arm64: entry-ftrace.S: avoid open-coded {adr,ldr}_l

Some places in the kernel open-code sequences using ADRP for a symbol
another instruction using a :lo12: relocation for that same symbol.
These sequences are easy to get wrong, and more painful to read than is
necessary. For these reasons, it is preferable to use the
{adr,ldr,str}_l macros for these cases.

This patch makes use of these in entry-ftrace.S, removing open-coded
sequences using adrp. This results in a minor code change, since a
temporary register is not used when generating the address for some
symbols, but this is fine, as the value of the temporary register is not
used elsewhere.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index aef02d2af3b50db44476e887291b09c4056bf1c2..8f1905b795f348eb4ae977039d31c229c4bc0a1f 100644 (file)
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -98,8 +98,7 @@
 ENTRY(_mcount)
        mcount_enter
 
-       adrp    x0, ftrace_trace_function
-       ldr     x2, [x0, #:lo12:ftrace_trace_function]
+       ldr_l   x2, ftrace_trace_function
        adr     x0, ftrace_stub
        cmp     x0, x2                  // if (ftrace_trace_function
        b.eq    skip_ftrace_call        //     != ftrace_stub) {
@@ -115,15 +114,12 @@ skip_ftrace_call:                 //   return;
        mcount_exit                     //   return;
                                        // }
 skip_ftrace_call:
-       adrp    x1, ftrace_graph_return
-       ldr     x2, [x1, #:lo12:ftrace_graph_return]
+       ldr_l   x2, ftrace_graph_return
        cmp     x0, x2                  //   if ((ftrace_graph_return
        b.ne    ftrace_graph_caller     //        != ftrace_stub)
 
-       adrp    x1, ftrace_graph_entry  //     || (ftrace_graph_entry
-       adrp    x0, ftrace_graph_entry_stub //     != ftrace_graph_entry_stub))
-       ldr     x2, [x1, #:lo12:ftrace_graph_entry]
-       add     x0, x0, #:lo12:ftrace_graph_entry_stub
+       ldr_l   x2, ftrace_graph_entry  //     || (ftrace_graph_entry
+       adr_l   x0, ftrace_graph_entry_stub //     != ftrace_graph_entry_stub))
        cmp     x0, x2
        b.ne    ftrace_graph_caller     //     ftrace_graph_caller();