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Message-Id: <20170712144424.19528-3-ard.biesheuvel@linaro.org>
Date: Wed, 12 Jul 2017 15:44:15 +0100
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: linux-arm-kernel@...ts.infradead.org,
kernel-hardening@...ts.openwall.com
Cc: mark.rutland@....com,
labbott@...oraproject.org,
will.deacon@....com,
dave.martin@....com,
catalin.marinas@....com,
Ard Biesheuvel <ard.biesheuvel@...aro.org>
Subject: [RFC PATCH 02/10] arm64/lib: copy_page: avoid x18 register in assembler code
Register x18 will no longer be used as a caller save register in the
future, so stop using it in the copy_page() code.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
arch/arm64/lib/copy_page.S | 38 ++++++++++----------
1 file changed, 19 insertions(+), 19 deletions(-)
diff --git a/arch/arm64/lib/copy_page.S b/arch/arm64/lib/copy_page.S
index 076c43715e64..ba84a992b362 100644
--- a/arch/arm64/lib/copy_page.S
+++ b/arch/arm64/lib/copy_page.S
@@ -45,45 +45,45 @@ alternative_else_nop_endif
ldp x14, x15, [x1, #96]
ldp x16, x17, [x1, #112]
- mov x18, #(PAGE_SIZE - 128)
+ add x0, x0, #256
add x1, x1, #128
1:
- subs x18, x18, #128
+ tst x0, #(PAGE_SIZE - 1)
alternative_if ARM64_HAS_NO_HW_PREFETCH
prfm pldl1strm, [x1, #384]
alternative_else_nop_endif
- stnp x2, x3, [x0]
+ stnp x2, x3, [x0, #-256]
ldp x2, x3, [x1]
- stnp x4, x5, [x0, #16]
+ stnp x4, x5, [x0, #-240]
ldp x4, x5, [x1, #16]
- stnp x6, x7, [x0, #32]
+ stnp x6, x7, [x0, #-224]
ldp x6, x7, [x1, #32]
- stnp x8, x9, [x0, #48]
+ stnp x8, x9, [x0, #-208]
ldp x8, x9, [x1, #48]
- stnp x10, x11, [x0, #64]
+ stnp x10, x11, [x0, #-192]
ldp x10, x11, [x1, #64]
- stnp x12, x13, [x0, #80]
+ stnp x12, x13, [x0, #-176]
ldp x12, x13, [x1, #80]
- stnp x14, x15, [x0, #96]
+ stnp x14, x15, [x0, #-160]
ldp x14, x15, [x1, #96]
- stnp x16, x17, [x0, #112]
+ stnp x16, x17, [x0, #-144]
ldp x16, x17, [x1, #112]
add x0, x0, #128
add x1, x1, #128
- b.gt 1b
+ b.ne 1b
- stnp x2, x3, [x0]
- stnp x4, x5, [x0, #16]
- stnp x6, x7, [x0, #32]
- stnp x8, x9, [x0, #48]
- stnp x10, x11, [x0, #64]
- stnp x12, x13, [x0, #80]
- stnp x14, x15, [x0, #96]
- stnp x16, x17, [x0, #112]
+ stnp x2, x3, [x0, #-256]
+ stnp x4, x5, [x0, #-240]
+ stnp x6, x7, [x0, #-224]
+ stnp x8, x9, [x0, #-208]
+ stnp x10, x11, [x0, #-192]
+ stnp x12, x13, [x0, #-176]
+ stnp x14, x15, [x0, #-160]
+ stnp x16, x17, [x0, #-144]
ret
ENDPROC(copy_page)
--
2.9.3
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