arm: Make get_unaligned() work with const pointers and GCC 4.1.
svn path=/dists/trunk/linux-2.6/; revision=7386
This commit is contained in:
Martin Michlmayr
parent
9ed734fff9
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f2b0e289dc
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@ -8,6 +8,7 @@ linux-2.6 (2.6.17+2.6.18-rc6-0experimental.2) UNRELEASED; urgency=low
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* arm/iop32x: Fix iop321 cpuid.
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* arm/footbridge: Enable the CIFS module (closes: #274808).
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* arm/nslu2: Drop flavour since this machine is supported by arm/ixp4xx.
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* arm: Make get_unaligned() work with const pointers and GCC 4.1.
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[ Sven Luther ]
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* [powerpc] Enabled the -prep flavour.
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@ -0,0 +1,128 @@
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# Make get_unaligned() work with const pointers and GCC 4.1
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# See
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# http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2006-September/035862.html
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From: Lennert Buytenhek <buytenh@wantstofly.org>
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On Wed, Sep 06, 2006 at 09:32:58AM +0100, Russell King - ARM Linux wrote:
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> > CC [M] drivers/net/wireless/zd1211rw/zd_usb.o
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> > drivers/net/wireless/zd1211rw/zd_usb.c: In function 'handle_rx_packet':
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> > drivers/net/wireless/zd1211rw/zd_usb.c:547: error: assignment of read-only variable '__v'
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> > This comes from
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> > if (get_unaligned(&length_info->tag) == cpu_to_le16(RX_LENGTH_INFO_TAG))
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> > which gets expanded to arm's __get_unaligned_le(). The code ends up
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> > being something like:
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The attached patch makes get_unaligned() work with const pointers,
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and doesn't seem to noticably affect code generation.
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Original code (2.6.18-rc5), format is instructions/registers:
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2.95.3 3.2.3 3.3.3 3.4.2 4.0.2 4.1.0
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original, u8 1/1 1/1 1/1 1/1 1/1 1/1
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original, u16 3/2 3/3 3/3 3/2 3/2 3/2
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original, u32 7/4 8/5 9/5 7/5 7/4 8/5
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original, u64 19/8 19/8 21/8 19/7 20/9 22/11
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After patch (* denotes change):
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2.95.3 3.2.3 3.3.3 3.4.2 4.0.2 4.1.0
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fixed, u8 1/1 1/1 1/1 1/1 1/1 1/1
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fixed, u16 3/2 3/3 3/3 3/2 3/2 3/2
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fixed, u32 7/4 9/6 * 9/6 * 7/5 7/4 8/5
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fixed, u64 19/8 19/8 20/8 * 19/7 20/9 22/11
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So, for gcc 3.2.3 in the u32 case we need 1 insn and 1 register more,
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on gcc 3.3.3 we need 1 reg more in the u32 case and save one insn in
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the u64 case, and all the other compiler versions don't seem to care
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at all.
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--- a/include/asm-arm/unaligned.h.orig 2006-09-07 00:36:56.937552584 +0200
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+++ b/include/asm-arm/unaligned.h 2006-09-07 02:03:40.522487432 +0200
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@@ -3,7 +3,7 @@
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#include <asm/types.h>
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-extern int __bug_unaligned_x(void *ptr);
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+extern int __bug_unaligned_x(const void *ptr);
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/*
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* What is the most efficient way of loading/storing an unaligned value?
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@@ -51,47 +51,34 @@
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#define __get_unaligned_4_be(__p) \
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(__p[0] << 24 | __p[1] << 16 | __p[2] << 8 | __p[3])
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-#define __get_unaligned_le(ptr) \
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- ({ \
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- __typeof__(*(ptr)) __v; \
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- __u8 *__p = (__u8 *)(ptr); \
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- switch (sizeof(*(ptr))) { \
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- case 1: __v = *(ptr); break; \
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- case 2: __v = __get_unaligned_2_le(__p); break; \
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- case 4: __v = __get_unaligned_4_le(__p); break; \
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- case 8: { \
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- unsigned int __v1, __v2; \
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- __v2 = __get_unaligned_4_le((__p+4)); \
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- __v1 = __get_unaligned_4_le(__p); \
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- __v = ((unsigned long long)__v2 << 32 | __v1); \
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- } \
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- break; \
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- default: __v = __bug_unaligned_x(__p); break; \
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- } \
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- __v; \
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+#define __get_unaligned_8_le(__p) \
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+ ((unsigned long long)__get_unaligned_4_le((__p+4)) << 32 | \
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+ __get_unaligned_4_le(__p))
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+
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+#define __get_unaligned_8_be(__p) \
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+ ((unsigned long long)__get_unaligned_4_le(__p) << 32 | \
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+ __get_unaligned_4_le((__p+4)))
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+
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+#define __get_unaligned_le(ptr) \
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+ ({ \
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+ const __u8 *__p = (const __u8 *)(ptr); \
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+ sizeof(*(ptr)) == 1 ? *__p : \
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+ sizeof(*(ptr)) == 2 ? __get_unaligned_2_le(__p) : \
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+ sizeof(*(ptr)) == 4 ? __get_unaligned_4_le(__p) : \
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+ sizeof(*(ptr)) == 8 ? __get_unaligned_8_le(__p) : \
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+ __bug_unaligned_x(__p); \
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})
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-#define __get_unaligned_be(ptr) \
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- ({ \
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- __typeof__(*(ptr)) __v; \
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- __u8 *__p = (__u8 *)(ptr); \
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- switch (sizeof(*(ptr))) { \
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- case 1: __v = *(ptr); break; \
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- case 2: __v = __get_unaligned_2_be(__p); break; \
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- case 4: __v = __get_unaligned_4_be(__p); break; \
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- case 8: { \
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- unsigned int __v1, __v2; \
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- __v2 = __get_unaligned_4_be(__p); \
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- __v1 = __get_unaligned_4_be((__p+4)); \
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- __v = ((unsigned long long)__v2 << 32 | __v1); \
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- } \
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- break; \
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- default: __v = __bug_unaligned_x(__p); break; \
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- } \
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- __v; \
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+#define __get_unaligned_be(ptr) \
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+ ({ \
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+ const __u8 *__p = (const __u8 *)(ptr); \
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+ sizeof(*(ptr)) == 1 ? *__p : \
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+ sizeof(*(ptr)) == 2 ? __get_unaligned_2_be(__p) : \
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+ sizeof(*(ptr)) == 4 ? __get_unaligned_4_be(__p) : \
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+ sizeof(*(ptr)) == 8 ? __get_unaligned_8_be(__p) : \
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+ __bug_unaligned_x(__p); \
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})
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-
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static inline void __put_unaligned_2_le(__u32 __v, register __u8 *__p)
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{
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*__p++ = __v;
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@ -1,3 +1,4 @@
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+ powerpc-mkvmlinuz-support-ppc.patch
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+ powerpc-mkvmlinuz-support-powerpc.patch
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+ arm-iop-fix-cpuid
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+ arm-get_unaligned-gcc41-const.patch
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