diff options
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/include/asm/ftrace.h | 52 | ||||
| -rw-r--r-- | arch/s390/include/asm/kprobes.h | 1 | ||||
| -rw-r--r-- | arch/s390/include/asm/lowcore.h | 4 | ||||
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 12 | ||||
| -rw-r--r-- | arch/s390/kernel/asm-offsets.c | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/early.c | 4 | ||||
| -rw-r--r-- | arch/s390/kernel/ftrace.c | 132 | ||||
| -rw-r--r-- | arch/s390/kernel/kprobes.c | 92 | ||||
| -rw-r--r-- | arch/s390/kernel/mcount.S | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/setup.c | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/smp.c | 1 |
11 files changed, 212 insertions, 90 deletions
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index 3aef8af..785041f 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -1,25 +1,67 @@ #ifndef _ASM_S390_FTRACE_H #define _ASM_S390_FTRACE_H +#define ARCH_SUPPORTS_FTRACE_OPS 1 + +#define MCOUNT_INSN_SIZE 24 +#define MCOUNT_RETURN_FIXUP 18 + #ifndef __ASSEMBLY__ -extern void _mcount(void); +void _mcount(void); +void ftrace_caller(void); + extern char ftrace_graph_caller_end; +extern unsigned long ftrace_plt; struct dyn_arch_ftrace { }; -#define MCOUNT_ADDR ((long)_mcount) +#define MCOUNT_ADDR ((unsigned long)_mcount) +#define FTRACE_ADDR ((unsigned long)ftrace_caller) +#define KPROBE_ON_FTRACE_NOP 0 +#define KPROBE_ON_FTRACE_CALL 1 static inline unsigned long ftrace_call_adjust(unsigned long addr) { return addr; } -#endif /* __ASSEMBLY__ */ +struct ftrace_insn { + u16 opc; + s32 disp; +} __packed; -#define MCOUNT_INSN_SIZE 18 +static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn) +{ +#ifdef CONFIG_FUNCTION_TRACER + /* jg .+24 */ + insn->opc = 0xc0f4; + insn->disp = MCOUNT_INSN_SIZE / 2; +#endif +} -#define ARCH_SUPPORTS_FTRACE_OPS 1 +static inline int is_ftrace_nop(struct ftrace_insn *insn) +{ +#ifdef CONFIG_FUNCTION_TRACER + if (insn->disp == MCOUNT_INSN_SIZE / 2) + 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 +} + +#endif /* __ASSEMBLY__ */ #endif /* _ASM_S390_FTRACE_H */ diff --git a/arch/s390/include/asm/kprobes.h b/arch/s390/include/asm/kprobes.h index 9862917..b47ad3b 100644 --- a/arch/s390/include/asm/kprobes.h +++ b/arch/s390/include/asm/kprobes.h @@ -60,6 +60,7 @@ typedef u16 kprobe_opcode_t; struct arch_specific_insn { /* copy of original instruction */ kprobe_opcode_t *insn; + unsigned int is_ftrace_insn : 1; }; struct prev_kprobe { diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h index 6cc51fe..34fbcac 100644 --- a/arch/s390/include/asm/lowcore.h +++ b/arch/s390/include/asm/lowcore.h @@ -147,7 +147,7 @@ struct _lowcore { __u32 softirq_pending; /* 0x02ec */ __u32 percpu_offset; /* 0x02f0 */ __u32 machine_flags; /* 0x02f4 */ - __u32 ftrace_func; /* 0x02f8 */ + __u8 pad_0x02f8[0x02fc-0x02f8]; /* 0x02f8 */ __u32 spinlock_lockval; /* 0x02fc */ __u8 pad_0x0300[0x0e00-0x0300]; /* 0x0300 */ @@ -297,7 +297,7 @@ struct _lowcore { __u64 percpu_offset; /* 0x0378 */ __u64 vdso_per_cpu_data; /* 0x0380 */ __u64 machine_flags; /* 0x0388 */ - __u64 ftrace_func; /* 0x0390 */ + __u8 pad_0x0390[0x0398-0x0390]; /* 0x0390 */ __u64 gmap; /* 0x0398 */ __u32 spinlock_lockval; /* 0x03a0 */ __u8 pad_0x03a0[0x0400-0x03a4]; /* 0x03a4 */ diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 00d4607..5ef1a26 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -133,6 +133,18 @@ extern unsigned long MODULES_END; #define MODULES_LEN (1UL << 31) #endif +static inline int is_module_addr(void *addr) +{ +#ifdef CONFIG_64BIT + BUILD_BUG_ON(MODULES_LEN > (1UL << 31)); + if (addr < (void *)MODULES_VADDR) + return 0; + if (addr > (void *)MODULES_END) + return 0; +#endif + return 1; +} + /* * A 31 bit pagetable entry of S390 has following format: * | PFRA | | OS | diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c index ef279a1..f3a7833 100644 --- a/arch/s390/kernel/asm-offsets.c +++ b/arch/s390/kernel/asm-offsets.c @@ -156,7 +156,6 @@ int main(void) DEFINE(__LC_INT_CLOCK, offsetof(struct _lowcore, int_clock)); DEFINE(__LC_MCCK_CLOCK, offsetof(struct _lowcore, mcck_clock)); DEFINE(__LC_MACHINE_FLAGS, offsetof(struct _lowcore, machine_flags)); - DEFINE(__LC_FTRACE_FUNC, offsetof(struct _lowcore, ftrace_func)); DEFINE(__LC_DUMP_REIPL, offsetof(struct _lowcore, ipib)); BLANK(); DEFINE(__LC_CPU_TIMER_SAVE_AREA, offsetof(struct _lowcore, cpu_timer_save_area)); diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c index cef2879e..302ac1f7 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -12,7 +12,6 @@ #include <linux/errno.h> #include <linux/string.h> #include <linux/ctype.h> -#include <linux/ftrace.h> #include <linux/lockdep.h> #include <linux/module.h> #include <linux/pfn.h> @@ -490,8 +489,5 @@ void __init startup_init(void) detect_machine_facilities(); setup_topology(); sclp_early_detect(); -#ifdef CONFIG_DYNAMIC_FTRACE - S390_lowcore.ftrace_func = (unsigned long)ftrace_caller; -#endif lockdep_on(); } diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 51d14fe5..5744d25 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -7,6 +7,7 @@ * Martin Schwidefsky <schwidefsky@de.ibm.com> */ +#include <linux/moduleloader.h> #include <linux/hardirq.h> #include <linux/uaccess.h> #include <linux/ftrace.h> @@ -15,60 +16,39 @@ #include <linux/kprobes.h> #include <trace/syscall.h> #include <asm/asm-offsets.h> +#include <asm/cacheflush.h> #include "entry.h" -void mcount_replace_code(void); -void ftrace_disable_code(void); -void ftrace_enable_insn(void); - /* * The mcount code looks like this: * stg %r14,8(%r15) # offset 0 * larl %r1,<&counter> # offset 6 * brasl %r14,_mcount # offset 12 * lg %r14,8(%r15) # offset 18 - * Total length is 24 bytes. The complete mcount block initially gets replaced - * by ftrace_make_nop. Subsequent calls to ftrace_make_call / ftrace_make_nop - * only patch the jg/lg instruction within the block. - * Note: we do not patch the first instruction to an unconditional branch, - * since that would break kprobes/jprobes. It is easier to leave the larl - * instruction in and only modify the second instruction. + * Total length is 24 bytes. Only the first instruction will be patched + * by ftrace_make_call / ftrace_make_nop. * The enabled ftrace code block looks like this: - * larl %r0,.+24 # offset 0 - * > lg %r1,__LC_FTRACE_FUNC # offset 6 - * br %r1 # offset 12 - * brcl 0,0 # offset 14 - * brc 0,0 # offset 20 + * > brasl %r0,ftrace_caller # offset 0 + * larl %r1,<&counter> # offset 6 + * brasl %r14,_mcount # offset 12 + * lg %r14,8(%r15) # offset 18 * The ftrace function gets called with a non-standard C function call ABI * where r0 contains the return address. It is also expected that the called * function only clobbers r0 and r1, but restores r2-r15. + * For module code we can't directly jump to ftrace caller, but need a + * trampoline (ftrace_plt), which clobbers also r1. * The return point of the ftrace function has offset 24, so execution * continues behind the mcount block. - * larl %r0,.+24 # offset 0 - * > jg .+18 # offset 6 - * br %r1 # offset 12 - * brcl 0,0 # offset 14 - * brc 0,0 # offset 20 + * The disabled ftrace code block looks like this: + * > jg .+24 # offset 0 + * larl %r1,<&counter> # offset 6 + * brasl %r14,_mcount # offset 12 + * lg %r14,8(%r15) # offset 18 * The jg instruction branches to offset 24 to skip as many instructions * as possible. */ -asm( - " .align 4\n" - "mcount_replace_code:\n" - " larl %r0,0f\n" - "ftrace_disable_code:\n" - " jg 0f\n" - " br %r1\n" - " brcl 0,0\n" - " brc 0,0\n" - "0:\n" - " .align 4\n" - "ftrace_enable_insn:\n" - " lg %r1,"__stringify(__LC_FTRACE_FUNC)"\n"); - -#define MCOUNT_BLOCK_SIZE 24 -#define MCOUNT_INSN_OFFSET 6 -#define FTRACE_INSN_SIZE 6 + +unsigned long ftrace_plt; int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) @@ -79,24 +59,62 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { - /* Initial replacement of the whole mcount block */ - if (addr == MCOUNT_ADDR) { - if (probe_kernel_write((void *) rec->ip - MCOUNT_INSN_OFFSET, - mcount_replace_code, - MCOUNT_BLOCK_SIZE)) - return -EPERM; - return 0; + struct ftrace_insn insn; + unsigned short op; + void *from, *to; + size_t size; + + ftrace_generate_nop_insn(&insn); + size = sizeof(insn); + from = &insn; + to = (void *) rec->ip; + if (probe_kernel_read(&op, (void *) rec->ip, sizeof(op))) + return -EFAULT; + /* + * If we find a breakpoint instruction, a kprobe has been placed + * at the beginning of the function. We write the constant + * KPROBE_ON_FTRACE_NOP into the remaining four bytes of the original + * instruction so that the kprobes handler can execute a nop, if it + * reaches this breakpoint. + */ + if (op == BREAKPOINT_INSTRUCTION) { + size -= 2; + from += 2; + to += 2; + insn.disp = KPROBE_ON_FTRACE_NOP; } - if (probe_kernel_write((void *) rec->ip, ftrace_disable_code, - MCOUNT_INSN_SIZE)) + if (probe_kernel_write(to, from, size)) return -EPERM; return 0; } int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { - if (probe_kernel_write((void *) rec->ip, ftrace_enable_insn, - FTRACE_INSN_SIZE)) + struct ftrace_insn insn; + unsigned short op; + void *from, *to; + size_t size; + + ftrace_generate_call_insn(&insn, rec->ip); + size = sizeof(insn); + from = &insn; + to = (void *) rec->ip; + if (probe_kernel_read(&op, (void *) rec->ip, sizeof(op))) + return -EFAULT; + /* + * If we find a breakpoint instruction, a kprobe has been placed + * at the beginning of the function. We write the constant + * KPROBE_ON_FTRACE_CALL into the remaining four bytes of the original + * instruction so that the kprobes handler can execute a brasl if it + * reaches this breakpoint. + */ + if (op == BREAKPOINT_INSTRUCTION) { + size -= 2; + from += 2; + to += 2; + insn.disp = KPROBE_ON_FTRACE_CALL; + } + if (probe_kernel_write(to, from, size)) return -EPERM; return 0; } @@ -111,6 +129,24 @@ int __init ftrace_dyn_arch_init(void) return 0; } +static int __init ftrace_plt_init(void) +{ + unsigned int *ip; + + ftrace_plt = (unsigned long) 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); + return 0; +} +device_initcall(ftrace_plt_init); + #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* * Hook the return address and push it in the stack of return addresses diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 014d472..d6716c2 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -29,6 +29,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/hardirq.h> +#include <linux/ftrace.h> #include <asm/cacheflush.h> #include <asm/sections.h> #include <asm/dis.h> @@ -60,10 +61,21 @@ struct kprobe_insn_cache kprobe_dmainsn_slots = { static void __kprobes copy_instruction(struct kprobe *p) { + unsigned long ip = (unsigned long) p->addr; s64 disp, new_disp; u64 addr, new_addr; - memcpy(p->ainsn.insn, p->addr, insn_length(p->opcode >> 8)); + if (ftrace_location(ip) == ip) { + /* + * If kprobes patches the instruction that is morphed by + * ftrace make sure that kprobes always sees the branch + * "jg .+24" that skips the mcount block + */ + ftrace_generate_nop_insn((struct ftrace_insn *)p->ainsn.insn); + p->ainsn.is_ftrace_insn = 1; + } else + memcpy(p->ainsn.insn, p->addr, insn_length(p->opcode >> 8)); + p->opcode = p->ainsn.insn[0]; if (!probe_is_insn_relative_long(p->ainsn.insn)) return; /* @@ -85,18 +97,6 @@ static inline int is_kernel_addr(void *addr) return addr < (void *)_end; } -static inline int is_module_addr(void *addr) -{ -#ifdef CONFIG_64BIT - BUILD_BUG_ON(MODULES_LEN > (1UL << 31)); - if (addr < (void *)MODULES_VADDR) - return 0; - if (addr > (void *)MODULES_END) - return 0; -#endif - return 1; -} - static int __kprobes s390_get_insn_slot(struct kprobe *p) { /* @@ -132,43 +132,63 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) return -EINVAL; if (s390_get_insn_slot(p)) return -ENOMEM; - p->opcode = *p->addr; copy_instruction(p); return 0; } -struct ins_replace_args { - kprobe_opcode_t *ptr; - kprobe_opcode_t opcode; +int arch_check_ftrace_location(struct kprobe *p) +{ + return 0; +} + +struct swap_insn_args { + struct kprobe *p; + unsigned int arm_kprobe : 1; }; -static int __kprobes swap_instruction(void *aref) +static int __kprobes swap_instruction(void *data) { struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); unsigned long status = kcb->kprobe_status; - struct ins_replace_args *args = aref; - + struct swap_insn_args *args = data; + struct ftrace_insn new_insn, *insn; + struct kprobe *p = args->p; + size_t len; + + new_insn.opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode; + len = sizeof(new_insn.opc); + if (!p->ainsn.is_ftrace_insn) + goto skip_ftrace; + len = sizeof(new_insn); + insn = (struct ftrace_insn *) p->addr; + if (args->arm_kprobe) { + if (is_ftrace_nop(insn)) + new_insn.disp = KPROBE_ON_FTRACE_NOP; + else + new_insn.disp = KPROBE_ON_FTRACE_CALL; + } else { + ftrace_generate_call_insn(&new_insn, (unsigned long)p->addr); + if (insn->disp == KPROBE_ON_FTRACE_NOP) + ftrace_generate_nop_insn(&new_insn); + } +skip_ftrace: kcb->kprobe_status = KPROBE_SWAP_INST; - probe_kernel_write(args->ptr, &args->opcode, sizeof(args->opcode)); + probe_kernel_write(p->addr, &new_insn, len); kcb->kprobe_status = status; return 0; } void __kprobes arch_arm_kprobe(struct kprobe *p) { - struct ins_replace_args args; + struct swap_insn_args args = {.p = p, .arm_kprobe = 1}; - args.ptr = p->addr; - args.opcode = BREAKPOINT_INSTRUCTION; stop_machine(swap_instruction, &args, NULL); } void __kprobes arch_disarm_kprobe(struct kprobe *p) { - struct ins_replace_args args; + struct swap_insn_args args = {.p = p, .arm_kprobe = 0}; - args.ptr = p->addr; - args.opcode = p->opcode; stop_machine(swap_instruction, &args, NULL); } @@ -459,6 +479,24 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) unsigned long ip = regs->psw.addr & PSW_ADDR_INSN; int fixup = probe_get_fixup_type(p->ainsn.insn); + /* Check if the kprobes location is an enabled ftrace caller */ + if (p->ainsn.is_ftrace_insn) { + struct ftrace_insn *insn = (struct ftrace_insn *) p->addr; + struct ftrace_insn call_insn; + + ftrace_generate_call_insn(&call_insn, (unsigned long) p->addr); + /* + * A kprobe on an enabled ftrace call site actually single + * stepped an unconditional branch (ftrace nop equivalent). + * Now we need to fixup things and pretend that a brasl r0,... + * was executed instead. + */ + if (insn->disp == KPROBE_ON_FTRACE_CALL) { + ip += call_insn.disp * 2 - MCOUNT_INSN_SIZE; + regs->gprs[0] = (unsigned long)p->addr + sizeof(*insn); + } + } + if (fixup & FIXUP_PSW_NORMAL) ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn; diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S index 4300ea3..b6dfc5b 100644 --- a/arch/s390/kernel/mcount.S +++ b/arch/s390/kernel/mcount.S @@ -27,6 +27,7 @@ ENTRY(ftrace_caller) .globl ftrace_regs_caller .set ftrace_regs_caller,ftrace_caller lgr %r1,%r15 + aghi %r0,MCOUNT_RETURN_FIXUP aghi %r15,-STACK_FRAME_SIZE stg %r1,__SF_BACKCHAIN(%r15) stg %r1,(STACK_PTREGS_GPRS+15*8)(%r15) diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index e80d9ff..4e532c6 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -41,7 +41,6 @@ #include <linux/ctype.h> #include <linux/reboot.h> #include <linux/topology.h> -#include <linux/ftrace.h> #include <linux/kexec.h> #include <linux/crash_dump.h> #include <linux/memory.h> @@ -356,7 +355,6 @@ static void __init setup_lowcore(void) lc->steal_timer = S390_lowcore.steal_timer; lc->last_update_timer = S390_lowcore.last_update_timer; lc->last_update_clock = S390_lowcore.last_update_clock; - lc->ftrace_func = S390_lowcore.ftrace_func; restart_stack = __alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0); restart_stack += ASYNC_SIZE; diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 6fd9e60..0b499f5 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -236,7 +236,6 @@ static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu) lc->percpu_offset = __per_cpu_offset[cpu]; lc->kernel_asce = S390_lowcore.kernel_asce; lc->machine_flags = S390_lowcore.machine_flags; - lc->ftrace_func = S390_lowcore.ftrace_func; lc->user_timer = lc->system_timer = lc->steal_timer = 0; __ctl_store(lc->cregs_save_area, 0, 15); save_access_regs((unsigned int *) lc->access_regs_save_area); |