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s390/ftrace: add HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALL support 

This is the s390 variant of commit 562955fe6a ("ftrace/x86: Add
register_ftrace_direct() for custom trampolines").

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20211012133802.2460757-2-hca@linux.ibm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2021-10-12 15:37:59 +02:00 committed by Vasily Gorbik
parent b2f583937a
commit 2ab3a0a9fa
3 changed files with 30 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/s390/Kconfig
View File

@ -154,6 +154,7 @@ config S390
select HAVE_DMA_CONTIGUOUS
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_ARGS
select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
select HAVE_EFFICIENT_UNALIGNED_ACCESS

12
arch/s390/include/asm/ftrace.h
View File

@ -58,6 +58,18 @@ static __always_inline void ftrace_instruction_pointer_set(struct ftrace_regs *f
regs->psw.addr = ip;
}
/*
* When an ftrace registered caller is tracing a function that is
* also set by a register_ftrace_direct() call, it needs to be
* differentiated in the ftrace_caller trampoline. To do this,
* place the direct caller in the ORIG_GPR2 part of pt_regs. This
* tells the ftrace_caller that there's a direct caller.
*/
static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
{
regs->orig_gpr2 = addr;
}
/*
* Even though the system call numbers are identical for s390/s390x a
* different system call table is used for compat tasks. This may lead

23
arch/s390/kernel/mcount.S
View File

@ -22,10 +22,11 @@ ENTRY(ftrace_stub)
BR_EX %r14
ENDPROC(ftrace_stub)
#define STACK_FRAME_SIZE (STACK_FRAME_OVERHEAD + __PT_SIZE)
#define STACK_PTREGS (STACK_FRAME_OVERHEAD)
#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
#define STACK_PTREGS_PSW (STACK_PTREGS + __PT_PSW)
#define STACK_FRAME_SIZE (STACK_FRAME_OVERHEAD + __PT_SIZE)
#define STACK_PTREGS (STACK_FRAME_OVERHEAD)
#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
#define STACK_PTREGS_PSW (STACK_PTREGS + __PT_PSW)
#define STACK_PTREGS_ORIG_GPR2 (STACK_PTREGS + __PT_ORIG_GPR2)
#ifdef __PACK_STACK
/* allocate just enough for r14, r15 and backchain */
#define TRACED_FUNC_FRAME_SIZE 24
@ -51,6 +52,7 @@ ENDPROC(ftrace_stub)
# allocate pt_regs and stack frame for ftrace_trace_function
aghi %r15,-STACK_FRAME_SIZE
stg %r1,(STACK_PTREGS_GPRS+15*8)(%r15)
xc STACK_PTREGS_ORIG_GPR2(8,%r15),STACK_PTREGS_ORIG_GPR2(%r15)
.if \allregs == 1
stg %r14,(STACK_PTREGS_PSW)(%r15)
@ -101,8 +103,17 @@ SYM_INNER_LABEL(ftrace_graph_caller, SYM_L_GLOBAL)
stg %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
.Lftrace_graph_caller_end:
#endif
lg %r1,(STACK_PTREGS_PSW+8)(%r15)
lmg %r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
lg %r0,(STACK_PTREGS_PSW+8)(%r15)
#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
ltg %r1,STACK_PTREGS_ORIG_GPR2(%r15)
locgrz %r1,%r0
#else
lg %r1,STACK_PTREGS_ORIG_GPR2(%r15)
ltgr %r1,%r1
jnz 0f
lgr %r1,%r0
#endif
0: lmg %r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
BR_EX %r1
SYM_CODE_END(ftrace_common)