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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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52a22e6c27
Allow KPROBES to use the ftrace infrastructure on PA-RISC. Signed-off-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Helge Deller <deller@gmx.de>
246 lines
5.4 KiB
C
246 lines
5.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Code for tracing calls in Linux kernel.
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* Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
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*
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* based on code for x86 which is:
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* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
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*
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* future possible enhancements:
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* - add CONFIG_STACK_TRACER
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*/
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#include <linux/init.h>
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#include <linux/ftrace.h>
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#include <linux/uaccess.h>
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#include <linux/kprobes.h>
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#include <linux/ptrace.h>
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#include <asm/assembly.h>
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#include <asm/sections.h>
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#include <asm/ftrace.h>
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#include <asm/patch.h>
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#define __hot __attribute__ ((__section__ (".text.hot")))
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/*
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* Hook the return address and push it in the stack of return addrs
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* in current thread info.
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*/
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static void __hot prepare_ftrace_return(unsigned long *parent,
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unsigned long self_addr)
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{
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unsigned long old;
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extern int parisc_return_to_handler;
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if (unlikely(ftrace_graph_is_dead()))
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return;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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old = *parent;
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if (!function_graph_enter(old, self_addr, 0, NULL))
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/* activate parisc_return_to_handler() as return point */
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*parent = (unsigned long) &parisc_return_to_handler;
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}
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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void notrace __hot ftrace_function_trampoline(unsigned long parent,
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unsigned long self_addr,
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unsigned long org_sp_gr3,
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struct pt_regs *regs)
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{
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#ifndef CONFIG_DYNAMIC_FTRACE
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extern ftrace_func_t ftrace_trace_function;
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#endif
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extern struct ftrace_ops *function_trace_op;
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if (function_trace_op->flags & FTRACE_OPS_FL_ENABLED &&
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ftrace_trace_function != ftrace_stub)
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ftrace_trace_function(self_addr, parent,
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function_trace_op, regs);
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
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ftrace_graph_entry != ftrace_graph_entry_stub) {
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unsigned long *parent_rp;
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/* calculate pointer to %rp in stack */
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parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
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/* sanity check: parent_rp should hold parent */
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if (*parent_rp != parent)
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return;
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prepare_ftrace_return(parent_rp, self_addr);
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return;
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}
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#endif
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}
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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int ftrace_enable_ftrace_graph_caller(void)
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{
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return 0;
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}
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int ftrace_disable_ftrace_graph_caller(void)
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{
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return 0;
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}
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#endif
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#ifdef CONFIG_DYNAMIC_FTRACE
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int __init ftrace_dyn_arch_init(void)
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{
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return 0;
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}
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int ftrace_update_ftrace_func(ftrace_func_t func)
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{
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return 0;
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}
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int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
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unsigned long addr)
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{
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return 0;
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}
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unsigned long ftrace_call_adjust(unsigned long addr)
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{
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return addr+(FTRACE_PATCHABLE_FUNCTION_SIZE-1)*4;
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}
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int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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{
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u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
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u32 *tramp;
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int size, ret, i;
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void *ip;
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#ifdef CONFIG_64BIT
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unsigned long addr2 =
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(unsigned long)dereference_function_descriptor((void *)addr);
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u32 ftrace_trampoline[] = {
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0x73c10208, /* std,ma r1,100(sp) */
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0x0c2110c1, /* ldd -10(r1),r1 */
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0xe820d002, /* bve,n (r1) */
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addr2 >> 32,
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addr2 & 0xffffffff,
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0xe83f1fd7, /* b,l,n .-14,r1 */
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};
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u32 ftrace_trampoline_unaligned[] = {
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addr2 >> 32,
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addr2 & 0xffffffff,
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0x37de0200, /* ldo 100(sp),sp */
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0x73c13e01, /* std r1,-100(sp) */
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0x34213ff9, /* ldo -4(r1),r1 */
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0x50213fc1, /* ldd -20(r1),r1 */
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0xe820d002, /* bve,n (r1) */
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0xe83f1fcf, /* b,l,n .-20,r1 */
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};
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BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline_unaligned) >
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FTRACE_PATCHABLE_FUNCTION_SIZE);
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#else
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u32 ftrace_trampoline[] = {
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(u32)addr,
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0x6fc10080, /* stw,ma r1,40(sp) */
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0x48213fd1, /* ldw -18(r1),r1 */
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0xe820c002, /* bv,n r0(r1) */
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0xe83f1fdf, /* b,l,n .-c,r1 */
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};
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#endif
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BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline) >
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FTRACE_PATCHABLE_FUNCTION_SIZE);
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size = sizeof(ftrace_trampoline);
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tramp = ftrace_trampoline;
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#ifdef CONFIG_64BIT
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if (rec->ip & 0x4) {
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size = sizeof(ftrace_trampoline_unaligned);
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tramp = ftrace_trampoline_unaligned;
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}
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#endif
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ip = (void *)(rec->ip + 4 - size);
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ret = probe_kernel_read(insn, ip, size);
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if (ret)
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return ret;
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for (i = 0; i < size / 4; i++) {
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if (insn[i] != INSN_NOP)
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return -EINVAL;
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}
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__patch_text_multiple(ip, tramp, size);
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return 0;
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}
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int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
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unsigned long addr)
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{
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u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
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int i;
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for (i = 0; i < ARRAY_SIZE(insn); i++)
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insn[i] = INSN_NOP;
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__patch_text((void *)rec->ip, INSN_NOP);
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__patch_text_multiple((void *)rec->ip + 4 - sizeof(insn),
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insn, sizeof(insn)-4);
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return 0;
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}
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#endif
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#ifdef CONFIG_KPROBES_ON_FTRACE
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void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *ops, struct pt_regs *regs)
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{
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struct kprobe_ctlblk *kcb;
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struct kprobe *p = get_kprobe((kprobe_opcode_t *)ip);
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if (unlikely(!p) || kprobe_disabled(p))
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return;
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if (kprobe_running()) {
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kprobes_inc_nmissed_count(p);
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return;
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}
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__this_cpu_write(current_kprobe, p);
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kcb = get_kprobe_ctlblk();
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kcb->kprobe_status = KPROBE_HIT_ACTIVE;
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regs->iaoq[0] = ip;
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regs->iaoq[1] = ip + 4;
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if (!p->pre_handler || !p->pre_handler(p, regs)) {
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regs->iaoq[0] = ip + 4;
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regs->iaoq[1] = ip + 8;
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if (unlikely(p->post_handler)) {
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kcb->kprobe_status = KPROBE_HIT_SSDONE;
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p->post_handler(p, regs, 0);
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}
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}
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__this_cpu_write(current_kprobe, NULL);
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}
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NOKPROBE_SYMBOL(kprobe_ftrace_handler);
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int arch_prepare_kprobe_ftrace(struct kprobe *p)
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{
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p->ainsn.insn = NULL;
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return 0;
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}
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#endif
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