On 12/04/2022 8:25 am, Tong Tiangen wrote:
[...]
diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h
index 0557af834e03..bb17f0829042 100644
--- a/arch/arm64/include/asm/asm-uaccess.h
+++ b/arch/arm64/include/asm/asm-uaccess.h
@@ -92,4 +92,20 @@ alternative_else_nop_endif
_asm_extable 8888b,\l;
.endm
+
+ .macro user_ldp_mc l, reg1, reg2, addr, post_inc
+8888: ldtr \reg1, [\addr];
+8889: ldtr \reg2, [\addr, #8];
+ add \addr, \addr, \post_inc;
+
+ _asm_extable_uaccess_mc 8888b, \l;
+ _asm_extable_uaccess_mc 8889b, \l;
+ .endm
You're replacing the only user of this, so please just
s/_asm_extable/_asm_extable_uaccess_mc/ in the existing macro and save
the rest of the churn.
Furthermore, how come you're not similarly updating user_stp, given that
you *are* updating the other stores in copy_to_user?
+
+ .macro user_ldst_mc l, inst, reg, addr, post_inc
+8888: \inst \reg, [\addr];
+ add \addr, \addr, \post_inc;
+
+ _asm_extable_uaccess_mc 8888b, \l;
+ .endm
Similarly, I think we can just update user_ldst itself. The two
instances that you're not replacing here are bogus anyway, and deserve
to be fixed with the patch below first.
[...]
@@ -62,7 +63,11 @@ SYM_FUNC_START(__arch_copy_from_user)
ret
// Exception fixups
-9997: cmp dst, dstin
+9997: mrs esr, esr_el1 // Check exception first
+ and esr, esr, #ESR_ELx_FSC
+ cmp esr, #ESR_ELx_FSC_EXTABT
Should we be checking EC to make sure it's a data abort - and thus FSC
is valid - in the first place? I'm a little fuzzy on all the possible
paths into fixup_exception(), and it's not entirely obvious whether this
is actually safe or not.
Thanks,
Robin.
----->8-----
Subject: [PATCH] arm64: mte: Clean up user tag accessors
Invoking user_ldst to explicitly add a post-increment of 0 is silly.
Just use a normal USER() annotation and save the redundant instruction.
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
---
arch/arm64/lib/mte.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S
index 8590af3c98c0..eeb9e45bcce8 100644
--- a/arch/arm64/lib/mte.S
+++ b/arch/arm64/lib/mte.S
@@ -93,7 +93,7 @@ SYM_FUNC_START(mte_copy_tags_from_user)
mov x3, x1
cbz x2, 2f
1:
- user_ldst 2f, ldtrb, w4, x1, 0
+USER(2f, ldtrb w4, [x1])
lsl x4, x4, #MTE_TAG_SHIFT
stg x4, [x0], #MTE_GRANULE_SIZE
add x1, x1, #1
@@ -120,7 +120,7 @@ SYM_FUNC_START(mte_copy_tags_to_user)
1:
ldg x4, [x1]
ubfx x4, x4, #MTE_TAG_SHIFT, #MTE_TAG_SIZE
- user_ldst 2f, sttrb, w4, x0, 0
+USER(2f, sttrb w4, [x0])
add x0, x0, #1
add x1, x1, #MTE_GRANULE_SIZE
subs x2, x2, #1
--
2.28.0.dirty
