Messages in this thread Patch in this message | | | Subject | [PATCH v2] arm: Defer vetting of atags to setup.c | From | Grant Likely <> | Date | Wed, 12 Jan 2011 11:03:07 -0700 |
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Since the debug macros no longer depend on atag data, the vetting can be deferred to setup_arch() in setup.c which simplifies the code somewhat.
This patch removes __vet_atags() from head.S and moves it setup_arch(). I've tried to preserve the existing behaviour in this patch so the extra atags vetting is only using when CONFIG_MMU is selected.
v2: Move removal of __machine_type_lookup to a separate patch.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca> --- arch/arm/kernel/head-common.S | 51 +++++++---------------------------------- arch/arm/kernel/head.S | 1 - arch/arm/kernel/setup.c | 16 +++++++++++++ 3 files changed, 25 insertions(+), 43 deletions(-)
diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S index c84b57d..8bb1829 100644 --- a/arch/arm/kernel/head-common.S +++ b/arch/arm/kernel/head-common.S @@ -11,50 +11,8 @@ * */ -#define ATAG_CORE 0x54410001 -#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2) -#define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2) - -/* - * Exception handling. Something went wrong and we can't proceed. We - * ought to tell the user, but since we don't have any guarantee that - * we're even running on the right architecture, we do virtually nothing. - * - * If CONFIG_DEBUG_LL is set we try to print out something about the error - * and hope for the best (useful if bootloader fails to pass a proper - * machine ID for example). - */ __HEAD -/* Determine validity of the r2 atags pointer. The heuristic requires - * that the pointer be aligned, in the first 16k of physical RAM and - * that the ATAG_CORE marker is first and present. Future revisions - * of this function may be more lenient with the physical address and - * may also be able to move the ATAGS block if necessary. - * - * Returns: - * r2 either valid atags pointer, or zero - * r5, r6 corrupted - */ -__vet_atags: - tst r2, #0x3 @ aligned? - bne 1f - - ldr r5, [r2, #0] @ is first tag ATAG_CORE? - cmp r5, #ATAG_CORE_SIZE - cmpne r5, #ATAG_CORE_SIZE_EMPTY - bne 1f - ldr r5, [r2, #4] - ldr r6, =ATAG_CORE - cmp r5, r6 - bne 1f - - mov pc, lr @ atag pointer is ok - -1: mov r2, #0 - mov pc, lr -ENDPROC(__vet_atags) - /* * The following fragment of code is executed with the MMU on in MMU mode, * and uses absolute addresses; this is not position independent. @@ -158,6 +116,15 @@ __lookup_processor_type_data: .long __proc_info_end .size __lookup_processor_type_data, . - __lookup_processor_type_data +/* + * Exception handling. Something went wrong and we can't proceed. We + * ought to tell the user, but since we don't have any guarantee that + * we're even running on the right architecture, we do virtually nothing. + * + * If CONFIG_DEBUG_LL is set we try to print out something about the error + * and hope for the best (useful if bootloader fails to pass a proper + * machine ID for example). + */ __error_p: #ifdef CONFIG_DEBUG_LL adr r0, str_p1 diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 19f3909..4b0cf4a 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -92,7 +92,6 @@ ENTRY(stext) * r1 = machine no, r2 = atags, * r9 = cpuid, r10 = procinfo */ - bl __vet_atags #ifdef CONFIG_SMP_ON_UP bl __fixup_smp #endif diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 77266a8..47cf110 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -851,6 +851,22 @@ void __init setup_arch(char **cmdline_p) if (mdesc->soft_reboot) reboot_setup("s"); +#if defined(CONFIG_MMU) + /* + * Determine validity of the atags pointer. The heuristic requires + * that the pointer be aligned, and that the ATAG_CORE marker is + * first and present. + */ + if (__atags_pointer & 0x3) + __atags_pointer = 0; + if (__atags_pointer) { + struct tag *t = phys_to_virt(__atags_pointer); + if ((t->hdr.size != tag_size(tag_core)) && + (t->hdr.size != sizeof(struct tag_header)) && + (t->hdr.tag != ATAG_CORE)) + __atags_pointer = 0; + } +#endif if (__atags_pointer) tags = phys_to_virt(__atags_pointer); else if (mdesc->boot_params)
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