diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2019-04-22 00:20:24 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-16 19:44:49 +0200 |
| commit | a8d13b36486220225ca5f9f64195762c6f643ebf (patch) | |
| tree | bfdcb856f8fb8b90a323bfcffed4708ec92af800 /arch/powerpc/lib | |
| parent | 0273c6d73a0323639c974ce7e5f78535b0f2065d (diff) | |
powerpc/asm: Add a patch_site macro & helpers for patching instructions
commit 06d0bbc6d0f56dacac3a79900e9a9a0d5972d818 upstream.
Add a macro and some helper C functions for patching single asm
instructions.
The gas macro means we can do something like:
1: nop
patch_site 1b, patch__foo
Which is less visually distracting than defining a GLOBAL symbol at 1,
and also doesn't pollute the symbol table which can confuse eg. perf.
These are obviously similar to our existing feature sections, but are
not automatically patched based on CPU/MMU features, rather they are
designed to be manually patched by C code at some arbitrary point.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/lib')
| -rw-r--r-- | arch/powerpc/lib/code-patching.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index d5edbeb8eb82..2ce6159d8983 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -32,6 +32,22 @@ int patch_branch(unsigned int *addr, unsigned long target, int flags) return patch_instruction(addr, create_branch(addr, target, flags)); } +int patch_branch_site(s32 *site, unsigned long target, int flags) +{ + unsigned int *addr; + + addr = (unsigned int *)((unsigned long)site + *site); + return patch_instruction(addr, create_branch(addr, target, flags)); +} + +int patch_instruction_site(s32 *site, unsigned int instr) +{ + unsigned int *addr; + + addr = (unsigned int *)((unsigned long)site + *site); + return patch_instruction(addr, instr); +} + unsigned int create_branch(const unsigned int *addr, unsigned long target, int flags) { |