This is a note to let you know that I've just added the patch titled
riscv: lib: uaccess: fold fixups into body
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
riscv-lib-uaccess-fold-fixups-into-body.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 150edc0ef3a113ef100bb0b4d3ffb7a5b759273d
Author: Jisheng Zhang <jszhang@xxxxxxxxxx>
Date: Thu Nov 18 19:25:14 2021 +0800
riscv: lib: uaccess: fold fixups into body
[ Upstream commit 9d504f9aa5c1b76673018da9503e76b351a24b8c ]
uaccess functions such __asm_copy_to_user(), __arch_copy_from_user()
and __clear_user() place their exception fixups in the `.fixup` section
without any clear association with themselves. If we backtrace the
fixup code, it will be symbolized as an offset from the nearest prior
symbol.
Similar as arm64 does, we must move fixups into the body of the
functions themselves, after the usual fast-path returns.
Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S
index 63bc691cff91b..ac34f0026adcd 100644
--- a/arch/riscv/lib/uaccess.S
+++ b/arch/riscv/lib/uaccess.S
@@ -173,6 +173,13 @@ ENTRY(__asm_copy_from_user)
csrc CSR_STATUS, t6
li a0, 0
ret
+
+ /* Exception fixup code */
+10:
+ /* Disable access to user memory */
+ csrs CSR_STATUS, t6
+ mv a0, t5
+ ret
ENDPROC(__asm_copy_to_user)
ENDPROC(__asm_copy_from_user)
EXPORT_SYMBOL(__asm_copy_to_user)
@@ -218,19 +225,12 @@ ENTRY(__clear_user)
addi a0, a0, 1
bltu a0, a3, 5b
j 3b
-ENDPROC(__clear_user)
-EXPORT_SYMBOL(__clear_user)
- .section .fixup,"ax"
- .balign 4
- /* Fixup code for __copy_user(10) and __clear_user(11) */
-10:
- /* Disable access to user memory */
- csrs CSR_STATUS, t6
- mv a0, t5
- ret
+ /* Exception fixup code */
11:
+ /* Disable access to user memory */
csrs CSR_STATUS, t6
mv a0, a1
ret
- .previous
+ENDPROC(__clear_user)
+EXPORT_SYMBOL(__clear_user)
