diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index 345cbe982a8b..e8b460f39c58 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -18,7 +18,6 @@ void ftrace_caller(void); extern char ftrace_graph_caller_end; -extern unsigned long ftrace_plt; extern void *ftrace_func; struct dyn_arch_ftrace { }; @@ -31,10 +30,11 @@ struct dyn_arch_ftrace { }; struct module; struct dyn_ftrace; -/* - * Either -mhotpatch or -mnop-mcount is used - no explicit init is required - */ -static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { return 0; } + +bool ftrace_need_init_nop(void); +#define ftrace_need_init_nop ftrace_need_init_nop + +int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); #define ftrace_init_nop ftrace_init_nop static inline unsigned long ftrace_call_adjust(unsigned long addr) @@ -42,42 +42,6 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) return addr; } -struct ftrace_insn { - u16 opc; - s32 disp; -} __packed; - -static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn) -{ -#ifdef CONFIG_FUNCTION_TRACER - /* brcl 0,0 */ - insn->opc = 0xc004; - insn->disp = 0; -#endif -} - -static inline int is_ftrace_nop(struct ftrace_insn *insn) -{ -#ifdef CONFIG_FUNCTION_TRACER - if (insn->disp == 0) - return 1; -#endif - return 0; -} - -static inline void ftrace_generate_call_insn(struct ftrace_insn *insn, - unsigned long ip) -{ -#ifdef CONFIG_FUNCTION_TRACER - unsigned long target; - - /* brasl r0,ftrace_caller */ - target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR; - insn->opc = 0xc005; - insn->disp = (target - ip) / 2; -#endif -} - /* * Even though the system call numbers are identical for s390/s390x a * different system call table is used for compat tasks. This may lead diff --git a/arch/s390/include/asm/ftrace.lds.h b/arch/s390/include/asm/ftrace.lds.h new file mode 100644 index 000000000000..968adfd41240 --- /dev/null +++ b/arch/s390/include/asm/ftrace.lds.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef DIV_ROUND_UP +#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d)) +#endif + +#define SIZEOF_MCOUNT_LOC_ENTRY 8 +#define SIZEOF_FTRACE_HOTPATCH_TRAMPOLINE 24 +#define FTRACE_HOTPATCH_TRAMPOLINES_SIZE(n) \ + DIV_ROUND_UP(SIZEOF_FTRACE_HOTPATCH_TRAMPOLINE * (n), \ + SIZEOF_MCOUNT_LOC_ENTRY) + +#ifdef CONFIG_FUNCTION_TRACER +#define FTRACE_HOTPATCH_TRAMPOLINES_TEXT \ + . = ALIGN(8); \ + __ftrace_hotpatch_trampolines_start = .; \ + . = . + FTRACE_HOTPATCH_TRAMPOLINES_SIZE(__stop_mcount_loc - \ + __start_mcount_loc); \ + __ftrace_hotpatch_trampolines_end = .; +#else +#define FTRACE_HOTPATCH_TRAMPOLINES_TEXT +#endif diff --git a/arch/s390/include/asm/module.h b/arch/s390/include/asm/module.h index 71e57b8af757..9f1eea15872c 100644 --- a/arch/s390/include/asm/module.h +++ b/arch/s390/include/asm/module.h @@ -28,6 +28,14 @@ struct mod_arch_specific { int nsyms; /* Additional symbol information (got and plt offsets). */ struct mod_arch_syminfo *syminfo; +#ifdef CONFIG_FUNCTION_TRACER + /* Start of memory reserved for ftrace hotpatch trampolines. */ + struct ftrace_hotpatch_trampoline *trampolines_start; + /* End of memory reserved for ftrace hotpatch trampolines. */ + struct ftrace_hotpatch_trampoline *trampolines_end; + /* Next unused ftrace hotpatch trampoline slot. */ + struct ftrace_hotpatch_trampoline *next_trampoline; +#endif /* CONFIG_FUNCTION_TRACER */ }; #endif /* _ASM_S390_MODULE_H */ diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 2d8f595d9196..0a464d328467 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -18,8 +18,11 @@ #include #include #include +#include +#include #include #include "entry.h" +#include "ftrace.h" /* * To generate function prologue either gcc's hotpatch feature (since gcc 4.8) @@ -41,7 +44,130 @@ */ void *ftrace_func __read_mostly = ftrace_stub; -unsigned long ftrace_plt; +struct ftrace_insn { + u16 opc; + s32 disp; +} __packed; + +asm( + " .align 16\n" + "ftrace_shared_hotpatch_trampoline_br:\n" + " lmg %r0,%r1,2(%r1)\n" + " br %r1\n" + "ftrace_shared_hotpatch_trampoline_br_end:\n" +); + +#ifdef CONFIG_EXPOLINE +asm( + " .align 16\n" + "ftrace_shared_hotpatch_trampoline_ex:\n" + " lmg %r0,%r1,2(%r1)\n" + " ex %r0," __stringify(__LC_BR_R1) "(%r0)\n" + " j .\n" + "ftrace_shared_hotpatch_trampoline_ex_end:\n" +); + +asm( + " .align 16\n" + "ftrace_shared_hotpatch_trampoline_exrl:\n" + " lmg %r0,%r1,2(%r1)\n" + " .insn ril,0xc60000000000,%r0,0f\n" /* exrl */ + " j .\n" + "0: br %r1\n" + "ftrace_shared_hotpatch_trampoline_exrl_end:\n" +); +#endif /* CONFIG_EXPOLINE */ + +#ifdef CONFIG_MODULES +static char *ftrace_plt; + +asm( + " .data\n" + "ftrace_plt_template:\n" + " basr %r1,%r0\n" + " lg %r1,0f-.(%r1)\n" + " br %r1\n" + "0: .quad ftrace_caller\n" + "ftrace_plt_template_end:\n" + " .previous\n" +); +#endif /* CONFIG_MODULES */ + +static const char *ftrace_shared_hotpatch_trampoline(const char **end) +{ + const char *tstart, *tend; + + tstart = ftrace_shared_hotpatch_trampoline_br; + tend = ftrace_shared_hotpatch_trampoline_br_end; +#ifdef CONFIG_EXPOLINE + if (!nospec_disable) { + tstart = ftrace_shared_hotpatch_trampoline_ex; + tend = ftrace_shared_hotpatch_trampoline_ex_end; + if (test_facility(35)) { /* exrl */ + tstart = ftrace_shared_hotpatch_trampoline_exrl; + tend = ftrace_shared_hotpatch_trampoline_exrl_end; + } + } +#endif /* CONFIG_EXPOLINE */ + if (end) + *end = tend; + return tstart; +} + +bool ftrace_need_init_nop(void) +{ + return ftrace_shared_hotpatch_trampoline(NULL); +} + +int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) +{ + static struct ftrace_hotpatch_trampoline *next_vmlinux_trampoline = + __ftrace_hotpatch_trampolines_start; + static const char orig[6] = { 0xc0, 0x04, 0x00, 0x00, 0x00, 0x00 }; + static struct ftrace_hotpatch_trampoline *trampoline; + struct ftrace_hotpatch_trampoline **next_trampoline; + struct ftrace_hotpatch_trampoline *trampolines_end; + struct ftrace_hotpatch_trampoline tmp; + struct ftrace_insn *insn; + const char *shared; + s32 disp; + + BUILD_BUG_ON(sizeof(struct ftrace_hotpatch_trampoline) != + SIZEOF_FTRACE_HOTPATCH_TRAMPOLINE); + + next_trampoline = &next_vmlinux_trampoline; + trampolines_end = __ftrace_hotpatch_trampolines_end; + shared = ftrace_shared_hotpatch_trampoline(NULL); +#ifdef CONFIG_MODULES + if (mod) { + next_trampoline = &mod->arch.next_trampoline; + trampolines_end = mod->arch.trampolines_end; + shared = ftrace_plt; + } +#endif + + if (WARN_ON_ONCE(*next_trampoline >= trampolines_end)) + return -ENOMEM; + trampoline = (*next_trampoline)++; + + /* Check for the compiler-generated fentry nop (brcl 0, .). */ + if (WARN_ON_ONCE(memcmp((const void *)rec->ip, &orig, sizeof(orig)))) + return -EINVAL; + + /* Generate the trampoline. */ + tmp.brasl_opc = 0xc015; /* brasl %r1, shared */ + tmp.brasl_disp = (shared - (const char *)&trampoline->brasl_opc) / 2; + tmp.interceptor = FTRACE_ADDR; + tmp.rest_of_intercepted_function = rec->ip + sizeof(struct ftrace_insn); + s390_kernel_write(trampoline, &tmp, sizeof(tmp)); + + /* Generate a jump to the trampoline. */ + disp = ((char *)trampoline - (char *)rec->ip) / 2; + insn = (struct ftrace_insn *)rec->ip; + s390_kernel_write(&insn->disp, &disp, sizeof(disp)); + + return 0; +} int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) @@ -49,11 +175,45 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, return 0; } +static void ftrace_generate_nop_insn(struct ftrace_insn *insn) +{ + /* brcl 0,0 */ + insn->opc = 0xc004; + insn->disp = 0; +} + +static void ftrace_generate_call_insn(struct ftrace_insn *insn, + unsigned long ip) +{ + unsigned long target; + + /* brasl r0,ftrace_caller */ + target = FTRACE_ADDR; +#ifdef CONFIG_MODULES + if (is_module_addr((void *)ip)) + target = (unsigned long)ftrace_plt; +#endif /* CONFIG_MODULES */ + insn->opc = 0xc005; + insn->disp = (target - ip) / 2; +} + +static void brcl_disable(void *brcl) +{ + u8 op = 0x04; /* set mask field to zero */ + + s390_kernel_write((char *)brcl + 1, &op, sizeof(op)); +} + int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { struct ftrace_insn orig, new, old; + if (ftrace_shared_hotpatch_trampoline(NULL)) { + brcl_disable((void *)rec->ip); + return 0; + } + if (copy_from_kernel_nofault(&old, (void *) rec->ip, sizeof(old))) return -EFAULT; /* Replace ftrace call with a nop. */ @@ -67,10 +227,22 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, return 0; } +static void brcl_enable(void *brcl) +{ + u8 op = 0xf4; /* set mask field to all ones */ + + s390_kernel_write((char *)brcl + 1, &op, sizeof(op)); +} + int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { struct ftrace_insn orig, new, old; + if (ftrace_shared_hotpatch_trampoline(NULL)) { + brcl_enable((void *)rec->ip); + return 0; + } + if (copy_from_kernel_nofault(&old, (void *) rec->ip, sizeof(old))) return -EFAULT; /* Replace nop with an ftrace call. */ @@ -95,22 +267,44 @@ int __init ftrace_dyn_arch_init(void) return 0; } +void arch_ftrace_update_code(int command) +{ + if (ftrace_shared_hotpatch_trampoline(NULL)) + ftrace_modify_all_code(command); + else + ftrace_run_stop_machine(command); +} + +static void __ftrace_sync(void *dummy) +{ +} + +int ftrace_arch_code_modify_post_process(void) +{ + if (ftrace_shared_hotpatch_trampoline(NULL)) { + /* Send SIGP to the other CPUs, so they see the new code. */ + smp_call_function(__ftrace_sync, NULL, 1); + } + return 0; +} + #ifdef CONFIG_MODULES static int __init ftrace_plt_init(void) { - unsigned int *ip; + const char *start, *end; - ftrace_plt = (unsigned long) module_alloc(PAGE_SIZE); + ftrace_plt = module_alloc(PAGE_SIZE); if (!ftrace_plt) panic("cannot allocate ftrace plt\n"); - ip = (unsigned int *) ftrace_plt; - ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */ - ip[1] = 0x100a0004; - ip[2] = 0x07f10000; - ip[3] = FTRACE_ADDR >> 32; - ip[4] = FTRACE_ADDR & 0xffffffff; - set_memory_ro(ftrace_plt, 1); + + start = ftrace_shared_hotpatch_trampoline(&end); + if (!start) { + start = ftrace_plt_template; + end = ftrace_plt_template_end; + } + memcpy(ftrace_plt, start, end - start); + set_memory_ro((unsigned long)ftrace_plt, 1); return 0; } device_initcall(ftrace_plt_init); @@ -147,17 +341,13 @@ NOKPROBE_SYMBOL(prepare_ftrace_return); */ int ftrace_enable_ftrace_graph_caller(void) { - u8 op = 0x04; /* set mask field to zero */ - - s390_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op)); + brcl_disable(__va(ftrace_graph_caller)); return 0; } int ftrace_disable_ftrace_graph_caller(void) { - u8 op = 0xf4; /* set mask field to all ones */ - - s390_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op)); + brcl_enable(__va(ftrace_graph_caller)); return 0; } diff --git a/arch/s390/kernel/ftrace.h b/arch/s390/kernel/ftrace.h new file mode 100644 index 000000000000..69e416f4c6b0 --- /dev/null +++ b/arch/s390/kernel/ftrace.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _FTRACE_H +#define _FTRACE_H + +#include + +struct ftrace_hotpatch_trampoline { + u16 brasl_opc; + s32 brasl_disp; + s16: 16; + u64 rest_of_intercepted_function; + u64 interceptor; +} __packed; + +extern struct ftrace_hotpatch_trampoline __ftrace_hotpatch_trampolines_start[]; +extern struct ftrace_hotpatch_trampoline __ftrace_hotpatch_trampolines_end[]; +extern const char ftrace_shared_hotpatch_trampoline_br[]; +extern const char ftrace_shared_hotpatch_trampoline_br_end[]; +extern const char ftrace_shared_hotpatch_trampoline_ex[]; +extern const char ftrace_shared_hotpatch_trampoline_ex_end[]; +extern const char ftrace_shared_hotpatch_trampoline_exrl[]; +extern const char ftrace_shared_hotpatch_trampoline_exrl_end[]; +extern const char ftrace_plt_template[]; +extern const char ftrace_plt_template_end[]; + +#endif /* _FTRACE_H */ diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c index 4055f1c49814..b01ba460b7ca 100644 --- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -23,6 +24,8 @@ #include #include #include +#include +#include #if 0 #define DEBUGP printk @@ -48,6 +51,13 @@ void *module_alloc(unsigned long size) return p; } +#ifdef CONFIG_FUNCTION_TRACER +void module_arch_cleanup(struct module *mod) +{ + module_memfree(mod->arch.trampolines_start); +} +#endif + void module_arch_freeing_init(struct module *mod) { if (is_livepatch_module(mod) && @@ -466,6 +476,30 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, write); } +#ifdef CONFIG_FUNCTION_TRACER +static int module_alloc_ftrace_hotpatch_trampolines(struct module *me, + const Elf_Shdr *s) +{ + char *start, *end; + int numpages; + size_t size; + + size = FTRACE_HOTPATCH_TRAMPOLINES_SIZE(s->sh_size); + numpages = DIV_ROUND_UP(size, PAGE_SIZE); + start = module_alloc(numpages * PAGE_SIZE); + if (!start) + return -ENOMEM; + set_memory_ro((unsigned long)start, numpages); + end = start + size; + + me->arch.trampolines_start = (struct ftrace_hotpatch_trampoline *)start; + me->arch.trampolines_end = (struct ftrace_hotpatch_trampoline *)end; + me->arch.next_trampoline = me->arch.trampolines_start; + + return 0; +} +#endif /* CONFIG_FUNCTION_TRACER */ + int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *me) @@ -473,6 +507,9 @@ int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *s; char *secstrings, *secname; void *aseg; +#ifdef CONFIG_FUNCTION_TRACER + int ret; +#endif if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable && me->arch.plt_size) { @@ -507,6 +544,14 @@ int module_finalize(const Elf_Ehdr *hdr, if (IS_ENABLED(CONFIG_EXPOLINE) && (str_has_prefix(secname, ".s390_return"))) nospec_revert(aseg, aseg + s->sh_size); + +#ifdef CONFIG_FUNCTION_TRACER + if (!strcmp(FTRACE_CALLSITE_SECTION, secname)) { + ret = module_alloc_ftrace_hotpatch_trampolines(me, s); + if (ret < 0) + return ret; + } +#endif /* CONFIG_FUNCTION_TRACER */ } jump_label_apply_nops(me); diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index b18288d26ca8..b6caa810af3a 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -5,6 +5,7 @@ #include #include +#include /* * Put .bss..swapper_pg_dir as the first thing in .bss. This will @@ -46,6 +47,7 @@ SECTIONS KPROBES_TEXT IRQENTRY_TEXT SOFTIRQENTRY_TEXT + FTRACE_HOTPATCH_TRAMPOLINES_TEXT *(.text.*_indirect_*) *(.fixup) *(.gnu.warning)