arm/ftrace: Use __patch_text()

Instead of flipping text protection, use the patch_text infrastructure
that uses a fixmap alias where required.

This removes the last user of set_all_modules_text_*().

Tested-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: ard.biesheuvel@linaro.org
Cc: james.morse@arm.com
Cc: rabin@rab.in
Link: https://lkml.kernel.org/r/20191113092636.GG4131@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 8cad59465af39ac44eafecc881e0ed9a6afc9893..a885172e504c21ef15125fe533c8a4c08a58228b 100644 (file)
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -49,8 +49,8 @@ obj-$(CONFIG_HAVE_ARM_SCU)    += smp_scu.o
 obj-$(CONFIG_HAVE_ARM_TWD)     += smp_twd.o
 obj-$(CONFIG_ARM_ARCH_TIMER)   += arch_timer.o
 obj-$(CONFIG_FUNCTION_TRACER)  += entry-ftrace.o
-obj-$(CONFIG_DYNAMIC_FTRACE)   += ftrace.o insn.o
-obj-$(CONFIG_FUNCTION_GRAPH_TRACER)    += ftrace.o insn.o
+obj-$(CONFIG_DYNAMIC_FTRACE)   += ftrace.o insn.o patch.o
+obj-$(CONFIG_FUNCTION_GRAPH_TRACER)    += ftrace.o insn.o patch.o
 obj-$(CONFIG_JUMP_LABEL)       += jump_label.o insn.o patch.o
 obj-$(CONFIG_KEXEC)            += machine_kexec.o relocate_kernel.o
 # Main staffs in KPROBES are in arch/arm/probes/ .

diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index bda949fd84e8b60b13ee3c79f5a28ad7e5151369..2a5ff69c28e68d195630c12bd9c05fc1bdf051b2 100644 (file)
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -22,6 +22,7 @@
 #include <asm/ftrace.h>
 #include <asm/insn.h>
 #include <asm/set_memory.h>
+#include <asm/patch.h>
 
 #ifdef CONFIG_THUMB2_KERNEL
 #define        NOP             0xf85deb04      /* pop.w {lr} */
@@ -35,9 +36,7 @@ static int __ftrace_modify_code(void *data)
 {
        int *command = data;
 
-       set_kernel_text_rw();
        ftrace_modify_all_code(*command);
-       set_kernel_text_ro();
 
        return 0;
 }
@@ -59,13 +58,11 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
 
 int ftrace_arch_code_modify_prepare(void)
 {
-       set_all_modules_text_rw();
        return 0;
 }
 
 int ftrace_arch_code_modify_post_process(void)
 {
-       set_all_modules_text_ro();
        /* Make sure any TLB misses during machine stop are cleared. */
        flush_tlb_all();
        return 0;
@@ -97,10 +94,7 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old,
                        return -EINVAL;
        }
 
-       if (probe_kernel_write((void *)pc, &new, MCOUNT_INSN_SIZE))
-               return -EPERM;
-
-       flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
+       __patch_text((void *)pc, new);
 
        return 0;
 }