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Message-ID: <20110112180257.6824.33147.stgit@localhost6.localdomain6>
Date: Wed, 12 Jan 2011 11:03:07 -0700
From: Grant Likely <grant.likely@...retlab.ca>
To: Russell King <linux@....linux.org.uk>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc: Catalin Marinas <catalin.marinas@....com>,
Jeremy Kerr <jeremy.kerr@...onical.com>,
Nicolas Pitre <nicolas.pitre@...onical.com>
Subject: [PATCH v2] arm: Defer vetting of atags to setup.c
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@...retlab.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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