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-rw-r--r--arch/s390/include/asm/ftrace.h52
-rw-r--r--arch/s390/include/asm/kprobes.h1
-rw-r--r--arch/s390/include/asm/lowcore.h4
-rw-r--r--arch/s390/include/asm/pgtable.h12
-rw-r--r--arch/s390/kernel/asm-offsets.c1
-rw-r--r--arch/s390/kernel/early.c4
-rw-r--r--arch/s390/kernel/ftrace.c132
-rw-r--r--arch/s390/kernel/kprobes.c92
-rw-r--r--arch/s390/kernel/mcount.S1
-rw-r--r--arch/s390/kernel/setup.c2
-rw-r--r--arch/s390/kernel/smp.c1
11 files changed, 212 insertions, 90 deletions
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 3aef8afec336..785041f1dc77 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -1,25 +1,67 @@
#ifndef _ASM_S390_FTRACE_H
#define _ASM_S390_FTRACE_H
+#define ARCH_SUPPORTS_FTRACE_OPS 1
+
+#define MCOUNT_INSN_SIZE 24
+#define MCOUNT_RETURN_FIXUP 18
+
#ifndef __ASSEMBLY__
-extern void _mcount(void);
+void _mcount(void);
+void ftrace_caller(void);
+
extern char ftrace_graph_caller_end;
+extern unsigned long ftrace_plt;
struct dyn_arch_ftrace { };
-#define MCOUNT_ADDR ((long)_mcount)
+#define MCOUNT_ADDR ((unsigned long)_mcount)
+#define FTRACE_ADDR ((unsigned long)ftrace_caller)
+#define KPROBE_ON_FTRACE_NOP 0
+#define KPROBE_ON_FTRACE_CALL 1
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
return addr;
}
-#endif /* __ASSEMBLY__ */
+struct ftrace_insn {
+ u16 opc;
+ s32 disp;
+} __packed;
-#define MCOUNT_INSN_SIZE 18
+static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+ /* jg .+24 */
+ insn->opc = 0xc0f4;
+ insn->disp = MCOUNT_INSN_SIZE / 2;
+#endif
+}
-#define ARCH_SUPPORTS_FTRACE_OPS 1
+static inline int is_ftrace_nop(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+ if (insn->disp == MCOUNT_INSN_SIZE / 2)
+ return 1;
+#endif
+ return 0;
+}
+
+static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
+ unsigned long ip)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+ unsigned long target;
+ /* brasl r0,ftrace_caller */
+ target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
+ insn->opc = 0xc005;
+ insn->disp = (target - ip) / 2;
+#endif
+}
+
+#endif /* __ASSEMBLY__ */
#endif /* _ASM_S390_FTRACE_H */
diff --git a/arch/s390/include/asm/kprobes.h b/arch/s390/include/asm/kprobes.h
index 98629173ce3b..b47ad3b642cc 100644
--- a/arch/s390/include/asm/kprobes.h
+++ b/arch/s390/include/asm/kprobes.h
@@ -60,6 +60,7 @@ typedef u16 kprobe_opcode_t;
struct arch_specific_insn {
/* copy of original instruction */
kprobe_opcode_t *insn;
+ unsigned int is_ftrace_insn : 1;
};
struct prev_kprobe {
diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index 6cc51fe84410..34fbcac61133 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -147,7 +147,7 @@ struct _lowcore {
__u32 softirq_pending; /* 0x02ec */
__u32 percpu_offset; /* 0x02f0 */
__u32 machine_flags; /* 0x02f4 */
- __u32 ftrace_func; /* 0x02f8 */
+ __u8 pad_0x02f8[0x02fc-0x02f8]; /* 0x02f8 */
__u32 spinlock_lockval; /* 0x02fc */
__u8 pad_0x0300[0x0e00-0x0300]; /* 0x0300 */
@@ -297,7 +297,7 @@ struct _lowcore {
__u64 percpu_offset; /* 0x0378 */
__u64 vdso_per_cpu_data; /* 0x0380 */
__u64 machine_flags; /* 0x0388 */
- __u64 ftrace_func; /* 0x0390 */
+ __u8 pad_0x0390[0x0398-0x0390]; /* 0x0390 */
__u64 gmap; /* 0x0398 */
__u32 spinlock_lockval; /* 0x03a0 */
__u8 pad_0x03a0[0x0400-0x03a4]; /* 0x03a4 */
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 00d460742e1e..5ef1a266936a 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -133,6 +133,18 @@ extern unsigned long MODULES_END;
#define MODULES_LEN (1UL << 31)
#endif
+static inline int is_module_addr(void *addr)
+{
+#ifdef CONFIG_64BIT
+ BUILD_BUG_ON(MODULES_LEN > (1UL << 31));
+ if (addr < (void *)MODULES_VADDR)
+ return 0;
+ if (addr > (void *)MODULES_END)
+ return 0;
+#endif
+ return 1;
+}
+
/*
* A 31 bit pagetable entry of S390 has following format:
* | PFRA | | OS |
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index ef279a136801..f3a78337ca86 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -156,7 +156,6 @@ int main(void)
DEFINE(__LC_INT_CLOCK, offsetof(struct _lowcore, int_clock));
DEFINE(__LC_MCCK_CLOCK, offsetof(struct _lowcore, mcck_clock));
DEFINE(__LC_MACHINE_FLAGS, offsetof(struct _lowcore, machine_flags));
- DEFINE(__LC_FTRACE_FUNC, offsetof(struct _lowcore, ftrace_func));
DEFINE(__LC_DUMP_REIPL, offsetof(struct _lowcore, ipib));
BLANK();
DEFINE(__LC_CPU_TIMER_SAVE_AREA, offsetof(struct _lowcore, cpu_timer_save_area));
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index cef2879edff3..302ac1f7f8e7 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -12,7 +12,6 @@
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/ctype.h>
-#include <linux/ftrace.h>
#include <linux/lockdep.h>
#include <linux/module.h>
#include <linux/pfn.h>
@@ -490,8 +489,5 @@ void __init startup_init(void)
detect_machine_facilities();
setup_topology();
sclp_early_detect();
-#ifdef CONFIG_DYNAMIC_FTRACE
- S390_lowcore.ftrace_func = (unsigned long)ftrace_caller;
-#endif
lockdep_on();
}
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 51d14fe5eb9a..5744d25c1d33 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -7,6 +7,7 @@
* Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
+#include <linux/moduleloader.h>
#include <linux/hardirq.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
@@ -15,60 +16,39 @@
#include <linux/kprobes.h>
#include <trace/syscall.h>
#include <asm/asm-offsets.h>
+#include <asm/cacheflush.h>
#include "entry.h"
-void mcount_replace_code(void);
-void ftrace_disable_code(void);
-void ftrace_enable_insn(void);
-
/*
* The mcount code looks like this:
* stg %r14,8(%r15) # offset 0
* larl %r1,<&counter> # offset 6
* brasl %r14,_mcount # offset 12
* lg %r14,8(%r15) # offset 18
- * Total length is 24 bytes. The complete mcount block initially gets replaced
- * by ftrace_make_nop. Subsequent calls to ftrace_make_call / ftrace_make_nop
- * only patch the jg/lg instruction within the block.
- * Note: we do not patch the first instruction to an unconditional branch,
- * since that would break kprobes/jprobes. It is easier to leave the larl
- * instruction in and only modify the second instruction.
+ * Total length is 24 bytes. Only the first instruction will be patched
+ * by ftrace_make_call / ftrace_make_nop.
* The enabled ftrace code block looks like this:
- * larl %r0,.+24 # offset 0
- * > lg %r1,__LC_FTRACE_FUNC # offset 6
- * br %r1 # offset 12
- * brcl 0,0 # offset 14
- * brc 0,0 # offset 20
+ * > brasl %r0,ftrace_caller # offset 0
+ * larl %r1,<&counter> # offset 6
+ * brasl %r14,_mcount # offset 12
+ * lg %r14,8(%r15) # offset 18
* The ftrace function gets called with a non-standard C function call ABI
* where r0 contains the return address. It is also expected that the called
* function only clobbers r0 and r1, but restores r2-r15.
+ * For module code we can't directly jump to ftrace caller, but need a
+ * trampoline (ftrace_plt), which clobbers also r1.
* The return point of the ftrace function has offset 24, so execution
* continues behind the mcount block.
- * larl %r0,.+24 # offset 0
- * > jg .+18 # offset 6
- * br %r1 # offset 12
- * brcl 0,0 # offset 14
- * brc 0,0 # offset 20
+ * The disabled ftrace code block looks like this:
+ * > jg .+24 # offset 0
+ * larl %r1,<&counter> # offset 6
+ * brasl %r14,_mcount # offset 12
+ * lg %r14,8(%r15) # offset 18
* The jg instruction branches to offset 24 to skip as many instructions
* as possible.
*/
-asm(
- " .align 4\n"
- "mcount_replace_code:\n"
- " larl %r0,0f\n"
- "ftrace_disable_code:\n"
- " jg 0f\n"
- " br %r1\n"
- " brcl 0,0\n"
- " brc 0,0\n"
- "0:\n"
- " .align 4\n"
- "ftrace_enable_insn:\n"
- " lg %r1,"__stringify(__LC_FTRACE_FUNC)"\n");
-
-#define MCOUNT_BLOCK_SIZE 24
-#define MCOUNT_INSN_OFFSET 6
-#define FTRACE_INSN_SIZE 6
+
+unsigned long ftrace_plt;
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
@@ -79,24 +59,62 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
unsigned long addr)
{
- /* Initial replacement of the whole mcount block */
- if (addr == MCOUNT_ADDR) {
- if (probe_kernel_write((void *) rec->ip - MCOUNT_INSN_OFFSET,
- mcount_replace_code,
- MCOUNT_BLOCK_SIZE))
- return -EPERM;
- return 0;
+ struct ftrace_insn insn;
+ unsigned short op;
+ void *from, *to;
+ size_t size;
+
+ ftrace_generate_nop_insn(&insn);
+ size = sizeof(insn);
+ from = &insn;
+ to = (void *) rec->ip;
+ if (probe_kernel_read(&op, (void *) rec->ip, sizeof(op)))
+ return -EFAULT;
+ /*
+ * If we find a breakpoint instruction, a kprobe has been placed
+ * at the beginning of the function. We write the constant
+ * KPROBE_ON_FTRACE_NOP into the remaining four bytes of the original
+ * instruction so that the kprobes handler can execute a nop, if it
+ * reaches this breakpoint.
+ */
+ if (op == BREAKPOINT_INSTRUCTION) {
+ size -= 2;
+ from += 2;
+ to += 2;
+ insn.disp = KPROBE_ON_FTRACE_NOP;
}
- if (probe_kernel_write((void *) rec->ip, ftrace_disable_code,
- MCOUNT_INSN_SIZE))
+ if (probe_kernel_write(to, from, size))
return -EPERM;
return 0;
}
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
- if (probe_kernel_write((void *) rec->ip, ftrace_enable_insn,
- FTRACE_INSN_SIZE))
+ struct ftrace_insn insn;
+ unsigned short op;
+ void *from, *to;
+ size_t size;
+
+ ftrace_generate_call_insn(&insn, rec->ip);
+ size = sizeof(insn);
+ from = &insn;
+ to = (void *) rec->ip;
+ if (probe_kernel_read(&op, (void *) rec->ip, sizeof(op)))
+ return -EFAULT;
+ /*
+ * If we find a breakpoint instruction, a kprobe has been placed
+ * at the beginning of the function. We write the constant
+ * KPROBE_ON_FTRACE_CALL into the remaining four bytes of the original
+ * instruction so that the kprobes handler can execute a brasl if it
+ * reaches this breakpoint.
+ */
+ if (op == BREAKPOINT_INSTRUCTION) {
+ size -= 2;
+ from += 2;
+ to += 2;
+ insn.disp = KPROBE_ON_FTRACE_CALL;
+ }
+ if (probe_kernel_write(to, from, size))
return -EPERM;
return 0;
}
@@ -111,6 +129,24 @@ int __init ftrace_dyn_arch_init(void)
return 0;
}
+static int __init ftrace_plt_init(void)
+{
+ unsigned int *ip;
+
+ ftrace_plt = (unsigned long) module_alloc(PAGE_SIZE);
+ if (!ftrace_plt)
+ panic("cannot allocate ftrace plt\n");
+ ip = (unsigned int *) ftrace_plt;
+ ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */
+ ip[1] = 0x100a0004;
+ ip[2] = 0x07f10000;
+ ip[3] = FTRACE_ADDR >> 32;
+ ip[4] = FTRACE_ADDR & 0xffffffff;
+ set_memory_ro(ftrace_plt, 1);
+ return 0;
+}
+device_initcall(ftrace_plt_init);
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/*
* Hook the return address and push it in the stack of return addresses
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 014d4729b134..d6716c29b7f8 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -29,6 +29,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/hardirq.h>
+#include <linux/ftrace.h>
#include <asm/cacheflush.h>
#include <asm/sections.h>
#include <asm/dis.h>
@@ -60,10 +61,21 @@ struct kprobe_insn_cache kprobe_dmainsn_slots = {
static void __kprobes copy_instruction(struct kprobe *p)
{
+ unsigned long ip = (unsigned long) p->addr;
s64 disp, new_disp;
u64 addr, new_addr;
- memcpy(p->ainsn.insn, p->addr, insn_length(p->opcode >> 8));
+ if (ftrace_location(ip) == ip) {
+ /*
+ * If kprobes patches the instruction that is morphed by
+ * ftrace make sure that kprobes always sees the branch
+ * "jg .+24" that skips the mcount block
+ */
+ ftrace_generate_nop_insn((struct ftrace_insn *)p->ainsn.insn);
+ p->ainsn.is_ftrace_insn = 1;
+ } else
+ memcpy(p->ainsn.insn, p->addr, insn_length(p->opcode >> 8));
+ p->opcode = p->ainsn.insn[0];
if (!probe_is_insn_relative_long(p->ainsn.insn))
return;
/*
@@ -85,18 +97,6 @@ static inline int is_kernel_addr(void *addr)
return addr < (void *)_end;
}
-static inline int is_module_addr(void *addr)
-{
-#ifdef CONFIG_64BIT
- BUILD_BUG_ON(MODULES_LEN > (1UL << 31));
- if (addr < (void *)MODULES_VADDR)
- return 0;
- if (addr > (void *)MODULES_END)
- return 0;
-#endif
- return 1;
-}
-
static int __kprobes s390_get_insn_slot(struct kprobe *p)
{
/*
@@ -132,43 +132,63 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return -EINVAL;
if (s390_get_insn_slot(p))
return -ENOMEM;
- p->opcode = *p->addr;
copy_instruction(p);
return 0;
}
-struct ins_replace_args {
- kprobe_opcode_t *ptr;
- kprobe_opcode_t opcode;
+int arch_check_ftrace_location(struct kprobe *p)
+{
+ return 0;
+}
+
+struct swap_insn_args {
+ struct kprobe *p;
+ unsigned int arm_kprobe : 1;
};
-static int __kprobes swap_instruction(void *aref)
+static int __kprobes swap_instruction(void *data)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
unsigned long status = kcb->kprobe_status;
- struct ins_replace_args *args = aref;
-
+ struct swap_insn_args *args = data;
+ struct ftrace_insn new_insn, *insn;
+ struct kprobe *p = args->p;
+ size_t len;
+
+ new_insn.opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode;
+ len = sizeof(new_insn.opc);
+ if (!p->ainsn.is_ftrace_insn)
+ goto skip_ftrace;
+ len = sizeof(new_insn);
+ insn = (struct ftrace_insn *) p->addr;
+ if (args->arm_kprobe) {
+ if (is_ftrace_nop(insn))
+ new_insn.disp = KPROBE_ON_FTRACE_NOP;
+ else
+ new_insn.disp = KPROBE_ON_FTRACE_CALL;
+ } else {
+ ftrace_generate_call_insn(&new_insn, (unsigned long)p->addr);
+ if (insn->disp == KPROBE_ON_FTRACE_NOP)
+ ftrace_generate_nop_insn(&new_insn);
+ }
+skip_ftrace:
kcb->kprobe_status = KPROBE_SWAP_INST;
- probe_kernel_write(args->ptr, &args->opcode, sizeof(args->opcode));
+ probe_kernel_write(p->addr, &new_insn, len);
kcb->kprobe_status = status;
return 0;
}
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
- struct ins_replace_args args;
+ struct swap_insn_args args = {.p = p, .arm_kprobe = 1};
- args.ptr = p->addr;
- args.opcode = BREAKPOINT_INSTRUCTION;
stop_machine(swap_instruction, &args, NULL);
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
- struct ins_replace_args args;
+ struct swap_insn_args args = {.p = p, .arm_kprobe = 0};
- args.ptr = p->addr;
- args.opcode = p->opcode;
stop_machine(swap_instruction, &args, NULL);
}
@@ -459,6 +479,24 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
unsigned long ip = regs->psw.addr & PSW_ADDR_INSN;
int fixup = probe_get_fixup_type(p->ainsn.insn);
+ /* Check if the kprobes location is an enabled ftrace caller */
+ if (p->ainsn.is_ftrace_insn) {
+ struct ftrace_insn *insn = (struct ftrace_insn *) p->addr;
+ struct ftrace_insn call_insn;
+
+ ftrace_generate_call_insn(&call_insn, (unsigned long) p->addr);
+ /*
+ * A kprobe on an enabled ftrace call site actually single
+ * stepped an unconditional branch (ftrace nop equivalent).
+ * Now we need to fixup things and pretend that a brasl r0,...
+ * was executed instead.
+ */
+ if (insn->disp == KPROBE_ON_FTRACE_CALL) {
+ ip += call_insn.disp * 2 - MCOUNT_INSN_SIZE;
+ regs->gprs[0] = (unsigned long)p->addr + sizeof(*insn);
+ }
+ }
+
if (fixup & FIXUP_PSW_NORMAL)
ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn;
diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
index 4300ea374826..b6dfc5bfcb89 100644
--- a/arch/s390/kernel/mcount.S
+++ b/arch/s390/kernel/mcount.S
@@ -27,6 +27,7 @@ ENTRY(ftrace_caller)
.globl ftrace_regs_caller
.set ftrace_regs_caller,ftrace_caller
lgr %r1,%r15
+ aghi %r0,MCOUNT_RETURN_FIXUP
aghi %r15,-STACK_FRAME_SIZE
stg %r1,__SF_BACKCHAIN(%r15)
stg %r1,(STACK_PTREGS_GPRS+15*8)(%r15)
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index e80d9ff9a56d..4e532c67832f 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -41,7 +41,6 @@
#include <linux/ctype.h>
#include <linux/reboot.h>
#include <linux/topology.h>
-#include <linux/ftrace.h>
#include <linux/kexec.h>
#include <linux/crash_dump.h>
#include <linux/memory.h>
@@ -356,7 +355,6 @@ static void __init setup_lowcore(void)
lc->steal_timer = S390_lowcore.steal_timer;
lc->last_update_timer = S390_lowcore.last_update_timer;
lc->last_update_clock = S390_lowcore.last_update_clock;
- lc->ftrace_func = S390_lowcore.ftrace_func;
restart_stack = __alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0);
restart_stack += ASYNC_SIZE;
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 6fd9e60101f1..0b499f5cbe19 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -236,7 +236,6 @@ static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
lc->percpu_offset = __per_cpu_offset[cpu];
lc->kernel_asce = S390_lowcore.kernel_asce;
lc->machine_flags = S390_lowcore.machine_flags;
- lc->ftrace_func = S390_lowcore.ftrace_func;
lc->user_timer = lc->system_timer = lc->steal_timer = 0;
__ctl_store(lc->cregs_save_area, 0, 15);
save_access_regs((unsigned int *) lc->access_regs_save_area);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-27 21:50:33 +0000