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[06/13] x86/crypto/crc32c-pcl-intel: Standardize jump table

Message ID 5357a039def90b8ef6b5874ef12cda008ecf18ba.1614182415.git.jpoimboe@redhat.com
State Accepted
Commit 2b02ed55482a1c5c310a7f53707292fcf1601e7a
Headers show
Series x86/crypto/asm: objtool support | expand

Commit Message

Josh Poimboeuf Feb. 24, 2021, 4:29 p.m. UTC
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 <jpoimboe@redhat.com>
---
 arch/x86/crypto/crc32c-pcl-intel-asm_64.S | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)
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Patch

diff --git a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
index 884dc767b051..ac1f303eed0f 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
 
 	################################################################