* [PATCH v2 1/5] LoongArch: Fix build error if CONFIG_DYNAMIC_FTRACE_WITH_REGS is not set
2023-04-27 2:12 [PATCH v2 0/5] LoongArch: ftrace: Add direct call support and code simplification Youling Tang
@ 2023-04-27 2:12 ` Youling Tang
2023-04-27 2:12 ` [PATCH v2 2/5] LoongArch: ftrace: Implement ftrace_find_callable_addr() to simplify code Youling Tang
` (3 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Youling Tang @ 2023-04-27 2:12 UTC (permalink / raw)
To: Huacai Chen, Steven Rostedt, Masami Hiramatsu, Mark Rutland
Cc: WANG Xuerui, linux-kernel, linux-trace-kernel, loongarch,
loongson-kernel
We can see the following build error on LoongArch if CONFIG_DYNAMIC_FTRACE_WITH_REGS
is not set:
arch/loongarch/kernel/ftrace_dyn.c: In function ‘ftrace_make_call’:
arch/loongarch/kernel/ftrace_dyn.c:167:23: error: implicit declaration of function ‘__get_mod’
167 | ret = __get_mod(&mod, pc);
| ^~~~~~~~~
arch/loongarch/kernel/ftrace_dyn.c:171:24: error: implicit declaration of function ‘get_plt_addr’
171 | addr = get_plt_addr(mod, addr);
| ^~~~~~~~~~~~
The reason is that the __get_mod and get_plt_addr functions will be called
in ftrace_make_{call,nop}.
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
---
arch/loongarch/kernel/ftrace_dyn.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c
index 4a3ef8516ccc..c5f4b4681ddc 100644
--- a/arch/loongarch/kernel/ftrace_dyn.c
+++ b/arch/loongarch/kernel/ftrace_dyn.c
@@ -30,8 +30,6 @@ static int ftrace_modify_code(unsigned long pc, u32 old, u32 new, bool validate)
return 0;
}
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
-
#ifdef CONFIG_MODULES
static inline int __get_mod(struct module **mod, unsigned long addr)
{
@@ -72,6 +70,7 @@ static unsigned long get_plt_addr(struct module *mod, unsigned long addr)
}
#endif
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)
{
u32 old, new;
@@ -102,7 +101,6 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned
return ftrace_modify_code(pc, old, new, true);
}
-
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
int ftrace_update_ftrace_func(ftrace_func_t func)
--
2.37.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v2 2/5] LoongArch: ftrace: Implement ftrace_find_callable_addr() to simplify code
2023-04-27 2:12 [PATCH v2 0/5] LoongArch: ftrace: Add direct call support and code simplification Youling Tang
2023-04-27 2:12 ` [PATCH v2 1/5] LoongArch: Fix build error if CONFIG_DYNAMIC_FTRACE_WITH_REGS is not set Youling Tang
@ 2023-04-27 2:12 ` Youling Tang
2023-04-27 2:12 ` [PATCH v2 3/5] LoongArch: ftrace: Add direct call support Youling Tang
` (2 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Youling Tang @ 2023-04-27 2:12 UTC (permalink / raw)
To: Huacai Chen, Steven Rostedt, Masami Hiramatsu, Mark Rutland
Cc: WANG Xuerui, linux-kernel, linux-trace-kernel, loongarch,
loongson-kernel
In the module processing part, the same code is reused by implementing
ftrace_find_callable_addr().
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
---
arch/loongarch/kernel/ftrace_dyn.c | 120 +++++++++++++++--------------
1 file changed, 61 insertions(+), 59 deletions(-)
diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c
index c5f4b4681ddc..3cc4f8159f48 100644
--- a/arch/loongarch/kernel/ftrace_dyn.c
+++ b/arch/loongarch/kernel/ftrace_dyn.c
@@ -31,16 +31,11 @@ static int ftrace_modify_code(unsigned long pc, u32 old, u32 new, bool validate)
}
#ifdef CONFIG_MODULES
-static inline int __get_mod(struct module **mod, unsigned long addr)
+static bool reachable_by_bl(unsigned long addr, unsigned long pc)
{
- preempt_disable();
- *mod = __module_text_address(addr);
- preempt_enable();
+ long offset = (long)addr - (long)pc;
- if (WARN_ON(!(*mod)))
- return -EINVAL;
-
- return 0;
+ return offset >= -SZ_128M && offset < SZ_128M;
}
static struct plt_entry *get_ftrace_plt(struct module *mod, unsigned long addr)
@@ -56,18 +51,63 @@ static struct plt_entry *get_ftrace_plt(struct module *mod, unsigned long addr)
return NULL;
}
-static unsigned long get_plt_addr(struct module *mod, unsigned long addr)
+/*
+ * Find the address the callsite must branch to in order to reach '*addr'.
+ *
+ * Due to the limited range of 'bl' instructions, modules may be placed too far
+ * away to branch directly and must use a PLT.
+ *
+ * Returns true when '*addr' contains a reachable target address, or has been
+ * modified to contain a PLT address. Returns false otherwise.
+ */
+static bool ftrace_find_callable_addr(struct dyn_ftrace *rec, struct module *mod,
+ unsigned long *addr)
{
+ unsigned long pc = rec->ip + LOONGARCH_INSN_SIZE;
struct plt_entry *plt;
- plt = get_ftrace_plt(mod, addr);
+ /*
+ * When the target is within range of the 'bl' instruction, use 'addr'
+ * as-is and branch to that directly.
+ */
+ if (reachable_by_bl(*addr, pc))
+ return true;
+
+ /*
+ * 'mod' is only set at module load time, but if we end up
+ * dealing with an out-of-range condition, we can assume it
+ * is due to a module being loaded far away from the kernel.
+ *
+ * NOTE: __module_text_address() must be called with preemption
+ * disabled, but we can rely on ftrace_lock to ensure that 'mod'
+ * retains its validity throughout the remainder of this code.
+ */
+ if (!mod) {
+ preempt_disable();
+ mod = __module_text_address(pc);
+ preempt_enable();
+ }
+
+ if (WARN_ON(!mod))
+ return false;
+
+ plt = get_ftrace_plt(mod, *addr);
if (!plt) {
- pr_err("ftrace: no module PLT for %ps\n", (void *)addr);
- return -EINVAL;
+ pr_err("ftrace: no module PLT for %ps\n", (void *)*addr);
+ return false;
}
- return (unsigned long)plt;
+ *addr = (unsigned long)plt;
+ return true;
}
+
+#else /* !CONFIG_MODULES */
+static bool ftrace_find_callable_addr(struct dyn_ftrace *rec, struct module *mod,
+ unsigned long *addr)
+{
+ return true;
+}
+
#endif
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
@@ -75,26 +115,14 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned
{
u32 old, new;
unsigned long pc;
- long offset __maybe_unused;
pc = rec->ip + LOONGARCH_INSN_SIZE;
-#ifdef CONFIG_MODULES
- offset = (long)pc - (long)addr;
-
- if (offset < -SZ_128M || offset >= SZ_128M) {
- int ret;
- struct module *mod;
-
- ret = __get_mod(&mod, pc);
- if (ret)
- return ret;
-
- addr = get_plt_addr(mod, addr);
+ if (!ftrace_find_callable_addr(rec, NULL, &addr))
+ return -EINVAL;
- old_addr = get_plt_addr(mod, old_addr);
- }
-#endif
+ if (!ftrace_find_callable_addr(rec, NULL, &old_addr))
+ return -EINVAL;
new = larch_insn_gen_bl(pc, addr);
old = larch_insn_gen_bl(pc, old_addr);
@@ -151,24 +179,11 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
u32 old, new;
unsigned long pc;
- long offset __maybe_unused;
pc = rec->ip + LOONGARCH_INSN_SIZE;
-#ifdef CONFIG_MODULES
- offset = (long)pc - (long)addr;
-
- if (offset < -SZ_128M || offset >= SZ_128M) {
- int ret;
- struct module *mod;
-
- ret = __get_mod(&mod, pc);
- if (ret)
- return ret;
-
- addr = get_plt_addr(mod, addr);
- }
-#endif
+ if (!ftrace_find_callable_addr(rec, NULL, &addr))
+ return -EINVAL;
old = larch_insn_gen_nop();
new = larch_insn_gen_bl(pc, addr);
@@ -180,24 +195,11 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long ad
{
u32 old, new;
unsigned long pc;
- long offset __maybe_unused;
pc = rec->ip + LOONGARCH_INSN_SIZE;
-#ifdef CONFIG_MODULES
- offset = (long)pc - (long)addr;
-
- if (offset < -SZ_128M || offset >= SZ_128M) {
- int ret;
- struct module *mod;
-
- ret = __get_mod(&mod, pc);
- if (ret)
- return ret;
-
- addr = get_plt_addr(mod, addr);
- }
-#endif
+ if (!ftrace_find_callable_addr(rec, NULL, &addr))
+ return -EINVAL;
new = larch_insn_gen_nop();
old = larch_insn_gen_bl(pc, addr);
--
2.37.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v2 3/5] LoongArch: ftrace: Add direct call support
2023-04-27 2:12 [PATCH v2 0/5] LoongArch: ftrace: Add direct call support and code simplification Youling Tang
2023-04-27 2:12 ` [PATCH v2 1/5] LoongArch: Fix build error if CONFIG_DYNAMIC_FTRACE_WITH_REGS is not set Youling Tang
2023-04-27 2:12 ` [PATCH v2 2/5] LoongArch: ftrace: Implement ftrace_find_callable_addr() to simplify code Youling Tang
@ 2023-04-27 2:12 ` Youling Tang
2023-04-27 2:12 ` [PATCH v2 4/5] LoongArch: ftrace: Add direct call trampoline samples support Youling Tang
2023-04-27 2:12 ` [PATCH v2 5/5] LoongArch: Abstract DYNAMIC_FTRACE_WITH_ARGS accesses Youling Tang
4 siblings, 0 replies; 9+ messages in thread
From: Youling Tang @ 2023-04-27 2:12 UTC (permalink / raw)
To: Huacai Chen, Steven Rostedt, Masami Hiramatsu, Mark Rutland
Cc: WANG Xuerui, linux-kernel, linux-trace-kernel, loongarch,
loongson-kernel, Qing Zhang
Select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide the
register_ftrace_direct[_multi] interfaces allowing users to register
the customed trampoline (direct_caller) as the mcount for one or
more target functions. And modify_ftrace_direct[_multi] are also
provided for modifying direct_caller.
There are a few cases to distinguish:
- If a direct call ops is the only one tracing a function AND the direct
called trampoline is within the reach of a 'bl' instruction
-> the ftrace patchsite jumps to the trampoline
- Else
-> the ftrace patchsite jumps to the ftrace_regs_caller trampoline points
to ftrace_list_ops so it iterates over all registered ftrace ops,
including the direct call ops and calls its call_direct_funcs handler
which stores the direct called trampoline's address in the ftrace_regs
and the ftrace_regs_caller trampoline will return to that address
instead of returning to the traced function
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/ftrace.h | 12 ++++++++++++
arch/loongarch/kernel/ftrace_dyn.c | 8 ++++++++
arch/loongarch/kernel/mcount_dyn.S | 7 ++++++-
4 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index bc82c87c32ef..b4e039729bc7 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -95,6 +95,7 @@ config LOONGARCH
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
select HAVE_EFFICIENT_UNALIGNED_ACCESS if !ARCH_STRICT_ALIGN
diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
index 3418d32d4fc7..f789e680f633 100644
--- a/arch/loongarch/include/asm/ftrace.h
+++ b/arch/loongarch/include/asm/ftrace.h
@@ -57,6 +57,18 @@ static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *
#define ftrace_graph_func ftrace_graph_func
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs);
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+static inline void
+__arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
+{
+ regs->regs[13] = addr; /* t1 */
+}
+
+#define arch_ftrace_set_direct_caller(fregs, addr) \
+ __arch_ftrace_set_direct_caller(&(fregs)->regs, addr)
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
#endif
#endif /* __ASSEMBLY__ */
diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c
index 3cc4f8159f48..4062a7e63137 100644
--- a/arch/loongarch/kernel/ftrace_dyn.c
+++ b/arch/loongarch/kernel/ftrace_dyn.c
@@ -66,6 +66,14 @@ static bool ftrace_find_callable_addr(struct dyn_ftrace *rec, struct module *mod
unsigned long pc = rec->ip + LOONGARCH_INSN_SIZE;
struct plt_entry *plt;
+ /*
+ * If a custom trampoline is unreachable, rely on the ftrace_regs_caller
+ * trampoline which knows how to indirectly reach that trampoline
+ * through ops->direct_call.
+ */
+ if (*addr != FTRACE_ADDR && *addr != FTRACE_REGS_ADDR && !reachable_by_bl(*addr, pc))
+ *addr = FTRACE_REGS_ADDR;
+
/*
* When the target is within range of the 'bl' instruction, use 'addr'
* as-is and branch to that directly.
diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S
index bbabf06244c2..1008fbc3cabc 100644
--- a/arch/loongarch/kernel/mcount_dyn.S
+++ b/arch/loongarch/kernel/mcount_dyn.S
@@ -42,7 +42,6 @@
.if \allregs
PTR_S tp, sp, PT_R2
PTR_S t0, sp, PT_R12
- PTR_S t1, sp, PT_R13
PTR_S t2, sp, PT_R14
PTR_S t3, sp, PT_R15
PTR_S t4, sp, PT_R16
@@ -64,6 +63,8 @@
PTR_S zero, sp, PT_R0
.endif
PTR_S ra, sp, PT_ERA /* Save trace function ra at PT_ERA */
+ move t1, zero
+ PTR_S t1, sp, PT_R13
PTR_ADDI t8, sp, PT_SIZE
PTR_S t8, sp, PT_R3
.endm
@@ -104,8 +105,12 @@ ftrace_common_return:
PTR_L a7, sp, PT_R11
PTR_L fp, sp, PT_R22
PTR_L t0, sp, PT_ERA
+ PTR_L t1, sp, PT_R13
PTR_ADDI sp, sp, PT_SIZE
+ bnez t1,.Ldirect
jr t0
+.Ldirect:
+ jr t1
SYM_CODE_END(ftrace_common)
SYM_CODE_START(ftrace_caller)
--
2.37.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v2 4/5] LoongArch: ftrace: Add direct call trampoline samples support
2023-04-27 2:12 [PATCH v2 0/5] LoongArch: ftrace: Add direct call support and code simplification Youling Tang
` (2 preceding siblings ...)
2023-04-27 2:12 ` [PATCH v2 3/5] LoongArch: ftrace: Add direct call support Youling Tang
@ 2023-04-27 2:12 ` Youling Tang
2023-05-23 14:34 ` Steven Rostedt
2023-04-27 2:12 ` [PATCH v2 5/5] LoongArch: Abstract DYNAMIC_FTRACE_WITH_ARGS accesses Youling Tang
4 siblings, 1 reply; 9+ messages in thread
From: Youling Tang @ 2023-04-27 2:12 UTC (permalink / raw)
To: Huacai Chen, Steven Rostedt, Masami Hiramatsu, Mark Rutland
Cc: WANG Xuerui, linux-kernel, linux-trace-kernel, loongarch,
loongson-kernel, Qing Zhang
The ftrace samples need per-architecture trampoline implementations
to save and restore argument registers around the calls to
my_direct_func* and to restore polluted registers (eg: ra).
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
---
arch/loongarch/Kconfig | 2 +
samples/ftrace/ftrace-direct-modify.c | 34 +++++++++++++++++
samples/ftrace/ftrace-direct-multi-modify.c | 41 +++++++++++++++++++++
samples/ftrace/ftrace-direct-multi.c | 25 +++++++++++++
samples/ftrace/ftrace-direct-too.c | 27 ++++++++++++++
samples/ftrace/ftrace-direct.c | 23 ++++++++++++
6 files changed, 152 insertions(+)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index b4e039729bc7..5e87eb686ed3 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -122,6 +122,8 @@ config LOONGARCH
select HAVE_PERF_USER_STACK_DUMP
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RSEQ
+ select HAVE_SAMPLE_FTRACE_DIRECT
+ select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
select HAVE_SETUP_PER_CPU_AREA if NUMA
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index d93abbcb1f4c..ca72c3b710eb 100644
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -96,6 +96,40 @@ asm (
#endif /* CONFIG_S390 */
+#ifdef CONFIG_LOONGARCH
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp1, @function\n"
+" .globl my_tramp1\n"
+" my_tramp1:\n"
+" addi.d $sp, $sp, -16\n"
+" st.d $t0, $sp, 0\n"
+" st.d $ra, $sp, 8\n"
+" bl my_direct_func1\n"
+" ld.d $t0, $sp, 0\n"
+" ld.d $ra, $sp, 8\n"
+" addi.d $sp, $sp, 16\n"
+" jr $t0\n"
+" .size my_tramp1, .-my_tramp1\n"
+
+" .type my_tramp2, @function\n"
+" .globl my_tramp2\n"
+" my_tramp2:\n"
+" addi.d $sp, $sp, -16\n"
+" st.d $t0, $sp, 0\n"
+" st.d $ra, $sp, 8\n"
+" bl my_direct_func2\n"
+" ld.d $t0, $sp, 0\n"
+" ld.d $ra, $sp, 8\n"
+" addi.d $sp, $sp, 16\n"
+" jr $t0\n"
+" .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_LOONGARCH */
+
static unsigned long my_tramp = (unsigned long)my_tramp1;
static unsigned long tramps[2] = {
(unsigned long)my_tramp1,
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index b58c594efb51..4708c24d47c6 100644
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -103,6 +103,47 @@ asm (
#endif /* CONFIG_S390 */
+#ifdef CONFIG_LOONGARCH
+#include <asm/asm.h>
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp1, @function\n"
+" .globl my_tramp1\n"
+" my_tramp1:\n"
+" addi.d $sp, $sp, -32\n"
+" st.d $a0, $sp, 0\n"
+" st.d $t0, $sp, 8\n"
+" st.d $ra, $sp, 16\n"
+" move $a0, $t0\n"
+" bl my_direct_func1\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $t0, $sp, 8\n"
+" ld.d $ra, $sp, 16\n"
+" addi.d $sp, $sp, 32\n"
+" jr $t0\n"
+" .size my_tramp1, .-my_tramp1\n"
+
+" .type my_tramp2, @function\n"
+" .globl my_tramp2\n"
+" my_tramp2:\n"
+" addi.d $sp, $sp, -32\n"
+" st.d $a0, $sp, 0\n"
+" st.d $t0, $sp, 8\n"
+" st.d $ra, $sp, 16\n"
+" move $a0, $t0\n"
+" bl my_direct_func2\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $t0, $sp, 8\n"
+" ld.d $ra, $sp, 16\n"
+" addi.d $sp, $sp, 32\n"
+" jr $t0\n"
+" .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_LOONGARCH */
+
static unsigned long my_tramp = (unsigned long)my_tramp1;
static unsigned long tramps[2] = {
(unsigned long)my_tramp1,
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index c27cf130c319..c2f1652c67bc 100644
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -66,6 +66,31 @@ asm (
#endif /* CONFIG_S390 */
+#ifdef CONFIG_LOONGARCH
+
+#include <asm/asm.h>
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\n"
+" addi.d $sp, $sp, -32\n"
+" st.d $a0, $sp, 0\n"
+" st.d $t0, $sp, 8\n"
+" st.d $ra, $sp, 16\n"
+" move $a0, $t0\n"
+" bl my_direct_func\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $t0, $sp, 8\n"
+" ld.d $ra, $sp, 16\n"
+" addi.d $sp, $sp, 32\n"
+" jr $t0\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_LOONGARCH */
+
static struct ftrace_ops direct;
static int __init ftrace_direct_multi_init(void)
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index 8139dce2a31c..ef64d7509773 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -70,6 +70,33 @@ asm (
#endif /* CONFIG_S390 */
+#ifdef CONFIG_LOONGARCH
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\n"
+" addi.d $sp, $sp, -48\n"
+" st.d $a0, $sp, 0\n"
+" st.d $a1, $sp, 8\n"
+" st.d $a2, $sp, 16\n"
+" st.d $t0, $sp, 24\n"
+" st.d $ra, $sp, 32\n"
+" bl my_direct_func\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $a1, $sp, 8\n"
+" ld.d $a2, $sp, 16\n"
+" ld.d $t0, $sp, 24\n"
+" ld.d $ra, $sp, 32\n"
+" addi.d $sp, $sp, 48\n"
+" jr $t0\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_LOONGARCH */
+
static int __init ftrace_direct_init(void)
{
return register_ftrace_direct((unsigned long)handle_mm_fault,
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index 1d3d307ca33d..9be720957bf8 100644
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -63,6 +63,29 @@ asm (
#endif /* CONFIG_S390 */
+#ifdef CONFIG_LOONGARCH
+
+asm (
+" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\n"
+" addi.d $sp, $sp, -32\n"
+" st.d $a0, $sp, 0\n"
+" st.d $t0, $sp, 8\n"
+" st.d $ra, $sp, 16\n"
+" bl my_direct_func\n"
+" ld.d $a0, $sp, 0\n"
+" ld.d $t0, $sp, 8\n"
+" ld.d $ra, $sp, 16\n"
+" addi.d $sp, $sp, 32\n"
+" jr $t0\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_LOONGARCH */
+
static int __init ftrace_direct_init(void)
{
return register_ftrace_direct((unsigned long)wake_up_process,
--
2.37.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH v2 4/5] LoongArch: ftrace: Add direct call trampoline samples support
2023-04-27 2:12 ` [PATCH v2 4/5] LoongArch: ftrace: Add direct call trampoline samples support Youling Tang
@ 2023-05-23 14:34 ` Steven Rostedt
0 siblings, 0 replies; 9+ messages in thread
From: Steven Rostedt @ 2023-05-23 14:34 UTC (permalink / raw)
To: Youling Tang
Cc: Huacai Chen, Masami Hiramatsu, Mark Rutland, WANG Xuerui,
linux-kernel, linux-trace-kernel, loongarch, loongson-kernel,
Qing Zhang
On Thu, 27 Apr 2023 10:12:31 +0800
Youling Tang <tangyouling@loongson.cn> wrote:
> The ftrace samples need per-architecture trampoline implementations
> to save and restore argument registers around the calls to
> my_direct_func* and to restore polluted registers (eg: ra).
>
> Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
> Signed-off-by: Youling Tang <tangyouling@loongson.cn>
> ---
> arch/loongarch/Kconfig | 2 +
> samples/ftrace/ftrace-direct-modify.c | 34 +++++++++++++++++
> samples/ftrace/ftrace-direct-multi-modify.c | 41 +++++++++++++++++++++
> samples/ftrace/ftrace-direct-multi.c | 25 +++++++++++++
> samples/ftrace/ftrace-direct-too.c | 27 ++++++++++++++
> samples/ftrace/ftrace-direct.c | 23 ++++++++++++
> 6 files changed, 152 insertions(+)
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
-- Steve
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2 5/5] LoongArch: Abstract DYNAMIC_FTRACE_WITH_ARGS accesses
2023-04-27 2:12 [PATCH v2 0/5] LoongArch: ftrace: Add direct call support and code simplification Youling Tang
` (3 preceding siblings ...)
2023-04-27 2:12 ` [PATCH v2 4/5] LoongArch: ftrace: Add direct call trampoline samples support Youling Tang
@ 2023-04-27 2:12 ` Youling Tang
2023-04-27 6:16 ` Enze Li
4 siblings, 1 reply; 9+ messages in thread
From: Youling Tang @ 2023-04-27 2:12 UTC (permalink / raw)
To: Huacai Chen, Steven Rostedt, Masami Hiramatsu, Mark Rutland
Cc: WANG Xuerui, linux-kernel, linux-trace-kernel, loongarch,
loongson-kernel, Qing Zhang
From: Qing Zhang <zhangqing@loongson.cn>
1. Adds new ftrace_regs_{get,set}_*() helpers which can be used to manipulate
ftrace_regs. When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y, these can always
be used on any ftrace_regs, and when CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n
these can be used when regs are available. A new ftrace_regs_has_args(fregs)
helper is added which code can use to check when these are usable.
2. Prepare ftrace_regs_set_instruction_pointer support in advance.
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
---
arch/loongarch/include/asm/ftrace.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
index f789e680f633..30ee01243416 100644
--- a/arch/loongarch/include/asm/ftrace.h
+++ b/arch/loongarch/include/asm/ftrace.h
@@ -54,6 +54,31 @@ static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *
return &fregs->regs;
}
+static __always_inline void
+ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
+ unsigned long ip)
+{
+ regs_set_return_value(&fregs->regs, ip);
+}
+
+static __always_inline unsigned long
+ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
+{
+ return instruction_pointer(&fregs->regs);
+}
+
+#define ftrace_regs_get_argument(fregs, n) \
+ regs_get_kernel_argument(&(fregs)->regs, n)
+#define ftrace_regs_get_stack_pointer(fregs) \
+ kernel_stack_pointer(&(fregs)->regs)
+#define ftrace_regs_return_value(fregs) \
+ regs_return_value(&(fregs)->regs)
+#define ftrace_regs_set_return_value(fregs, ret) \
+ regs_set_return_value(&(fregs)->regs, ret)
+#define ftrace_override_function_with_return(fregs) \
+ override_function_with_return(&(fregs)->regs)
+#define ftrace_regs_query_register_offset(name) \
+
#define ftrace_graph_func ftrace_graph_func
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs);
--
2.37.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH v2 5/5] LoongArch: Abstract DYNAMIC_FTRACE_WITH_ARGS accesses
2023-04-27 2:12 ` [PATCH v2 5/5] LoongArch: Abstract DYNAMIC_FTRACE_WITH_ARGS accesses Youling Tang
@ 2023-04-27 6:16 ` Enze Li
2023-04-27 6:47 ` Youling Tang
0 siblings, 1 reply; 9+ messages in thread
From: Enze Li @ 2023-04-27 6:16 UTC (permalink / raw)
To: Youling Tang
Cc: Huacai Chen, Steven Rostedt, Masami Hiramatsu, Mark Rutland,
WANG Xuerui, linux-kernel, linux-trace-kernel, loongarch,
loongson-kernel, Qing Zhang
On Thu, Apr 27 2023 at 10:12:32 AM +0800, Youling Tang wrote:
> From: Qing Zhang <zhangqing@loongson.cn>
>
> 1. Adds new ftrace_regs_{get,set}_*() helpers which can be used to manipulate
> ftrace_regs. When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y, these can always
> be used on any ftrace_regs, and when CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n
> these can be used when regs are available. A new ftrace_regs_has_args(fregs)
> helper is added which code can use to check when these are usable.
>
> 2. Prepare ftrace_regs_set_instruction_pointer support in advance.
>
> Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
> ---
> arch/loongarch/include/asm/ftrace.h | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
> index f789e680f633..30ee01243416 100644
> --- a/arch/loongarch/include/asm/ftrace.h
> +++ b/arch/loongarch/include/asm/ftrace.h
> @@ -54,6 +54,31 @@ static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *
> return &fregs->regs;
> }
>
> +static __always_inline void
> +ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
> + unsigned long ip)
> +{
> + regs_set_return_value(&fregs->regs, ip);
> +}
> +
> +static __always_inline unsigned long
> +ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
> +{
> + return instruction_pointer(&fregs->regs);
> +}
> +
> +#define ftrace_regs_get_argument(fregs, n) \
> + regs_get_kernel_argument(&(fregs)->regs, n)
> +#define ftrace_regs_get_stack_pointer(fregs) \
> + kernel_stack_pointer(&(fregs)->regs)
> +#define ftrace_regs_return_value(fregs) \
> + regs_return_value(&(fregs)->regs)
> +#define ftrace_regs_set_return_value(fregs, ret) \
Hi Youling,
> + regs_set_return_value(&(fregs)->regs, ret)
^^^^^^^^^^^^^^^^^^^^^^^^
I can not find the implementation of this function, am I missing
something?
> +#define ftrace_override_function_with_return(fregs) \
> + override_function_with_return(&(fregs)->regs)
> +#define ftrace_regs_query_register_offset(name) \
^^^^^^
There seems to be a missing function here. Otherwise, the backslash
should be redundant. Did I understand correctly?
Best Regards,
Enze
> +
> #define ftrace_graph_func ftrace_graph_func
> void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
> struct ftrace_ops *op, struct ftrace_regs *fregs);
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH v2 5/5] LoongArch: Abstract DYNAMIC_FTRACE_WITH_ARGS accesses
2023-04-27 6:16 ` Enze Li
@ 2023-04-27 6:47 ` Youling Tang
0 siblings, 0 replies; 9+ messages in thread
From: Youling Tang @ 2023-04-27 6:47 UTC (permalink / raw)
To: Enze Li
Cc: Huacai Chen, Steven Rostedt, Masami Hiramatsu, Mark Rutland,
WANG Xuerui, linux-kernel, linux-trace-kernel, loongarch,
loongson-kernel, Qing Zhang
Hi, Enze
On 04/27/2023 02:16 PM, Enze Li wrote:
> On Thu, Apr 27 2023 at 10:12:32 AM +0800, Youling Tang wrote:
>
>> From: Qing Zhang <zhangqing@loongson.cn>
>>
>> 1. Adds new ftrace_regs_{get,set}_*() helpers which can be used to manipulate
>> ftrace_regs. When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y, these can always
>> be used on any ftrace_regs, and when CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n
>> these can be used when regs are available. A new ftrace_regs_has_args(fregs)
>> helper is added which code can use to check when these are usable.
>>
>> 2. Prepare ftrace_regs_set_instruction_pointer support in advance.
>>
>> Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
>> ---
>> arch/loongarch/include/asm/ftrace.h | 25 +++++++++++++++++++++++++
>> 1 file changed, 25 insertions(+)
>>
>> diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
>> index f789e680f633..30ee01243416 100644
>> --- a/arch/loongarch/include/asm/ftrace.h
>> +++ b/arch/loongarch/include/asm/ftrace.h
>> @@ -54,6 +54,31 @@ static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *
>> return &fregs->regs;
>> }
>>
>> +static __always_inline void
>> +ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
>> + unsigned long ip)
>> +{
>> + regs_set_return_value(&fregs->regs, ip);
>> +}
>> +
>> +static __always_inline unsigned long
>> +ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
>> +{
>> + return instruction_pointer(&fregs->regs);
>> +}
>> +
>> +#define ftrace_regs_get_argument(fregs, n) \
>> + regs_get_kernel_argument(&(fregs)->regs, n)
>> +#define ftrace_regs_get_stack_pointer(fregs) \
>> + kernel_stack_pointer(&(fregs)->regs)
>> +#define ftrace_regs_return_value(fregs) \
>> + regs_return_value(&(fregs)->regs)
>> +#define ftrace_regs_set_return_value(fregs, ret) \
>
> Hi Youling,
>
>> + regs_set_return_value(&(fregs)->regs, ret)
> ^^^^^^^^^^^^^^^^^^^^^^^^
> I can not find the implementation of this function, am I missing
> something?
Note: This patch depends on regs_set_return_value() in the patch
"LoongArch: Add support for function error injection".
https://github.com/chenhuacai/linux/commit/c78e80c75b98feeb02b9a6eefb9de759f9036f42
>
>> +#define ftrace_override_function_with_return(fregs) \
>> + override_function_with_return(&(fregs)->regs)
>> +#define ftrace_regs_query_register_offset(name) \
> ^^^^^^
> There seems to be a missing function here. Otherwise, the backslash
> should be redundant. Did I understand correctly?
Sorry for my oversight.
ftrace_regs_query_register_offset() will reuse
regs_query_register_offset(), I will modify it as follows,
#define ftrace_regs_query_register_offset(name) \
regs_query_register_offset(name)
Thanks,
Youling.
>
> Best Regards,
> Enze
>
>> +
>> #define ftrace_graph_func ftrace_graph_func
>> void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
>> struct ftrace_ops *op, struct ftrace_regs *fregs);
^ permalink raw reply [flat|nested] 9+ messages in thread