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authorJason Baron <jbaron@redhat.com>2010-09-17 11:09:00 -0400
committerSteven Rostedt <rostedt@goodmis.org>2010-09-22 16:29:41 -0400
commitbf5438fca2950b03c21ad868090cc1a8fcd49536 (patch)
tree9fc5693763263704de8d8ba1c37a84172dbe5eb7 /include/asm-generic
parentfa6f2cc77081792e4edca9168420a3422299ef15 (diff)
downloadop-kernel-dev-bf5438fca2950b03c21ad868090cc1a8fcd49536.zip
op-kernel-dev-bf5438fca2950b03c21ad868090cc1a8fcd49536.tar.gz
jump label: Base patch for jump label
base patch to implement 'jump labeling'. Based on a new 'asm goto' inline assembly gcc mechanism, we can now branch to labels from an 'asm goto' statment. This allows us to create a 'no-op' fastpath, which can subsequently be patched with a jump to the slowpath code. This is useful for code which might be rarely used, but which we'd like to be able to call, if needed. Tracepoints are the current usecase that these are being implemented for. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com> [ cleaned up some formating ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/vmlinux.lds.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 8a92a17..ef2af99 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -220,6 +220,8 @@
\
BUG_TABLE \
\
+ JUMP_TABLE \
+ \
/* PCI quirks */ \
.pci_fixup : AT(ADDR(.pci_fixup) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start_pci_fixups_early) = .; \
@@ -563,6 +565,14 @@
#define BUG_TABLE
#endif
+#define JUMP_TABLE \
+ . = ALIGN(8); \
+ __jump_table : AT(ADDR(__jump_table) - LOAD_OFFSET) { \
+ VMLINUX_SYMBOL(__start___jump_table) = .; \
+ *(__jump_table) \
+ VMLINUX_SYMBOL(__stop___jump_table) = .; \
+ }
+
#ifdef CONFIG_PM_TRACE
#define TRACEDATA \
. = ALIGN(4); \
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