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Message-ID: <AANLkTi=dNaOF0wxU+OYEKiWfoGeVKGnqvF3gK8-mQjo5@mail.gmail.com>
Date: Wed, 12 Jan 2011 10:49:12 -0700
From: Grant Likely <grant.likely@...retlab.ca>
To: Russell King - ARM Linux <linux@....linux.org.uk>
Cc: Nicolas Pitre <nico@...xnic.net>, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
Catalin Marinas <catalin.marinas@....com>,
Jeremy Kerr <jeremy.kerr@...onical.com>
Subject: Re: [RFC] arm: Defer lookup of machine_type and vet of atags to setup.c
On Wed, Jan 12, 2011 at 10:25 AM, Russell King - ARM Linux
<linux@....linux.org.uk> wrote:
> 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@...xnic.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.
Heh, that look pretty close to identical to what I was just about to send.
Acked-by: Grant Likely <grant.likely@...retlab.ca>
I'll send the updated atags patch rebased and retested on top of this one.
g.
>
> 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)
> {
>
>
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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