[ARM] Move read of processor ID out of lookup_processor_type()

Read the processor ID at boot, and save it in "processor_id" as we
did before.  Later, when we re-parse the CPU type in the setup.c code,
re-use the value stored in "processor_id".

This allows a cleaner work-around for noMMU devices without CP#15.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 11 insertions, 8 deletions

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 1aca1775b28f..571d6d584919 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -82,6 +82,7 @@
 ENTRY(stext)
         msr     cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC @ ensure svc mode
                                                 @ and irqs disabled
+        mrc     p15, 0, r9, c0, c0              @ get processor id
         bl      __lookup_processor_type         @ r5=procinfo r9=cpuid
         movs    r10, r5                         @ invalid processor (r5=0)?
         beq     __error_p                       @ yes, error 'p'
@@ -156,6 +157,7 @@ ENTRY(secondary_startup)
          * as it has already been validated by the primary processor.
          */
         msr     cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC
+        mrc     p15, 0, r9, c0, c0              @ get processor id
         bl      __lookup_processor_type
         movs    r10, r5                         @ invalid processor?
         moveq   r0, #'p'                        @ yes, error 'p'
@@ -450,19 +452,19 @@ __error:
  * (and therefore, we are not in the correct address space).  We have to
  * calculate the offset.
  *
+ *      r9 = cpuid
  * Returns:
  *      r3, r4, r6 corrupted
  *      r5 = proc_info pointer in physical address space
- *      r9 = cpuid
+ *      r9 = cpuid (preserved)
  */
         .type   __lookup_processor_type, %function
 __lookup_processor_type:
         adr     r3, 3f
-        ldmda   r3, {r5, r6, r9}
-        sub     r3, r3, r9                      @ get offset between virt&phys
+        ldmda   r3, {r5 - r7}
+        sub     r3, r3, r7                      @ get offset between virt&phys
         add     r5, r5, r3                      @ convert virt addresses to
         add     r6, r6, r3                      @ physical address space
-        mrc     p15, 0, r9, c0, c0              @ get processor id
 1:      ldmia   r5, {r3, r4}                    @ value, mask
         and     r4, r4, r9                      @ mask wanted bits
         teq     r3, r4
@@ -477,10 +479,11 @@ __lookup_processor_type:
  * This provides a C-API version of the above function.
  */
 ENTRY(lookup_processor_type)
-        stmfd   sp!, {r4 - r6, r9, lr}
+        stmfd   sp!, {r4 - r7, r9, lr}
+        mov     r9, r0
         bl      __lookup_processor_type
         mov     r0, r5
-        ldmfd   sp!, {r4 - r6, r9, pc}
+        ldmfd   sp!, {r4 - r7, r9, pc}
 
 /*
  * Look in include/asm-arm/procinfo.h and arch/arm/kernel/arch.[ch] for
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 08974cbe9824..b7cd280bfd63 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -278,7 +278,7 @@ int cpu_architecture(void)
  * These functions re-use the assembly code in head.S, which
  * already provide the required functionality.
  */
-extern struct proc_info_list *lookup_processor_type(void);
+extern struct proc_info_list *lookup_processor_type(unsigned int);
 extern struct machine_desc *lookup_machine_type(unsigned int);
 
 static void __init setup_processor(void)
@@ -290,7 +290,7 @@ static void __init setup_processor(void)
          * types.  The linker builds this table for us from the
          * entries in arch/arm/mm/proc-*.S
          */
-        list = lookup_processor_type();
+        list = lookup_processor_type(processor_id);
         if (!list) {
                 printk("CPU configuration botched (ID %08x), unable "
                        "to continue.\n", processor_id);