linux-kernel - [PATCH] arm64: use mov_q instead of literal ldr

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Message-Id: <20200312094014.153356-1-remi@remlab.net>
Date:   Thu, 12 Mar 2020 11:40:14 +0200
From:   Rémi Denis-Courmont <remi@...lab.net>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, maz@...nel.org, james.morse@....com,
        julien.thierry.kdev@...il.com, suzuki.poulose@....com,
        kvmarm@...ts.cs.columbia.edu, will@...nel.org,
        catalin.marinas@....com
Subject: [PATCH] arm64: use mov_q instead of literal ldr

From: Remi Denis-Courmont <remi.denis.courmont@...wei.com>

In practice, this requires only 2 instructions, or even only 1 for
the idmap_pg_dir size (with 4 or 64 KiB pages). Only the MAIR values
needed more than 2 instructions and it was already converted to mov_q
by 95b3f74bec203804658e17f86fe20755bb8abcb9.

Signed-off-by: Remi Denis-Courmont <remi.denis.courmont@...wei.com>
---
 arch/arm64/kernel/cpu-reset.S       |  2 +-
 arch/arm64/kernel/hyp-stub.S        |  2 +-
 arch/arm64/kernel/relocate_kernel.S |  4 +---
 arch/arm64/kvm/hyp-init.S           | 10 ++++------
 arch/arm64/mm/proc.S                |  2 +-
 5 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S
index 32c7bf858dd9..38087b4c0432 100644
--- a/arch/arm64/kernel/cpu-reset.S
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -32,7 +32,7 @@
 ENTRY(__cpu_soft_restart)
 	/* Clear sctlr_el1 flags. */
 	mrs	x12, sctlr_el1
-	ldr	x13, =SCTLR_ELx_FLAGS
+	mov_q	x13, SCTLR_ELx_FLAGS
 	bic	x12, x12, x13
 	pre_disable_mmu_workaround
 	msr	sctlr_el1, x12
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 73d46070b315..e473ead806ed 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -63,7 +63,7 @@ el1_sync:
 	beq	9f				// Nothing to reset!
 
 	/* Someone called kvm_call_hyp() against the hyp-stub... */
-	ldr	x0, =HVC_STUB_ERR
+	mov_q	x0, HVC_STUB_ERR
 	eret
 
 9:	mov	x0, xzr
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index c1d7db71a726..c40ce496c78b 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -41,7 +41,7 @@ ENTRY(arm64_relocate_new_kernel)
 	cmp	x0, #CurrentEL_EL2
 	b.ne	1f
 	mrs	x0, sctlr_el2
-	ldr	x1, =SCTLR_ELx_FLAGS
+	mov_q	x1, SCTLR_ELx_FLAGS
 	bic	x0, x0, x1
 	pre_disable_mmu_workaround
 	msr	sctlr_el2, x0
@@ -113,8 +113,6 @@ ENTRY(arm64_relocate_new_kernel)
 
 ENDPROC(arm64_relocate_new_kernel)
 
-.ltorg
-
 .align 3	/* To keep the 64-bit values below naturally aligned. */
 
 .Lcopy_end:
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 84f32cf5abc7..6e6ed5581eed 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -60,7 +60,7 @@ alternative_else_nop_endif
 	msr	ttbr0_el2, x4
 
 	mrs	x4, tcr_el1
-	ldr	x5, =TCR_EL2_MASK
+	mov_q	x5, TCR_EL2_MASK
 	and	x4, x4, x5
 	mov	x5, #TCR_EL2_RES1
 	orr	x4, x4, x5
@@ -102,7 +102,7 @@ alternative_else_nop_endif
 	 * as well as the EE bit on BE. Drop the A flag since the compiler
 	 * is allowed to generate unaligned accesses.
 	 */
-	ldr	x4, =(SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
+	mov_q	x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
 CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)
 	msr	sctlr_el2, x4
 	isb
@@ -142,7 +142,7 @@ reset:
 	 * case we coming via HVC_SOFT_RESTART.
 	 */
 	mrs	x5, sctlr_el2
-	ldr	x6, =SCTLR_ELx_FLAGS
+	mov_q	x6, SCTLR_ELx_FLAGS
 	bic	x5, x5, x6		// Clear SCTL_M and etc
 	pre_disable_mmu_workaround
 	msr	sctlr_el2, x5
@@ -155,11 +155,9 @@ reset:
 	eret
 
 1:	/* Bad stub call */
-	ldr	x0, =HVC_STUB_ERR
+	mov_q	x0, HVC_STUB_ERR
 	eret
 
 SYM_CODE_END(__kvm_handle_stub_hvc)
 
-	.ltorg
-
 	.popsection
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 1b871f141eb4..6bd228067ebc 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -411,7 +411,7 @@ SYM_FUNC_START(__cpu_setup)
 	 * Set/prepare TCR and TTBR. We use 512GB (39-bit) address range for
 	 * both user and kernel.
 	 */
-	ldr	x10, =TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
+	mov_q	x10, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
 			TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
 			TCR_TBI0 | TCR_A1 | TCR_KASAN_FLAGS
 	tcr_clear_errata_bits x10, x9, x5
-- 
2.25.1