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SubjectRe: [PATCH] arm64: use mov_q instead of literal ldr
On Thu, Mar 12, 2020 at 11:40:14AM +0200, Rémi Denis-Courmont wrote:
> From: Remi Denis-Courmont <remi.denis.courmont@huawei.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@huawei.com>

FWIW:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
> 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
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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