller : insn_la_mcount[0]; #ifdef CONFIG_64BIT @@ -263,7 +265,7 @@ int ftrace_disable_ftrace_graph_caller(void) #define S_R_SP (0xafb0 << 16) /* s{d,w} R, offset(sp) */ #define OFFSET_MASK 0xffff /* stack offset range: 0 ~ PT_SIZE */ -unsigned long ftrace_get_parent_ra_addr(unsigned long self_ra, unsigned long +static unsigned long ftrace_get_parent_ra_addr(unsigned long self_ra, unsigned long old_parent_ra, unsigned long parent_ra_addr, unsigned long fp) { unsigned long sp, ip, tmp; @@ -321,7 +323,6 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra, unsigned long fp) { unsigned long old_parent_ra; - struct ftrace_graph_ent trace; unsigned long return_hooker = (unsigned long) &return_to_handler; int faulted, insns; @@ -333,20 +334,21 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra, return; /* - * "parent_ra_addr" is the stack address saved the return address of - * the caller of _mcount. + * "parent_ra_addr" is the stack address where the return address of + * the caller of _mcount is saved. * - * if the gcc < 4.5, a leaf function does not save the return address - * in the stack address, so, we "emulate" one in _mcount's stack space, - * and hijack it directly, but for a non-leaf function, it save the - * return address to the its own stack space, we can not hijack it - * directly, but need to find the real stack address, - * ftrace_get_parent_addr() does it! + * If gcc < 4.5, a leaf function does not save the return address + * in the stack address, so we "emulate" one in _mcount's stack space, + * and hijack it directly. + * For a non-leaf function, it does save the return address to its own + * stack space, so we can not hijack it directly, but need to find the + * real stack address, which is done by ftrace_get_parent_addr(). * - * if gcc>= 4.5, with the new -mmcount-ra-address option, for a + * If gcc >= 4.5, with the new -mmcount-ra-address option, for a * non-leaf function, the location of the return address will be saved - * to $12 for us, and for a leaf function, only put a zero into $12. we - * do it in ftrace_graph_caller of mcount.S. + * to $12 for us. + * For a leaf function, it just puts a zero into $12, so we handle + * it in ftrace_graph_caller() of mcount.S. */ /* old_parent_ra = *parent_ra_addr; */ @@ -360,7 +362,7 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra, * If fails when getting the stack address of the non-leaf function's * ra, stop function graph tracer and return */ - if (parent_ra_addr == 0) + if (parent_ra_addr == NULL) goto out; #endif /* *parent_ra_addr = return_hooker; */ @@ -368,12 +370,6 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra, if (unlikely(faulted)) goto out; - if (ftrace_push_return_trace(old_parent_ra, self_ra, &trace.depth, fp, - NULL) == -EBUSY) { - *parent_ra_addr = old_parent_ra; - return; - } - /* * Get the recorded ip of the current mcount calling site in the * __mcount_loc section, which will be used to filter the function @@ -381,13 +377,10 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra, */ insns = core_kernel_text(self_ra) ? 2 : MCOUNT_OFFSET_INSNS + 1; - trace.func = self_ra - (MCOUNT_INSN_SIZE * insns); + self_ra -= (MCOUNT_INSN_SIZE * insns); - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) { - current->curr_ret_stack--; + if (function_graph_enter(old_parent_ra, self_ra, fp, NULL)) *parent_ra_addr = old_parent_ra; - } return; out: ftrace_graph_stop(); @@ -409,13 +402,13 @@ unsigned long __init arch_syscall_addr(int nr) unsigned long __init arch_syscall_addr(int nr) { #ifdef CONFIG_MIPS32_N32 - if (nr >= __NR_N32_Linux && nr <= __NR_N32_Linux + __NR_N32_Linux_syscalls) + if (nr >= __NR_N32_Linux && nr < __NR_N32_Linux + __NR_N32_Linux_syscalls) return (unsigned long)sysn32_call_table[nr - __NR_N32_Linux]; #endif - if (nr >= __NR_64_Linux && nr <= __NR_64_Linux + __NR_64_Linux_syscalls) + if (nr >= __NR_64_Linux && nr < __NR_64_Linux + __NR_64_Linux_syscalls) return (unsigned long)sys_call_table[nr - __NR_64_Linux]; #ifdef CONFIG_MIPS32_O32 - if (nr >= __NR_O32_Linux && nr <= __NR_O32_Linux + __NR_O32_Linux_syscalls) + if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) return (unsigned long)sys32_call_table[nr - __NR_O32_Linux]; #endif |