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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>
This commit is contained in:
Mark Rutland 2017-01-17 16:10:58 +00:00 committed by Will Deacon
parent 526d10ae02
commit 829d2bd133
1 changed files with 4 additions and 8 deletions
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12
arch/arm64/kernel/entry-ftrace.S
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@ -98,8 +98,7 @@
ENTRY(_mcount) ENTRY(_mcount)
mcount_enter mcount_enter
adrp x0, ftrace_trace_function ldr_l x2, ftrace_trace_function
ldr x2, [x0, #:lo12:ftrace_trace_function]
adr x0, ftrace_stub adr x0, ftrace_stub
cmp x0, x2 // if (ftrace_trace_function cmp x0, x2 // if (ftrace_trace_function
b.eq skip_ftrace_call // != ftrace_stub) { b.eq skip_ftrace_call // != ftrace_stub) {
@ -115,15 +114,12 @@ skip_ftrace_call: // return;
mcount_exit // return; mcount_exit // return;
// } // }
skip_ftrace_call: skip_ftrace_call:
adrp x1, ftrace_graph_return ldr_l x2, ftrace_graph_return
ldr x2, [x1, #:lo12:ftrace_graph_return]
cmp x0, x2 // if ((ftrace_graph_return cmp x0, x2 // if ((ftrace_graph_return
b.ne ftrace_graph_caller // != ftrace_stub) b.ne ftrace_graph_caller // != ftrace_stub)
adrp x1, ftrace_graph_entry // || (ftrace_graph_entry ldr_l x2, ftrace_graph_entry // || (ftrace_graph_entry
adrp x0, ftrace_graph_entry_stub // != ftrace_graph_entry_stub)) adr_l x0, ftrace_graph_entry_stub // != ftrace_graph_entry_stub))
ldr x2, [x1, #:lo12:ftrace_graph_entry]
add x0, x0, #:lo12:ftrace_graph_entry_stub
cmp x0, x2 cmp x0, x2
b.ne ftrace_graph_caller // ftrace_graph_caller(); b.ne ftrace_graph_caller // ftrace_graph_caller();