arm64: ftrace: Add direct call trampoline samples support

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: x30).

These samples also include <asm/asm-offsets.h> which, on arm64, is not
necessary and redefines previously defined macros (resulting in
warnings) so these includes are guarded by !CONFIG_ARM64.

Link: https://lkml.kernel.org/r/20230427140700.625241-3-revest@chromium.org
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7856c3a..a2511b3 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -197,6 +197,8 @@ config ARM64
                    !CC_OPTIMIZE_FOR_SIZE)
        select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
                if DYNAMIC_FTRACE_WITH_ARGS
+       select HAVE_SAMPLE_FTRACE_DIRECT
+       select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
        select HAVE_EFFICIENT_UNALIGNED_ACCESS
        select HAVE_FAST_GUP
        select HAVE_FTRACE_MCOUNT_RECORD

diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index 06d8891..e5ed080 100644 (file)
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -2,7 +2,9 @@
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/ftrace.h>
+#ifndef CONFIG_ARM64
 #include <asm/asm-offsets.h>
+#endif
 
 extern void my_direct_func1(void);
 extern void my_direct_func2(void);
@@ -96,6 +98,38 @@ asm (
 
 #endif /* CONFIG_S390 */
 
+#ifdef CONFIG_ARM64
+
+asm (
+"      .pushsection    .text, \"ax\", @progbits\n"
+"      .type           my_tramp1, @function\n"
+"      .globl          my_tramp1\n"
+"   my_tramp1:"
+"      bti     c\n"
+"      sub     sp, sp, #16\n"
+"      stp     x9, x30, [sp]\n"
+"      bl      my_direct_func1\n"
+"      ldp     x30, x9, [sp]\n"
+"      add     sp, sp, #16\n"
+"      ret     x9\n"
+"      .size           my_tramp1, .-my_tramp1\n"
+
+"      .type           my_tramp2, @function\n"
+"      .globl          my_tramp2\n"
+"   my_tramp2:"
+"      bti     c\n"
+"      sub     sp, sp, #16\n"
+"      stp     x9, x30, [sp]\n"
+"      bl      my_direct_func2\n"
+"      ldp     x30, x9, [sp]\n"
+"      add     sp, sp, #16\n"
+"      ret     x9\n"
+"      .size           my_tramp2, .-my_tramp2\n"
+"      .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
 #ifdef CONFIG_LOONGARCH
 
 asm (

diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index 62f6b68..292cff2 100644 (file)
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -2,7 +2,9 @@
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/ftrace.h>
+#ifndef CONFIG_ARM64
 #include <asm/asm-offsets.h>
+#endif
 
 extern void my_direct_func1(unsigned long ip);
 extern void my_direct_func2(unsigned long ip);
@@ -103,6 +105,44 @@ asm (
 
 #endif /* CONFIG_S390 */
 
+#ifdef CONFIG_ARM64
+
+asm (
+"      .pushsection    .text, \"ax\", @progbits\n"
+"      .type           my_tramp1, @function\n"
+"      .globl          my_tramp1\n"
+"   my_tramp1:"
+"      bti     c\n"
+"      sub     sp, sp, #32\n"
+"      stp     x9, x30, [sp]\n"
+"      str     x0, [sp, #16]\n"
+"      mov     x0, x30\n"
+"      bl      my_direct_func1\n"
+"      ldp     x30, x9, [sp]\n"
+"      ldr     x0, [sp, #16]\n"
+"      add     sp, sp, #32\n"
+"      ret     x9\n"
+"      .size           my_tramp1, .-my_tramp1\n"
+
+"      .type           my_tramp2, @function\n"
+"      .globl          my_tramp2\n"
+"   my_tramp2:"
+"      bti     c\n"
+"      sub     sp, sp, #32\n"
+"      stp     x9, x30, [sp]\n"
+"      str     x0, [sp, #16]\n"
+"      mov     x0, x30\n"
+"      bl      my_direct_func2\n"
+"      ldp     x30, x9, [sp]\n"
+"      ldr     x0, [sp, #16]\n"
+"      add     sp, sp, #32\n"
+"      ret     x9\n"
+"      .size           my_tramp2, .-my_tramp2\n"
+"      .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
 #ifdef CONFIG_LOONGARCH
 #include <asm/asm.h>
 

diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index 5482cf6..b4391e0 100644 (file)
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -4,7 +4,9 @@
 #include <linux/mm.h> /* for handle_mm_fault() */
 #include <linux/ftrace.h>
 #include <linux/sched/stat.h>
+#ifndef CONFIG_ARM64
 #include <asm/asm-offsets.h>
+#endif
 
 extern void my_direct_func(unsigned long ip);
 
@@ -66,6 +68,29 @@ asm (
 
 #endif /* CONFIG_S390 */
 
+#ifdef CONFIG_ARM64
+
+asm (
+"      .pushsection    .text, \"ax\", @progbits\n"
+"      .type           my_tramp, @function\n"
+"      .globl          my_tramp\n"
+"   my_tramp:"
+"      bti     c\n"
+"      sub     sp, sp, #32\n"
+"      stp     x9, x30, [sp]\n"
+"      str     x0, [sp, #16]\n"
+"      mov     x0, x30\n"
+"      bl      my_direct_func\n"
+"      ldp     x30, x9, [sp]\n"
+"      ldr     x0, [sp, #16]\n"
+"      add     sp, sp, #32\n"
+"      ret     x9\n"
+"      .size           my_tramp, .-my_tramp\n"
+"      .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
 #ifdef CONFIG_LOONGARCH
 
 #include <asm/asm.h>

diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index 7986033..e9804c5 100644 (file)
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -3,7 +3,9 @@
 
 #include <linux/mm.h> /* for handle_mm_fault() */
 #include <linux/ftrace.h>
+#ifndef CONFIG_ARM64
 #include <asm/asm-offsets.h>
+#endif
 
 extern void my_direct_func(struct vm_area_struct *vma, unsigned long address,
                           unsigned int flags, struct pt_regs *regs);
@@ -72,6 +74,30 @@ asm (
 
 #endif /* CONFIG_S390 */
 
+#ifdef CONFIG_ARM64
+
+asm (
+"      .pushsection    .text, \"ax\", @progbits\n"
+"      .type           my_tramp, @function\n"
+"      .globl          my_tramp\n"
+"   my_tramp:"
+"      bti     c\n"
+"      sub     sp, sp, #48\n"
+"      stp     x9, x30, [sp]\n"
+"      stp     x0, x1, [sp, #16]\n"
+"      stp     x2, x3, [sp, #32]\n"
+"      bl      my_direct_func\n"
+"      ldp     x30, x9, [sp]\n"
+"      ldp     x0, x1, [sp, #16]\n"
+"      ldp     x2, x3, [sp, #32]\n"
+"      add     sp, sp, #48\n"
+"      ret     x9\n"
+"      .size           my_tramp, .-my_tramp\n"
+"      .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
 #ifdef CONFIG_LOONGARCH
 
 asm (

diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index 06879bb..20f4a7c 100644 (file)
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -3,7 +3,9 @@
 
 #include <linux/sched.h> /* for wake_up_process() */
 #include <linux/ftrace.h>
+#ifndef CONFIG_ARM64
 #include <asm/asm-offsets.h>
+#endif
 
 extern void my_direct_func(struct task_struct *p);
 
@@ -63,6 +65,28 @@ asm (
 
 #endif /* CONFIG_S390 */
 
+#ifdef CONFIG_ARM64
+
+asm (
+"      .pushsection    .text, \"ax\", @progbits\n"
+"      .type           my_tramp, @function\n"
+"      .globl          my_tramp\n"
+"   my_tramp:"
+"      bti     c\n"
+"      sub     sp, sp, #32\n"
+"      stp     x9, x30, [sp]\n"
+"      str     x0, [sp, #16]\n"
+"      bl      my_direct_func\n"
+"      ldp     x30, x9, [sp]\n"
+"      ldr     x0, [sp, #16]\n"
+"      add     sp, sp, #32\n"
+"      ret     x9\n"
+"      .size           my_tramp, .-my_tramp\n"
+"      .popsection\n"
+);
+
+#endif /* CONFIG_ARM64 */
+
 #ifdef CONFIG_LOONGARCH
 
 asm (