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Message-Id: <201203302104.q2UL4uKK006260@farm-0012.internal.tilera.com>
Date: Thu, 29 Mar 2012 13:30:31 -0400
From: Chris Metcalf <cmetcalf@...era.com>
To: Chris Metcalf <cmetcalf@...era.com>,
Rusty Russell <rusty@...tcorp.com.au>,
Mike Frysinger <vapier@...too.org>,
Jonas Bonn <jonas@...thpole.se>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH] arch/tile: support building big-endian kernel
The toolchain supports big-endian mode now, so add support for building
the kernel to run big-endian as well.
Signed-off-by: Chris Metcalf <cmetcalf@...era.com>
---
arch/tile/include/asm/byteorder.h | 20 ++++++++++++++++++++
arch/tile/include/asm/elf.h | 5 +++++
arch/tile/kernel/module.c | 12 +++++++++++-
arch/tile/kernel/single_step.c | 16 ++++++++++++----
arch/tile/lib/memchr_64.c | 8 +++-----
arch/tile/lib/memcpy_64.c | 23 +++++++++++++++++++++--
arch/tile/lib/strchr_64.c | 15 +++++----------
arch/tile/lib/string-endian.h | 33 +++++++++++++++++++++++++++++++++
arch/tile/lib/strlen_64.c | 11 ++++-------
9 files changed, 114 insertions(+), 29 deletions(-)
create mode 100644 arch/tile/lib/string-endian.h
diff --git a/arch/tile/include/asm/byteorder.h b/arch/tile/include/asm/byteorder.h
index 9558416..fb72ecf 100644
--- a/arch/tile/include/asm/byteorder.h
+++ b/arch/tile/include/asm/byteorder.h
@@ -1 +1,21 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#if defined (__BIG_ENDIAN__)
+#include <linux/byteorder/big_endian.h>
+#elif defined (__LITTLE_ENDIAN__)
#include <linux/byteorder/little_endian.h>
+#else
+#error "__BIG_ENDIAN__ or __LITTLE_ENDIAN__ must be defined."
+#endif
diff --git a/arch/tile/include/asm/elf.h b/arch/tile/include/asm/elf.h
index 623a6bb..d16d006 100644
--- a/arch/tile/include/asm/elf.h
+++ b/arch/tile/include/asm/elf.h
@@ -44,7 +44,11 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
#else
#define ELF_CLASS ELFCLASS32
#endif
+#ifdef __BIG_ENDIAN__
+#define ELF_DATA ELFDATA2MSB
+#else
#define ELF_DATA ELFDATA2LSB
+#endif
/*
* There seems to be a bug in how compat_binfmt_elf.c works: it
@@ -59,6 +63,7 @@ enum { ELF_ARCH = CHIP_ELF_TYPE() };
*/
#define elf_check_arch(x) \
((x)->e_ident[EI_CLASS] == ELF_CLASS && \
+ (x)->e_ident[EI_DATA] == ELF_DATA && \
(x)->e_machine == CHIP_ELF_TYPE())
/* The module loader only handles a few relocation types. */
diff --git a/arch/tile/kernel/module.c b/arch/tile/kernel/module.c
index b90ab99..bb2dc1e 100644
--- a/arch/tile/kernel/module.c
+++ b/arch/tile/kernel/module.c
@@ -157,7 +157,17 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
switch (ELF_R_TYPE(rel[i].r_info)) {
-#define MUNGE(func) (*location = ((*location & ~func(-1)) | func(value)))
+#ifdef __LITTLE_ENDIAN
+# define MUNGE(func) \
+ (*location = ((*location & ~func(-1)) | func(value)))
+#else
+/*
+ * Instructions are always little-endian, so when we read them as data,
+ * we have to swap them around before and after modifying them.
+ */
+# define MUNGE(func) \
+ (*location = swab64((swab64(*location) & ~func(-1)) | func(value)))
+#endif
#ifndef __tilegx__
case R_TILE_32:
diff --git a/arch/tile/kernel/single_step.c b/arch/tile/kernel/single_step.c
index b7a8795..b231ef4 100644
--- a/arch/tile/kernel/single_step.c
+++ b/arch/tile/kernel/single_step.c
@@ -152,9 +152,6 @@ static tile_bundle_bits rewrite_load_store_unaligned(
if (((unsigned long)addr % size) == 0)
return bundle;
-#ifndef __LITTLE_ENDIAN
-# error We assume little-endian representation with copy_xx_user size 2 here
-#endif
/* Handle unaligned load/store */
if (mem_op == MEMOP_LOAD || mem_op == MEMOP_LOAD_POSTINCR) {
unsigned short val_16;
@@ -175,8 +172,19 @@ static tile_bundle_bits rewrite_load_store_unaligned(
state->update = 1;
}
} else {
+ unsigned short val_16;
val = (val_reg == TREG_ZERO) ? 0 : regs->regs[val_reg];
- err = copy_to_user(addr, &val, size);
+ switch (size) {
+ case 2:
+ val_16 = val;
+ err = copy_to_user(addr, &val_16, sizeof(val_16));
+ break;
+ case 4:
+ err = copy_to_user(addr, &val, sizeof(val));
+ break;
+ default:
+ BUG();
+ }
}
if (err) {
diff --git a/arch/tile/lib/memchr_64.c b/arch/tile/lib/memchr_64.c
index 84fdc8d..6f867db 100644
--- a/arch/tile/lib/memchr_64.c
+++ b/arch/tile/lib/memchr_64.c
@@ -15,6 +15,7 @@
#include <linux/types.h>
#include <linux/string.h>
#include <linux/module.h>
+#include "string-endian.h"
void *memchr(const void *s, int c, size_t n)
{
@@ -39,11 +40,8 @@ void *memchr(const void *s, int c, size_t n)
/* Read the first word, but munge it so that bytes before the array
* will not match goal.
- *
- * Note that this shift count expression works because we know
- * shift counts are taken mod 64.
*/
- before_mask = (1ULL << (s_int << 3)) - 1;
+ before_mask = MASK(s_int);
v = (*p | before_mask) ^ (goal & before_mask);
/* Compute the address of the last byte. */
@@ -65,7 +63,7 @@ void *memchr(const void *s, int c, size_t n)
/* We found a match, but it might be in a byte past the end
* of the array.
*/
- ret = ((char *)p) + (__insn_ctz(bits) >> 3);
+ ret = ((char *)p) + (CFZ(bits) >> 3);
return (ret <= last_byte_ptr) ? ret : NULL;
}
EXPORT_SYMBOL(memchr);
diff --git a/arch/tile/lib/memcpy_64.c b/arch/tile/lib/memcpy_64.c
index 3fab9a6..c79b8e7 100644
--- a/arch/tile/lib/memcpy_64.c
+++ b/arch/tile/lib/memcpy_64.c
@@ -15,7 +15,6 @@
#include <linux/types.h>
#include <linux/string.h>
#include <linux/module.h>
-#define __memcpy memcpy
/* EXPORT_SYMBOL() is in arch/tile/lib/exports.c since this should be asm. */
/* Must be 8 bytes in size. */
@@ -188,6 +187,7 @@ int USERCOPY_FUNC(void *__restrict dstv, const void *__restrict srcv, size_t n)
/* n != 0 if we get here. Write out any trailing bytes. */
dst1 = (char *)dst8;
+#ifndef __BIG_ENDIAN__
if (n & 4) {
ST4((uint32_t *)dst1, final);
dst1 += 4;
@@ -202,11 +202,30 @@ int USERCOPY_FUNC(void *__restrict dstv, const void *__restrict srcv, size_t n)
}
if (n)
ST1((uint8_t *)dst1, final);
+#else
+ if (n & 4) {
+ ST4((uint32_t *)dst1, final >> 32);
+ dst1 += 4;
+ }
+ else
+ {
+ final >>= 32;
+ }
+ if (n & 2) {
+ ST2((uint16_t *)dst1, final >> 16);
+ dst1 += 2;
+ }
+ else
+ {
+ final >>= 16;
+ }
+ if (n & 1)
+ ST1((uint8_t *)dst1, final >> 8);
+#endif
return RETVAL;
}
-
#ifdef USERCOPY_FUNC
#undef ST1
#undef ST2
diff --git a/arch/tile/lib/strchr_64.c b/arch/tile/lib/strchr_64.c
index 617a927..f39f9dc 100644
--- a/arch/tile/lib/strchr_64.c
+++ b/arch/tile/lib/strchr_64.c
@@ -15,8 +15,7 @@
#include <linux/types.h>
#include <linux/string.h>
#include <linux/module.h>
-
-#undef strchr
+#include "string-endian.h"
char *strchr(const char *s, int c)
{
@@ -33,13 +32,9 @@ char *strchr(const char *s, int c)
* match neither zero nor goal (we make sure the high bit of each
* byte is 1, and the low 7 bits are all the opposite of the goal
* byte).
- *
- * Note that this shift count expression works because we know shift
- * counts are taken mod 64.
*/
- const uint64_t before_mask = (1ULL << (s_int << 3)) - 1;
- uint64_t v = (*p | before_mask) ^
- (goal & __insn_v1shrsi(before_mask, 1));
+ const uint64_t before_mask = MASK(s_int);
+ uint64_t v = (*p | before_mask) ^ (goal & __insn_v1shrui(before_mask, 1));
uint64_t zero_matches, goal_matches;
while (1) {
@@ -55,8 +50,8 @@ char *strchr(const char *s, int c)
v = *++p;
}
- z = __insn_ctz(zero_matches);
- g = __insn_ctz(goal_matches);
+ z = CFZ(zero_matches);
+ g = CFZ(goal_matches);
/* If we found c before '\0' we got a match. Note that if c == '\0'
* then g == z, and we correctly return the address of the '\0'
diff --git a/arch/tile/lib/string-endian.h b/arch/tile/lib/string-endian.h
new file mode 100644
index 0000000..c0eed7c
--- /dev/null
+++ b/arch/tile/lib/string-endian.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ *
+ * Provide a mask based on the pointer alignment that
+ * sets up non-zero bytes before the beginning of the string.
+ * The MASK expression works because shift counts are taken mod 64.
+ * Also, specify how to count "first" and "last" bits
+ * when the bits have been read as a word.
+ */
+
+#include <asm/byteorder.h>
+
+#ifdef __LITTLE_ENDIAN
+#define MASK(x) (__insn_shl(1ULL, (x << 3)) - 1)
+#define NULMASK(x) ((2ULL << x) - 1)
+#define CFZ(x) __insn_ctz(x)
+#define REVCZ(x) __insn_clz(x)
+#else
+#define MASK(x) (__insn_shl(-2LL, ((-x << 3) - 1)))
+#define NULMASK(x) (-2LL << (63 - x))
+#define CFZ(x) __insn_clz(x)
+#define REVCZ(x) __insn_ctz(x)
+#endif
diff --git a/arch/tile/lib/strlen_64.c b/arch/tile/lib/strlen_64.c
index 1c92d46..9583fc3 100644
--- a/arch/tile/lib/strlen_64.c
+++ b/arch/tile/lib/strlen_64.c
@@ -15,8 +15,7 @@
#include <linux/types.h>
#include <linux/string.h>
#include <linux/module.h>
-
-#undef strlen
+#include "string-endian.h"
size_t strlen(const char *s)
{
@@ -24,15 +23,13 @@ size_t strlen(const char *s)
const uintptr_t s_int = (uintptr_t) s;
const uint64_t *p = (const uint64_t *)(s_int & -8);
- /* Read the first word, but force bytes before the string to be nonzero.
- * This expression works because we know shift counts are taken mod 64.
- */
- uint64_t v = *p | ((1ULL << (s_int << 3)) - 1);
+ /* Read and MASK the first word. */
+ uint64_t v = *p | MASK(s_int);
uint64_t bits;
while ((bits = __insn_v1cmpeqi(v, 0)) == 0)
v = *++p;
- return ((const char *)p) + (__insn_ctz(bits) >> 3) - s;
+ return ((const char *)p) + (CFZ(bits) >> 3) - s;
}
EXPORT_SYMBOL(strlen);
--
1.6.5.2
--
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