diff options
Diffstat (limited to 'arch/arm/boot/compressed/head.S')
| -rw-r--r-- | arch/arm/boot/compressed/head.S | 52 |
1 files changed, 45 insertions, 7 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index c41a793b519c..2c45b5709fa4 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -10,8 +10,11 @@ */ #include <linux/linkage.h> #include <asm/assembler.h> +#include <asm/v7m.h> + + AR_CLASS( .arch armv7-a ) + M_CLASS( .arch armv7-m ) - .arch armv7-a /* * Debugging stuff * @@ -114,7 +117,12 @@ * sort out different calling conventions */ .align - .arm @ Always enter in ARM state + /* + * Always enter in ARM state for CPUs that support the ARM ISA. + * As of today (2014) that's exactly the members of the A and R + * classes. + */ + AR_CLASS( .arm ) start: .type start,#function .rept 7 @@ -132,14 +140,15 @@ start: THUMB( .thumb ) 1: - ARM_BE8( setend be ) @ go BE8 if compiled for BE8 - mrs r9, cpsr + ARM_BE8( setend be ) @ go BE8 if compiled for BE8 + AR_CLASS( mrs r9, cpsr ) #ifdef CONFIG_ARM_VIRT_EXT bl __hyp_stub_install @ get into SVC mode, reversibly #endif mov r7, r1 @ save architecture ID mov r8, r2 @ save atags pointer +#ifndef CONFIG_CPU_V7M /* * Booting from Angel - need to enter SVC mode and disable * FIQs/IRQs (numeric definitions from angel arm.h source). @@ -155,6 +164,7 @@ not_angel: safe_svcmode_maskall r0 msr spsr_cxsf, r9 @ Save the CPU boot mode in @ SPSR +#endif /* * Note that some cache flushing and other stuff may * be needed here - is there an Angel SWI call for this? @@ -168,9 +178,26 @@ not_angel: .text #ifdef CONFIG_AUTO_ZRELADDR - @ determine final kernel image address + /* + * Find the start of physical memory. As we are executing + * without the MMU on, we are in the physical address space. + * We just need to get rid of any offset by aligning the + * address. + * + * This alignment is a balance between the requirements of + * different platforms - we have chosen 128MB to allow + * platforms which align the start of their physical memory + * to 128MB to use this feature, while allowing the zImage + * to be placed within the first 128MB of memory on other + * platforms. Increasing the alignment means we place + * stricter alignment requirements on the start of physical + * memory, but relaxing it means that we break people who + * are already placing their zImage in (eg) the top 64MB + * of this range. + */ mov r4, pc and r4, r4, #0xf8000000 + /* Determine final kernel image address. */ add r4, r4, #TEXT_OFFSET #else ldr r4, =zreladdr @@ -810,6 +837,16 @@ __common_mmu_cache_on: call_cache_fn: adr r12, proc_types #ifdef CONFIG_CPU_CP15 mrc p15, 0, r9, c0, c0 @ get processor ID +#elif defined(CONFIG_CPU_V7M) + /* + * On v7-M the processor id is located in the V7M_SCB_CPUID + * register, but as cache handling is IMPLEMENTATION DEFINED on + * v7-M (if existant at all) we just return early here. + * If V7M_SCB_CPUID were used the cpu ID functions (i.e. + * __armv7_mmu_cache_{on,off,flush}) would be selected which + * use cp15 registers that are not implemented on v7-M. + */ + bx lr #else ldr r9, =CONFIG_PROCESSOR_ID #endif @@ -1310,8 +1347,9 @@ __hyp_reentry_vectors: __enter_kernel: mov r0, #0 @ must be 0 - ARM( mov pc, r4 ) @ call kernel - THUMB( bx r4 ) @ entry point is always ARM + ARM( mov pc, r4 ) @ call kernel + M_CLASS( add r4, r4, #1 ) @ enter in Thumb mode for M class + THUMB( bx r4 ) @ entry point is always ARM for A/R classes reloc_code_end: |