linux-kernel - [PATCH 3.16 272/294] ARM: 8221/1: PJ4: allow building in Thumb-2 mode

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Message-ID: <lsq.1510009382.829338490@decadent.org.uk>
Date:   Mon, 06 Nov 2017 23:03:02 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Nicolas Pitre" <nico@...aro.org>,
        "Ard Biesheuvel" <ard.biesheuvel@...aro.org>,
        "Arnd Bergmann" <arnd@...db.de>, "Olof Johansson" <olof@...om.net>,
        "Russell King" <rmk+kernel@....linux.org.uk>
Subject: [PATCH 3.16 272/294] ARM: 8221/1: PJ4: allow building in Thumb-2 mode

3.16.50-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ard Biesheuvel <ard.biesheuvel@...aro.org>

commit 13d1b9575ac2c2da143cd2236b6cf0fc314570f8 upstream.

Two files that get included when building the multi_v7_defconfig target
fail to build when selecting THUMB2_KERNEL for this configuration.

In both cases, we can just build the file as ARM code, as none of its
symbols are exported to modules, so there are no interworking concerns.
In the iwmmxt.S case, add ENDPROC() declarations so the symbols are
annotated as functions, resulting in the linker to emit the appropriate
mode switches.

Acked-by: Nicolas Pitre <nico@...aro.org>
Tested-by: Olof Johansson <olof@...om.net>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/arm/kernel/Makefile |  1 +
 arch/arm/kernel/iwmmxt.S | 13 +++++++++++++
 2 files changed, 14 insertions(+)

--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_CPU_PJ4B)		+= pj4-cp0.o
 obj-$(CONFIG_IWMMXT)		+= iwmmxt.o
 obj-$(CONFIG_PERF_EVENTS)	+= perf_regs.o
 obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o perf_event_cpu.o
+CFLAGS_pj4-cp0.o		:= -marm
 AFLAGS_iwmmxt.o			:= -Wa,-mcpu=iwmmxt
 obj-$(CONFIG_ARM_CPU_TOPOLOGY)  += topology.o
 
--- a/arch/arm/kernel/iwmmxt.S
+++ b/arch/arm/kernel/iwmmxt.S
@@ -58,6 +58,7 @@
 #define MMX_SIZE		(0x98)
 
 	.text
+	.arm
 
 /*
  * Lazy switching of Concan coprocessor context
@@ -182,6 +183,8 @@ concan_load:
 	tmcr	wCon, r2
 	mov	pc, lr
 
+ENDPROC(iwmmxt_task_enable)
+
 /*
  * Back up Concan regs to save area and disable access to them
  * (mainly for gdb or sleep mode usage)
@@ -232,6 +235,8 @@ ENTRY(iwmmxt_task_disable)
 1:	msr	cpsr_c, ip			@ restore interrupt mode
 	ldmfd	sp!, {r4, pc}
 
+ENDPROC(iwmmxt_task_disable)
+
 /*
  * Copy Concan state to given memory address
  *
@@ -268,6 +273,8 @@ ENTRY(iwmmxt_task_copy)
 	msr	cpsr_c, ip			@ restore interrupt mode
 	mov	pc, r3
 
+ENDPROC(iwmmxt_task_copy)
+
 /*
  * Restore Concan state from given memory address
  *
@@ -304,6 +311,8 @@ ENTRY(iwmmxt_task_restore)
 	msr	cpsr_c, ip			@ restore interrupt mode
 	mov	pc, r3
 
+ENDPROC(iwmmxt_task_restore)
+
 /*
  * Concan handling on task switch
  *
@@ -335,6 +344,8 @@ ENTRY(iwmmxt_task_switch)
 	mrc	p15, 0, r1, c2, c0, 0
 	sub	pc, lr, r1, lsr #32		@ cpwait and return
 
+ENDPROC(iwmmxt_task_switch)
+
 /*
  * Remove Concan ownership of given task
  *
@@ -353,6 +364,8 @@ ENTRY(iwmmxt_task_release)
 	msr	cpsr_c, r2			@ restore interrupts
 	mov	pc, lr
 
+ENDPROC(iwmmxt_task_release)
+
 	.data
 concan_owner:
 	.word	0