linux_dsm_epyc7002/arch/s390/kernel/entry.h
Sven Schnelle 17248ea036 s390: fix __EMIT_BUG() macro
Setting a kprobe on getname_flags() failed:

$ echo 'p:tmr1 getname_flags +0(%r2):ustring' > kprobe_events
-bash: echo: write error: Invalid argument

Debugging the kprobes code showed that the address of
getname_flags() is contained in the __bug_table. Kprobes
doesn't allow to set probes at BUG() locations.

$ objdump -j  __bug_table -x build/fs/namei.o
[..]
0000000000000108 R_390_PC32        .text+0x00000000000075a8
000000000000010c R_390_PC32        .L223+0x0000000000000004

I was expecting getname_flags() to start with a BUG(), but:

7598:       e3 20 10 00 00 04       lg      %r2,0(%r1)
759e:       c0 f4 00 00 00 00       jg      759e <putname+0x7e>
75a0: R_390_PLT32DBL    kmem_cache_free+0x2
75a4:       a7 f4 00 01             j       75a6 <putname+0x86>

00000000000075a8 <getname_flags>:
75a8:       c0 04 00 00 00 00       brcl    0,75a8 <getname_flags>
75ae:       eb 6f f0 48 00 24       stmg    %r6,%r15,72(%r15)
75b4:       b9 04 00 ef             lgr     %r14,%r15
75b8:       e3 f0 ff a8 ff 71       lay     %r15,-88(%r15)

So the BUG() is actually the last opcode of the previous function.
Fix this by switching to using the MONITOR CALL (MC) instruction,
and set the entry in __bug_table to the beginning of that MC.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-01-22 13:05:35 +01:00

93 lines
3.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ENTRY_H
#define _ENTRY_H
#include <linux/percpu.h>
#include <linux/types.h>
#include <linux/signal.h>
#include <asm/ptrace.h>
#include <asm/idle.h>
extern void *restart_stack;
extern unsigned long suspend_zero_pages;
void system_call(void);
void pgm_check_handler(void);
void ext_int_handler(void);
void io_int_handler(void);
void mcck_int_handler(void);
void restart_int_handler(void);
void restart_call_handler(void);
asmlinkage long do_syscall_trace_enter(struct pt_regs *regs);
asmlinkage void do_syscall_trace_exit(struct pt_regs *regs);
void do_protection_exception(struct pt_regs *regs);
void do_dat_exception(struct pt_regs *regs);
void addressing_exception(struct pt_regs *regs);
void data_exception(struct pt_regs *regs);
void default_trap_handler(struct pt_regs *regs);
void divide_exception(struct pt_regs *regs);
void execute_exception(struct pt_regs *regs);
void hfp_divide_exception(struct pt_regs *regs);
void hfp_overflow_exception(struct pt_regs *regs);
void hfp_significance_exception(struct pt_regs *regs);
void hfp_sqrt_exception(struct pt_regs *regs);
void hfp_underflow_exception(struct pt_regs *regs);
void illegal_op(struct pt_regs *regs);
void operand_exception(struct pt_regs *regs);
void overflow_exception(struct pt_regs *regs);
void privileged_op(struct pt_regs *regs);
void space_switch_exception(struct pt_regs *regs);
void special_op_exception(struct pt_regs *regs);
void specification_exception(struct pt_regs *regs);
void transaction_exception(struct pt_regs *regs);
void translation_exception(struct pt_regs *regs);
void vector_exception(struct pt_regs *regs);
void monitor_event_exception(struct pt_regs *regs);
void do_per_trap(struct pt_regs *regs);
void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str);
void syscall_trace(struct pt_regs *regs, int entryexit);
void kernel_stack_overflow(struct pt_regs * regs);
void do_signal(struct pt_regs *regs);
void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
struct pt_regs *regs);
void do_notify_resume(struct pt_regs *regs);
void __init init_IRQ(void);
void do_IRQ(struct pt_regs *regs, int irq);
void do_restart(void);
void __init startup_init_nobss(void);
void __init startup_init(void);
void die(struct pt_regs *regs, const char *str);
int setup_profiling_timer(unsigned int multiplier);
void __init time_init(void);
void s390_early_resume(void);
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long sp, unsigned long ip);
struct s390_mmap_arg_struct;
struct fadvise64_64_args;
struct old_sigaction;
long sys_rt_sigreturn(void);
long sys_sigreturn(void);
long sys_s390_personality(unsigned int personality);
long sys_s390_runtime_instr(int command, int signum);
long sys_s390_guarded_storage(int command, struct gs_cb __user *);
long sys_s390_pci_mmio_write(unsigned long, const void __user *, size_t);
long sys_s390_pci_mmio_read(unsigned long, void __user *, size_t);
long sys_s390_sthyi(unsigned long function_code, void __user *buffer, u64 __user *return_code, unsigned long flags);
DECLARE_PER_CPU(u64, mt_cycles[8]);
void gs_load_bc_cb(struct pt_regs *regs);
void set_fs_fixup(void);
unsigned long stack_alloc(void);
void stack_free(unsigned long stack);
#endif /* _ENTRY_H */