ARM: Defer lookup of machine_type to setup.c

Since the debug macros no longer depend on the machine type information,
the machine type lookup can be deferred to setup_arch() in setup.c which
simplifies the code somewhat.

We also move the __error_a functionality into setup.c for displaying a
message when a bad machine ID is passed to the kernel via the LL debug
code.  We also log this into the kernel ring buffer which makes it
possible to retrieve the message via a debugger.

Original idea from Grant Likely.

Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

4 files changed, 40 insertions, 101 deletions

diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
index 8f57515bbdb0..c84b57d27d07 100644
--- a/arch/arm/kernel/head-common.S
+++ b/arch/arm/kernel/head-common.S
@@ -25,83 +25,6 @@
  * machine ID for example).
  */
         __HEAD
-__error_a:
-#ifdef CONFIG_DEBUG_LL
-        mov     r4, r1                          @ preserve machine ID
-        adr     r0, str_a1
-        bl      printascii
-        mov     r0, r4
-        bl      printhex8
-        adr     r0, str_a2
-        bl      printascii
-        adr     r3, __lookup_machine_type_data
-        ldmia   r3, {r4, r5, r6}                @ get machine desc list
-        sub     r4, r3, r4                      @ get offset between virt&phys
-        add     r5, r5, r4                      @ convert virt addresses to
-        add     r6, r6, r4                      @ physical address space
-1:      ldr     r0, [r5, #MACHINFO_TYPE]        @ get machine type
-        bl      printhex8
-        mov     r0, #'\t'
-        bl      printch
-        ldr     r0, [r5, #MACHINFO_NAME]        @ get machine name
-        add     r0, r0, r4
-        bl      printascii
-        mov     r0, #'\n'
-        bl      printch
-        add     r5, r5, #SIZEOF_MACHINE_DESC    @ next machine_desc
-        cmp     r5, r6
-        blo     1b
-        adr     r0, str_a3
-        bl      printascii
-        b       __error
-ENDPROC(__error_a)
-
-str_a1: .asciz  "\nError: unrecognized/unsupported machine ID (r1 = 0x"
-str_a2: .asciz  ").\n\nAvailable machine support:\n\nID (hex)\tNAME\n"
-str_a3: .asciz  "\nPlease check your kernel config and/or bootloader.\n"
-        .align
-#else
-        b       __error
-#endif
-
-/*
- * Lookup machine architecture in the linker-build list of architectures.
- * Note that we can't use the absolute addresses for the __arch_info
- * lists since we aren't running with the MMU on (and therefore, we are
- * not in the correct address space).  We have to calculate the offset.
- *
- *  r1 = machine architecture number
- * Returns:
- *  r3, r4, r6 corrupted
- *  r5 = mach_info pointer in physical address space
- */
-__lookup_machine_type:
-        adr     r3, __lookup_machine_type_data
-        ldmia   r3, {r4, r5, r6}
-        sub     r3, r3, r4                      @ get offset between virt&phys
-        add     r5, r5, r3                      @ convert virt addresses to
-        add     r6, r6, r3                      @ physical address space
-1:      ldr     r3, [r5, #MACHINFO_TYPE]        @ get machine type
-        teq     r3, r1                          @ matches loader number?
-        beq     2f                              @ found
-        add     r5, r5, #SIZEOF_MACHINE_DESC    @ next machine_desc
-        cmp     r5, r6
-        blo     1b
-        mov     r5, #0                          @ unknown machine
-2:      mov     pc, lr
-ENDPROC(__lookup_machine_type)
-
-/*
- * Look in arch/arm/kernel/arch.[ch] for information about the
- * __arch_info structures.
- */
-        .align  2
-        .type   __lookup_machine_type_data, %object
-__lookup_machine_type_data:
-        .long   .
-        .long   __arch_info_begin
-        .long   __arch_info_end
-        .size   __lookup_machine_type_data, . - __lookup_machine_type_data
 
 /* Determine validity of the r2 atags pointer.  The heuristic requires
  * that the pointer be aligned, in the first 16k of physical RAM and
@@ -109,8 +32,6 @@ __lookup_machine_type_data:
  * of this function may be more lenient with the physical address and
  * may also be able to move the ATAGS block if necessary.
  *
- * r8  = machinfo
- *
  * Returns:
  *  r2 either valid atags pointer, or zero
  *  r5, r6 corrupted
@@ -185,17 +106,6 @@ __mmap_switched_data:
         .size   __mmap_switched_data, . - __mmap_switched_data
 
 /*
- * This provides a C-API version of __lookup_machine_type
- */
-ENTRY(lookup_machine_type)
-        stmfd   sp!, {r4 - r6, lr}
-        mov     r1, r0
-        bl      __lookup_machine_type
-        mov     r0, r5
-        ldmfd   sp!, {r4 - r6, pc}
-ENDPROC(lookup_machine_type)
-
-/*
  * This provides a C-API version of __lookup_processor_type
  */
 ENTRY(lookup_processor_type)
diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index 814ce1a73270..6b1e0ad9ec3b 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -44,9 +44,6 @@ ENTRY(stext)
         bl      __lookup_processor_type         @ r5=procinfo r9=cpuid
         movs    r10, r5                         @ invalid processor (r5=0)?
         beq     __error_p                               @ yes, error 'p'
-        bl      __lookup_machine_type           @ r5=machinfo
-        movs    r8, r5                          @ invalid machine (r5=0)?
-        beq     __error_a                       @ yes, error 'a'
 
         adr     lr, BSYM(__after_proc_init)     @ return (PIC) address
  ARM(   add     pc, r10, #PROCINFO_INITFUNC     )
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index c0225da3fb21..8a154b940fef 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -87,14 +87,10 @@ ENTRY(stext)
         movs    r10, r5                         @ invalid processor (r5=0)?
  THUMB( it      eq )            @ force fixup-able long branch encoding
         beq     __error_p                       @ yes, error 'p'
-        bl      __lookup_machine_type           @ r5=machinfo
-        movs    r8, r5                          @ invalid machine (r5=0)?
- THUMB( it      eq )            @ force fixup-able long branch encoding
-        beq     __error_a                       @ yes, error 'a'
 
         /*
          * r1 = machine no, r2 = atags,
-         * r8 = machinfo, r9 = cpuid, r10 = procinfo
+         * r9 = cpuid, r10 = procinfo
          */
         bl      __vet_atags
 #ifdef CONFIG_SMP_ON_UP
@@ -105,7 +101,7 @@ ENTRY(stext)
         /*
          * The following calls CPU specific code in a position independent
          * manner.  See arch/arm/mm/proc-*.S for details.  r10 = base of
-         * xxx_proc_info structure selected by __lookup_machine_type
+         * xxx_proc_info structure selected by __lookup_processor_type
          * above.  On return, the CPU will be ready for the MMU to be
          * turned on, and r0 will hold the CPU control register value.
          */
@@ -124,7 +120,6 @@ ENDPROC(stext)
  * amount which are required to get the kernel running, which
  * generally means mapping in the kernel code.
  *
- * r8  = machinfo
  * r9  = cpuid
  * r10 = procinfo
  *
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 420b8d6485d6..78678b07901c 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -308,7 +308,44 @@ static void __init cacheid_init(void)
  * already provide the required functionality.
  */
 extern struct proc_info_list *lookup_processor_type(unsigned int);
-extern struct machine_desc *lookup_machine_type(unsigned int);
+
+static void __init early_print(const char *str, ...)
+{
+        extern void printascii(const char *);
+        char buf[256];
+        va_list ap;
+
+        va_start(ap, str);
+        vsnprintf(buf, sizeof(buf), str, ap);
+        va_end(ap);
+
+#ifdef CONFIG_DEBUG_LL
+        printascii(buf);
+#endif
+        printk("%s", buf);
+}
+
+static struct machine_desc * __init lookup_machine_type(unsigned int type)
+{
+        extern struct machine_desc __arch_info_begin[], __arch_info_end[];
+        struct machine_desc *p;
+
+        for (p = __arch_info_begin; p < __arch_info_end; p++)
+                if (type == p->nr)
+                        return p;
+
+        early_print("\n"
+                "Error: unrecognized/unsupported machine ID (r1 = 0x%08x).\n\n"
+                "Available machine support:\n\nID (hex)\tNAME\n", type);
+
+        for (p = __arch_info_begin; p < __arch_info_end; p++)
+                early_print("%08x\t%s\n", p->nr, p->name);
+
+        early_print("\nPlease check your kernel config and/or bootloader.\n");
+
+        while (true)
+                /* can't use cpu_relax() here as it may require MMU setup */;
+}
 
 static void __init feat_v6_fixup(void)
 {