[RFC] arm: Defer lookup of machine_type and vet of atags to setup.c
Russell King - ARM Linux
linux at arm.linux.org.uk
Wed Jan 12 12:25:52 EST 2011
On Wed, Jan 12, 2011 at 10:16:44AM -0700, Grant Likely wrote:
> On Wed, Jan 12, 2011 at 9:53 AM, Nicolas Pitre <nico at fluxnic.net> wrote:
> > On Wed, 12 Jan 2011, Grant Likely wrote:
> >
> >> Actually it looks like the real problem is that the mmu has been
> >> turned on, but the virtual mappings for devices have not yet been
> >> established, and so the debug macros aren't using a valid address.
> >
> > A temporary virtual mapping should be there -- look for addruart in
> > head.S.
>
> Hi Russell and Nicolas,
>
> Oops, yes all the early debug stuff works fine. Stupid human trick on
> my end, but I've sorted it out now. Thanks for the help. I'll have
> patches to post later today.
I just hacked this up, and on Versatile (real hardware) it produces
the below for an invalid r1 value - and of course works for a proper r1
value.
Uncompressing Linux... done, booting the kernel.
Error: unrecognized/unsupported machine ID (r1 = 0x00123456).
Available machine support:
ID (hex) NAME
00000183 ARM-Versatile PB
0000025e ARM-Versatile AB
Please check your kernel config and/or bootloader.
diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
index bbecaac..c84b57d 100644
--- a/arch/arm/kernel/head-common.S
+++ b/arch/arm/kernel/head-common.S
@@ -25,81 +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
-#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
@@ -107,8 +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
@@ -183,17 +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 814ce1a..6b1e0ad 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 06aed19..084db6c 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
@@ -108,7 +104,7 @@ 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.
*/
@@ -127,7 +123,6 @@ 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 7c5499d..eb952a7 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)
{
More information about the linux-arm-kernel
mailing list