* [PATCH] arm64: Use mov_q to load KPTI_NG_PTE_FLAGS/SWAPPER_R*_MMUFLAGS
@ 2022-07-21 12:42 Marc Zyngier
2022-07-21 15:21 ` Catalin Marinas
0 siblings, 1 reply; 3+ messages in thread
From: Marc Zyngier @ 2022-07-21 12:42 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Will Deacon, Catalin Marinas, Mark Rutland, pcc, Ard Biesheuvel,
kernel-team
With f7b4c3b82e7d ("arm64: set UXN on swapper page tables"),
the kernel fails to build:
arch/arm64/kernel/head.S: Assembler messages:
arch/arm64/kernel/head.S:334: Error: immediate cannot be moved by a single instruction
arch/arm64/kernel/head.S:343: Error: immediate cannot be moved by a single instruction
arch/arm64/kernel/head.S:354: Error: immediate cannot be moved by a single instruction
arch/arm64/kernel/head.S:379: Error: immediate cannot be moved by a single instruction
as the constants that inherit SWAPPER_P*_FLAGS cannot be loaded
using a single 'mov' instruction. Move over to mov_q to fix this.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kernel/head.S | 8 ++++----
arch/arm64/mm/proc.S | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index cefe6a73ee54..aa7c58689f68 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -331,7 +331,7 @@ SYM_FUNC_START_LOCAL(create_idmap)
adrp x0, init_idmap_pg_dir
adrp x3, _text
adrp x6, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE
- mov x7, SWAPPER_RX_MMUFLAGS
+ mov_q x7, SWAPPER_RX_MMUFLAGS
map_memory x0, x1, x3, x6, x7, x3, IDMAP_PGD_ORDER, x10, x11, x12, x13, x14, EXTRA_SHIFT
@@ -340,7 +340,7 @@ SYM_FUNC_START_LOCAL(create_idmap)
adrp x2, init_pg_dir
adrp x3, init_pg_end
bic x4, x2, #SWAPPER_BLOCK_SIZE - 1
- mov x5, SWAPPER_RW_MMUFLAGS
+ mov_q x5, SWAPPER_RW_MMUFLAGS
mov x6, #SWAPPER_BLOCK_SHIFT
bl remap_region
@@ -351,7 +351,7 @@ SYM_FUNC_START_LOCAL(create_idmap)
bfi x22, x21, #0, #SWAPPER_BLOCK_SHIFT // remapped FDT address
add x3, x2, #MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE
bic x4, x21, #SWAPPER_BLOCK_SIZE - 1
- mov x5, SWAPPER_RW_MMUFLAGS
+ mov_q x5, SWAPPER_RW_MMUFLAGS
mov x6, #SWAPPER_BLOCK_SHIFT
bl remap_region
@@ -376,7 +376,7 @@ SYM_FUNC_START_LOCAL(create_kernel_mapping)
adrp x3, _text // runtime __pa(_text)
sub x6, x6, x3 // _end - _text
add x6, x6, x5 // runtime __va(_end)
- mov x7, SWAPPER_RW_MMUFLAGS
+ mov_q x7, SWAPPER_RW_MMUFLAGS
map_memory x0, x1, x5, x6, x7, x3, (VA_BITS - PGDIR_SHIFT), x10, x11, x12, x13, x14
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 7837a69524c5..e5578a6e80c0 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -293,7 +293,7 @@ SYM_FUNC_START(idmap_kpti_install_ng_mappings)
isb
mov temp_pte, x5
- mov pte_flags, #KPTI_NG_PTE_FLAGS
+ mov_q pte_flags, KPTI_NG_PTE_FLAGS
/* Everybody is enjoying the idmap, so we can rewrite swapper. */
/* PGD */
--
2.34.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] arm64: Use mov_q to load KPTI_NG_PTE_FLAGS/SWAPPER_R*_MMUFLAGS
2022-07-21 12:42 [PATCH] arm64: Use mov_q to load KPTI_NG_PTE_FLAGS/SWAPPER_R*_MMUFLAGS Marc Zyngier
@ 2022-07-21 15:21 ` Catalin Marinas
2022-07-21 16:10 ` Marc Zyngier
0 siblings, 1 reply; 3+ messages in thread
From: Catalin Marinas @ 2022-07-21 15:21 UTC (permalink / raw)
To: Marc Zyngier
Cc: linux-arm-kernel, Will Deacon, Mark Rutland, pcc, Ard Biesheuvel,
kernel-team
On Thu, Jul 21, 2022 at 01:42:44PM +0100, Marc Zyngier wrote:
> With f7b4c3b82e7d ("arm64: set UXN on swapper page tables"),
> the kernel fails to build:
>
> arch/arm64/kernel/head.S: Assembler messages:
> arch/arm64/kernel/head.S:334: Error: immediate cannot be moved by a single instruction
> arch/arm64/kernel/head.S:343: Error: immediate cannot be moved by a single instruction
> arch/arm64/kernel/head.S:354: Error: immediate cannot be moved by a single instruction
> arch/arm64/kernel/head.S:379: Error: immediate cannot be moved by a single instruction
>
> as the constants that inherit SWAPPER_P*_FLAGS cannot be loaded
> using a single 'mov' instruction. Move over to mov_q to fix this.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
Thanks for the fix Marc, this only applies to -next. We could either
revert Peter's patch [1] in -next but keep it for 5.19 or simply drop it
from for-next/fixes and send it to stable post 5.19. I'm more inclined
to do the latter.
Catalin
[1] https://lore.kernel.org/r/20220719234909.1398992-1-pcc@google.com
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] arm64: Use mov_q to load KPTI_NG_PTE_FLAGS/SWAPPER_R*_MMUFLAGS
2022-07-21 15:21 ` Catalin Marinas
@ 2022-07-21 16:10 ` Marc Zyngier
0 siblings, 0 replies; 3+ messages in thread
From: Marc Zyngier @ 2022-07-21 16:10 UTC (permalink / raw)
To: Catalin Marinas
Cc: linux-arm-kernel, Will Deacon, Mark Rutland, pcc, Ard Biesheuvel,
kernel-team
On Thu, 21 Jul 2022 16:21:55 +0100,
Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> On Thu, Jul 21, 2022 at 01:42:44PM +0100, Marc Zyngier wrote:
> > With f7b4c3b82e7d ("arm64: set UXN on swapper page tables"),
> > the kernel fails to build:
> >
> > arch/arm64/kernel/head.S: Assembler messages:
> > arch/arm64/kernel/head.S:334: Error: immediate cannot be moved by a single instruction
> > arch/arm64/kernel/head.S:343: Error: immediate cannot be moved by a single instruction
> > arch/arm64/kernel/head.S:354: Error: immediate cannot be moved by a single instruction
> > arch/arm64/kernel/head.S:379: Error: immediate cannot be moved by a single instruction
> >
> > as the constants that inherit SWAPPER_P*_FLAGS cannot be loaded
> > using a single 'mov' instruction. Move over to mov_q to fix this.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
>
> Thanks for the fix Marc, this only applies to -next. We could either
> revert Peter's patch [1] in -next but keep it for 5.19 or simply drop it
> from for-next/fixes and send it to stable post 5.19. I'm more inclined
> to do the latter.
Agreed, this seems like a sensible decision. This is unlikely to
affect a large user base at this stage anyway.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-07-21 12:42 [PATCH] arm64: Use mov_q to load KPTI_NG_PTE_FLAGS/SWAPPER_R*_MMUFLAGS Marc Zyngier
2022-07-21 15:21 ` Catalin Marinas
2022-07-21 16:10 ` Marc Zyngier
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