[RFC] arm: Defer lookup of machine_type and vet of atags to setup.c
From: Russell King - ARM Linux <hidden>
Date: 2011-01-12 17:26:09
Also in:
lkml
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
On Wed, Jan 12, 2011 at 10:16:44AM -0700, Grant Likely wrote:
On Wed, Jan 12, 2011 at 9:53 AM, Nicolas Pitre [off-list ref] wrote:quoted
On Wed, 12 Jan 2011, Grant Likely wrote:quoted
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) {