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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2011-03-25 18:41:20 +0300
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2011-03-25 18:41:20 +0300
commit7bf7e370d5919112c223a269462cd0b546903829 (patch)
tree03ccc715239df14ae168277dbccc9d9cf4d8a2c8 /arch/arm/include/asm/spinlock.h
parent68b1a1e786f29c900fa1c516a402e24f0ece622a (diff)
parentd39dd11c3e6a7af5c20bfac40594db36cf270f42 (diff)
downloadlinux-7bf7e370d5919112c223a269462cd0b546903829.tar.xz
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus-1
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6: (9356 commits) [media] rc: update for bitop name changes fs: simplify iget & friends fs: pull inode->i_lock up out of writeback_single_inode fs: rename inode_lock to inode_hash_lock fs: move i_wb_list out from under inode_lock fs: move i_sb_list out from under inode_lock fs: remove inode_lock from iput_final and prune_icache fs: Lock the inode LRU list separately fs: factor inode disposal fs: protect inode->i_state with inode->i_lock lib, arch: add filter argument to show_mem and fix private implementations SLUB: Write to per cpu data when allocating it slub: Fix debugobjects with lockless fastpath autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd() autofs4 - remove autofs4_lock autofs4 - fix d_manage() return on rcu-walk autofs4 - fix autofs4_expire_indirect() traversal autofs4 - fix dentry leak in autofs4_expire_direct() autofs4 - reinstate last used update on access vfs - check non-mountpoint dentry might block in __follow_mount_rcu() ... NOTE! This merge commit was created to fix compilation error. The block tree was merged upstream and removed the 'elv_queue_empty()' function which the new 'mtdswap' driver is using. So a simple merge of the mtd tree with upstream does not compile. And the mtd tree has already be published, so re-basing it is not an option. To fix this unfortunate situation, I had to merge upstream into the mtd-2.6.git tree without committing, put the fixup patch on top of this, and then commit this. The result is that we do not have commits which do not compile. In other words, this merge commit "merges" 3 things: the MTD tree, the upstream tree, and the fixup patch.
Diffstat (limited to 'arch/arm/include/asm/spinlock.h')
-rw-r--r--arch/arm/include/asm/spinlock.h53
1 files changed, 41 insertions, 12 deletions
diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h
index 17eb355707dd..fdd3820edff8 100644
--- a/arch/arm/include/asm/spinlock.h
+++ b/arch/arm/include/asm/spinlock.h
@@ -5,17 +5,52 @@
#error SMP not supported on pre-ARMv6 CPUs
#endif
+/*
+ * sev and wfe are ARMv6K extensions. Uniprocessor ARMv6 may not have the K
+ * extensions, so when running on UP, we have to patch these instructions away.
+ */
+#define ALT_SMP(smp, up) \
+ "9998: " smp "\n" \
+ " .pushsection \".alt.smp.init\", \"a\"\n" \
+ " .long 9998b\n" \
+ " " up "\n" \
+ " .popsection\n"
+
+#ifdef CONFIG_THUMB2_KERNEL
+#define SEV ALT_SMP("sev.w", "nop.w")
+/*
+ * For Thumb-2, special care is needed to ensure that the conditional WFE
+ * instruction really does assemble to exactly 4 bytes (as required by
+ * the SMP_ON_UP fixup code). By itself "wfene" might cause the
+ * assembler to insert a extra (16-bit) IT instruction, depending on the
+ * presence or absence of neighbouring conditional instructions.
+ *
+ * To avoid this unpredictableness, an approprite IT is inserted explicitly:
+ * the assembler won't change IT instructions which are explicitly present
+ * in the input.
+ */
+#define WFE(cond) ALT_SMP( \
+ "it " cond "\n\t" \
+ "wfe" cond ".n", \
+ \
+ "nop.w" \
+)
+#else
+#define SEV ALT_SMP("sev", "nop")
+#define WFE(cond) ALT_SMP("wfe" cond, "nop")
+#endif
+
static inline void dsb_sev(void)
{
#if __LINUX_ARM_ARCH__ >= 7
__asm__ __volatile__ (
"dsb\n"
- "sev"
+ SEV
);
-#elif defined(CONFIG_CPU_32v6K)
+#else
__asm__ __volatile__ (
"mcr p15, 0, %0, c7, c10, 4\n"
- "sev"
+ SEV
: : "r" (0)
);
#endif
@@ -46,9 +81,7 @@ static inline void arch_spin_lock(arch_spinlock_t *lock)
__asm__ __volatile__(
"1: ldrex %0, [%1]\n"
" teq %0, #0\n"
-#ifdef CONFIG_CPU_32v6K
-" wfene\n"
-#endif
+ WFE("ne")
" strexeq %0, %2, [%1]\n"
" teqeq %0, #0\n"
" bne 1b"
@@ -107,9 +140,7 @@ static inline void arch_write_lock(arch_rwlock_t *rw)
__asm__ __volatile__(
"1: ldrex %0, [%1]\n"
" teq %0, #0\n"
-#ifdef CONFIG_CPU_32v6K
-" wfene\n"
-#endif
+ WFE("ne")
" strexeq %0, %2, [%1]\n"
" teq %0, #0\n"
" bne 1b"
@@ -176,9 +207,7 @@ static inline void arch_read_lock(arch_rwlock_t *rw)
"1: ldrex %0, [%2]\n"
" adds %0, %0, #1\n"
" strexpl %1, %0, [%2]\n"
-#ifdef CONFIG_CPU_32v6K
-" wfemi\n"
-#endif
+ WFE("mi")
" rsbpls %0, %1, #0\n"
" bmi 1b"
: "=&r" (tmp), "=&r" (tmp2)