diff options
Diffstat (limited to 'arch/parisc/kernel/ftrace.c')
| -rw-r--r-- | arch/parisc/kernel/ftrace.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c new file mode 100644 index 000000000..4d392e4ed --- /dev/null +++ b/arch/parisc/kernel/ftrace.c @@ -0,0 +1,251 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Code for tracing calls in Linux kernel. + * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de> + * + * based on code for x86 which is: + * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> + * + * future possible enhancements: + * - add CONFIG_STACK_TRACER + */ + +#include <linux/init.h> +#include <linux/ftrace.h> +#include <linux/uaccess.h> +#include <linux/kprobes.h> +#include <linux/ptrace.h> +#include <linux/jump_label.h> + +#include <asm/assembly.h> +#include <asm/sections.h> +#include <asm/ftrace.h> +#include <asm/patch.h> + +#define __hot __section(".text.hot") + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +static DEFINE_STATIC_KEY_FALSE(ftrace_graph_enable); + +/* + * Hook the return address and push it in the stack of return addrs + * in current thread info. + */ +static void __hot prepare_ftrace_return(unsigned long *parent, + unsigned long self_addr) +{ + unsigned long old; + extern int parisc_return_to_handler; + + if (unlikely(ftrace_graph_is_dead())) + return; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + old = *parent; + + if (!function_graph_enter(old, self_addr, 0, NULL)) + /* activate parisc_return_to_handler() as return point */ + *parent = (unsigned long) &parisc_return_to_handler; +} +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +static ftrace_func_t ftrace_func; + +void notrace __hot ftrace_function_trampoline(unsigned long parent, + unsigned long self_addr, + unsigned long org_sp_gr3, + struct ftrace_regs *fregs) +{ + extern struct ftrace_ops *function_trace_op; + + ftrace_func(self_addr, parent, function_trace_op, fregs); + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + if (static_branch_unlikely(&ftrace_graph_enable)) { + unsigned long *parent_rp; + + /* calculate pointer to %rp in stack */ + parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET); + /* sanity check: parent_rp should hold parent */ + if (*parent_rp != parent) + return; + + prepare_ftrace_return(parent_rp, self_addr); + return; + } +#endif +} + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +int ftrace_enable_ftrace_graph_caller(void) +{ + static_key_enable(&ftrace_graph_enable.key); + return 0; +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + static_key_enable(&ftrace_graph_enable.key); + return 0; +} +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + ftrace_func = func; + return 0; +} + +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr) +{ + return 0; +} + +unsigned long ftrace_call_adjust(unsigned long addr) +{ + return addr+(FTRACE_PATCHABLE_FUNCTION_SIZE-1)*4; +} + +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE]; + u32 *tramp; + int size, ret, i; + void *ip; + +#ifdef CONFIG_64BIT + unsigned long addr2 = + (unsigned long)dereference_function_descriptor((void *)addr); + + u32 ftrace_trampoline[] = { + 0x73c10208, /* std,ma r1,100(sp) */ + 0x0c2110c1, /* ldd -10(r1),r1 */ + 0xe820d002, /* bve,n (r1) */ + addr2 >> 32, + addr2 & 0xffffffff, + 0xe83f1fd7, /* b,l,n .-14,r1 */ + }; + + u32 ftrace_trampoline_unaligned[] = { + addr2 >> 32, + addr2 & 0xffffffff, + 0x37de0200, /* ldo 100(sp),sp */ + 0x73c13e01, /* std r1,-100(sp) */ + 0x34213ff9, /* ldo -4(r1),r1 */ + 0x50213fc1, /* ldd -20(r1),r1 */ + 0xe820d002, /* bve,n (r1) */ + 0xe83f1fcf, /* b,l,n .-20,r1 */ + }; + + BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline_unaligned) > + FTRACE_PATCHABLE_FUNCTION_SIZE); +#else + u32 ftrace_trampoline[] = { + (u32)addr, + 0x6fc10080, /* stw,ma r1,40(sp) */ + 0x48213fd1, /* ldw -18(r1),r1 */ + 0xe820c002, /* bv,n r0(r1) */ + 0xe83f1fdf, /* b,l,n .-c,r1 */ + }; +#endif + + BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline) > + FTRACE_PATCHABLE_FUNCTION_SIZE); + + size = sizeof(ftrace_trampoline); + tramp = ftrace_trampoline; + +#ifdef CONFIG_64BIT + if (rec->ip & 0x4) { + size = sizeof(ftrace_trampoline_unaligned); + tramp = ftrace_trampoline_unaligned; + } +#endif + + ip = (void *)(rec->ip + 4 - size); + + ret = copy_from_kernel_nofault(insn, ip, size); + if (ret) + return ret; + + for (i = 0; i < size / 4; i++) { + if (insn[i] != INSN_NOP) + return -EINVAL; + } + + __patch_text_multiple(ip, tramp, size); + return 0; +} + +int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, + unsigned long addr) +{ + u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE]; + int i; + + for (i = 0; i < ARRAY_SIZE(insn); i++) + insn[i] = INSN_NOP; + + __patch_text((void *)rec->ip, INSN_NOP); + __patch_text_multiple((void *)rec->ip + 4 - sizeof(insn), + insn, sizeof(insn)-4); + return 0; +} +#endif + +#ifdef CONFIG_KPROBES_ON_FTRACE +void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *ops, struct ftrace_regs *fregs) +{ + struct kprobe_ctlblk *kcb; + struct pt_regs *regs; + struct kprobe *p; + int bit; + + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) + return; + + regs = ftrace_get_regs(fregs); + p = get_kprobe((kprobe_opcode_t *)ip); + if (unlikely(!p) || kprobe_disabled(p)) + goto out; + + if (kprobe_running()) { + kprobes_inc_nmissed_count(p); + goto out; + } + + __this_cpu_write(current_kprobe, p); + + kcb = get_kprobe_ctlblk(); + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + + regs->iaoq[0] = ip; + regs->iaoq[1] = ip + 4; + + if (!p->pre_handler || !p->pre_handler(p, regs)) { + regs->iaoq[0] = ip + 4; + regs->iaoq[1] = ip + 8; + + if (unlikely(p->post_handler)) { + kcb->kprobe_status = KPROBE_HIT_SSDONE; + p->post_handler(p, regs, 0); + } + } + __this_cpu_write(current_kprobe, NULL); +out: + ftrace_test_recursion_unlock(bit); +} +NOKPROBE_SYMBOL(kprobe_ftrace_handler); + +int arch_prepare_kprobe_ftrace(struct kprobe *p) +{ + p->ainsn.insn = NULL; + return 0; +} +#endif |