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riscv: lib: uaccess: fold fixups into body

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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@kernel.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Jisheng Zhang 2021-11-18 19:25:14 +08:00 • committed by Palmer Dabbelt
parent 4c2e7ce8b9
commit 9d504f9aa5
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1 changed files with 11 additions and 11 deletions
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22
arch/riscv/lib/uaccess.S
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@ -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)