The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     2b02ed55482a1c5c310a7f53707292fcf1601e7a
Gitweb:        
https://git.kernel.org/tip/2b02ed55482a1c5c310a7f53707292fcf1601e7a
Author:        Josh Poimboeuf <jpoim...@redhat.com>
AuthorDate:    Wed, 24 Feb 2021 10:29:19 -06:00
Committer:     Josh Poimboeuf <jpoim...@redhat.com>
CommitterDate: Mon, 19 Apr 2021 12:36:34 -05:00

x86/crypto/crc32c-pcl-intel: Standardize jump table

Simplify the jump table code so that it resembles a compiler-generated
table.

This enables ORC unwinding by allowing objtool to follow all the
potential code paths.

Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
Tested-by: Ard Biesheuvel <a...@kernel.org>
Acked-by: Ard Biesheuvel <a...@kernel.org>
Tested-by: Sami Tolvanen <samitolva...@google.com>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Acked-by: Herbert Xu <herb...@gondor.apana.org.au>
Link: 
https://lore.kernel.org/r/5357a039def90b8ef6b5874ef12cda008ecf18ba.1614182415.git.jpoim...@redhat.com
---
 arch/x86/crypto/crc32c-pcl-intel-asm_64.S | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S 
b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
index 884dc76..ac1f303 100644
--- a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
+++ b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
@@ -53,7 +53,7 @@
 .endm
 
 .macro JMPTBL_ENTRY i
-.word crc_\i - crc_array
+.quad crc_\i
 .endm
 
 .macro JNC_LESS_THAN j
@@ -168,10 +168,7 @@ continue_block:
        xor     crc2, crc2
 
        ## branch into array
-       lea     jump_table(%rip), %bufp
-       movzwq  (%bufp, %rax, 2), len
-       lea     crc_array(%rip), %bufp
-       lea     (%bufp, len, 1), %bufp
+       mov     jump_table(,%rax,8), %bufp
        JMP_NOSPEC bufp
 
        ################################################################

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