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author | Nicholas Piggin <npiggin@gmail.com> | 2020-05-07 22:13:32 +1000 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-05-15 11:58:54 +1000 |
commit | 4e0e45b07d790253643ee05300784ab2156e2d5e (patch) | |
tree | 8945f0e66bed685345be9fa12472e21893db7a41 /arch/arm/mach-aspeed | |
parent | 912237ea166428edcbf3c137adf12cb987c477f2 (diff) |
powerpc: Use trap metadata to prevent double restart rather than zeroing trap
It's not very nice to zero trap for this, because then system calls no
longer have trap_is_syscall(regs) invariant, and we can't distinguish
between sc and scv system calls (in a later patch).
Take one last unused bit from the low bits of the pt_regs.trap word
for this instead. There is not a really good reason why it should be
in trap as opposed to another field, but trap has some concept of
flags and it exists. Ideally I think we would move trap to 2-byte
field and have 2 more bytes available independently.
Add a selftests case for this, which can be seen to fail if
trap_norestart() is changed to return false.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Make them static inlines]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200507121332.2233629-4-mpe@ellerman.id.au
Diffstat (limited to 'arch/arm/mach-aspeed')
0 files changed, 0 insertions, 0 deletions