diff options
Diffstat (limited to 'arch/mips/kernel/ftrace.c')
| -rw-r--r-- | arch/mips/kernel/ftrace.c | 173 |
1 files changed, 113 insertions, 60 deletions
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index dba90ec0dc38..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. * @@ -11,11 +12,14 @@ #include <linux/uaccess.h> #include <linux/init.h> #include <linux/ftrace.h> +#include <linux/syscalls.h> #include <asm/asm.h> #include <asm/asm-offsets.h> #include <asm/cacheflush.h> +#include <asm/syscall.h> #include <asm/uasm.h> +#include <asm/unistd.h> #include <asm-generic/sections.h> @@ -33,24 +37,6 @@ void arch_ftrace_update_code(int command) ftrace_modify_all_code(command); } -#endif - -/* - * Check if the address is in kernel space - * - * Clone core_kernel_text() from kernel/extable.c, but doesn't call - * init_kernel_text() for Ftrace doesn't trace functions in init sections. - */ -static inline int in_kernel_space(unsigned long ip) -{ - if (ip >= (unsigned long)_stext && - ip <= (unsigned long)_etext) - return 1; - return 0; -} - -#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) @@ -60,7 +46,7 @@ static inline int in_kernel_space(unsigned long ip) ((unsigned int)(JAL | (((addr) >> 2) & ADDR_MASK))) static unsigned int insn_jal_ftrace_caller __read_mostly; -static unsigned int insn_lui_v1_hi16_mcount __read_mostly; +static unsigned int insn_la_mcount[2] __read_mostly; static unsigned int insn_j_ftrace_graph_caller __maybe_unused __read_mostly; static inline void ftrace_dyn_arch_init_insns(void) @@ -68,10 +54,20 @@ static inline void ftrace_dyn_arch_init_insns(void) u32 *buf; unsigned int v1; - /* lui v1, hi16_mcount */ - v1 = 3; - buf = (u32 *)&insn_lui_v1_hi16_mcount; - UASM_i_LA_mostly(&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; @@ -108,11 +104,35 @@ static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1, safe_store_code(new_code1, ip, faulted); if (unlikely(faulted)) return -EFAULT; + ip += 4; safe_store_code(new_code2, ip, faulted); if (unlikely(faulted)) return -EFAULT; - flush_icache_range(ip, ip + 8); /* original ip + 12 */ + + ip -= 4; + flush_icache_range(ip, ip + 8); + + return 0; +} + +static int ftrace_modify_code_2r(unsigned long ip, unsigned int new_code1, + unsigned int new_code2) +{ + int faulted; + + ip += 4; + safe_store_code(new_code2, ip, faulted); + if (unlikely(faulted)) + return -EFAULT; + + ip -= 4; + safe_store_code(new_code1, ip, faulted); + if (unlikely(faulted)) + return -EFAULT; + + flush_icache_range(ip, ip + 8); + return 0; } #endif @@ -124,13 +144,14 @@ static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1, * * move at, ra * jal _mcount --> nop + * sub sp, sp, 8 --> nop (CONFIG_32BIT) * * 2. For modules: * * 2.1 For KBUILD_MCOUNT_RA_ADDRESS and CONFIG_32BIT * * lui v1, hi_16bit_of_mcount --> b 1f (0x10000005) - * addiu v1, v1, low_16bit_of_mcount + * addiu v1, v1, low_16bit_of_mcount --> nop (CONFIG_32BIT) * move at, ra * move $12, ra_address * jalr v1 @@ -139,7 +160,7 @@ static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1, * 2.2 For the Other situations * * lui v1, hi_16bit_of_mcount --> b 1f (0x10000004) - * addiu v1, v1, low_16bit_of_mcount + * addiu v1, v1, low_16bit_of_mcount --> nop (CONFIG_32BIT) * move at, ra * jalr v1 * nop | move $12, ra_address | sub sp, sp, 8 @@ -158,7 +179,7 @@ int ftrace_make_nop(struct module *mod, * If ip is in kernel space, no long call, otherwise, long call is * needed. */ - new = in_kernel_space(ip) ? INSN_NOP : INSN_B_1F; + new = core_kernel_text(ip) ? INSN_NOP : INSN_B_1F; #ifdef CONFIG_64BIT return ftrace_modify_code(ip, new); #else @@ -178,10 +199,21 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) unsigned int new; unsigned long ip = rec->ip; - new = in_kernel_space(ip) ? insn_jal_ftrace_caller : - insn_lui_v1_hi16_mcount; + /* 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 return ftrace_modify_code(ip, new); +#else + return ftrace_modify_code_2r(ip, new, core_kernel_text(ip) ? + INSN_NOP : insn_la_mcount[1]); +#endif } #define FTRACE_CALL_IP ((unsigned long)(&ftrace_call)) @@ -195,7 +227,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func) return ftrace_modify_code(FTRACE_CALL_IP, new); } -int __init ftrace_dyn_arch_init(void *data) +int __init ftrace_dyn_arch_init(void) { /* Encode the instructions when booting */ ftrace_dyn_arch_init_insns(); @@ -203,9 +235,6 @@ int __init ftrace_dyn_arch_init(void *data) /* Remove "b ftrace_stub" to ensure ftrace_caller() is executed */ ftrace_modify_code(MCOUNT_ADDR, INSN_NOP); - /* The return code is retured via data */ - *(unsigned long *)data = 0; - return 0; } #endif /* CONFIG_DYNAMIC_FTRACE */ @@ -236,7 +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; @@ -248,7 +277,7 @@ unsigned long ftrace_get_parent_ra_addr(unsigned long self_ra, unsigned long * instruction "lui v1, hi_16bit_of_mcount"(offset is 24), but for * kernel, move after the instruction "move ra, at"(offset is 16) */ - ip = self_ra - (in_kernel_space(self_ra) ? 16 : 24); + ip = self_ra - (core_kernel_text(self_ra) ? 16 : 24); /* * search the text until finding the non-store instruction or "s{d,w} @@ -294,29 +323,32 @@ 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; + if (unlikely(ftrace_graph_is_dead())) + return; + if (unlikely(atomic_read(¤t->tracing_graph_pause))) 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; */ @@ -330,7 +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; */ @@ -338,29 +370,50 @@ 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) - == -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 * entries configured through the tracing/set_graph_function interface. */ - insns = in_kernel_space(self_ra) ? 2 : MCOUNT_OFFSET_INSNS + 1; - trace.func = self_ra - (MCOUNT_INSN_SIZE * insns); + insns = core_kernel_text(self_ra) ? 2 : MCOUNT_OFFSET_INSNS + 1; + 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(); WARN_ON(1); } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_FTRACE_SYSCALLS + +#ifdef CONFIG_32BIT +unsigned long __init arch_syscall_addr(int nr) +{ + return (unsigned long)sys_call_table[nr - __NR_O32_Linux]; +} +#endif + +#ifdef CONFIG_64BIT + +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) + return (unsigned long)sysn32_call_table[nr - __NR_N32_Linux]; +#endif + 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) + return (unsigned long)sys32_call_table[nr - __NR_O32_Linux]; +#endif + + return (unsigned long) &sys_ni_syscall; +} +#endif + +#endif /* CONFIG_FTRACE_SYSCALLS */ |