On Jun 23, 2008, at 8:32 PM, Michael Ellerman wrote:
This commit adds some new routines for patching code, they will be
used
in a following commit.
Signed-off-by: Michael Ellerman <[EMAIL PROTECTED]>
---
arch/powerpc/lib/code-patching.c | 107 ++++++++++++++++++++++++++
+++++++++
include/asm-powerpc/code-patching.h | 8 +++
2 files changed, 115 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/
code-patching.c
index 430f4c1..27957c4 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -41,3 +41,110 @@ unsigned int create_branch(const unsigned int
*addr,
return instruction;
}
+
+unsigned int create_cond_branch(const unsigned int *addr,
+ unsigned long target, int flags)
+{
it would be nice to have some idea what flags is suppose to be.
+ unsigned int instruction;
+ long offset;
+
+ offset = target;
+ if (! (flags & BRANCH_ABSOLUTE))
+ offset = offset - (unsigned long)addr;
+
+ /* Check we can represent the target in the instruction format */
+ if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3)
+ return 0;
+
+ /* Mask out the flags and target, so they don't step on each
other. */
+ instruction = 0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC);
+
+ return instruction;
+}
[snip]
+unsigned int translate_branch(const unsigned int *dest, const
unsigned int *src)
+{
I'm not sure I get what this function is trying to do.
+ unsigned long target;
+
+ target = branch_target(src);
+
+ if (instr_is_branch_iform(*src))
+ return create_branch(dest, target, *src);
+ else if (instr_is_branch_bform(*src))
+ return create_cond_branch(dest, target, *src);
+
+ return 0;
+}
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