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-rw-r--r--arch/s390/include/asm/ftrace.h46
-rw-r--r--arch/s390/include/asm/ftrace.lds.h21
-rw-r--r--arch/s390/include/asm/module.h8
-rw-r--r--arch/s390/kernel/ftrace.c222
-rw-r--r--arch/s390/kernel/ftrace.h26
-rw-r--r--arch/s390/kernel/module.c45
-rw-r--r--arch/s390/kernel/vmlinux.lds.S2
7 files changed, 313 insertions, 57 deletions
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 345cbe982a8b..e8b460f39c58 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -18,7 +18,6 @@
void ftrace_caller(void);
extern char ftrace_graph_caller_end;
-extern unsigned long ftrace_plt;
extern void *ftrace_func;
struct dyn_arch_ftrace { };
@@ -31,10 +30,11 @@ struct dyn_arch_ftrace { };
struct module;
struct dyn_ftrace;
-/*
- * Either -mhotpatch or -mnop-mcount is used - no explicit init is required
- */
-static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { return 0; }
+
+bool ftrace_need_init_nop(void);
+#define ftrace_need_init_nop ftrace_need_init_nop
+
+int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
#define ftrace_init_nop ftrace_init_nop
static inline unsigned long ftrace_call_adjust(unsigned long addr)
@@ -42,42 +42,6 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
return addr;
}
-struct ftrace_insn {
- u16 opc;
- s32 disp;
-} __packed;
-
-static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
-{
-#ifdef CONFIG_FUNCTION_TRACER
- /* brcl 0,0 */
- insn->opc = 0xc004;
- insn->disp = 0;
-#endif
-}
-
-static inline int is_ftrace_nop(struct ftrace_insn *insn)
-{
-#ifdef CONFIG_FUNCTION_TRACER
- if (insn->disp == 0)
- 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
-}
-
/*
* Even though the system call numbers are identical for s390/s390x a
* different system call table is used for compat tasks. This may lead
diff --git a/arch/s390/include/asm/ftrace.lds.h b/arch/s390/include/asm/ftrace.lds.h
new file mode 100644
index 000000000000..968adfd41240
--- /dev/null
+++ b/arch/s390/include/asm/ftrace.lds.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef DIV_ROUND_UP
+#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+#endif
+
+#define SIZEOF_MCOUNT_LOC_ENTRY 8
+#define SIZEOF_FTRACE_HOTPATCH_TRAMPOLINE 24
+#define FTRACE_HOTPATCH_TRAMPOLINES_SIZE(n) \
+ DIV_ROUND_UP(SIZEOF_FTRACE_HOTPATCH_TRAMPOLINE * (n), \
+ SIZEOF_MCOUNT_LOC_ENTRY)
+
+#ifdef CONFIG_FUNCTION_TRACER
+#define FTRACE_HOTPATCH_TRAMPOLINES_TEXT \
+ . = ALIGN(8); \
+ __ftrace_hotpatch_trampolines_start = .; \
+ . = . + FTRACE_HOTPATCH_TRAMPOLINES_SIZE(__stop_mcount_loc - \
+ __start_mcount_loc); \
+ __ftrace_hotpatch_trampolines_end = .;
+#else
+#define FTRACE_HOTPATCH_TRAMPOLINES_TEXT
+#endif
diff --git a/arch/s390/include/asm/module.h b/arch/s390/include/asm/module.h
index 71e57b8af757..9f1eea15872c 100644
--- a/arch/s390/include/asm/module.h
+++ b/arch/s390/include/asm/module.h
@@ -28,6 +28,14 @@ struct mod_arch_specific {
int nsyms;
/* Additional symbol information (got and plt offsets). */
struct mod_arch_syminfo *syminfo;
+#ifdef CONFIG_FUNCTION_TRACER
+ /* Start of memory reserved for ftrace hotpatch trampolines. */
+ struct ftrace_hotpatch_trampoline *trampolines_start;
+ /* End of memory reserved for ftrace hotpatch trampolines. */
+ struct ftrace_hotpatch_trampoline *trampolines_end;
+ /* Next unused ftrace hotpatch trampoline slot. */
+ struct ftrace_hotpatch_trampoline *next_trampoline;
+#endif /* CONFIG_FUNCTION_TRACER */
};
#endif /* _ASM_S390_MODULE_H */
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 2d8f595d9196..0a464d328467 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -18,8 +18,11 @@
#include <trace/syscall.h>
#include <asm/asm-offsets.h>
#include <asm/cacheflush.h>
+#include <asm/ftrace.lds.h>
+#include <asm/nospec-branch.h>
#include <asm/set_memory.h>
#include "entry.h"
+#include "ftrace.h"
/*
* To generate function prologue either gcc's hotpatch feature (since gcc 4.8)
@@ -41,7 +44,130 @@
*/
void *ftrace_func __read_mostly = ftrace_stub;
-unsigned long ftrace_plt;
+struct ftrace_insn {
+ u16 opc;
+ s32 disp;
+} __packed;
+
+asm(
+ " .align 16\n"
+ "ftrace_shared_hotpatch_trampoline_br:\n"
+ " lmg %r0,%r1,2(%r1)\n"
+ " br %r1\n"
+ "ftrace_shared_hotpatch_trampoline_br_end:\n"
+);
+
+#ifdef CONFIG_EXPOLINE
+asm(
+ " .align 16\n"
+ "ftrace_shared_hotpatch_trampoline_ex:\n"
+ " lmg %r0,%r1,2(%r1)\n"
+ " ex %r0," __stringify(__LC_BR_R1) "(%r0)\n"
+ " j .\n"
+ "ftrace_shared_hotpatch_trampoline_ex_end:\n"
+);
+
+asm(
+ " .align 16\n"
+ "ftrace_shared_hotpatch_trampoline_exrl:\n"
+ " lmg %r0,%r1,2(%r1)\n"
+ " .insn ril,0xc60000000000,%r0,0f\n" /* exrl */
+ " j .\n"
+ "0: br %r1\n"
+ "ftrace_shared_hotpatch_trampoline_exrl_end:\n"
+);
+#endif /* CONFIG_EXPOLINE */
+
+#ifdef CONFIG_MODULES
+static char *ftrace_plt;
+
+asm(
+ " .data\n"
+ "ftrace_plt_template:\n"
+ " basr %r1,%r0\n"
+ " lg %r1,0f-.(%r1)\n"
+ " br %r1\n"
+ "0: .quad ftrace_caller\n"
+ "ftrace_plt_template_end:\n"
+ " .previous\n"
+);
+#endif /* CONFIG_MODULES */
+
+static const char *ftrace_shared_hotpatch_trampoline(const char **end)
+{
+ const char *tstart, *tend;
+
+ tstart = ftrace_shared_hotpatch_trampoline_br;
+ tend = ftrace_shared_hotpatch_trampoline_br_end;
+#ifdef CONFIG_EXPOLINE
+ if (!nospec_disable) {
+ tstart = ftrace_shared_hotpatch_trampoline_ex;
+ tend = ftrace_shared_hotpatch_trampoline_ex_end;
+ if (test_facility(35)) { /* exrl */
+ tstart = ftrace_shared_hotpatch_trampoline_exrl;
+ tend = ftrace_shared_hotpatch_trampoline_exrl_end;
+ }
+ }
+#endif /* CONFIG_EXPOLINE */
+ if (end)
+ *end = tend;
+ return tstart;
+}
+
+bool ftrace_need_init_nop(void)
+{
+ return ftrace_shared_hotpatch_trampoline(NULL);
+}
+
+int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
+{
+ static struct ftrace_hotpatch_trampoline *next_vmlinux_trampoline =
+ __ftrace_hotpatch_trampolines_start;
+ static const char orig[6] = { 0xc0, 0x04, 0x00, 0x00, 0x00, 0x00 };
+ static struct ftrace_hotpatch_trampoline *trampoline;
+ struct ftrace_hotpatch_trampoline **next_trampoline;
+ struct ftrace_hotpatch_trampoline *trampolines_end;
+ struct ftrace_hotpatch_trampoline tmp;
+ struct ftrace_insn *insn;
+ const char *shared;
+ s32 disp;
+
+ BUILD_BUG_ON(sizeof(struct ftrace_hotpatch_trampoline) !=
+ SIZEOF_FTRACE_HOTPATCH_TRAMPOLINE);
+
+ next_trampoline = &next_vmlinux_trampoline;
+ trampolines_end = __ftrace_hotpatch_trampolines_end;
+ shared = ftrace_shared_hotpatch_trampoline(NULL);
+#ifdef CONFIG_MODULES
+ if (mod) {
+ next_trampoline = &mod->arch.next_trampoline;
+ trampolines_end = mod->arch.trampolines_end;
+ shared = ftrace_plt;
+ }
+#endif
+
+ if (WARN_ON_ONCE(*next_trampoline >= trampolines_end))
+ return -ENOMEM;
+ trampoline = (*next_trampoline)++;
+
+ /* Check for the compiler-generated fentry nop (brcl 0, .). */
+ if (WARN_ON_ONCE(memcmp((const void *)rec->ip, &orig, sizeof(orig))))
+ return -EINVAL;
+
+ /* Generate the trampoline. */
+ tmp.brasl_opc = 0xc015; /* brasl %r1, shared */
+ tmp.brasl_disp = (shared - (const char *)&trampoline->brasl_opc) / 2;
+ tmp.interceptor = FTRACE_ADDR;
+ tmp.rest_of_intercepted_function = rec->ip + sizeof(struct ftrace_insn);
+ s390_kernel_write(trampoline, &tmp, sizeof(tmp));
+
+ /* Generate a jump to the trampoline. */
+ disp = ((char *)trampoline - (char *)rec->ip) / 2;
+ insn = (struct ftrace_insn *)rec->ip;
+ s390_kernel_write(&insn->disp, &disp, sizeof(disp));
+
+ return 0;
+}
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
@@ -49,11 +175,45 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
return 0;
}
+static void ftrace_generate_nop_insn(struct ftrace_insn *insn)
+{
+ /* brcl 0,0 */
+ insn->opc = 0xc004;
+ insn->disp = 0;
+}
+
+static void ftrace_generate_call_insn(struct ftrace_insn *insn,
+ unsigned long ip)
+{
+ unsigned long target;
+
+ /* brasl r0,ftrace_caller */
+ target = FTRACE_ADDR;
+#ifdef CONFIG_MODULES
+ if (is_module_addr((void *)ip))
+ target = (unsigned long)ftrace_plt;
+#endif /* CONFIG_MODULES */
+ insn->opc = 0xc005;
+ insn->disp = (target - ip) / 2;
+}
+
+static void brcl_disable(void *brcl)
+{
+ u8 op = 0x04; /* set mask field to zero */
+
+ s390_kernel_write((char *)brcl + 1, &op, sizeof(op));
+}
+
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
unsigned long addr)
{
struct ftrace_insn orig, new, old;
+ if (ftrace_shared_hotpatch_trampoline(NULL)) {
+ brcl_disable((void *)rec->ip);
+ return 0;
+ }
+
if (copy_from_kernel_nofault(&old, (void *) rec->ip, sizeof(old)))
return -EFAULT;
/* Replace ftrace call with a nop. */
@@ -67,10 +227,22 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
return 0;
}
+static void brcl_enable(void *brcl)
+{
+ u8 op = 0xf4; /* set mask field to all ones */
+
+ s390_kernel_write((char *)brcl + 1, &op, sizeof(op));
+}
+
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
struct ftrace_insn orig, new, old;
+ if (ftrace_shared_hotpatch_trampoline(NULL)) {
+ brcl_enable((void *)rec->ip);
+ return 0;
+ }
+
if (copy_from_kernel_nofault(&old, (void *) rec->ip, sizeof(old)))
return -EFAULT;
/* Replace nop with an ftrace call. */
@@ -95,22 +267,44 @@ int __init ftrace_dyn_arch_init(void)
return 0;
}
+void arch_ftrace_update_code(int command)
+{
+ if (ftrace_shared_hotpatch_trampoline(NULL))
+ ftrace_modify_all_code(command);
+ else
+ ftrace_run_stop_machine(command);
+}
+
+static void __ftrace_sync(void *dummy)
+{
+}
+
+int ftrace_arch_code_modify_post_process(void)
+{
+ if (ftrace_shared_hotpatch_trampoline(NULL)) {
+ /* Send SIGP to the other CPUs, so they see the new code. */
+ smp_call_function(__ftrace_sync, NULL, 1);
+ }
+ return 0;
+}
+
#ifdef CONFIG_MODULES
static int __init ftrace_plt_init(void)
{
- unsigned int *ip;
+ const char *start, *end;
- ftrace_plt = (unsigned long) module_alloc(PAGE_SIZE);
+ ftrace_plt = 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);
+
+ start = ftrace_shared_hotpatch_trampoline(&end);
+ if (!start) {
+ start = ftrace_plt_template;
+ end = ftrace_plt_template_end;
+ }
+ memcpy(ftrace_plt, start, end - start);
+ set_memory_ro((unsigned long)ftrace_plt, 1);
return 0;
}
device_initcall(ftrace_plt_init);
@@ -147,17 +341,13 @@ NOKPROBE_SYMBOL(prepare_ftrace_return);
*/
int ftrace_enable_ftrace_graph_caller(void)
{
- u8 op = 0x04; /* set mask field to zero */
-
- s390_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op));
+ brcl_disable(__va(ftrace_graph_caller));
return 0;
}
int ftrace_disable_ftrace_graph_caller(void)
{
- u8 op = 0xf4; /* set mask field to all ones */
-
- s390_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op));
+ brcl_enable(__va(ftrace_graph_caller));
return 0;
}
diff --git a/arch/s390/kernel/ftrace.h b/arch/s390/kernel/ftrace.h
new file mode 100644
index 000000000000..69e416f4c6b0
--- /dev/null
+++ b/arch/s390/kernel/ftrace.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _FTRACE_H
+#define _FTRACE_H
+
+#include <asm/types.h>
+
+struct ftrace_hotpatch_trampoline {
+ u16 brasl_opc;
+ s32 brasl_disp;
+ s16: 16;
+ u64 rest_of_intercepted_function;
+ u64 interceptor;
+} __packed;
+
+extern struct ftrace_hotpatch_trampoline __ftrace_hotpatch_trampolines_start[];
+extern struct ftrace_hotpatch_trampoline __ftrace_hotpatch_trampolines_end[];
+extern const char ftrace_shared_hotpatch_trampoline_br[];
+extern const char ftrace_shared_hotpatch_trampoline_br_end[];
+extern const char ftrace_shared_hotpatch_trampoline_ex[];
+extern const char ftrace_shared_hotpatch_trampoline_ex_end[];
+extern const char ftrace_shared_hotpatch_trampoline_exrl[];
+extern const char ftrace_shared_hotpatch_trampoline_exrl_end[];
+extern const char ftrace_plt_template[];
+extern const char ftrace_plt_template_end[];
+
+#endif /* _FTRACE_H */
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 4055f1c49814..b01ba460b7ca 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -14,6 +14,7 @@
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
+#include <linux/ftrace.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/kasan.h>
@@ -23,6 +24,8 @@
#include <asm/alternative.h>
#include <asm/nospec-branch.h>
#include <asm/facility.h>
+#include <asm/ftrace.lds.h>
+#include <asm/set_memory.h>
#if 0
#define DEBUGP printk
@@ -48,6 +51,13 @@ void *module_alloc(unsigned long size)
return p;
}
+#ifdef CONFIG_FUNCTION_TRACER
+void module_arch_cleanup(struct module *mod)
+{
+ module_memfree(mod->arch.trampolines_start);
+}
+#endif
+
void module_arch_freeing_init(struct module *mod)
{
if (is_livepatch_module(mod) &&
@@ -466,6 +476,30 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
write);
}
+#ifdef CONFIG_FUNCTION_TRACER
+static int module_alloc_ftrace_hotpatch_trampolines(struct module *me,
+ const Elf_Shdr *s)
+{
+ char *start, *end;
+ int numpages;
+ size_t size;
+
+ size = FTRACE_HOTPATCH_TRAMPOLINES_SIZE(s->sh_size);
+ numpages = DIV_ROUND_UP(size, PAGE_SIZE);
+ start = module_alloc(numpages * PAGE_SIZE);
+ if (!start)
+ return -ENOMEM;
+ set_memory_ro((unsigned long)start, numpages);
+ end = start + size;
+
+ me->arch.trampolines_start = (struct ftrace_hotpatch_trampoline *)start;
+ me->arch.trampolines_end = (struct ftrace_hotpatch_trampoline *)end;
+ me->arch.next_trampoline = me->arch.trampolines_start;
+
+ return 0;
+}
+#endif /* CONFIG_FUNCTION_TRACER */
+
int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
@@ -473,6 +507,9 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *s;
char *secstrings, *secname;
void *aseg;
+#ifdef CONFIG_FUNCTION_TRACER
+ int ret;
+#endif
if (IS_ENABLED(CONFIG_EXPOLINE) &&
!nospec_disable && me->arch.plt_size) {
@@ -507,6 +544,14 @@ int module_finalize(const Elf_Ehdr *hdr,
if (IS_ENABLED(CONFIG_EXPOLINE) &&
(str_has_prefix(secname, ".s390_return")))
nospec_revert(aseg, aseg + s->sh_size);
+
+#ifdef CONFIG_FUNCTION_TRACER
+ if (!strcmp(FTRACE_CALLSITE_SECTION, secname)) {
+ ret = module_alloc_ftrace_hotpatch_trampolines(me, s);
+ if (ret < 0)
+ return ret;
+ }
+#endif /* CONFIG_FUNCTION_TRACER */
}
jump_label_apply_nops(me);
diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index b18288d26ca8..b6caa810af3a 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -5,6 +5,7 @@
#include <asm/thread_info.h>
#include <asm/page.h>
+#include <asm/ftrace.lds.h>
/*
* Put .bss..swapper_pg_dir as the first thing in .bss. This will
@@ -46,6 +47,7 @@ SECTIONS
KPROBES_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
+ FTRACE_HOTPATCH_TRAMPOLINES_TEXT
*(.text.*_indirect_*)
*(.fixup)
*(.gnu.warning)
generated by cgit v1.2.3 (git 2.39.0) at 2025-02-10 14:59:12 +0300