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parisc/ftrace: Add KPROBES_ON_FTRACE
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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>
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Sven Schnelle authored and Helge Deller committed Aug 3, 2019
1 parent d562aca commit 52a22e6
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Showing 4 changed files with 157 additions and 4 deletions.
2 changes: 1 addition & 1 deletion Documentation/features/debug/kprobes-on-ftrace/arch-support.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@
| nds32: | TODO |
| nios2: | TODO |
| openrisc: | TODO |
| parisc: | TODO |
| parisc: | ok |
| powerpc: | ok |
| riscv: | TODO |
| s390: | TODO |
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2 changes: 2 additions & 0 deletions arch/parisc/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,8 @@ config PARISC
select HAVE_KRETPROBES
select HAVE_DYNAMIC_FTRACE if $(cc-option,-fpatchable-function-entry=1,1)
select HAVE_FTRACE_MCOUNT_RECORD if HAVE_DYNAMIC_FTRACE
select HAVE_KPROBES_ON_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_REGS

help
The PA-RISC microprocessor is designed by Hewlett-Packard and used
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99 changes: 99 additions & 0 deletions arch/parisc/kernel/entry.S
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Original file line number Diff line number Diff line change
Expand Up @@ -1996,6 +1996,7 @@ _mcount:
* calling mcount(), and 2 instructions for ftrace_stub(). That way we
* have all on one L1 cacheline.
*/
ldi 0, %arg3
b ftrace_function_trampoline
copy %r3, %arg2 /* caller original %sp */
ftrace_stub:
Expand Down Expand Up @@ -2048,6 +2049,7 @@ ftrace_caller:
LDREG 0(%r3), %r25
copy %rp, %r26
ldo -8(%r25), %r25
ldi 0, %r23 /* no pt_regs */
b,l ftrace_function_trampoline, %rp
copy %r3, %r24

Expand Down Expand Up @@ -2075,6 +2077,103 @@ ftrace_caller:

ENDPROC_CFI(ftrace_caller)

#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS
ENTRY_CFI(ftrace_regs_caller,caller,frame=FTRACE_FRAME_SIZE+PT_SZ_ALGN,
CALLS,SAVE_RP,SAVE_SP)
ftrace_regs_caller:
.global ftrace_regs_caller

ldo -FTRACE_FRAME_SIZE(%sp), %r1
STREG %rp, -RP_OFFSET(%r1)

copy %sp, %r1
ldo PT_SZ_ALGN(%sp), %sp

STREG %rp, PT_GR2(%r1)
STREG %r3, PT_GR3(%r1)
STREG %r4, PT_GR4(%r1)
STREG %r5, PT_GR5(%r1)
STREG %r6, PT_GR6(%r1)
STREG %r7, PT_GR7(%r1)
STREG %r8, PT_GR8(%r1)
STREG %r9, PT_GR9(%r1)
STREG %r10, PT_GR10(%r1)
STREG %r11, PT_GR11(%r1)
STREG %r12, PT_GR12(%r1)
STREG %r13, PT_GR13(%r1)
STREG %r14, PT_GR14(%r1)
STREG %r15, PT_GR15(%r1)
STREG %r16, PT_GR16(%r1)
STREG %r17, PT_GR17(%r1)
STREG %r18, PT_GR18(%r1)
STREG %r19, PT_GR19(%r1)
STREG %r20, PT_GR20(%r1)
STREG %r21, PT_GR21(%r1)
STREG %r22, PT_GR22(%r1)
STREG %r23, PT_GR23(%r1)
STREG %r24, PT_GR24(%r1)
STREG %r25, PT_GR25(%r1)
STREG %r26, PT_GR26(%r1)
STREG %r27, PT_GR27(%r1)
STREG %r28, PT_GR28(%r1)
STREG %r29, PT_GR29(%r1)
STREG %r30, PT_GR30(%r1)
STREG %r31, PT_GR31(%r1)
mfctl %cr11, %r26
STREG %r26, PT_SAR(%r1)

copy %rp, %r26
LDREG -FTRACE_FRAME_SIZE-PT_SZ_ALGN(%sp), %r25
ldo -8(%r25), %r25
copy %r3, %arg2
b,l ftrace_function_trampoline, %rp
copy %r1, %arg3 /* struct pt_regs */

ldo -PT_SZ_ALGN(%sp), %r1

LDREG PT_SAR(%r1), %rp
mtctl %rp, %cr11

LDREG PT_GR2(%r1), %rp
LDREG PT_GR3(%r1), %r3
LDREG PT_GR4(%r1), %r4
LDREG PT_GR5(%r1), %r5
LDREG PT_GR6(%r1), %r6
LDREG PT_GR7(%r1), %r7
LDREG PT_GR8(%r1), %r8
LDREG PT_GR9(%r1), %r9
LDREG PT_GR10(%r1),%r10
LDREG PT_GR11(%r1),%r11
LDREG PT_GR12(%r1),%r12
LDREG PT_GR13(%r1),%r13
LDREG PT_GR14(%r1),%r14
LDREG PT_GR15(%r1),%r15
LDREG PT_GR16(%r1),%r16
LDREG PT_GR17(%r1),%r17
LDREG PT_GR18(%r1),%r18
LDREG PT_GR19(%r1),%r19
LDREG PT_GR20(%r1),%r20
LDREG PT_GR21(%r1),%r21
LDREG PT_GR22(%r1),%r22
LDREG PT_GR23(%r1),%r23
LDREG PT_GR24(%r1),%r24
LDREG PT_GR25(%r1),%r25
LDREG PT_GR26(%r1),%r26
LDREG PT_GR27(%r1),%r27
LDREG PT_GR28(%r1),%r28
LDREG PT_GR29(%r1),%r29
LDREG PT_GR30(%r1),%r30
LDREG PT_GR31(%r1),%r31

ldo -PT_SZ_ALGN(%sp), %sp
LDREGM -FTRACE_FRAME_SIZE(%sp), %r1
/* Adjust return point to jump back to beginning of traced function */
ldo -4(%r1), %r1
bv,n (%r1)

ENDPROC_CFI(ftrace_regs_caller)

#endif
#endif

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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58 changes: 55 additions & 3 deletions arch/parisc/kernel/ftrace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@
#include <linux/init.h>
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>

#include <asm/assembly.h>
#include <asm/sections.h>
Expand Down Expand Up @@ -48,7 +50,8 @@ static void __hot prepare_ftrace_return(unsigned long *parent,

void notrace __hot ftrace_function_trampoline(unsigned long parent,
unsigned long self_addr,
unsigned long org_sp_gr3)
unsigned long org_sp_gr3,
struct pt_regs *regs)
{
#ifndef CONFIG_DYNAMIC_FTRACE
extern ftrace_func_t ftrace_trace_function;
Expand All @@ -58,11 +61,11 @@ void notrace __hot ftrace_function_trampoline(unsigned long parent,
if (function_trace_op->flags & FTRACE_OPS_FL_ENABLED &&
ftrace_trace_function != ftrace_stub)
ftrace_trace_function(self_addr, parent,
function_trace_op, NULL);
function_trace_op, regs);

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
ftrace_graph_entry != ftrace_graph_entry_stub) {
ftrace_graph_entry != ftrace_graph_entry_stub) {
unsigned long *parent_rp;

/* calculate pointer to %rp in stack */
Expand Down Expand Up @@ -100,6 +103,12 @@ int ftrace_update_ftrace_func(ftrace_func_t 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;
Expand Down Expand Up @@ -191,3 +200,46 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
return 0;
}
#endif

#ifdef CONFIG_KPROBES_ON_FTRACE
void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ops, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb;
struct kprobe *p = get_kprobe((kprobe_opcode_t *)ip);

if (unlikely(!p) || kprobe_disabled(p))
return;

if (kprobe_running()) {
kprobes_inc_nmissed_count(p);
return;
}

__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);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);

int arch_prepare_kprobe_ftrace(struct kprobe *p)
{
p->ainsn.insn = NULL;
return 0;
}
#endif

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