Some platforms always enter the kernel in the ARM state even if
the kernel is compiled for THUMB2. Add a small wrapper on top of
cpu_resume() that switches into THUMB2 state.
This fixes a problem reported by Kevin Hilman on next-20150601
where the ifc6410 fails to boot a THUMB2 kernel because the
platform's firmware always enters the kernel in ARM mode from
deep idle states.
Reported-by: Kevin Hilman <khilman@xxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Lina Iyer <lina.iyer@xxxxxxxxxx>
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---
arch/arm/include/asm/suspend.h | 1 +
arch/arm/kernel/sleep.S | 7 +++++++
2 files changed, 8 insertions(+)
diff --git a/arch/arm/include/asm/suspend.h b/arch/arm/include/asm/suspend.h
index cd20029bcd94..6c7182f32cef 100644
--- a/arch/arm/include/asm/suspend.h
+++ b/arch/arm/include/asm/suspend.h
@@ -7,6 +7,7 @@ struct sleep_save_sp {
};
extern void cpu_resume(void);
+extern void cpu_resume_arm(void);
extern int cpu_suspend(unsigned long, int (*)(unsigned long));
#endif
diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
index 76bb3128e135..f37593567ef5 100644
--- a/arch/arm/kernel/sleep.S
+++ b/arch/arm/kernel/sleep.S
@@ -118,6 +118,12 @@ ENDPROC(cpu_resume_after_mmu)
.text
.align
+ .arm
+ENTRY(cpu_resume_arm)
+ THUMB( badr r9, 1f ) @ Kernel is entered in ARM.
+ THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
+ THUMB( .thumb ) @ switch to Thumb now.
+ THUMB(1: )
ENTRY(cpu_resume)
ARM_BE8(setend be) @ ensure we are in BE mode
#ifdef CONFIG_ARM_VIRT_EXT
@@ -149,6 +155,7 @@ THUMB( ldmia r0!, {r1, r2, r3} )
THUMB( mov sp, r2 )
THUMB( bx r3 )
ENDPROC(cpu_resume)
+ENDPROC(cpu_resume_arm)
.align 2
_sleep_save_sp:
--
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