5.4-stable review patch. If anyone has any objections, please let me know.
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From: Michael Karcher kernel@mkarcher.dialup.fu-berlin.de
[ Upstream commit 0b67c8fc10b13a9090340c5f8a37d308f4e1571c ]
The referenced commit introduced exception handlers on user-space memory references in copy_from_user and copy_to_user. These handlers return from the respective function and calculate the remaining bytes left to copy using the current register contents. This commit fixes a couple of bad calculations and a broken epilogue in the exception handlers. This will prevent crashes and ensure correct return values of copy_from_user and copy_to_user in the faulting case. The behaviour of memcpy stays unchanged.
Fixes: 7ae3aaf53f16 ("sparc64: Convert NGcopy_{from,to}_user to accurate exception reporting.") Tested-by: John Paul Adrian Glaubitz glaubitz@physik.fu-berlin.de # on SPARC T4 with modified kernel to use Niagara 1 code Tested-by: Magnus Lindholm linmag7@gmail.com # on Sun Fire T2000 Signed-off-by: Michael Karcher kernel@mkarcher.dialup.fu-berlin.de Tested-by: Ethan Hawke ehawk@ember.systems # on Sun Fire T2000 Tested-by: Ken Link iissmart@numberzero.org # on Sun Fire T1000 Reviewed-by: Andreas Larsson andreas@gaisler.com Link: https://lore.kernel.org/r/20250905-memcpy_series-v4-3-1ca72dda195b@mkarcher.... Signed-off-by: Andreas Larsson andreas@gaisler.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/sparc/lib/NGmemcpy.S | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-)
diff --git a/arch/sparc/lib/NGmemcpy.S b/arch/sparc/lib/NGmemcpy.S index 8e4d22a6ba0b2..846a8c4ea394f 100644 --- a/arch/sparc/lib/NGmemcpy.S +++ b/arch/sparc/lib/NGmemcpy.S @@ -80,8 +80,8 @@ #ifndef EX_RETVAL #define EX_RETVAL(x) x __restore_asi: - ret wr %g0, ASI_AIUS, %asi + ret restore ENTRY(NG_ret_i2_plus_i4_plus_1) ba,pt %xcc, __restore_asi @@ -126,15 +126,16 @@ ENTRY(NG_ret_i2_plus_g1_minus_56) ba,pt %xcc, __restore_asi add %i2, %g1, %i0 ENDPROC(NG_ret_i2_plus_g1_minus_56) -ENTRY(NG_ret_i2_plus_i4) +ENTRY(NG_ret_i2_plus_i4_plus_16) + add %i4, 16, %i4 ba,pt %xcc, __restore_asi add %i2, %i4, %i0 -ENDPROC(NG_ret_i2_plus_i4) -ENTRY(NG_ret_i2_plus_i4_minus_8) - sub %i4, 8, %i4 +ENDPROC(NG_ret_i2_plus_i4_plus_16) +ENTRY(NG_ret_i2_plus_i4_plus_8) + add %i4, 8, %i4 ba,pt %xcc, __restore_asi add %i2, %i4, %i0 -ENDPROC(NG_ret_i2_plus_i4_minus_8) +ENDPROC(NG_ret_i2_plus_i4_plus_8) ENTRY(NG_ret_i2_plus_8) ba,pt %xcc, __restore_asi add %i2, 8, %i0 @@ -161,6 +162,12 @@ ENTRY(NG_ret_i2_and_7_plus_i4) ba,pt %xcc, __restore_asi add %i2, %i4, %i0 ENDPROC(NG_ret_i2_and_7_plus_i4) +ENTRY(NG_ret_i2_and_7_plus_i4_plus_8) + and %i2, 7, %i2 + add %i4, 8, %i4 + ba,pt %xcc, __restore_asi + add %i2, %i4, %i0 +ENDPROC(NG_ret_i2_and_7_plus_i4) #endif
.align 64 @@ -406,13 +413,13 @@ FUNC_NAME: /* %i0=dst, %i1=src, %i2=len */ andn %i2, 0xf, %i4 and %i2, 0xf, %i2 1: subcc %i4, 0x10, %i4 - EX_LD(LOAD(ldx, %i1, %o4), NG_ret_i2_plus_i4) + EX_LD(LOAD(ldx, %i1, %o4), NG_ret_i2_plus_i4_plus_16) add %i1, 0x08, %i1 - EX_LD(LOAD(ldx, %i1, %g1), NG_ret_i2_plus_i4) + EX_LD(LOAD(ldx, %i1, %g1), NG_ret_i2_plus_i4_plus_16) sub %i1, 0x08, %i1 - EX_ST(STORE(stx, %o4, %i1 + %i3), NG_ret_i2_plus_i4) + EX_ST(STORE(stx, %o4, %i1 + %i3), NG_ret_i2_plus_i4_plus_16) add %i1, 0x8, %i1 - EX_ST(STORE(stx, %g1, %i1 + %i3), NG_ret_i2_plus_i4_minus_8) + EX_ST(STORE(stx, %g1, %i1 + %i3), NG_ret_i2_plus_i4_plus_8) bgu,pt %XCC, 1b add %i1, 0x8, %i1 73: andcc %i2, 0x8, %g0 @@ -469,7 +476,7 @@ FUNC_NAME: /* %i0=dst, %i1=src, %i2=len */ subcc %i4, 0x8, %i4 srlx %g3, %i3, %i5 or %i5, %g2, %i5 - EX_ST(STORE(stx, %i5, %o0), NG_ret_i2_and_7_plus_i4) + EX_ST(STORE(stx, %i5, %o0), NG_ret_i2_and_7_plus_i4_plus_8) add %o0, 0x8, %o0 bgu,pt %icc, 1b sllx %g3, %g1, %g2