From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: Nicolas Pitre <nico@fluxnic.net>, Marc Zyngier <maz@kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Russell King <linux@armlinux.org.uk>,
Stefan Agner <stefan@agner.ch>, Peter Smith <Peter.Smith@arm.com>,
Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 10/12] ARM: head.S: use PC-relative insn sequences for __fixup_pv_table
Date: Mon, 14 Sep 2020 12:57:04 +0300 [thread overview]
Message-ID: <20200914095706.3985-11-ardb@kernel.org> (raw)
In-Reply-To: <20200914095706.3985-1-ardb@kernel.org>
Replace the open coded PC relative offset calculations with adr_l
and mov_l invocations. This removes some open coded arithmetic involving
virtual addresses and avoids literal pools on v7+. Note that the footprint
of the code increases slightly, but the resulting code is a bit easier to
follow.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm/kernel/head.S | 27 ++++++--------------
1 file changed, 8 insertions(+), 19 deletions(-)
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 5f6436a40db1..6f334df5d3b9 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -576,14 +576,11 @@ ENDPROC(fixup_smp)
*/
__HEAD
__fixup_pv_table:
- adr r0, 1f
- ldmia r0, {r3-r7}
+ adr_l r6, __pv_phys_pfn_offset
+ adr_l r7, __pv_offset @ __pa(__pv_offset)
+ mov_l r3, __pv_offset @ __va(__pv_offset)
mvn ip, #0
- subs r3, r0, r3 @ PHYS_OFFSET - PAGE_OFFSET
- add r4, r4, r3 @ adjust table start address
- add r5, r5, r3 @ adjust table end address
- add r6, r6, r3 @ adjust __pv_phys_pfn_offset address
- add r7, r7, r3 @ adjust __pv_offset address
+ subs r3, r7, r3 @ PHYS_OFFSET - PAGE_OFFSET
mov r0, r8, lsr #PAGE_SHIFT @ convert to PFN
str r0, [r6] @ save computed PHYS_OFFSET to __pv_phys_pfn_offset
strcc ip, [r7, #HIGH_OFFSET] @ save to __pv_offset high bits
@@ -592,20 +589,15 @@ __fixup_pv_table:
THUMB( it ne @ cross section branch )
bne __error
str r3, [r7, #LOW_OFFSET] @ save to __pv_offset low bits
+ adr_l r4, __pv_table_begin
+ adr_l r5, __pv_table_end
b __fixup_a_pv_table
ENDPROC(__fixup_pv_table)
-
- .align
-1: .long .
- .long __pv_table_begin
- .long __pv_table_end
-2: .long __pv_phys_pfn_offset
- .long __pv_offset
+ .ltorg
.text
__fixup_a_pv_table:
- adr r0, 3f
- ldr r6, [r0]
+ mov_l r6, __pv_offset
add r6, r6, r3
ldr r0, [r6, #HIGH_OFFSET] @ pv_offset high word
ldr r6, [r6, #LOW_OFFSET] @ pv_offset low word
@@ -674,9 +666,6 @@ ARM_BE8(rev16 ip, ip)
#endif
ENDPROC(__fixup_a_pv_table)
- .align
-3: .long __pv_offset
-
ENTRY(fixup_pv_table)
stmfd sp!, {r4 - r7, lr}
mov r3, #0 @ no offset
--
2.17.1
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next prev parent reply other threads:[~2020-09-14 10:00 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-14 9:56 [PATCH 00/12] ARM: use adr_l/ldr_l macros for PC-relative references Ard Biesheuvel
2020-09-14 9:56 ` [PATCH 01/12] ARM: assembler: introduce adr_l, ldr_l and str_l macros Ard Biesheuvel
2020-09-15 7:35 ` Ard Biesheuvel
2020-09-15 17:51 ` Nick Desaulniers
2020-09-14 9:56 ` [PATCH 02/12] ARM: efistub: replace adrl pseudo-op with adr_l macro invocation Ard Biesheuvel
2020-09-14 9:56 ` [PATCH 03/12] ARM: module: add support for place relative relocations Ard Biesheuvel
2020-09-14 13:35 ` Nicolas Pitre
2020-09-14 16:11 ` Russell King - ARM Linux admin
2020-09-14 9:56 ` [PATCH 04/12] ARM: head-common.S: use PC-relative insn sequence for __proc_info Ard Biesheuvel
2020-09-14 9:56 ` [PATCH 05/12] ARM: head-common.S: use PC-relative insn sequence for idmap creation Ard Biesheuvel
2020-09-14 9:57 ` [PATCH 06/12] ARM: head.S: use PC-relative insn sequence for secondary_data Ard Biesheuvel
2020-09-14 9:57 ` [PATCH 07/12] ARM: kernel: use relative references for UP/SMP alternatives Ard Biesheuvel
2020-09-14 9:57 ` [PATCH 08/12] ARM: head: use PC-relative insn sequence for __smp_alt Ard Biesheuvel
2020-09-14 9:57 ` [PATCH 09/12] ARM: sleep.S: use PC-relative insn sequence for sleep_save_sp/mpidr_hash Ard Biesheuvel
2020-09-14 9:57 ` Ard Biesheuvel [this message]
2020-09-14 9:57 ` [PATCH 11/12] ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET Ard Biesheuvel
2020-09-14 9:57 ` [PATCH 12/12] ARM: kvm: replace open coded VA->PA calculations with adr_l call Ard Biesheuvel
2020-09-14 14:06 ` [PATCH 00/12] ARM: use adr_l/ldr_l macros for PC-relative references Nicolas Pitre
2020-09-15 19:32 ` Nick Desaulniers
2020-09-15 21:29 ` Ard Biesheuvel
2020-09-15 23:31 ` Nick Desaulniers
2020-09-16 5:54 ` Ard Biesheuvel
2020-09-16 19:53 ` Nick Desaulniers
2020-09-16 20:45 ` Ard Biesheuvel
2020-09-16 21:25 ` Nick Desaulniers
2020-09-17 0:16 ` Nick Desaulniers
2020-09-17 5:19 ` Mike Rapoport
2020-09-17 6:01 ` Ard Biesheuvel
2020-09-18 20:03 ` Nick Desaulniers
2020-09-18 20:44 ` Ard Biesheuvel
2020-09-18 21:06 ` Nick Desaulniers
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