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From: Ard Biesheuvel <ardb@kernel.org>
To: linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org
Cc: Ard Biesheuvel <ardb@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Linus Walleij <linus.walleij@linaro.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Subject: [PATCH 5/8] ARM: ftrace: avoid unnecessary literal loads
Date: Tue, 25 Jan 2022 16:36:53 +0100	[thread overview]
Message-ID: <20220125153656.1802079-6-ardb@kernel.org> (raw)
In-Reply-To: <20220125153656.1802079-1-ardb@kernel.org>

Avoid explicit literal loads and instead, use accessor macros that
generate the optimal sequence depending on the architecture revision
being targeted.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/kernel/entry-ftrace.S | 27 ++++++++------------
 1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S
index 67548c38a567..99720064a4c5 100644
--- a/arch/arm/kernel/entry-ftrace.S
+++ b/arch/arm/kernel/entry-ftrace.S
@@ -35,23 +35,20 @@
 
 .macro __mcount suffix
 	mcount_enter
-	ldr	r0, =ftrace_trace_function
-	ldr	r2, [r0]
+	ldr_va	r2, ftrace_trace_function
 	badr	r0, .Lftrace_stub
 	cmp	r0, r2
 	bne	1f
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	ldr     r1, =ftrace_graph_return
-	ldr     r2, [r1]
-	cmp     r0, r2
-	bne     ftrace_graph_caller\suffix
-
-	ldr     r1, =ftrace_graph_entry
-	ldr     r2, [r1]
-	ldr     r0, =ftrace_graph_entry_stub
-	cmp     r0, r2
-	bne     ftrace_graph_caller\suffix
+	ldr_va	r2, ftrace_graph_return
+	cmp	r0, r2
+	bne	ftrace_graph_caller\suffix
+
+	ldr_va	r2, ftrace_graph_entry
+	mov_l	r0, ftrace_graph_entry_stub
+	cmp	r0, r2
+	bne	ftrace_graph_caller\suffix
 #endif
 
 	mcount_exit
@@ -87,8 +84,7 @@
 
 	mov	r3, sp				@ struct pt_regs*
 
-	ldr r2, =function_trace_op
-	ldr r2, [r2]				@ pointer to the current
+	ldr_va	r2, function_trace_op		@ pointer to the current
 						@ function tracing op
 
 	ldr	r1, [sp, #S_LR]			@ lr of instrumented func
@@ -141,8 +137,7 @@ ftrace_graph_regs_call:
 	mcount_adjust_addr	r0, lr		@ instrumented function
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
-	ldr r2, =function_trace_op
-	ldr r2, [r2]				@ pointer to the current
+	ldr_va	r2, function_trace_op		@ pointer to the current
 						@ function tracing op
 	mov r3, #0				@ regs is NULL
 #endif
-- 
2.30.2


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  parent reply	other threads:[~2022-01-25 15:52 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-25 15:36 [PATCH 0/8] ARM: ftrace fixes and cleanups Ard Biesheuvel
2022-01-25 15:36 ` [PATCH 1/8] ARM: ftrace: ensure that ADR take Thumb bit into account Ard Biesheuvel
2022-01-25 19:14   ` Nick Desaulniers
2022-02-02 23:53   ` Linus Walleij
2022-01-25 15:36 ` [PATCH 2/8] ARM: ftrace: use ADD not POP to counter PUSH at entry Ard Biesheuvel
2022-01-25 19:23   ` Nick Desaulniers
2022-02-02 23:59   ` Linus Walleij
2022-01-25 15:36 ` [PATCH 3/8] ARM: ftrace: use trampolines to keep .init.text in branching range Ard Biesheuvel
2022-01-25 20:20   ` Nick Desaulniers
2022-02-03  0:12   ` Linus Walleij
2022-01-25 15:36 ` [PATCH 4/8] ARM: ftrace: avoid redundant loads or clobbering IP Ard Biesheuvel
2022-01-25 15:36 ` Ard Biesheuvel [this message]
2022-01-25 20:27   ` [PATCH 5/8] ARM: ftrace: avoid unnecessary literal loads Nick Desaulniers
2022-01-25 15:36 ` [PATCH 6/8] ARM: ftrace: enable HAVE_FUNCTION_GRAPH_FP_TEST Ard Biesheuvel
2022-01-25 15:36 ` [PATCH 7/8] ARM: unwind: track location of LR value in stack frame Ard Biesheuvel
2022-01-25 15:36 ` [PATCH 8/8] ARM: ftrace: enable the graph tracer with the EABI unwinder Ard Biesheuvel

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